Unkown brass case

[joem]

A friend brought over some brass he picked up when cleaning out a widow lady basement. He's getting into reloading and I'm helping him. One case is about twice the size of a .50 BMG but the ID on the neck is .500. It is US and has a TW head stamp. I'll try to get a pic as soon as I can.

[da gimp]

20mm?

[Tuna]

It can't be a 20 MM if the neck is .500. Pictures would sure help. Might have been an experimental case? What kind of rim does it have, rimed or rimless?

[raymeketa]

There were experimentls where both the 60 caliber and the 20mm were necked down to 50. A photo is the only way to ID what it is. And some dimensions too.

Ray

[joem]

I'll see what I can do about pics. I don't think an experimental the head stamp is TW and it's rimless.

[raymeketa]

joem

The experimentals often used existing cases so it's not uncommon to find them with headstamps from the different Ordnance Plants. Both the 60 Cal and the 20mm were rimless.

Ray

[da gimp]

the 20mm necked down to .50 was intended to be a high velocity, long range round. There were guys that wildcatted it in bench rifles that were very heavy. It's probably 15 or 20 years ago that I first heard of it being done.

[jimb]

It could also be an artillery spotting round for practice with one of the recoiless rifles.

[Lee T.]

Just for comparison sake........can you imagime the 20mm necked down as da gimp says?
20mm - .50 BMG - .30-06 M2

[da gimp]

Warren Page mentioned years ago in an article, & if I remember right, he said he WATCHED others shooting it..... only, even with a 30lb rifle, that sucker would kick.

Friend has a fairly light single shot bolt action .50BMG that he's been urging me to shoot for years, I figure the recoil is way worse than a 5 1/2 lb 3-1/2" 12 ga using heavy loads, something I experienced when Mossberg 1st produced a pump for that round, so I've always passed.