NO 4 firing pin

[Doco overboard]

I want to use this firing pin for a No4 project gun. Is it the right type and can I adjust the protrusion on the ledge that is absent on the other example. It does not allow for protrusion at all when inside the bolt well. It also does not seem as well made as the other one which has buggered threads. Thanks. Attachment 86065

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[green]

Right or left in pic?
The left is for an early SMLE.

[Maxwell Smart]

The one on the left is not for a No 4. As well as the lug on the front of the collar (which engaged a slot in the tenon of the bolt head and allowed for unscrewing without a special tool), the thread form at the other end is different and a No 4 cocking piece will not screw on.

How bad are the threads on your No 4 striker? At least the No 4 had standard thread forms - might be possible to chase the thread with a die nut? 1/4" BSF 26 tpi according to on-line source

[Doco overboard]

Thanks should have been more clear. The one on the left is what I intended to use. It screws right on to the cocking piece tightly but the semicircular recess where the lock screw works against is also shaped differently which should be easy to remedy but it is more of a shallow recess.I want to remove the protrusion and use it if at all possible. Will it work temporarily if it is reshaped? The only difference that I can tell between the two that I can tell is the diameter at the end of the pin may be slightly smaller and the tip looks like it almost has a slightly square shape. There is no slop in the port of the bolt head and it looks like if the protrusion is adjusted like the one on the right it will work. The other pin is in bad shape. I guess I can section them and get what I need between the two worst case. Thanks for the info it was very helpful, at least I know the one I wanted to fit was incorrect.

[browningautorifle]

I think you're talking about altering a scarce firing pin when there's guys here have handfuls of common ones...I'm sure you can find one here...?

[Doco overboard]

I just went and looked at it. That protrusion is is the same width that the cocking piece stands off from the rear of the bolt body. The threads are the same. The end of the firing pin (the one with the protrusion) times perfectly with the locking screw and it goes together perfectly. Once it is assembled, the cocking piece and collar minus the protrusion will contact each other at the same time as the collar to the radius at the rear of the bolt head. It looks like its the bolt head that arrests forward movement as well as the cocking piece at the same time. The pin that I want to alter is flat on the threaded end and the other is round. The other thing is, once that lug is gone the end of the pin will need to be dressed to proper protrusion, it will be grossly entirely too long and will match the taper of the boogered one. If I shouldn't fool with it, I wont but it will work after it is modified. If its something out of the ordinary and it would suit someone else no problem. Im just fiddling about trying to assemble a rifle entirely from reading Capt. Laidler's articles and enjoying the challenge. Two more things, the width of the collar is smaller by about .002 and the tapered portion of the pin has a rougher exterior at the taper than the ruined one but its straight to a fine point.

[Peter Laidler]

Personally, I'd just use the correct part unless it was totally non available and only then would I mix-and-match

[Doco overboard]

Shouldn't be to difficult to find another pin, that's what Ill do. No sense in getting bogged down unnecessarily. Thanks.

[browningautorifle]

I agree, I don't see it as a challenge, I see it as the wrong part being cobbled in to make it work. The correct ones are available at reasonable prices.

[Mk VII]

Save early parts like this for those who are restoring something, and get the proper one, which is much available anyway. Someone will probably swap you for it.