Question about firing pins.

[rge0012]

I recently bought a Lee Enfield No.4 Mk1/2, and although it seemed to perform very well at the range, I noticed some of the primers were slightly penetrated. When I inspected the firing pin, I saw that the tip had a few tiny dents which may have been the problem. The tip is not completely smooth. I ordered two firing pins from Numrich, but one was in even worse condition, and neither fit. The thread diameters of the replacement pins were too large for the cocking piece. I also tried a different cocking piece, and still had the same problem. Is that common with No.4 parts?

Bottom line: I'm looking for a replacement firing pin. Does anyone have any recommendations?

Thanks!

Information

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[Parashooter]

Why not just repair the rough tip?

[Bruce_in_Oz]

Getting the correct shape is important to prevent primer ruptures that will, themselves, cause rapid destruction of your striker AND bolt-head face, by way of high-velocity / high-pressure gas jets. (Like miniature plasma cutters).

Check that you indeed have the correct pattern of striker.

Both SMLE and No4 are .250" diameter and have "fine" threads.

HOWEVER: SMLE thread is 1/4" x30 TPI "Enfield Special"; No4 is 1/4" x 26.

Furthermore, whilst the threaded portion needs to be a "close" fit, the KEY to system "longevity" is the fit of the parallel sections on the tail of the striker and in the cocking-piece itself.

The striker must be effectively a "zero-tolerance", virtually interference fit in the cocking piece, otherwise it will shake itself sloppy in very short order. A "loose" fit will mean very poor consistency of trigger-pull for a start; ranging to major issues with operation of the safety lever and catch and potentially dangerous engagement of the sear with the cocking-piece.

If the tip of the striker is "adjusted" too much, effective protrusion will fall below specified minimum and ignition reliability will suffer.

The path to "happiness" is in several stages:

Select a striker that, by itself, gauges correctly for protrusion with the bare bolt-head you intend to use.

Ensure that the parallel section of the striker just forward of the thread is NOT, under any circumstances, below 0.250" diameter

If you have plug gauges or a "hole micrometer", check that the diameter of the parallel part of the bore in the cocking-piece is not MORE than .0.250. This assembly is not a "racing fit", rather, a seriously precise one.

Ensure that the cocking piece has not been " adjusted" such that the full bent (front face) is "radiused" or otherwise "modified". Any deviation from correct length, perfect flatness (and at the correct angle) is cause for rejection. Attempting to "recover" a dodgy cocking-piece, by regrinding the front face, will likely lead to breaking through the case-hardening AND result in misalignment with the locking lever / safety catch in the "cocked" condition; NOT a good thing.

The ideal solution is to start with a NEW striker and cocking piece and proceed carefully. You will need a properly robust striker tool and a solid vise with "soft" jaws (or the original "special tool") to secure the cocking-piece. You will also need patience and a sense of adventure / humour. A dab of graphite grease on the threads and parallel surfaces is useful as well.

While you have the thing apart, you may as well replace the striker spring (EXACTLY the same component in SMLEs and No4 / 5 rifles), as well; it may have been there a while.

[rge0012]

Thank you for your advice! I would like to replace the striker as you recommended, but where is a good source? I've had bad luck with the Numrich parts that were flawed and didn't fit.

Thanks again.

[Bruce_in_Oz]

This bloke: http://www.jackfirstgun.com/

seems to have all sorts of stuff but also seems to have a limited "online" presence.

I have a set of his catalogues from over a decade ago; not much help, really.

There may be other, smaller operations in your part of the world. Contact your local gun shop as well as fellow shooters on the range.

You may also find "un-butchered" parts, even complete bolt assemblies, in the "scrap-heap" / parts "bins" as found in the back of many older gun-shops. No harm in asking and leaving your contact details; you never know what may turn up.

Gun shows in "outlying" regions might also be worth visiting; again there is always the prospect of finding "collateral" goodies.

[WarPig1976]

Take some 320 grit sandpaper and carefully reshape the tip. Then polish with whatever you have around to polish metal and be done with it. Check that your protrusion is within spec "which can be found around here somewhere" and off to the range.

[Roger Payne]

The most likely reason that the two replacements won't fit is that you've been sent SMLE strikers rather than No4. You may well get away with repolishing the tip of the original, but what Bruce has outlined is the counsel of perfection for doing it properly.

[Seaspriter]

Exactly how far should the striker pin extend from the bolt head to be within spec? (I have a dial micrometer depth gauge)

As a reference, on one FTR'd No.4 the striker pin protrudes .035" from the bolt head in the fully released position. Is this in the correct range?

[WarPig1976]

Sure, the proper way for an armorer. Why make a mountain out of a mole hill? This is a simple problem that could be corrected in about 10 minutes by any average Joe without all the complications. I've done it numerous times on all sorts of weapons. I did a thread here on an Yugo M48 that was popping primers because the FP was too long. Not saying Bruce is wrong or off base just there's an easier way from point A to point B.

[rge0012]

Everyone, Thank you for your advice!

My first choice is to replace the striker and perhaps the cocking piece. Since I have already had bad luck with Numrich, can anyone recommend another source for these parts?

Thanks again!

Greg