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What is up with this 90mm " M71 " ???

D

DEADLINE222

Well-Known Member
I have had this projectile for several years, and just now noticed a few things:

The rotating band may not be copper. I think it is brass.

The rotating band may be way too big, and whatever material it is continues to the base of the projectile.

There is no crimping grove.

The body and ogtive is steel and accepts standard fuzes.

It is stamped as "HE -O-T-71 1953 90MM M71"

If I had to guess, I would say it is a rather fancy training projectile. But why would it be stamped as a service projectile?

90mm.jpg
 
In addition to the things you have noted, the boattail is larger than usual (it usually tapers down much smaller. It is also missing the groove behind the rotating band, for the band material to move into when it is fired through the rifling. It was made during the Korean War. It might be an experimental HE round for the High Velocity 90mm tank gun that was experimental around that time. It used a taller thinner case.
 
HAZORD said:
It might be an experimental HE round for the High Velocity 90mm tank gun that was experimental around that time. It used a taller thinner case.
Click to expand...

That one sounds interesting Hazord. Do you have any more detail on it you can post please?
Dave.
 
With your statement that the base is of the same material and looking at the uniform pattern of the rotating band, is it possible that someone turned it on a lathe to finish a partial projectile? On most bands of that width you get high spots and low spots, narrow grooves and wide grooves, but very rarely are they uniform.
 
Dave,

I will have to find the manual that shows the round. I have a case. It is shown in Ammunition General TM 9-1900 from I believe the 1950s.
 
HAZORD said:
Dave,

I will have to find the manual that shows the round. I have a case. It is shown in Ammunition General TM 9-1900 from I believe the 1950s.
Click to expand...
Thanks John, I have TM 9 - 1900 from 1956. Can't see it. Any idea of page/figure number?
Any info is of interest, expt tank rounds are right there in my collecting area :)
Dave.
 
P1010018.JPGP1010021.JPGP1010020.JPG

Here is a drawing of the round John mentioned earlier. It's designation was T42 HE & T44 HVAP. The complete cartridge was 50" in length, was separate loading, and was used in the T15E2 "super velocity" gun attached to the T26E4 "Super Pershing" tank developed at the very end of WWII. The tank never saw action and the program was dropped shortly after the surrender. Although deadline222's projectile rotating band is a little different style then the one in the drawing, I believe this may be one prototype of that shell. This tank gun was developed to match the 88mm KwK 43 round of the King Tiger.

Best regards,

Randall
 
Nice informaiton Shelldude.

Was brass ever used as material for a rotating band? Once again; assuming the material on my projectile is brass?
 
Yes Deadline222, brass used to be used as DB material. For example one sees 47x131R projectiles with those "rippled" DBs in both copper and brass.
Of course brass is an alloy ("cartridge brass" is commonly 70% copper and 30% zinc). DBs may have used different recipes.

Hi Shelldude, any chance of some dimensions for the experimental 90mm tank case, please.
Thanks very much
Charley
 
Hello Charley,

I need to correct myself. The 50 inch projectile I mentioned earlier went to the T15E1 super pershing gun and was a one piece fixed ammunition round. The two piece separate loading T42HE & T44 HVAP projectiles were even longer then 50 inches, thus requiring the separate loading technique. The unique casing was designated T10 but I have never been able to find exact dimensions. The T42 HE projectile was 23.2 lbs and the T44 HVAP was 16.7 lbs. The complete two piece T42 HE round weighed 50.4 lbs and the T44HVAP weighed 44 lbs. The muzzle velocity of the T42 was 3,200 ft/sec. while the T44 was 3,750 ft/sec. The penetration ability of the T44HVAP was 8.7 inches at 1000 yards. I hope I didn't put you to sleep...

Best regards,

Randall
 
shelldude said:
Hello Charley,

I need to correct myself. The 50 inch projectile I mentioned earlier went to the T15E1 super pershing gun and was a one piece fixed ammunition round. The two piece separate loading T42HE & T44 HVAP projectiles were even longer then 50 inches, thus requiring the separate loading technique. The unique casing was designated T10 but I have never been able to find exact dimensions. The T42 HE projectile was 23.2 lbs and the T44 HVAP was 16.7 lbs. The complete two piece T42 HE round weighed 50.4 lbs and the T44HVAP weighed 44 lbs. The muzzle velocity of the T42 was 3,200 ft/sec. while the T44 was 3,750 ft/sec. The penetration ability of the T44HVAP was 8.7 inches at 1000 yards. I hope I didn't put you to sleep...

Best regards,

Randall
Click to expand...

That's all good, thanks Randall. I'm hopeing John can post a photo of the expt case he has, I've never seen one.
Dave.
 
I actually have 3 experimental cases. I have the long thin one shown in Randall's illustrations, with cork mouth plug for the HE projo, and I have 2 different bottleneck cases for hypervelocity Sabot rounds. I will take a group shot when I get home, in comparison to a normal M19 case.

I also have an experimental 155mm tank gun case, if there is an interest in that one.
 
HAZORD said:
I actually have 3 experimental cases. I have the long thin one shown in Randall's illustrations, with cork mouth plug for the HE projo, and I have 2 different bottleneck cases for hypervelocity Sabot rounds. I will take a group shot when I get home, in comparison to a normal M19 case.

I also have an experimental 155mm tank gun case, if there is an interest in that one.
Click to expand...

Thanks John, yes I'd like to see photos of all of them.
Ta,
Dave.
 
Hello John,

Can't wait to see your photographs! The 155mm was the largest projectile ever used in an experimental U.S. tank to the best of my recollection. Can you imagine what it was like inside the turret of that SOB?

Randall
 
It is hard to imagine, except the Germans had that tank that fired the huge rockets. Those things are about 5 feet tall and about 16 inches in diameter and 5 or 6 hundred pounds at least. One of our members had one of those rockets at one time, but I haven't seen it lately.

The 155mm case is supposed to be a 120mm case blown out straight.
 
P1010002.jpgP1010001.JPG

Hello John,

I don't know if you've ever seen a photograph of the 155mm beast that we've discussed, but here are a couple of photos of the U.S. Heavy Tank T30. The 155mm ammunition used in this tank was obviously separate loading also.

Best regards,

Randall
 
Thanks Randall
All your info is very interesting and, in fact, more likely to wake me than send me to sleep!

And hello Hazord, eagerly awaiting photos of those cases (and please provide lengths and rim diameters, too)
VERY interesting indeed.
 
HAZORD said:
I actually have 3 experimental cases. I have the long thin one shown in Randall's illustrations, with cork mouth plug for the HE projo, and I have 2 different bottleneck cases for hypervelocity Sabot rounds. I will take a group shot when I get home, in comparison to a normal M19 case.

I also have an experimental 155mm tank gun case, if there is an interest in that one.
Click to expand...


Greetings Hazord,
Have you had a chance to measure and photograph your three 90mm experimental tankk round cases? And the 155mm one?
Thanks very much
Charley
 
Charley,

Sorry about the delay. I've had a lot going on as of late. Glad you bumped this thread. I should have time this week to take photos and measurements.
 
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