bolt gap ? +4 roller didn't help

[cwhitmeyer]

I'm no expert but I know a a little about HK clones, so help me out. My C-93 came with a bolt gap of 0.05 so I figured #$%! but no problem install +4 rollers and I'm GtG. Well installed the new rollers, cleaned everything and what do you know - gap is 0.07 WTF. Locking piece doesn't look worn, what am I missing?

[csbrit007]

I would suggest contacting the manufacturer to have the weapon sent back for repair or replacement under warranty rather than try to figure it out on your own.

The warranty is there for that purpose and even though it is a PITA to send it off your better off doing it this way to retain that warranty for any future service IMHO.

That being said, if you are adament about trying to solve the issue on your own I would start by looking at the bolt and locking piece for excessive wear in the areas where the rollers ride.

Those two pieces are cheaper to test/replace than the worst case scenario which could be a poorly pinned barrel or a worn out trunnion.

[Hk33]

are you sure you Have +4 rollers..just checking

[gw11]

Did you check the old rollers for their size before the =4's?

standard- 8mm or .31496"
+2 - 8.02mm or .31575"
+4 - 8.04mm or .31654"

And did your Cocking Handle Support contact your Carrier, giving a false Bolt Gap?
There should be a space between the CH Support and the Carrier approx .015" -.020" max so this will not occur. And to help the Handle to release the Bolt correctly.

gw11

[csbrit007]

Here is a good example of an excessively worn bolt. Even +4 rollers couldn't get the gap in check on this 66 date coded G3 bolt requiring replacement.

[cwhitmeyer]

Did you check the old rollers for their size before the =4's?

standard- 8mm or .31496"
+2 - 8.02mm or .31575"
+4 - 8.04mm or .31654"

And did your Cocking Handle Support contact your Carrier, giving a false Bolt Gap?
There should be a space between the CH Support and the Carrier approx .015" -.020" max so this will not occur. And to help the Handle to release the Bolt correctly.

gw11

will double check rollers, I'm thinking there might be an issue with the CH / carrier interface - there is no gap (but the handle is not binding so there is some separation) and it looks like the carrier side has been ground down a bit. This is a Century C-93 built by ?, so I think the warranty advise is where I'm headed.

[gw11]

cwhitmeyer

Normally your Cocking Handle should lift approx 1/4" [freely] then the cam action should be felt.
If yours is down with no free play [your carrier is contacting the Support] I would agree as above and if at all possible, send it back.

If your carrier has been ground with a short Bolt Gap, Century may have set the barrel incorrectly or pinned it with too little [press fit] at the Barrel pin. This may allow the barrel to continue to shift as you fire it. Unfortunately Century leaves many folks with unlimited imaginations!

Good luck!
gw11

[cwhitmeyer]

Original rollers look like their maybe +2 (.3158") new are check out as +4's. recheck the gap with the original rollers and get .004" = go, .005" = no go. bolt doesn't look worn at the roller interface like seen in the above picture.

[gw11]

cwhitmeyer

The worn Bolt in the pic does have meaning when installing it to a new build that has already been pinned. But when the worn bolt is set into a new build and then pinned/ with the worn bolt. It has less meaning, for the barrel is placed according to that bolts fit!

Meaning if you had a gun built with a perfect Bolt and you now install a worn bolt then there would be a loss in Bolt Gap.




gw11

[cwhitmeyer]

Also cocking handle has free-lift of 1/4" prior to cam action