M10 Booker Combat Vehicle / Mobile Protected Firepower (MPF)

[Scott Kenny]

My personal understanding is that an assault gun should be a vehicle that fights continuously on the front line alongside infantry, and therefore it naturally needs sufficient survivability, APS and adequate armor.

A fire support vehicle, by contrast, sounds like something that would operate slightly farther from the front line and provide fire support when opportunities arise.

If the Army was unsure, or wanted both at the same time, then that seems to be exactly the light tank concept it claimed to reject.

So which one did the Army actually want at that time?

Program name was Mobile Protected Firepower. They wanted what would be a fire support vehicle by your definition.

Most of the people calling it an Assault Gun were using that instead of calling it a tank of any type. "It's not a tank, it's an assault gun!"

Also, I don't believe that your definition of Assault Gun is correct. The original source was "a mobile artillery gun with enough armor to work up front with the troops." See the Sturmgeschutz.

That being said it's kinda weird why the Army asked for a 40t tracked design, especially the tracked part. The old 3x3 LAV AVGP refitted with a low pressure 90nmm turret and new NERAs and an APS could prove a reasonable baseline to work from. Crews could transition straight from the MGS. AFAIK Cockerill offers a 90mm turret, pretty proven and Moog could ask for licensing if needed.

90mm is not a NATO standard caliber anymore. Hasn't been since the last of the M48A3s left service. 105mm was in service and easier.

That said, the Army did not actually specify what gun caliber they wanted.

I'm kinda surprised nobody offered a 165mm demolition gun.​

But it'd totally have been possible that someone could have offered the low-pressure 90mm.

That they didn't suggests that the targets the Army specified were not necessarily vulnerable to 90mmLP rounds.

 

[GruntFox]

That they didn't suggests that the targets the Army specified were not necessarily vulnerable to 90mmLP rounds.

The problem is that the 'floor' (so to speak) has outdated 90mm cannon entirely. With HE and chemical effect rounds, it starts to look like DnD's 'Linear Warriors, Quadratic Wizards' problem (though, in this case, kinetic rounds scale linearly, chemical effect rounds start to look quadratic; case in point, the difference in killing potential of a 152mm and 155mm howitzer is a lot more than it implies as three extra millimeters in diameter makes a surprising difference). It also doesn't help that the current APFSDS dart caliber is 40mm, but nations are looking to increase it to 45mm and beyond (we literally can't get the darts longer without causing effects similar to early APS rounds, where they start tumbling and thus are made useless after a certain distance).

105mm is the minimum in many cases.

 

[yeetmahboi]

90mm is not a NATO standard caliber anymore. Hasn't been since the last of the M48A3s left service. 105mm was in service and easier.

Yep, it's understandable that they would want to reuse stock and toolings. That being said recoil length absolutely matters.

That said, the Army did not actually specify what gun caliber they wanted.
I'm kinda surprised nobody offered a 165mm demolition gun.But it'd totally have been possible that someone could have offered the low-pressure 90mm.

The Sheridan 152mm was a pretty good demolition gun with the big HEAT round. They went as far as to propose a casemate fire support vehicle with it.
https://www.secretprojects.co.uk/th...rived-assault-gun-proposal.30588/#post-333280

That they didn't suggests that the targets the Army specified were not necessarily vulnerable to 90mmLP rounds.

Like I said, GIGO. There's really nothing in the Insurgent black market that could dig a wall strong enough to tank a 90mm HEAT, and people could make big holes just fine with AT4s, so it's kinda moot. I think it's all just to justify keeping the 105mm, which again is not bad. But recoil length, which is a big factor in determining internal working space, really suffers from having to stomach a 105mm HV tank gun. Engineering is about tradeoffs, but sometimes the tradeoffs are so bad you have to reflect from the start.

 

[Scott Kenny]

The Sheridan 152mm was a pretty good demolition gun with the big HEAT round. They went as far as to propose a casemate fire support vehicle with it.
https://www.secretprojects.co.uk/th...rived-assault-gun-proposal.30588/#post-333280

Oh, that's different...

