How to: Create an army from scratch


Some countries have armed forces that are FUBAR, with terrible cultural traditions and an inability to reform thoroughly. Some other countries lack armed forces. This is a beginner's guide on how to create an army (a new one) from scratch.

It's not terribly complicated at first, unless one makes it so. That's why guerilla armies can form.

The basis of a military is the transformation of personnel (let's call them "men" for brevity) from civilians to military personnel. This is about about acceptance of an authority framework, an adaption of expectations regarding comforts and a willingness to learn skills that are utterly irrelevant in the civilian world. 

Guerilla armies have their own ways, but regular armies use a combination of stick (conscription; threat of jailing) and carrot (pay especially for non-conscripts, retirement pay and medical care promises) to motivate men to undergo this transformation. So you need a budget to set up an army.

A build-up of a civilian bureaucracy to support the uniformed armed bureaucracy is a typical approach, but you don't necessarily need that initially. See how Russian mobiks equip themselves, even without having gotten vouchers or money from the government to do so. Let's face it; soldiers in NATO armies regularly wear boots and other items that were not provided by the bureaucracy as well. Few items require actual dedicated military procurement; night vision, secure radios, most weapons and munitions.

The training can be set up as a snowball system to some degree. A small group devises basic regulations using foreign regulations (especially the Americans are publishing great many (and low quality) field manuals, but also some other countries and in Germany you could buy the "Der Reibert" book that summarises many things a common soldier needs to know and more). This small group needs to know its own work well and becomes trainers to more recruits, the best of which get selected to become trainers (and possibly junior NCOs) as well. Junior NCO training gets devised again by a small author team using foreign source materials.

The idea is to create a very personnel-intensive defensive infantry battalion. Some natural leaders emerge and get a chance to prove themselves in leadership positions two and more levels above the basic level of hierarchy (officers).

Six defence-capable battalions form the basis for a brigade and its support troops. 

  • Three battalions get qualified further to infantry (including offensive actions capability)
  • One battalion gets qualified further to become an indirect fires (and their supply, closely related sensors) battalion.
  • One battalion gets qualified further to provide non-combat support (supply, drinkable water, medical, recovery & repair)
  • One battalion worth of troops gets converted into a training force, a brigade headquarter, military police, an officer pool for liaison duties, military intelligence, field manual writing teams, equipment testing & selection teams and more.

It should be possible to set up the first brigade from almost nothing within four years, and then to double the brigade count every two years.

Simplicity, modesty and self-discipline would be the most important virtues. You could see this in the hardware, which would ideally include

  • ruggedized and normal laptops all with the same operating system and USB-C interface
  • ruggedized tablet computers all with the same operating system and USB-C interface
  • one handheld radio and one vehicle & backpack radio of the same radio family (compatible with the laptop and usable as fibreoptic field telephone)
  • one type of portable electrical power generator
  • one low light vision system (firearm and helmet-mounted)
  • one thermal optic type (weapon-mounted)
  • civilian flare gun & pyrotechnics
  • one (day&night) spotter quadcopter
  • one type of (crew-)portable forward observer kit (thermal, E/O, LRF, canting sensors, multiple GNSS capable, USB-C interface)
  • one type of indirect fire gun (105 mm)
  • one machinegun type of identical calibre as the carbine/rifle
  • one guided missile to defeat MBTs (day&night capable)
  • one ManPADS
  • one carbine/rifle type
  • one light anti-tank munition
  • one type of 6x6/8x8 lorry in several versions but all with the same engine and tire size
  • use of civilian pallet and container standards
  • one 4wd car in several versions but all with the same engine and tire size
  • one demolitions explosive 'brick' with multiple interfaces for a fuse

Legal affairs, personnel affairs, many construction works, mil-only equipment & vehicle procurement, major vehicle repairs, major medical care, entrance tests (including medical & IQ) and much else could be left to civilians, either (pre-existing) government agencies or civilian contractors.

(c) Jantusla

I suppose I've by now sketched out enough how an extreme keep it simple, stupid! (KISS) + snowballing effort to build an army from scratch could work out. Other details would either simply not be part of such an army or be developed about the same way.

