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No M-900 105mm APFSDS


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I think that it basically comes down to a lack of information about it.

I brought this subject up before and was told that if I could find some firing tables or measurements of velocity at various ranges, they could work on it, but that info doesn't seem to be available on the net. They could, of course, make an educated guess or simply take an existing round and tweak it's performance a bit, but they seem to prefer only working on things when they have some hard data in their hands.

Until/If it gets added, I suggest just using the DM63 PPTFS or CMC105 round as a substitute. The DM63 has some 600mm of penetration, which is equivalent to a 120mm DM33 or M829.

I have the strange feeling that 600mm is getting very close to squeezing everything you possibly can out of the L7 / M68, so even if we did get M900 it would only be slightly better, and at the end of the day NATO made the switch to the M256 for a reason - the L7 / M68 wasn't quite cutting it any more.

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Sorry, I didn't realize that. There not mine, just photos I found doing a google image search that referenced the round. If need be, I can just go back and post links to the forums where the images are shown.

I did come across this 1994 TM 43-0001-28 Army Ammunition Data Sheets document here in pdf format approved for public release: https://ia801509.us.archive.org/24/items/milmanual-tm-43-0001-28-army-ammunition-data-sheets/tm_43-0001-28_army_ammunition_data_sheets.pdf

Page 2-75 has the M900 round listed, which seems to be where the photos were uploaded from on some of the sites I listed above.

Also this estimation of velocity from a japanese site: http://translate.google.com/translate?hl=en&sl=ja&u=http://sus3041.sakura.ne.jp/contents/shell_db/105_M900_apfsds.htm&prev=/search%3Fq%3Dm900%2Bapfsds%26start%3D30%26sa%3DN%26biw%3D1354%26bih%3D927

(Through thickness 撃角 0 degrees, 50%) values ​​were corrected to estimate the result of the expression of JPLambert

It is not taking into account the self-sharpening effect.

Distance [m] 0m 1000m 2000m 3000m

Existing speed [m / sec] 1505 1455 (estimated) 1405 (estimated) 1355 (estimated)

50% through thickness [mm] 520 (estimated) 492 (estimated) 463 (estimated) 435 (estimated)

Edited by Invader ZIM
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I do have a copy of Jane's Ammunition Handbook 2009, and while it is good for what it attempts to be, usually th efigures and data points in it are missing elements that would allow a more detailed estimation that is more than just pure speculation/guesswork.

The estimates on that Japanese site are a nice gesture, but it would help a lot to know how they actually came to their conclusions. Figures are worthless if neither the original source data nor the methodology are being presented for dissemination. So, excerpts of a firing table would be my minimum requirement.

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Yea, I understand what you mean with the ballistic tables Ssnake, I found it a challenge just to get what I posted above on the round.

It seems this is pretty much an outdated round, but it's interesting that you can't find more info on it. As Maj. Hans said, it's got to be near the epitome of 105mm design.

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Depends on what is considered to be EFC 1, whether that is excessively high or only moderate... If EFC 1 corresponds to M792 or an equivalent then EFC 3 is relatively high (HEP/HESH would be far more moderate, with an EFC of 0.3 or so?) On the other hand an EFC of 1 for M392 HEP or M452 HEAT, would give a modest wear rate at 3.0 which seems unlikely... in any case the same reference should be used for tube life and projectiles.

ISTR that M829A2/DM53 were quoted as EFC 5 for the RM tube in 120mm, and M829A3 speculated at 6.0, according to Bumar(?) engineering papers from Poland.

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Well, everything is a trade off.

I imagine if you start pushing things to the limit in order to get more performance out of your existing gun, you're going to have a trade off.

Then again, when that round was in development in the 1980s, excessive barrel wear might not have been seen as a real problem. Punching holes in Soviet tanks at the cost of wearing the barrel out might have seemed like a good option compared to bouncing outdated ammunition off their turrets.

Edit: Plus, let's consider the fact that the M900 is/was restricted to only certain batches of M68s, and only to be fired from the M1/M1IP. I haven't heard about any restriction on the use of M833 in those guns or in M60s, so that also makes me think that M900 is a very "hot" load.

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Of course, that could mean all sorts of things.

I'm far more familiar with small arms than I am with anti tank weapons, but, perhaps they decreased the weight of the sabot assembly by switching to a composite material like the M829A2.

Normally that would allow for better performance, but if you're already at the limit I suppose you could also reduce the powder charge a little bit, and get the same performance with lower chamber pressures.

Like I said before, my purely uneducated "gut feeling" on the subject is that both M900 and DM63 are very close to or right at the very limit of what the 105mm L7 / M68 can do.

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  • 5 years later...

From what I have read, the M900 can be fired from M1128 Stryker's M68A2 gun, so there is a reason to introduce into the game. The army was left with substantial stocks of the round when the M1 was retired, so no new production has occurred, "The MGS' 105 mm cannon can fire four types of ammunition: the M900 kinetic energy penetrator to destroy armored vehicles; the M456A2 high explosive anti-tank round to destroy thin-skinned vehicles and provide anti-personnel fragmentation; the M393A3 high explosive plastic round to destroy bunkers, machine gun and sniper positions, and create openings in walls for infantry to access; and M1040 canister shot for use against dismounted infantry in the open."

 

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