Like I said, GIGO. There's really nothing in the Insurgent black market that could dig a wall strong enough to tank a 90mm HEAT, and people could make big holes just fine with AT4s, so it's kinda moot. I think it's all just to justify keeping the 105mm, which again is not bad. But recoil length, which is a big factor in determining internal working space, really suffers from having to stomach a 105mm HV tank gun. Engineering is about tradeoffs, but sometimes the tradeoffs are so bad you have to reflect from the start.

I think they messed up on the weight specification, personally.

But again, there was no gun caliber specified in the contract.

 

[Ainen]

I also have another question.
A few years ago, the Booker seemed to be described as an assault gun and as some kind of fire support vehicle, but these two concepts appear to be somewhat different. My personal understanding is that an assault gun should be a vehicle that fights continuously on the front line alongside infantry, and therefore it naturally needs sufficient survivability, APS and adequate armor.

A fire support vehicle, by contrast, sounds like something that would operate slightly farther from the front line and provide fire support when opportunities arise.

If the Army was unsure, or wanted both at the same time, then that seems to be exactly the light tank concept it claimed to reject.

So which one did the Army actually want at that time?

Given that now(when politics don't matter anymore) M10 Booker officialy became medium tank - they always wanted just that. And it was rather clear from the product, which, is, excuse me, tank.

It was just pure funding nonsense, to not interfere/threaten funding of M1 series.

90mm is not a NATO standard caliber anymore. Hasn't been since the last of the M48A3s left service. 105mm was in service and easier.

Honestly speaking, this "standard caliber" has turned into some sort of religious law (like in Iran, when someone has freedom of religion, but can only convert to Islam and not the opposite way; the opposite is punishable by death. Literally).
If something isn't standard but does job better at a given weight point - just add it.

Would've made things massively easier for XM1302, for example.
Ultimately, infantry support tank has several basic targets:
-AFV other than MBT frontally. Can be served by any gun above 2".
-field fortification. As we aren't in 1930s anymore, this is any gun that can penetrate reasonable amount of concrete wall and then have explosion to clean a single space after that. Any gun above 2" can do that in principle, any gone above 3" does that in a single shot.
-Wall demolition/breach opening. The more, the better, but 3" can do that already. It'll just take more shots.

-Trench clearing. Any gun with airburst, or just a AGL onboard.

I think they messed up on the weight specification, personally.

They didn't truly - weight specification was quite specific. They failed to keep it up, and for this M10 was canstellationed.
How they failed is another thing - going from day 1 way too close to the limit (without even taking into account future growth) was certainly a big suspect.
And honestly, M10 was always far, far too conservative. Comparing its stats with ZTZ100 brings tears.

 

[Desertfox]

M10 should have had a 3-man crew and 90mm LV gun. Heck a Panhard ERC-90 could do the job reasonably well.

 

[Ainen]

M10 should have had a 3-man crew and 90mm LV gun. Heck a Panhard ERC-90 could do the job reasonably well.

They ultimately needed tracks (cross country) and baseline protection for assault mission. Light armored car won't give you that.
For example, Russian 2S25SDM gives you all the gun, but you're suicidal to do any assault on that.
XM1302 did, but was overall a compromise vehicle due to margins(still the preferred option for airrborne, ofc).
And M10 most certainly wasn't meant to be another AGS. it's a tracked AFV with significant protection(~M1 from every direction other than front) and huge ready rack(like x2 the XM1302).

And this could be a crucial breaker(i am obviously not insider and can't confirm, but):
MBT, which fights around itself, can afford this: 2x ish ready rack - couple of engagements, (6-7 rds each+some backup just in case) then go back and ressuply under armor from secondary racks.

Infantry support vehicle can not: not only targets stopping infantry advance tend to be plentiful and often unclear(requiring blind shots just to be sure), you can't interrupt support of leg infantry too frequently, it can't disengage just because you can. In this way, M8/XM1302 with its grand total of 21 shots is a clear huh.

 

[fightingirish]

Hello folks, in my opinion, here’s a good overview of the M10 Booker Combat Vehicle.
Wishing everyone a great weekend, even if it’s spent on the couch recovering from a head cold like I am.

The Tragic Tale of M10 Booker
An in-depth assessment of the timeline, background and processes which resulted in the creation, adoption and cancellation of a niche vehicle which turned out to be an unaffordable luxury.
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Video:

View: https://www.youtube.com/watch?v=N6N3rYpfGnI

https://www.youtube.com/watch?v=N6N3rYpfGnI