I suppose this blog post looks like total, accomplished idiocy to any army bureaucracy. Well, we have military history evidence that armed forces can be built from scratch (usually a lot less orderly than my description). We also have military history evidence that such rapidly built armed forces can be a match to long-time established armed bureaucracies. Such newcomers have some advantages and some disadvantages. They learn particularly well and rapidly by involvement in hot conflicts. Ukraine's volunteer forces in 2014/2015 and 2022 are examples just as the Waffen-SS, guerilla armies and (regarding the doubling of formations within two years) the German army 1934-1939.

Established armed bureaucracies also have advantages, but they also have disadvantages (such as red tape, bad legacies). It might be a good idea to reset entire armies, as many armed bureaucracies are FUBAR and more of a waste of public funds than superior to a new-built force.

This whole blog post was meant to stretch the horizon, make readers think themselves about the issue. Maybe it would help to have some more KISS in an army, maybe even only the threat of being disbanded in favour of a new-built force would have a healthy effect on our armed bureaucracies?

One thing is for certain; all armies claim to be competent when challenged, but military history called many such bluffs already.





Modern trench warfare

The Russo-Ukrainian War revealed many weaknesses of the Russian armed forces, including inexcusable ineptitude in trench war (both layout of field fortifications and assaults).
At the same time, it did expose that the Ukrainians appear to have a very limited skill set as well. Their offensive skill appears to be limited (= they didn't show more yet) to attacks with limited objectives and pushing on rearguards while the opposing force retreats (around Kherson autumn '22).
There's plenty equipment in their possession that would enable more than that; artillery, tanks and BMP IFVs could be used to form forces for rapid breakthrough (advancing 10 km in mere hours) followed by exploitation (most reasonably advancing to Azov sea or a two-pronged encirclement) and widening the breakthrough by rolling up defence lines left and right (the frontal instead of 360° defence orientation of Russian field fortifications is among their visible mistakes).
We saw something similar in the Iraq-Iran War (Gulf War 1980...1988). Both sides had all the tools for mechanised warfare, but were unable to fight better than European armies in 1916.
An army can be reasonably competent, yet still have a very incomplete repertoire. Rapid mechanised warfare is among the most demanding forms of land warfare (though let's forget about the American talk about how difficult combined arms is - they complicate everything because they deal with their own issues).
The rapid advances of 1940 and 1941 are technically very feasible, but hardly any army (maybe nowadays none) can actually execute those any more. Manstein's forces raced about 300 km in four days to establish a Dvina bridgehead. The invasions of Iraq were slow by comparison, despite modern motor vehicles being much faster and logistics vehicles having much higher capacity (thus better road usage efficiency).

The normal mode of army operation appears to be very different from such rapid advances. It appears that superior firepower application for higher attrition during a static phase is the dominant approach. This serves not only to wear down the opposing forces so much that they become progressively less competent; it also serves as shaping operation for a later advance by demoralising the opposing forces, by temporarily disabling their headquarters and by destroying high value targets such as high-powered radio frequency jammers or battlefield air defence assets. We saw this in 1991 and 2022 very clearly.
The advance phase is then much less ambitious and rapid, thus less "overrunning" than the advances in 1940 & 1941. It's rather a shallow push into softened defences (in Ukraine) or a methodical advance with security efforts against opposing forces that put up a fight that's disproportionally small compared to their nominal strength (in Iraq). The artillery has largely the purpose to suppress or neutralise during the advance phase, whereas it's almost all about lethality (remember how popular that buzzword is in the U.S. armed forces?) during the static phase.

NATO probably likes this; it has good reason to expect a superiority in air/ground attack, its air forces would need some time to wear down radar-based battlefield air defences, rapid advances would multiply interoperability issues among the multinational forces of NATO and it has (at least in U.S. stocks) many guided artillery munitions. The biggest issues in this context are the small size of 'dumb' artillery munitions stocks and that NATO armies are rather weak on infantry and thus not so good at holding a wide frontage.

This dominant approach to warfare is also a slow approach to warfare, though. You cannot win a war in three weeks if you first soften up the opposition over four months before you begin to advance.

We could cut some military expenditures if we accept that we're really only competent enough for such a land war model of static phase with attrition by firepower followed by brief phase of advance.

