M85 7.62x39 problem

[HeadDamage]

A friend just bought an M85 with a case of Norinco ammo from Canada Ammo and it has a couple of problems:

- It misfires about 50% of the time, requiring recocking and firing a second time to ignite the round (this is with the package deal ammo)

- The other issue is that around 5 to 10% of the rounds will not chamber in the rifle, the bolt can't be closed on them. These same rounds will chamber alright in my Ruger M77 7.62x39

Is there anyway to reasonably fix these problems or is this M85 a lemon?

 

[Hitzy]

It's not really designed for milsurp ammo, nothing wrong with the rifle....

 

[RDMC]

For the misfire I suspect that hard primers are the cause, for the bold not closing.... Surplus ammo has looser tolerance than any other kind

 

[hoytcanon]

It is not the gun... the older M77's had a loose chamber, designed for milsurp ammo... the M85 does not... try a box of factory PRVI 123 gr. Ammo in the gun... I bet it works perfectly. You can have the M85 chambered for milsurp... it will cost $50 if you can find a smith with the reamer... or $175 to buy a reamer and T-handle and do it by hand... only takes a couple minutes with cutting oil... you will get at least $125 of that back as there are always guys looking to open their chambers for milsurp... I personally don't shoot that crap, but I reload so my costs are way down. If I didn't reload, I could see the attraction.

 

[EL34/6L6]

Corwin currently sells the nicer full stock versions of this rifle which also has now been adapted to shoot the harder milsurp primers.

 

[Boomer]

For the misfire I suspect that hard primers are the cause, for the bold not closing.... Surplus ammo has looser tolerance than any other kind

Actually milspec ammo has to be kept to fairly precise dimensional tolerances so it can run reliably in full auto weapons. While the same cannot necessarily be said for the tolerances of bullet weight and powder charge, some lots are surprisingly good. The question is whose dimensions were cut in the chamber, SAAMI and CIP dimensions are not the same, so CIP ammo in a SAAMI chamber or vice-versa can be an issue.

 

[Brian46]

Corwin currently sells the nicer full stock versions of this rifle which also has now been adapted to shoot the harder milsurp primers.

Yes, unfortunately he will not be bringing more in because of all the cheaper USA made M85's being imported by dealers making him unable to compete even though the problems seem limited to the USA versions

 

[lejarretnoir]

I have an older Ruger M77 MKII, CZ 527 and a reamer that will shoot all milsurp flawlessly. The CZ chamber is a little tighter than the Ruger, but runs great.
In fact, I tailored the reamer to almost match the Ruger chamber. It will shoot milsurp in a .308 bore like the Rugers, no problem.

A stronger firing pin spring will cure the light military primer strikes. Had to do that on a Rem 788.