Mossberg 640K 22 Mag Bolt Loose?

[Dave1]

I have a very old Mossberg 640 K Chuckster 22 mag bolt action rifle (deluxe model). It has a 24" barrel and has been a great utility rifle. The problem I have is the bolt has become worn where it friction locks into the slot in the reciever. The bolt will not stay closed and I have noticed the fired cases have some burnt gas signs all around the brass case. I believe this indicates the cartridge is not being held tight in the chamber and gases are blowing back around the case when fired.

Can this be repaired? If so, how? Expense? Should I try to find a new or used bolt for the gun?

Thanks, Dave

 

[Hackmaster]

A new bolt handle would be an almost certain fix however it may require fitting. I would suggest checking the mating surfaces for burrs. If there are any gently push them back into place with a (very) small hammer. You could also have the bolt handle welded up at the mating surface and work it down until you regain the tight fit you desire.

 

[Dave1]

The bolt in the closed position is a loose lock up fit now as friction wear over the years has taken its toll. I am guessing that welding the bolt handle surface and then milling it back to original specs is the only way to fix it. Probably be an expensive fix.

I looked around online a bit thinking I might find a new bolt but did not find such.

Dave

 

[Hackmaster]

That is unless you have an adept welder friend or neighbor that you could swap a six pack for a weld job

 

[Dave1]

On the Numrich Gun Parts website they list a bolt assembly for this gun for $54 but are out of stock. That would likely be the best and cheapest fix.

To weld the bolt then mill it down to exact specs would require more than the home welder can do. I have a wire gun but would not attempt this intricate weld/repair project. The repair would require a small TIG to do the build up, then a milling machine to cut the surface to exact spec, perfectly flat, etc. It may be the wear on the other rotating surfaces in the bolt are contributing to the problem. If that is the case, a new bolt is the best fix for all.

Dave

 

[Old Shooter]

Okay, here's a good old boy trick that might get the problem fixed for you for a while, mayby for good.

Get a small piece of shim stock, (I've used pieces of 22 rimfire cases on some projects) and JB weld. Clean the surface in question with a good solvent, put a dab of JB weld on it and then put the shim on and press it home. Wipe off all the excess and let it set for a day or two.

If it is going to hold it will last forever, if not it will come off within a dozen cycles or so.

You might want to consider if you would use this method on the bolt or on the receiver section that the bolt sits against.