No M-900 105mm APFSDS

[EasyE]

Hi Guys

This round seemed to be the hot 105mm apfsds of the late 1980s and early 1990s. Any reason it was not included in this version of the game? Or is it known under a different designation?

Merry Christmas Everyone!

[MAJ_Fubar]

Currently Esim lacks sufficient information on this round...if you happen to have the firing tables though, I'm sure Ssnake would be interested in hearing from you.

[Maj.Hans]

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.

[Invader ZIM]

Don't know if this will help, but here's what I found.

[Invader ZIM]

Info on testing of the round here:

http://www.globalsecurity.org/military/systems/munitions/m900.htm

http://www.noduhawaii.com/strykerDU.pdf

spin times, etc: http://books.google.com/books?id=7cdm9VOpB1oC&pg=PA432&lpg=PA432&dq=m900+round+velocity&source=bl&ots=fUdFlRJax2&sig=hGHyG7gegBZXiybsVxso3ptIOJo&hl=en&sa=X&ei=zq-5UsjrD9DpkQe604CQDA&ved=0CGEQ6AEwBw#v=onepage&q=m900%20round%20velocity&f=false

http://echo501.tripod.com/Military/105ammo.htm

above site seems to be claiming 520mm penetration at 2km range.

105mm M-900 n/a Jake Collins Armor Page United States n/a n/a 520mm n/a 2km n/a 1991 n/a DU

[Grenny]

Don't know if Jane's like seeing copied pages of their journal here....8-)

[Invader ZIM]

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 December 24, 2013 by Invader ZIM

[Ssnake]

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.

[Maj.Hans]

IMHO, they could probably just clone the existing DM63, increase penetration a little bit, adjust the muzzle velocity a bit, rename it to "M900 APFSDS" and call it good.

How much more could you possibly squeeze out of a 105mm gun?

[Invader ZIM]

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.

[john.gear]

I have to look. I just may have the firing tables. I want to say the M900 had a EFC of 3.

I think it is very safe to say that we were at the absolute end of the spectrum in the early 90s with the M68, 105mm gun.

[Gibsonm]

3!

Crickey

[GSprocket]

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.

[Maj.Hans]

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.

[Invader ZIM]

Indications do seem to point to a very hot load.

Interestingly, there appears to be an M900A1 variant, but I can't find any other info on it except that it's advertized as being able to be used by tanks other than the M1 series.

[Maj.Hans]

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.

[Grenny]

Besides that the DM 63 is a 120mm round...

[Maj.Hans]

There are more than one DM63

http://www.steelbeasts.com/sbwiki/index.php/Ammunition_Data

105mm L7: PPTFS DM 63C LS 4000 600 1455

[Ssnake]

Any DM number is incomplete without prefixing the caliber and cartridge length. We usually skip that since the context is clear, but in this case...

[Invader ZIM]

I have to admit, I was pleasantly surprised using the Centaro with the 105mm L7: PPTFS DM 63C.

I haven't tried it, but can we use the 105mm L7: PPTFS DM 63C round in the M-60A3? In Steel Beasts that is, as a substitute for the M900 or M900A1?

[Ssnake]

Sure you can.

[Maj.Hans]

I do that all the time.

I imagine it's probably pretty close to what the M900 is like too.

[Invader ZIM]

Yea, seems like a reasonable replacement for the M900 "Squint Harder" lol.

I'll use it for my late 80's missions designs then, haven't had much time to visit the M-60A3 with all the goodies in 3.0.

[Col Beausabre]

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.^"

 

[TSe419E]

The M900 is available as an ammo selection in the mission editor.