I have been seeing a lot of controversy and discussion on the internet and other forums about "Headspace" on CETME Rifles.
Being a Gunsmith , and a CETME owner, I decided to do Research and find out what is correct as far as "Headspacing" this Gun.
When I checked My Rifle , the "Headspace" (Bolt gap) was over the .019 thousandths maximum , by .004 thousandths, But even so, My rifle has always functioned properly. It is my feeling after over 30 years of experience that some battle rifles need to be a bit on the loose side to keep working under dirty or adverse conditions.
I disassembled my rifle , and examined the bolt and carrier , the rollers, The roller bearing surface in the trunnion , and the cocking Mechanism.
I made a discovery in the process , as my bolt closed into battery , the long tube part of the bolt carrier was slamming against the cocking lever , forcing it against the end of the cocking tube. This causes wear and possible metal fatigue,so I decided to remove a small amount of metal from the bolt carrier tube, to give it a few thousandths of clearance. After removing just a small amount of metal from the end , and re-chamfering it both internally and externally, I re-inserted my Bolt and carrier , and discovered that my excess Bolt gap was gone , and now gauged at .011 thousandths , with about a .003 thousandths clearance on the cocking lever when it is in full battery.
I believe this is something that CETME owners should check on their rifles, and correct if necessary. It saved me from buying Oversized rollers and the hassle of changing them out to get a correct tolerance on the bolt / carrier clearance for the Delayed Blowback unocking system to function properly.
The Bolt Spec. Clearance from HK is listed at .004 to .019 and Mine is about in the middle now.
I hope this helps some of you guys with excessive bolt gaps that may be because of Cocking lever interference.
Rich
Being a Gunsmith , and a CETME owner, I decided to do Research and find out what is correct as far as "Headspacing" this Gun.
When I checked My Rifle , the "Headspace" (Bolt gap) was over the .019 thousandths maximum , by .004 thousandths, But even so, My rifle has always functioned properly. It is my feeling after over 30 years of experience that some battle rifles need to be a bit on the loose side to keep working under dirty or adverse conditions.
I disassembled my rifle , and examined the bolt and carrier , the rollers, The roller bearing surface in the trunnion , and the cocking Mechanism.
I made a discovery in the process , as my bolt closed into battery , the long tube part of the bolt carrier was slamming against the cocking lever , forcing it against the end of the cocking tube. This causes wear and possible metal fatigue,so I decided to remove a small amount of metal from the bolt carrier tube, to give it a few thousandths of clearance. After removing just a small amount of metal from the end , and re-chamfering it both internally and externally, I re-inserted my Bolt and carrier , and discovered that my excess Bolt gap was gone , and now gauged at .011 thousandths , with about a .003 thousandths clearance on the cocking lever when it is in full battery.
I believe this is something that CETME owners should check on their rifles, and correct if necessary. It saved me from buying Oversized rollers and the hassle of changing them out to get a correct tolerance on the bolt / carrier clearance for the Delayed Blowback unocking system to function properly.
The Bolt Spec. Clearance from HK is listed at .004 to .019 and Mine is about in the middle now.
I hope this helps some of you guys with excessive bolt gaps that may be because of Cocking lever interference.
Rich