For starters, the IFV concept isn't meant for this way of advancing. Moreover, tanks don't need to be built for Blitzkrieg if they are meant to support infantry. They would better be built for 98% indirect fires and 2% rapid reaction fires during overwatch. We don't need to mechanise things like battalion command posts or passive electronic warfare (direction finding) gear. To add an armoured vehicle to these makes hiding more difficult and may actually reduce their survivability. We would need armoured transport vehicles for moving things and people on the last couple kilometres where the opposing forces may observe the movement of said supplies and people. This means APCs with folding seats or benches, preferably (band)tracked, with armour against artillery fragmentation and defences against drones (loitering munitions). Nobody needs a turret with autocannon and gadgets on this, especially not if that reduces the volume available for transportation.

Infantry might be divided between trench infantry and (rarely in action) assault infantry then, not some general infantry/mountain/para/marine/mechanised differentiation and there's certainly no reason to emphasise any "light" or "airmobile" role.

The logistics need to be three- to four-staged in such a trench war;
  • (transportation by sea or rail)
  • transportation by civilian lorries
  • transportation by military lorries within artillery range (40...120 km depending on opposition)
  • transportation by protected off-road vehicle within observed / FPV range (2...10 km)
The supplies need to be compatible; 
  • 20 ft ISO containers
  • military lorries with DROPS/PLS/MULTI load handling equipment can either take the container directly or pull a big pallet out of it
  • smaller pallets or boxes that fit into/onto vehicles for the last few kilometres
A breakthrough operation should not be made visible days in advance by massing of vehicles and supplies or by suspiciously increased fires. The logistical system should thus be a bit deceiving; emptied containers could be left standing and removed only much later. This would make it invisible when more supplies get stocked in one sector of the front for a breakthrough operation. Everything within artillery range needs to be dispersed (low value supplies such as diesel fuel, S-wire, construction materials) or hidden from detection (certainly all high value munitions).

Battlefield air defences would consist of very low level counter-UAV and of rear area intercept of precision rockets to span an umbrella of protection over clusters of high value targets (brigade supply depots, brigade HQ, important bridges, high powered radars).

The forces could be trained for limited repertoires instead of pretending we could do it all:
  • Infantry brigades to fortify, hold and slowly push forward a frontline (few combat AFVs)
  • Independent artillery regiments for larger calibre main effort breakthrough & counter-offence firepower (could be substituted by airpower)
  • Small and agile armour brigades for rapid exploitation of breakthroughs and for flank counterattacks against breakthroughs, worst case mission rearguard during a withdrawal
- - - - -
One objection is totally obvious: This would be a force design to fight the current war ("the last war"). There are two problems with such a force design; the next war may be different and the very different strengths of NATO would let the current war look very differently if NATO was fighting itself.
Regarding the latter issue; the mentioned land forces design approach suits NATO's air power and missile strengths very well. Regarding the more general 'preparing for the last war' argument:
  • There's hardly any good reason for Europeans to fight a land war far away from their continent. Thus European (great power) war scenarios are the only ones that really matter. The toying around of the British and French governments in faraway places didn't never yield net benefits to the British and French nations for more than a hundred years by now.
  • The war in Ukraine actually looks eerily similar to WW1, WW2, the recent wars in the Caucasus area, the Iraq-Iran War '80...'88. It's not a one-off. Moreover, preparing for "the last war" was historically not a bad idea if said "last war" was a conventional one. Lessons learned in the Russo-Japanese War of 1904/05 and the Boer Wars (the conventional stages of the latter) should have been respected more by European armies until 1914. A U.S. Army still mentally, organisationally and materially configured to fight in 1950 as it did in 1945 would have done much better in the Korean War. Besides, look at our armies; they use formations not very much unlike the tank divisions and American infantry divisions of WW2.
Much of my past writing assumed a mediocre degree of military competence on part of the Russian Armed Forces and thus I concluded that defensible frontlines are unrealistic in the early phase of a hot Russia-NATO conflict. The observations from the Russo-Ukrainian War indicate that defensible frontlines are still a valid concept against Russian Armed Forces, and they offer risk mitigation and cost-cutting potential for NATO (cheap territorial reserve infantry formations were used by Ukraine to hold the frontline).
The much more demanding concepts that I wrote about around 2011 might work brilliantly, but are more demanding and thus not the most cost-efficient approach to deterrence & defence by NATO against Russia.
The relatively affordable forces of the line make much sense at least until autonomous drones take over land warfare.



Artillery calibres and concepts


The most common artillery (gun) calibres are nowadays in the 105...155 mm range. Bigger guns largely fell out of favour due to aircraft bombs taking over their roles and smaller guns largely fell out of favour because direct artillery fires lost importance post-1914.


