No. 1 MK III Problems - Help needed.

[P-07ShortLee]

After firing a standard round (and whilst pulling the bolt rearward) I noticed the bolt wouldn't retract past the charger bridge, to my suprise the bolt head had jumped the rec. rail!

After cleaning I found that while the bolt head appears snug and secure while closed, there is a spot about about 2 centimeters rearward where the head can be "jumped" by hand while pressing up.

Is it safe?

Information

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[Peter Laidler]

Distorted body........................

[smellie]

Most likely the rifle is safe enough to FIRE, but this kind of thing just is not supposed to happen.

You have a worn receiver rail, friend. It does happen from time to time.

How much slop is there between the underside lug of the bolthead and the receiver rail as you draw the bolt backward? What's the MINIMUM clearance? This is the amount that you can forge the bolthead lug INWARDS by, without interfering with bolt travel. If you can do this, it should cure the problem. You can minimise the problem by making certain that the bolthead and receiver rail are lubricated adequately. A dab of grease will do a good job of this.

Also, think about a diferent bolt-head. There were tolerances on these things, too, and substituting an unworn head might solve your problem all by its little iron self. This would leave you with an interchangeable rifle, of course.

If you alter the bolthead which you already are using, you will end up with a rifle which is OUT OF SPEC, but which will work. This is a very real problem if you have 6,000 more rifles on your rack and you expect the parts to interchange. On the other hand, most of us can`t afford 6,000 SMLEs, even if we would like to have them, so this might not be a problem for you.

Whatever. This is where the problem is, and you have two ways to attempt to cure it.

Hope this helps.
.

[Peter Laidler]

Thinking about this, the tech information says that the bolt head must never leave the track under any circumstances. If it does, it indicates a distorted or a worn body. That set me thinking....... how worn can it be for heavens sake before the bolt head leaves the track.

It's simple! If the rear boltway on the body is worn away, and they often are, it will allow the bolt to twist over to the right and taking accumulative error into account, a lot of wear at the rear will allow the front of the bolt and bolt head to move to the right. The nett result is that the overhang of the bolt head will clear the body at the front of the track. Just as it's done in this case.

So your problem P-07 can only be one of three things. Worn body, worn bolt or distorted body

[Thunderbox]

I've just checked a rifle that had a similar problem - bolthead jumping the track. Turned out that the rifle (a 1942 Dispersal, rebuilt as a complete horrid bitsa by some genius) seemed to have a perfectly decent receiver, but it had a mismatched bolt where someone had further ground the locking faces. Headspace was off the scale, and the bolt had considerable lateral and vertical movement. A change of bolt gave a nice tight action and solved the problems instantly.

An old armourer & gunsmith mentioned that "worn or distorted bolt rails" were extremely rare; their shop method involved a quick application of a cold chisel down through the magazine well to persuade the right hand side to move over a bit....

[Peter Laidler]

It doesn't mention that method of repair in the EMER or during our apprenticeships. But quite how you'd repair a worn out boltway behind the bridge charged guide is another matter. But I have heard that some of the rebuilders have been known to squeeze the sides together in a press. It takes all sorts as that say...........................

[P-07ShortLee]

Thanks for the suggestions, I'll check some other bolt/heads and see if the results are different.

[tbonesmith]

I've got the same issue on one I was going to get up and running again. Changed the bolthead, still jumped, changed the bolt body, still sloppy but won't jump out. Is there any real repair or do you just strip all parts and junk the action body?

[Thunderbox]

I've got the same issue on one I was going to get up and running again. Changed the bolthead, still jumped, changed the bolt body, still sloppy but won't jump out. Is there any real repair or do you just strip all parts and junk the action body?

If a bolt change fixes the problem, why junk the action?

Just because a bolt feels sloppy, doesn't mean its not functioning correctly. Some wartime rifles would have been like that from brand new.

[tbonesmith]

Just unsure of where to draw the line, as to what's worthwhile and what's a piece of junk.