Any info on this American 75mm APC projectile?

[Kilroy]

Hi again,

This is another in my small collection of mixed nation ordnance from WWII. In the U.S. the nomenclature for any of probably a dozen different guns that were variously referred to as "75mm" or "76mm" or "3 inch" was incredibly confusing, and all could be further differentiated by barrel length such as the USN 3"/50 caliber so well known.

Here is an example of a projectile that I believe was used excluseively with the size 75mm, and was most probably used as the weapon of choice for anti-tank applications or hardened targets of other types by the original Sherman M-4 tank.

Now comes some diferentiation.

This projectile had a driver band width of .475", measured with guage pins to a tight fit at .474 of an inch.

Yet, I have seen this same type projectiile with a driver band much thicker, about 1 inch wide, and with 2 grooves turned into the band at equal spacing to the edges of about .05" inch thick and maybe as deep.

Also, the back of this projectile is bored out and threaded, most likely for a small inner charge of TNT to burst once it had penetrated and a base fuse would then detonate this charge inside the vehicle.

Could someone place where this type of projectile was fired from, and could it have been used variously like I think I saw, with both a .475" inch drive band and also a 1 inch band with two grooves in it?

Also, for those with eyes to see, I have restored the driver band on this, I bought it with no driver band and made one to fit. I programmed machine tools for 12 years, and I got some brass and did it myself. I did not have copper, but I have been told that brass goes pretty brown when you put vinegar on it eventually, so it should come out looking fairly normal sometime or other.

So what is this I have here?!?!?!?

Thanks,
Walt

 

[ordman]

It's a 75mm APC common round used in the sherman tank WWII
the 76mm and 3"/50 APC where the same round quite often the nomenclature included the army designation or vice versa
The 76mm was adapted for the armys upgunned sherman later in the war
to have more punch against the german armore
Confusing yes

 

[HAZORD]

Kilroy,

As Ordman stated your projectile is for the 75mm Sherman tank and would also have been fired by the 75mm Gun that was mounted on some B-25 aircraft and used for killing ships in the European area during WWII.

The projectiles you have seen with the 1 inch wide rotating band were fired by the 3 inch M-10 tank destroyer, 3 inch antiaircraft guns, or the 76mm gun on the super sherman. Those projectiles are 76mm/3 inch diameter.

3 inch 50 cal AP-capped projectiles have a band similar to yours but are shorter than the Sherman projectile.

The bursting charge in armor piercing projectiles would not be TNT. The extreme shock of impacting armor would cause TNT to detonate prematurely before the projectile could pierce the armor. Armor piercing U.S. projectiles of the WWII era and later use Explosive-D as a bursting charge. It is an ammonia based explosive and is very insensitive. That is why the booster charge on base fuse uses such a large quantity of tetryl.

The only common thing between the Army 3 inch and Navy 3 inch AP-capped projectiles, is that they both used the Army fuze.

 

[Western]

Kilroy,

You painted the projectile black? Black paint with white markings this projectile had no bursting charge and fuze but a closing plug with tracer.
Same projectile painted olive drab with yellow markings did have bursting charge and fuze.

 

[Kilroy]

Hi Hazord,

You bring up a few interesting points.

I have seen in just a few pictures those B-25's that were fitted with a 75mm cannon but I always wondered if it was a special
"ultra-light" type round to allow the fuselage to dissipate a recoil it was not really designed to withstand. Would you know if
that projectile was mated to a Sherman type case filled with propellant, something more like a pack howitzer sized load, or was it
specially loaded for that mission?

It was certainly one of the more hairy adaptations of an American plane.

Back to the 76mm issue. You said the 76mm was used on the M10, which was a tank killer in wide use, I am reading about them right now, but
what did the 76mm on the M-10 use as it's AT projectile?

I think I am getting to the bottom of this little by little, but I don't believe I have seen a typical AT projectile from the M-10 type useage.

I think I have a round here that could be considered an HE round used on such vehicles, but I don't think I have seen what the M-10
or the Hellcat or others used to penetrate enemy armor.

Note the middle shell of the three shown. Is this a 76mm HE type round?

Also, is the one on the right a WWI era round or just an early Sherman round?

 

[Kilroy]

Hi Western,

Yes, right now it is the wrong color for the type it really is, but I just wanted to see what it would look like.

I bought that same manual, and saw that it was incorrect afterwards, but pretty soon I will be on unemployment, and there will
be time a-plenty to give it the OD paint and yellow stenciling.

Walt

 

[HAZORD]

Kilroy,

OK, heres the dope on your stuff. Left round is your Sherman AP-Capped. As was stated, if it was painted OD with yellow letters, it would have been explosive filled. It is the same round fired in the B-25s. No difference in ammo loading for the bomber carried gun versus the Sherman gun.

Your middle HE projectile is an M-42 HE projo used in the 76mm gun or the 3 inch M-10 Tank Killer, or 3 inch antiaircraft guns. Right now it is in a M-26B1 steel case (76mm case) for the super sherman. The gun used on the m-10 tank destroyer is designated 3 inch and used a bottle necked case. It was not the 76mm gun which used a straight case like yours. The HE projo on the right of your photos is a Mk. I HE projo originating in WWI and used for training mostly in WWII. In WWI it was fired by the French 75 field gun and used the same cartridge case as the Sherman. It could have been fired in the Sherman for training and in early stages of WWII.

The projectiles used in the 76mm straight case or 3 inch bottlenecked case were the same projectiles, they were just painted with different lettering due to case type which specified which gun they were fired in.