75 mm was considered the minimum calibre for a high explosive (HE) round to be really good at supporting infantry with direct fires. Infantry support tanks of late 1930's received guns of such a calibre, albeit wartime experiences led to the introduction of bigger calibres (up to 152 mm plus one freak design) for that role.

75 mm infantry gun, for supporting infantry

75 mm calibre guns had often a high muzzle velocity, which gave them a secondary anti-tank capability. This also allowed for a little better ranges than the common 105 mm howitzers of the time had. Their indirect fires usefulness was hampered by the small explosion signature (bang, smoke, dust) of their 75 mm HE shells, though. It was difficult to observe the explosions with sound ranging or visual observation from afar. There's no correction of fires without feedback from observers, thus poor accuracy.

105 mm howitzer HE was an indirect fires sweet spot for a long time, and probably still is. The Russian/Soviet 122 mm calibre was a bit more powerful and the British 87.6 mm (25 pdr) calibre was fairly close as well, but 105 mm was understood to be very efficient for fragmentation effect and suppression. 150...155 mm HE shells were more powerful individually, but covered less area with fragmentation effect or suppression effect than did the 105 mm HE - pound for pound. 105 mm HE also enjoyed a reputation for being more capable at shooting danger close (at targets very close to friendlies), albeit this is a negligible difference when the guns don't have a tight dispersion.

I've seen tables and lessons learned about 105 and 150 mm howitzers use in WW2 and the conclusion from the different quantities of munitions needed for certain effects was simple: You did not need more 105 mm munitions mass for the purpose than 150 mm munitions mass. The calibres were largely substitutes for effects. You needed more 105 mm shells for the job than 150 mm shells, but a 105 mm shell weighs about 17 kg, and a 150 mm shell weighed about 40 kg. 105 mm howitzers also had a little higher burst rate of fire (fires in first minute before the barrel is hot and rate of fire has to match how quickly the barrel cools down). 150 mm howitzers had some manpower efficiency and sustained firepower advantages (both calibres sustained about the same rate of fire).

150...155 mm had two big advantages over 105 mm  during the world wars, though. One, it was more capable of piercing overhead cover and the roofs of field fortification bunkers (several layers of wooden logs plus earth, supported by wooden logs). This is where the 150...155 mm success came from; Germans tested field fortifications around 1900 and came to the conclusion that a 150 mm shell was required to penetrate a field bunker (but keep in mind howitzers had poor muzzle velocities at that time). Such intent to destroy almost entire sections or platoons in a field bunker led to a mass employment of heavy howitzers (and even heavier artillery) in the Great War a.k.a. First World War.

Two, larger calibres are also more efficient for long range (better ratio of kinetic energy to drag), and howitzers grew into high velocity (and thus long range) guns especially after the Cold War. Today's 155 mm L/52 howitzers have ballistics that rival late WW2 high-performance cannons of about the same calibre.

modern 155 mm L/52:  43...43.5 kg shell, approx. 945 m/s with maximum charges

150 mm Type 5 (1945): 41 kg shell, 930 m/s

155 mm is thus superior to 105...122 mm for two purposes; destructive fires on field fortifications and long range fires. The latter were a nice niche for dumb shells in the 1990's till 00's, but it's obvious that guided rockets are more suitable for it because it's much easier to give guidance to a rocket than to an abruptly launched (electronics need be hardened to this shock) projectile. Shells are normally spin-stabilised, which prohibits normal steering by rudders. Guided 155 mm projectiles are fin-stabilised and thus differ only in the mode of acceleration from rockets. The barrel restricts the calibre, so using rockets launched from pods makes much more sense for long range fires.

Which leaves us with the destructive fires on field fortifications (and rare effects on armoured vehicles) for the 155 m calibre. So let's talk about what I meant with "destructive fires".

There are harassing fires, suppressive fires, neutralising fires and destructive fires.

Harassing fires are almost always bollocks, waste of munitions and at times plain war crimes (if shot at the wrong coordinates).

Suppressive fires are more intense and shall limit hostile activities, especially how much hostiles dare to move or shoot. It's not so effective at limiting how much they observe and report. Suppressive fires may make sense to support (= protect) exposed (usually that's = moving) friendly forces.

