What is this part on a Model 1917?

[ElDorado]

http://i1202.photobucket.com/albums/bb364/ElDoradoJeff/ForumPics/1917_Part.jpg

A friend just acquired a US Model 1917 rifle. While disassembling it for the first time, he noticed a strange part on the bolt that doesn’t show up in any of the diagrams or instructions that we can find. It looks like something that has been added on. He said it can’t figure out what its function is, although he has noticed that if the safety is in the “On” position, the part will move it to the “Off” position when he closes the bolt, but I’m not convinced that that is its purpose. It’s not one of those cock-on-opening devices, because the bolt still cocks on closing. The only other thing that we can think of is that it is some sort of protection, for either the shooter or the cocking piece.
Does anybody have any idea of what this might be?

[Frank46]

Got me there, I'll take a wild guess that's a home made shroud but the piece with the set screw
is something I've never seen before. Frank

[frnkeore]

Possibly a gas deflector?

Frank

[MtGun44]

Maybe a cock on closing to cock on opening conversion? The 1917 is a cock on
closing action, some prefer cock on opening and there is a conversion, never saw one
though.

Bill

[leadman]

I do remember seeing an ad for a gas deflector in an old magazine but don't remember which rifle it was for. I do remember it was for a U.S. military arm.

[Bullshop]

I have a custom 1917 with the same striker cover. Its a very handsomely done sporter but I have no idea when it was done or who did it.

[MtGun44]

Cock on open or closing?

Bill

[Bullshop]

Mine is on closing.

[ElDorado]

I think you guys are right.

The owner brought the part by today and I got a chance to look at it first-hand. It does appear to be a shroud of some sort. It's closed in the rear, I presume to prevent gas blow-back. I wonder if the previous owner had a problem of that sort with this rifle, or if he was just being precautionary. The rest of the rifle is unmodified, which makes this little add-on strange.

Apparently the issue with the safety I spoke about in the original post was a misunderstanding. He was having problems disassembling the bolt according to the instructions he had because of the shroud. It doesn’t affect the action of the bolt. The bolt still cocks on closing as designed.

If Bullshop has one just like it, maybe these were commercially manufactured. This one was machined, but it looks homemade. It was turned on a lathe, and then the cut-out at the bottom was milled. Two brass-tipped set screws hold it in place. It’s blued but not polished.

The owner also reported that the rifle shoots fine using the Greek M2 Ball from the CMP. No boolits yet. The guy just started reloading recently, and he’s saving up the Greek brass. I may have to give him some Lyman 311335s to get him weaned off the j-words.

And thanks for your help. This is the go-to place for answers.

[MtGun44]

Greek M2 ball is good stuff, IME. Accurate and good quality ammo.

So, it is apparently a gas blowback protector. Interesting. Learned something.

Bill

[shotman]

sometimes they had a blow back Bet that was saftey that would protect your eye. I have a krag that some one cut the pull knob off the back of fireing pin. Why??? I shot it and good thing I was wearing glasses. there was a little by pass and could feel it . With the knob there it would deflect blow by . Try to take a krag bolt apart without the knob.

[Char-Gar]

I don't know about the particular part, but "back in the day", I recall that "gas proof" shrouds were sold for various rifles. Mostly a fix for a non-existent problem