So I have occasional light primer strikes with my NHM-91.

I have been researching, and have heard that this can be fixed by replacing the bolt since the NHM-91 has a ground down/stepped  bolt and firing pin.

I was wondering if this is the bolt I should buy to replace my current bolt.

http://stores.polytechparts.com/ak47-polytech-complete-bolt-fully-assembled-chinese-ak-rifle/

My current bolt is free float, while the new Poly-Tech bolt is spring loaded.

There is a review on the sight for this bolt by a person who replaced their shorter free float bolt with this, but it was a MAK-90

I understand that this will need to be head spaced, and I plan on having a gunsmith do that.

I am just wanting to make sure that this bolt is compatible before I buy I buy it, as it is very expensive.

Thanks!

You do not have to specifically use a Chinese bolt. Any bolt, except the newer thin stem bolt will work as long as it is head spaced to the rifle.  GARY

Have you personally done this?

I have read that with Chinese AKs, you cannot just drop in a European bolt. They have to be Chinese.

Yes. One day, just for sh$ts & giggles I stuck a bolt from a milled Bulgy AK in my Mak 90, & squeezed off 5 shots. Didn't even check for head space. Worked fine. GARY

Huh, didn't know you worked for IO.



OP, I hope that you will check headspace with an actual gauge after installing your new bolt. If you can find a Bulgarian, Polish, Hungarian, etc. Type 3 bolt that would be a close design match to your Chinese bolt.

I don't, & I also don't build guns to sell to the public. But I wanted to see if the bulgy bolt would work, & it did, just fine. While I wouldn't have left the bolt in there forever, I felt that for my own "will it work", it did, w/o any problem. If my Chinese bolt had died, & that bolt was going in as a replacement, I'd have had it properly head spaced.  GARY

Yes, I know that you don't work at IO. It was a joke.

Yes, it should be compatible, but you have no way of knowing if it will head-space properly.  If it doesn't, you have an expensive paperweight.

This is my thread on the subject.  I happened to have 2 spare Chinese bolts and one of them head-spaced perfectly.  However, that was pure luck on my part.

http://www.ar15.com/forums/t_4_78/160736_FTF__Light_primer_strike_with_question_of_soft_firing_pin_on_an_NHM_91__Updated_04_03_2016.html