Neutralising fires are more intense than suppressive fires and shall render hostiles combat ineffective through psychological effects (up to shell shock). The targeted troops may have a few per cent losses of personnel and material through blast or fragments, but that's not what matters. Properly done neutralising fires allow almost none of the targeted hostiles to be effective shooters for minutes after the end of the neutralising fires. Neutralising fires make much sense when friendly troops assault and take the targeted position soon after the neutralising fires ceased. Neutralising fires are thus most important for manoeuvring forces and for attacks with limited objectives (by forces of the line).

Destructive fires are not necessarily more intense, but they require much more munitions (or precise knowledge of hostile positions and great precision at firing at them with powerful-enough munitions). This is wasteful for manoeuvring forces such as a armoured formation on a rampage after breaking through a frontline. Destructive fires usually take more time and more munitions than neutralising fires (and may make the ground less trafficable by cratering), which is really bad for a manoeuvre force (force of exploitation).

also see FM 3-09 pages 3-25 and 3-26 if in doubt

Coming back to the forces of the line and forces of exploitation distinction, we can see that the middle calibre group of 100...105 (maybe up to 122) mm calibre was very suitable to support forces of exploitation.

The same calibre group was also very suitable for forces of the line most of the time. The two exceptions were long range fires (especially in WWI), which could be left to levels above divisions and destructive fires. Bigger calibres for destructive fires were not essential when breakthrough (using artillery mostly for neutralisation of the assaulted positions and suppression of other possibly intervening positions) was possible. The possibility of breakthrough depends more on morale and competence than on equipment, and some armies had this competence from late 1917 onwards.

The actual niche for 150...155 mm calibres was thus attrition through destructive fires along the frontline. This was likely the main reason for why 150...155 mm "heavy" howitzers were used by most European and American infantry divisions of WW2 and also considered essential during WW1. Their popularity also stemmed a bit from (slightly) better ranges than 105 mm had and subjective preference of bigger bangs. The weights particularly of WW2 howitzers were troublesome if not intolerable for horse draft, though.

152...155 mm calibre munitions are also more efficient for the deployment of cluster submunition types than 105 mm, but this advantage is now gone due to the widely followed cluster munitions ban.

The smaller size of 105 mm guns and their easy integration into wheeled motor vehicles (such as 6x6 or 8x8 lorries, which allows for a fragmentation and bullet protection, 360° turret, 85° maximum elevation, whole crew onboard, RCWS and lots of munitions onboard) as well as their danger close qualities position them as rivals of 120 mm mortars. Meanwhile, their muzzle velocity allows their use as heavy anti-air gun against easy targets (such as multicopters) with appropriate proximity or electronic time fuses. Their much better range (and dispersion at range) than 120 mm mortars opens up opportunities for covering larger areas, including assisting neighbouring units by massing fires.


So long story short; 105 mm is still a great calibre. 155 mm is more impressive and can do almost all the same jobs (except danger close shots), but 155 mm is far from a necessity. A mix of 105 mm howitzers and precision-guided rockets of long range (as much maximum range as target detection range) would do the artillery job just fine and render mortars unnecessary. 105 mm is less demanding regarding platforms, purchase costs and just generally lends itself better to the battalion battlegroup organic fires role (and to small brigades).








How to fix ... the Irish Land Forces (Army and Army Reserve)

To join NATO appears to be in fashion, and there's occasionally talk about whether Ireland should join. I took this as a welcome thought experiment.
My conclusions are not terribly different from my other "How to fix..." blog posts, especially the Belgian one.
Another relevant article is the one about a 'budget brigade' that aged fairly well:
Super-brief introductions on real existing Irish land forces are
I cross-checked the equipment claims with my (dated) Jane's Infantry Weapons book and they check out (not identical info, but plausible that the few changes happened that way since the book was published).
So, first things first. Is the notorious "2% GDP military spending requirement" something to be applied to Ireland?
No, that's total bollocks on every angle. For starters, there's no such requirement to any NATO member. It's made-up nonsene, a scam.

The same reasoning applies as with Belgium:
My stance is that membership in a large alliance does NOT mean that you need to pay more to be a "good" ally and actually helper to some of the most aggressive alliance members. The purpose is to enable small powers to achieve deterrence and defence in the first place to maintain peace and sovereignty and secondarily it makes security and defence cheaper. 

