M456 HEAT dimensions

[wingsofwrath]

Hello, I recently acquired an 105mm M148A1B1 case fitted with an ELEC M63 primer, dated 1972 and manufactured by Norris Industries.
The markings as well as the very high dot crimp on the case would make it correct for a M456A1 HEAT as used by the M60A1 tank (it's too early for APFSDS and, as far as I know, the M392A1 APDS-T used the ELEC M120 primer and wasn't crimped in the case).
Unfortunately, I've been unable to find proper dimensions for this projectile outside of these sketches.

Does anybody have a better blueprint or an actual example that can be measured? Thank you!

 

[apfsds]

Really Nice case. Can you show a picture of the head stamp. If not in bad shape, sometimes if you view it at an angle, you can see the very faint markings of possible stenciling? If so, you may see exactly which projectile was attached? I can say that all of the US adopted APFSDS projectiles utilized the M148A1B1 case fitted with the ELEC M120 primer. The M900 APFSDS round used a modified ELEC M120 primer that had a shortened primer tube to allow for the longer sub projectile dart. Not sure about the HEAT rounds, but most APDS ad TPDS used the M115 case variants. Same exact profile as the M148A1B1 but about 1/4 inch higher shoulder neck.

Jason

 

[wingsofwrath]

Unfortunately the headstamp was rusted almost completely and the only stencilling visible are the "A" in "Ammo" and the "C" from "CRTG" on line three. I in fact had to scrub quite vigorously to even get to read the date/manufacturer.

1972 is waay to early for any of the APFSDS variants which were introduced starting in 1977 and in the meantime I did some more reading and discovered the M392 APDS-T used U.K. L4A1 or L4A2 primers, because it was a copy of the British L36A1 while the M724 TPDS-T version used M80A1 bridge-wire primers, so those can be also discounted.

I am pretty sure my case held an M456A1 HEAT because the ELEC M63 primer on it only reaches about half-way inside the case, which would fit with the extra lenght of the fins, while none of the other projectiles like the M393 HEP-T and the M494 APERS-T need such a short primer.

 

[HAZORD]

First of all, secure a copy of TM 43-0001-28 Army Ammunition Data Sheets. It gives detailed descriptions of the round components and firing performance data. It can be found in PDF format on the web for free. It lists all non classified 105mm Gun rounds, as of the date of printing. You will find that there are three models of 105mm gun cases, M115, M150, and M148. These cases exist in Brass and Steel. Early development of these cases were in brass. All recent manufacture is the B1 versions in steel. The cases differ by primer length as related to the depth of the projectile intrusion in the case, and the case mouth details where the specific projectiles are inserted and crimped. As an example, the M150 case mouth is a larger diameter, because two of the three rotating bands are inserted into the case, and it is crimped between those two bands.

M115 cases are only used for APDS and TPDS projectiles
M150 cases are used for HEP-T, WP-T, Flechette, and the TP M467 (simulates HEP and WP more or less)
The M148A1B1 has been used for three different projectiles, the APFSDS-T, the M456, and the M490 TP, which is the same shape and ballistic performance as the M456. There is a relatively new M490 variation that does not have a tail boom and fins, but it still uses the M148A1B1 case. Typically, if a case is fired domestically, TP projectiles are 10-20 or even 30 times more likely to be fired than a service round, except on Proving grounds.

The only projectile that isn't listed is the new Canister round used in Iraq and Afghanistan. No case info on that round, but I would guess M115A1B1 due to projectile shape.

Don't get distracted by primer numbers. Concentrate on the model of the case, and which projectiles are loaded in that model. M148 cases have shortest primer, M115 have the longest primer with a plug in the end of the primer tube.

 

[apfsds]

First of all, secure a copy of TM 43-0001-28 Army Ammunition Data Sheets. It gives detailed descriptions of the round components and firing performance data. It can be found in PDF format on the web for free. It lists all non classified 105mm Gun rounds, as of the date of printing. You will find that there are three models of 105mm gun cases, M115, M150, and M148. These cases exist in Brass and Steel. Early development of these cases were in brass. All recent manufacture is the B1 versions in steel. The cases differ by primer length as related to the depth of the projectile intrusion in the case, and the case mouth details where the specific projectiles are inserted and crimped. As an example, the M150 case mouth is a larger diameter, because two of the three rotating bands are inserted into the case, and it is crimped between those two bands.

M115 cases are only used for APDS and TPDS projectiles
M150 cases are used for HEP-T, WP-T, Flechette, and the TP M467 (simulates HEP and WP more or less)
The M148A1B1 has been used for three different projectiles, the APFSDS-T, the M456, and the M490 TP, which is the same shape and ballistic performance as the M456. There is a relatively new M490 variation that does not have a tail boom and fins, but it still uses the M148A1B1 case. Typically, if a case is fired domestically, TP projectiles are 10-20 or even 30 times more likely to be fired than a service round, except on Proving grounds.

The only projectile that isn't listed is the new Canister round used in Iraq and Afghanistan. No case info on that round, but I would guess M115A1B1 due to projectile shape.

Don't get distracted by primer numbers. Concentrate on the model of the case, and which projectiles are loaded in that model. M148 cases have shortest primer, M115 have the longest primer with a plug in the end of the primer tube.

Excellent Information, John! Thank you.

You are of course correct that the case type and profile are the most important thing when trying to match up a projectile. The only reason I am a total nerd on having the correct primer is that I love to make sectioned rounds out of my specimens. I will only do a section if every component is factory correct. If just to match up a projectile the correct case is all that really matters.

