[Chrisvic]

Howdy all. I have been reading the forums for the past few days trying to solve my problem. I picked up a C93 about 2 years ago and have never had any problems with it.

The last time I was at the range was about 2 months ago. Put about 200 round through with no issues. Got home cleaned it up and put it away. 2 weeks ago took it out, it chambers the first round, fires the first round, but the bolt does not blow back. Manually cycled it round fires but no bolt movement. Checked bolt gap and got .008.

Pulled everything apart and checked everything for wear and tear and it all looks good. Any suggestion?

 

[Discogodfather]

.008 is small, should be in the .010-.020" realm. That in and of itself will not cause the problem you described. Try to go through this list:

1) Ammo (short cycling)
2) Bolt lockout claw mechanism (is it stuck or stiff)
3) Test the function of the roillers- does the key push them all the way out, is there any abnormal wear or burrs inside the bolt head, etc. Look at the roller retention plate).

 

[Chrisvic]

Ammo has never been an issue in the past. Love thin rifle because it eats anything I put in it .223 or 5.56, brass or steel.
The bolt lockout has always been very tight. When I first got it I had to use a tool to desperate the bolt from the carrier. 1-2k round later it has now loosened up to where I can turn it by hand.
The bolt and rollers are all operating properly. If I guide the charging handle toward to put the bolt almost in battery, then push the bolt forward to seat it in the chamber I can feel and hear the rollers locking in place.
There if no abnormal wear on the bolt face, or any sign of wear in the chamber. The trunion is nice and tight with no dings or dents from the bolt face slamming into it.
I ordered +4 and +6 rollers to correct to bolt gap. But I agree with you saying that the bolt gap should not be causing the problem
.

 

[killergrapes]

Does it seem harder to operate by hand when you charge the rifle? It almost sounds like you have a physical obstruction somewhere. Check out the receiver rails for grime or dents, and maybe check the bolt carrier where it holds the recoil spring, see if anything got caught in there. Try oiling the **** out of the rollers, too.