A simple model shows this; two countries are border on each other and a third, larger and threatening country. Going alone they would need to maintain armed forces to deter an attack by the bigger neighbour on their own, and deter by being able to inflict punishing damage on both neighbours at once if they attack. An alliance between the two smaller countries enables them to not consider each other as a threat any more, and to spend roughly half as much as without the alliance, for they would stand together against aggression by their larger neighbour.

It's a simple, reasonable and rational principle - and utterly covered up by the nonsense that politicians spew about how smaller allies should spend much on their military [...] because they are in an alliance.
It makes no sense for Ireland to create a fast jet air force. It would be tiny and irrelevant. Air policing over Ireland is not an issue. Who's supposed to violate their airspace? Tu-95 flying a long distance just to annoy Ireland and NATO? And what would be the harm in that? Why would they overfly Ireland if no air policing is present, but not if it's present? It's not as if NATO fighters would actually shoot down a Russian military aircraft only because it violates sovereign air space of a NATO country. The fighters would accompany it, shoot some tracer rounds past the Tu-95 for warning and intimidation, document the transgression and then return.

It makes no sense to set up a real navy, either. Again, it would be tiny and irrelevant to collective defence.

This is why I pay attention to the land forces instead (also ignoring the helos, which have mostly domestic functions that could be done by civilian helos as well).

The simplistic equipment list of the Irish Army looks acceptable quality-wise, though some additions are advisable. I wouldn't have picked most of that gear on a clean slate force design, but there's no good reason to spend much on replacing the kit (unless it's -unknown to me- worn out already).

Keep in mind, I write this as a superficial case study to apply some of my rather general thoughts (opinions based on reasoning), not as a real recommendation by someone who knows what exactly is wrong with the Irish Army (and there's always something wrong in any army). 
The current army has a mostly domestic role, though it also features some equipment that does not quite fit to that (Javelin ATGMs, which were very new high-tech when they were introduced about two decades ago). I'll pretend that the domestic tasks (such as disaster aid) can still be met satisfactorily with the structure that I propose.
- - - - -
The multiple brigades make little sense in a context of about 7,000 army personnel. A highly agile small brigade type might be small enough that two brigades would make sense, but there's no reason why one should expect such a thing from Ireland.

Thus I say they should consolidate into one brigade with some reservist components, some capability additions to get ready for conventional warfare in Europe and with the logistics to support such a brigade on the continent. Additionally, the participation in non-combat blue helmet missions requires some more abilities.

For the continental warfare part; that's mostly what I wrote in the 'budget brigade' blog post, minus the tanks.
For blue helmet missions: I assume a deployment of a company or two of infantry with protected wheeled vehicles. They would benefit greatly by a tailored sustainment company, a detachment for military intelligence and passive EW and sensor drones, engineers with demining/EOD and construction equipment, a military police detachment with investigative capabilities, a Civ-Mil relations detachment, a small workshop, a medical detachment and attached snipers.
HQ Company (including signals detachment and MP plt)
2 Infantry Battalions (including the Piranha III vehicles, each one sniper plt)
1 Reserve Infantry Battalion (no AFVs, only light equipment in sealed storage - no cannibalisation)
1 Artillery Battalion (24 105 mm guns, 120 mm mortars, RBS-70)
1 Sensing Battalion (small; drones, passive EW, MI cell)
1 Logistics Battalion (incl. workshop, medical teams)
1 Engineer Company
1 CivMil team

So why no tanks this time? It would be a significant investment to add those (even assuming they're refurbished M1A2s and M88s), add huge operating expenses and are not absolutely necessary for defence of a frontline + attacks with (very) limited objectives. The current crop of Russian tanks can be defeated en masse without 105...125 mm tank guns.
I would add some M1043 (lightly armoured HMMWV) and M997 (HMMWV MedEvac vehicle). I'm normally no proponent of this vehicle class, but such vehicles are dirt cheap (especially refurbished ones) compared to new-built ones, and the newer designs followed a bad path with excessive emphasis on IED protection. IEDs and AT mines would not be relevant to the Irish Army's missions, not even be important in blue helmet missions. I'd hand over the aforementioned M1043s to the artillery (which has 24 105 mm guns, 120 mm mortars and forward observer teams). I'm not sure if a M1043 can properly tow a M118/M119, though (base HMMWV can do). These British light field howitzers are significantly heavier than the less durable French competitor, the LG1.
Logistics vehicles would need to be added, but this can be done with a low cost strategy
A lot of flying drones should be procured, primarily as standoff sensors with bird's view advantage. An overflight of hostile forces or their terrain would be more ambitious and thus either more expensive or a less trustworthy capability. I'm inclined towards a mix of tethered multicopters (should be fine for up to 30 kph base vehicle speed) and VTOL fixed wing drones (easy and safe operation combined with good endurance and not giving away the base vehicle's location so easily). The sensors should be zoomable E/O, zoomable IIR and (in a tethered type only) also passive 30...88 MHz listening and direction finding to map emitting tactical radios.
Forward observer teams and infantry platoons would have their own quadcopters with zoomable E/O camera (sensitive enough to sense near infrared illuminators at 500 m distance at night) and a thermal camera. DJI Mavic 3 quality with encrypted datalink and trustworthy control software (including returning based on INS if contact is lost) would make sense.

