Cetme Rifle Questions

[Soundguy]

This last post brought up an idea. On 2 different arms I've had a hard to unlock bolt.. on both of them I noticed burs on the ejector. One was on a broomhandle mauser. Removing the ejector arm and hitting it in a few spots with a set of needle files made it fit nicely, and also eject perfectly 98% of the time vs about 50%! The other gun was a M95 manlicher carbine in the more rare 8x50R chambering.. straight pull bolt.. it's extractor actually broke off when it was being cycled.. i had to get a parts gun and have the extractor fitted to my shooter..

soundguy

 

[rtimgray]

After doing some more checking into it, and spending a lot of time with a flashlight, it appears that they rollers on the locking piece are where the difficulty stems from. I've got the charging handle working back and forth freely - it's just a matter of where the rollers lock into their grooves, they will not unlock without a jerk. I am going to investigate if there is any different spring for this (that is the part that the seller initially changed). Maybe there is an intermediate that will work that won't be so hard to charge the weapon. I may also need to polish the chamber that the rollers lock into.

Thanks for the help so far.

 

[Z-Michigan]

Some degree of jerkiness/stickiness is normal and inherent in the design. I assume you've decided there is too much. You might consider measuring the rollers' size and looking to see how close they are to original spec (sorry, I don't have that info available) and determining if replacement rollers of either original size or larger size (which is a common practice to compensate for wear) is appropriate. I know you mentioned an issue with web filters, but try to get on a CETME board if you can. Some parts are available from Welcome to PTR 91 Inc. Home to the PTR-91 Series of Rifles.

I don't think polishing the rollers' recess is appropriate, but making it clean certainly is. The design is inherently pretty dirty as a blowback (albeit delayed blowback) mechanism. I was a bit disappointed, it's no cleaner than an AR!

 

[rtimgray]

So far I have just cleaned it - I haven't tried to polish the area that the rollers lock into. I've had it apart a dozen times, but I have to admit I have not really examined the rollers themselves - I'll have a look at that.

I understand that the stickiness may be normal, but I have to bump the stock on the ground to break the action free (or give it a hard bump with my hand - and that hurts). However, as mentioned once it's cocked it'll blow through 20 rounds with no problem (now if only I could hit something - and the accuracy problem is between the trigger and ground).

Thanks for your help. I've found a couple of forums that I've started looking for information in. I will check out the link that you have posted.

Thanks (again) for your advice and help.

 

[Z-Michigan]

OK, didn't realize there had been no change in having to bump the stock to unlock. That's not right. Good luck with that.

I think the rifle's inherent accuracy is decent (probably 2-3 MOA) but I find it hard to shoot accurately too. Too much weight out front is part of it. The length of pull on a PTR-91 is nice and long, I think about right for me (6' tall) but maybe too long. I also don't like the iron sights and am considering putting some kind of scope or red dot on it. I can shoot well with other iron sights, particularly the AR/M14 variety, but not the HK style with those tiny tiny little apertures. I think the CETME may have slightly different iron sights than my PTR.

You're very welcome, I enjoy this stuff!

 

[Western]

I had something similar occur with a tactical weapon I had.
Cycled fine with or without ammo as long as it wasn't fired. When fired it would not discharged the empty case fully. At first I thought the gas tube was dirty or faulty, it wasn't. Long story short, Took to gunsmith found that the seat and or the chamber was slightly over sized, like a couple of microns, so when the weapon was fired the shell case basically was able to expand and wedge itself enough to cause the extraction problem, salution for me was a new BAR barrel.

 

[Z-Michigan]

Ummm - that's 180 degrees opposite the problem that Rtimgray describes.

Maybe if you combined your BAR and his CETME you'd get a reliable and easy to operate rifle?

I'll file it away for future reference with gas-operated guns though.

 

[Soundguy]

I deffinately wouldn't keep live ammo anywhere near a gun that was that hard to charge... it is really begging for a gunsmith to fix it..

soundguy

 

[Western]

As a delayed blowback weapon, it is sensitive to the type of cartridge case. I think they prefer harder cases, and supposedly work fine with steel-cased Wolf. However, most US commercial ammo has fairly soft brass and that can potentially cause extraction problems because it molds better to the chamber and therefore sticks. (This is unique to the delayed blowback mechanism, and the fact that it doesn't happen in your bolt-action or gas operated semiauto is irrelevant.) .


I was refering to this actually.
Thanks

 

[Erik_in_Hoyt]

I also don't like the iron sights and am considering putting some kind of scope or red dot on it. I can shoot well with other iron sights, particularly the AR/M14 variety, but not the HK style with those tiny tiny little apertures. I think the CETME may have slightly different iron sights than my PTR.

You're very welcome, I enjoy this stuff!

check CDNN for HK style claw mounts - they're advertising the mount for $140 in their latest catalog. (fits Cetme as well)
they also sell an acessory rail adapter so you can use standard mounts instead of HK dedicated stuff.

also - there's an HK ejector buffer you can add to the port that will help with the case denting issue.

as to ammo - gunsmith buddy who used to have a CETME told me winchester white box feeds good in them. The other thought I had for the feeding problems was worn out magazine. Sorry I don't have any suggestions for the charging handle issue.