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Thread: Cetme sanity check

  1. #1
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    Cetme sanity check

    Hi all, just picked up my first cetme the other day and going through it all checking things over before I fire it. It's a cast SS century rifle. SN C06xxx marked Georgia, VT. My bolt gap is .005 and the bolt head appears unmolested at 1.832". Pulled the rollers and found them to be 7.94mm so that should mean it was built with -6 rollers. From what I've read some -2 rollers should get me close to the .016+/- sweet spot, correct? No evidence of any impacts of the carrier and cocking tube, weapon charges with about the right amount of force from what i'd expect and what I remember of a G3 I had years ago. LP and everything appears to have minimal wear if any. Should be low round count which matches story that came with it. All sound about right?

    Looking forward to going through it and getting some rounds downrange. I'll get some pics up once it's all put back together.

    thanks for any insight and if anyone can verify what I've read is accurate and reasonable.

  2. #2
    holescreek's Avatar
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    Good catch on the rollers, kind of makes you wonder why they had -6's in place to begin with. moving up to -2 rollers should put you around .014/.015". Check your LP shoulder and bolt openings for dimples (roller impacts) while you're apart.

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    Thank you, I looked it over and appears to be good. With the gap that small to begin with and all the horror stories, I was prepared for a disaster so when I found the bolt hadn't been ground on and that the rollers were undersized I was very relieved.

    Thanks again, I'll follow up when the rollers are in.

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    Welcome to the forum and show us some pics of that Cetme when you get a chance.
    14EH AIT Instructor-PATRIOT Fire Control Enhanced Operator/Maintainer

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    Well, I'm a bit confused now. Got the -2 rollers in and bolt gap is.... .009 Not nearly the change I was expecting but at least in the right direction. I verified again old rollers were 7.94 and new ones are 7.98. Just seems odd for the gap to not move as much as anticipated. What else should i check or should i just go shoot it and see how it runs at the .009?

    To add, If I'm doing the cocking lever gap test correctly it's .007 and i question that because the support moved but so did the carrier, it wasn't slack it was just like acting against a spring. Removed the support and remeasured bolt gap and it's 0 now so definitely an issue. Found a post elsewhere that mentioned taking material off the support or the carrier but it's strange me to remove material to move the carrier forward to somehow get more gap. Starting to go cross eyed...

    A little more reading and it seems I need to get my bolt gap set proper without the charging lever/support installed as that's my true bolt gap. THEN i can worry about setting the gap at the charging handle at the +.015 figure. So bigger rollers again or new LP potentially or what?

    thx!
    Last edited by damndirtyape; 03-08-2019 at 03:48 PM.

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    holescreek's Avatar
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    Removed the support and remeasured bolt gap and it's 0 now so definitely an issue.
    If you removed the cocking handle support and your bolt gap dropped to zero you may have bigger problems. You need a good gap (.004~.020") without resting on the carrier support.

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    Anything I can measure to clue me in on where my issue lies? Maybe some way to eliminate a barrel/trunnion issue vs a locking piece / roller issue? LPs and rollers are cheap enough to swap blindly but I don't want to go down that road if the barrel needs re-installed or something drastic. I've read about the roller window being worn causing an issue but didn't see any specs on that to verify my bolt is good beyond overall length.

  8. #8
    holescreek's Avatar
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    Here's the deal in a nutshell. You need to have a normal gap (.004" min) without the carrier resting on the cocking handle support. Right now you have zero with -2's. There is a chance that you can still grow the gap by adding larger rollers, the question is -where to start?

    I suggest that you take a good clear picture of both the bolt face and the face of the barrel (taken from the rear of the receiver) before you spend money on rollers. Also get a shot of the LP shoulder angle and the front of the bolt head window. The reason for all the pics is that it could be a combination of wear and not just a barrel issue.

    Here's a pic of a demilled trunnion. You can see where the bolt head is hitting on the rim around the inside of the trunnion (as well as having smashed the extractor into the barrel face).

    20180316_120213.jpg

    Here's a really worn LP:

    worn stuff 005.jpg

    A worn bolt head (roller dimple in window):

    worn stuff 008.jpg

  9. #9
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    I've definitely got the smash marks.

    UIqSZLL.jpg

    Bolt face

    AWyCArr.jpg

    Window

    PRTbHkS.jpg
    ZBSwayh.jpg

    Here's the LP

    l3URHWn.jpg

    Looks a lot crustier in pictures. Looks like a little dimple on the window is there and I can see where the locking lever if wearing on the bolt.

    I really appreciate the help. A little sad this is turning into a project but at least I enjoy tinkering. I just hate the wait on parts.

  10. #10
    holescreek's Avatar
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    Well that tells me what's wrong, absolutely everything.

    Your barrel has been pushed forward in the trunnion and the bolt face is striking the trunnion rim. This means your headspace is also bad by a minimum of .005", probably a little more.

    The correct way to fix the problems would be to replace the bolt head and locking piece (I'm assuming the LP is bad even though there is no picture of the shoulder), reassemble it with the -2 rollers, and then repress the barrel to provide the correct bolt gap and then oversize the barrel pin. Once completed, I'd bet your C-tube gap will have increased to it's proper size.

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