Some kind of effective yet affordable counter to small flying drones needs to be found and introduced, but this should be a MOTS (military off the shelf) purchase with zero R&D expenses for Ireland. It's fairly obvious that there should be some battlefield radars, which should also detect and track drones. I do generally prefer a mast-mounted solution for this, though a portable one could be mounted on roofs of buildings - ideally both would be of one type. Giraffe 1X is a candidate, but there are more candidates.
Spares and munitions (save for Javelin) should suffice for at least two years of peacetime operation + 30 days of combat. Munition storage sites do not need hardening, just sabotage & theft protection. The Javelins, the Javelin 1st generation command launch units and the RBS-70 missiles may be in need of refurbishment.
Expenses for "interoperability" should be limited to getting compatible signals equipment at brigade level. All other communications compatibility needs can be handled by neighbouring allied forces detaching a liaison team to Irish battalion command teams or by detaching a forward observer team (JFST).
The detachment of officers to NATO institutions should be minimised. There's nothing to be gained from participating in those anyway. Playing with big boys is no value in itself for the nation, and officers who want to do it for their own fun may do it while on unpaid leave if they insist.
The readiness should suffice to get the brigade without the blue helmet-deployed elements to Suwalki/Poland within 20 days, at 90% (fully trained) personnel, material and supplies (for 3 combat days) strength excluding the reserve infantry battalion. This includes a couple days for calling up reservists and giving them a refresher training of several days. The assumption is that the armoured vehicles would be shipped to Hamburg for further self-deployment (1000 km or 18 hrs driving time under peacetime conditions to Suwalki/Poland).
The further munitions should be stored on pallets that can easily be loaded into, stacked in and transported by commercial semi-trailer vehicles. These would need to be commandeered and driven by reservists in case of an emergency.

The Irish should not spend more for the military after joining NATO, as this would be senseless. They would not really gain security by joining, so why spending more? To join NATO would be mostly a symbolic affair, as "NATO" is increasingly synonymous with the Western society system and civilisation in Europe.

Thus ways to cut expenses should be sought and found, and so far I only wrote about things that sound like adding expenses. A reduction of personnel strength and some reductions during the restructuring process would have to offer savings and I have a hunch that all army ranks above Colonel are bollocks for them. Eight ranks (recruit to Colonel) should suffice in this case.
There's a minimum threshold in my opinion; it's about motivation of the troops and national self-respect. One decent brigade is IMO the minimum for a nation of Ireland's size in NATO. Anything below that would make sense as an army. To go any cheaper than one decent brigade would only make sense if it's about forming an anti-occupation and disaster aid militia incapable of conventional warfare. That would rather suit a neutral Ireland than a NATO member Ireland, though.

I hardly mentioned the reserves. It makes little sense to have a smaller formation than a brigade as the army's active component, and if a proper light brigade already risks asking for a budget increase, then the budget does not offer room for large reserves, regardless of their cost efficiency. I do thus conclude that the best choice for the army reserve would be a decently-administrated individual reserve in order to have all the logistics vehicles drivers, demolition experts, EOD experts, emergency room doctors (including for eye and burn injuries), emergency room nurses, motor vehicle mechanics, reserve infantry battalion perosnnel and generally individual replacements that they need in an alliance emergency. Personnel that left service after serving in the infantry battalions (or the rangers, which I consider pointless and its civilian tasks could and should be met by a police unit) would be available to fill out the reserve infantry battalion.