I made an action/rifle in .300 Whisper using Bill Holmes book as a guide. It fired for about a box of ammo and the nose of the cocking piece broke.

The effort to cam back the cocking piece is substantial. I may have just compressed the spring too much. But is there any other area I should look at?

Should I relieve the shroud so that the side of the cocking piece is bearing against the slot in the tail of the action instead of the shroud (and then "cocking" as the ears of the shroud bear against the sides of the bolt raceway)?

Appreciate any help.

Steve

That's just a tad vague. Of the 40,000 different firearms listed in the RCMP database I could maybe throw a dart. Any particular make and model?

Sorry, it's the model that Bill Holmes describes making in his book, "Guide to Building Bolt-Action Rifles". Only I made it with two locking lugs instead of three (albeit longer). Dimensions in the book weren't consistent, so I cheated heavy.

It's a fat-body bolt to avoid long broaching operation and it's similar to a Winchester Model 70 as far as the bolt, cocking piece and shroud are arranged.

What is an RCMP?
I see you made your own action; if it is cocking hard, maybe you need to smooth up the cocking cam and cocking piece nose. No, it does not rely on the receiver slot for bearing. It is controlled by the bolt shroud, but it could bear against the receiver slot if you wanted it to. More added friction though.

Thanks, will check that.

RCMP is Royal Canadian Mounted Police--The Mounties.

The cocking cam and the nose of the cocking piece have to be pretty damned hard or they will cause hard lift. They should also be of differing hardness. As a rule the cocking piece is made 4 points harder than the bolt body on most actions. If they are the same hardness they will gall and fight one another.

The cocking cam needs to be a true helix rather than a simple angle.

Thanks, will check that too. Bolt body is Rc 43, but I case-hardened the mild steel cocking piece and not sure how hard it is. Plus, might have ground through thin case shaping the nose that engages the cam surface.

Ah, the Mounties! I used to watch Sergeant Preston of the Yukon; that is all I know about them. Red coats.

quote:

Originally posted by Craftsman:
The cocking cam needs to be a true helix rather than a simple angle.

It's occurred to me that this would be better. On older Winchesters and Remingtons, the cocking cam is cut this way, but the new ones are a straight cut.

quote:

Originally posted by skl1:
Thanks, will check that too. Bolt body is Rc 43, but I case-hardened the mild steel cocking piece and not sure how hard it is. Plus, might have ground through thin case shaping the nose that engages the cam surface.

Yeah, some people like to argue the point to hell and back, but case hardening and firearms generally don't go to well together. Once you break through the case you are in a world of hurt. It was fine when we didn't have steel to play with, but now days, with all of our modern materials there are much better ways of doing things. I generally make cocking pieces from 4350 or 4140.

I take it you don't watch the cartoon "Fugget About It" dpcd ?

https://www.youtube.com/watch?v=NVjKojTuq48

No, but I watched Dudley Doright too.

quote:

Originally posted by dpcd:
No, but I watched Dudley Doright too.

Yeah, they don't let you guys get the good Adult Canadian cartoons. I think Teletoon rated Fugget About It as 18A for sexuality, violence, and swearing. Which means you have to be 18 and have some pretty low social standards to watch it. Which is pretty funny in Kanukian terms, but downright disgusting in Merican standards. The cold and the high test beer fogs our widdle haids up here. LMAO

Yeah, I have no idea what you just said but it sounded funny.