There sad thing is, in the 25+ years that I have specialized in tank fired DS rounds, I have so far only ever found one M148A1B1 case with the correct ELEC M120 primer, a combo used on all type classified US APFSDS-T rounds (M735, M774, M833). The M900 uses a modified ELEC M120 and oddly enough, I did find a stenciled case for it years ago. I am saving your info guide on the proper case designations. Been trying to figure out that out for a while. Just awesome.

Jason

 

[wingsofwrath]

First of all, secure a copy of TM 43-0001-28 Army Ammunition Data Sheets. It gives detailed descriptions of the round components and firing performance data. It can be found in PDF format on the web for free. It lists all non classified 105mm Gun rounds, as of the date of printing. You will find that there are three models of 105mm gun cases, M115, M150, and M148. These cases exist in Brass and Steel. Early development of these cases were in brass. All recent manufacture is the B1 versions in steel. The cases differ by primer length as related to the depth of the projectile intrusion in the case, and the case mouth details where the specific projectiles are inserted and crimped. As an example, the M150 case mouth is a larger diameter, because two of the three rotating bands are inserted into the case, and it is crimped between those two bands.

M115 cases are only used for APDS and TPDS projectiles
M150 cases are used for HEP-T, WP-T, Flechette, and the TP M467 (simulates HEP and WP more or less)
The M148A1B1 has been used for three different projectiles, the APFSDS-T, the M456, and the M490 TP, which is the same shape and ballistic performance as the M456. There is a relatively new M490 variation that does not have a tail boom and fins, but it still uses the M148A1B1 case. Typically, if a case is fired domestically, TP projectiles are 10-20 or even 30 times more likely to be fired than a service round, except on Proving grounds.

The only projectile that isn't listed is the new Canister round used in Iraq and Afghanistan. No case info on that round, but I would guess M115A1B1 due to projectile shape.

Don't get distracted by primer numbers. Concentrate on the model of the case, and which projectiles are loaded in that model. M148 cases have shortest primer, M115 have the longest primer with a plug in the end of the primer tube.

Thank you!
Yes, I looked through TM-43-0001-28 and it only further confirms my suspicion that my case held an M456A1 HEAT.

Unfortunately I'm no closer to finding out what the actual dimensions of the projectile are so I could make my 3d-printed replica as a a "case-filler"- I could try to extrapolate from the few dimensions I do have using one of the drawings, but I have no way of knowing how accurate they are. In the end though that seems to be the path I'm going to have to take...

 

[HAZORD]

Why not try to find a real projectile or replica on the open Market? Where do you live?

 

[wingsofwrath]

I live in Romania. We do not use the caliber so any projectile would have to be imported, most likely from the US which, considering the fact it weighs in at 10.2 kg, it's going to be pretty expensive, probably more than the projectile itself is worth...

And if we're talking replica, then why would I buy it from someone else when I'm a skilled model maker with 200+ various pieces of ordnance under my belt and most of the fun resides in making the model itself?
I just need the dimensions, but apparently they aren't to be found so I'm going to have to work from photos and whatever blueprints I could find.

 

[apfsds]

I live in Romania. We do not use the caliber so any projectile would have to be imported, most likely from the US which, considering the fact it weighs in at 10.2 kg, it's going to be pretty expensive, probably more than the projectile itself is worth...

And if we're talking replica, then why would I buy it from someone else when I'm a skilled model maker with 200+ various pieces of ordnance under my belt and most of the fun resides in making the model itself?
I just need the dimensions, but apparently they aren't to be found so I'm going to have to work from photos and whatever blueprints I could find.

Are you sure your case has an ELEC M63 Primer? My records show that the HEAT projectile you are looking to 3D print utilizes the ELEC M83. As HAZORD, mentioned, the primer does not matter if you just want the correct look, but since you are so hot to trot to print what you think is the correct case projectile for your exact case/primer config you may have more projectile options to choose from then the HEAT project that use the ELEC M63??? Just a random thought. I really hope you get the measurements you are after.

Jason

 

[HAZORD]

Maybe someone has a copy or access to a Russian "Frag Guide" of U.S. projectiles, that has all the measurements you need.

And to Jason's point and my earlier comment, it is 10 - 20 times more likely that your case held a TP M490 projectile.

 

[wingsofwrath]

Are you sure your case has an ELEC M63 Primer? My records show that the HEAT projectile you are looking to 3D print utilizes the ELEC M83. As HAZORD, mentioned, the primer does not matter if you just want the correct look, but since you are so hot to trot to print what you think is the correct case projectile for your exact case/primer config you may have more projectile options to choose from then the HEAT project that use the ELEC M63??? Just a random thought. I really hope you get the measurements you are after.

Jason

Pretty sure, it's written on it and it can be seen in the photograph I submitted. I think the reason this munition is described as having an ELEC M83 primer is because TM-43-0001-28 is from 1994 and updated in 2003 whereas my example was manufactured in 1977, so we can assume the ELEC M83 is probably an improvement on the original ELEC M63 that had been fitted to these rounds previously.

Maybe someone has a copy or access to a Russian "Frag Guide" of U.S. projectiles, that has all the measurements you need.

And to Jason's point and my earlier comment, it is 10 - 20 times more likely that your case held a TP M490 projectile.

Oh I agree that it most likely it held a TP M490, considering that most cold war ammunition was expended in training, but if I'm making it myself and I have no way of telling which one of them it was anyway, why not paint it up as a war shot?
After all, it'll fit very nice besides my Romanian Army 100mm BK5M HEAT, whose case is clearly marked as a dummy "PROBA -06 FARA AMORSA" (TEST-06 WITHOUT PRIMER) although obviously made from a formerly expended UBK4 round, presumably also during training, so I chose to represent this earlier projectile.