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Discussion Starter #1
I am having an issue with my CETME's firing pin spring. The one I got with the rifle seems to be to light and doesn't hold the firing pin back creating a slam fire situation. I got a new spring and this spring is much heavier. When you shoot the rifle the bolt stays back. Got the replacement spring from HK Parts. Replacement Spring is a lot heavier than the one that was in the gun. Put the old spring back in and the gun cycles but doesn't hold the firing pin back and then creates the slam fire. The new spring will not let the bolt cock and bolt stays back. Bolt hangs back and if you clear the weapon and hit the butstock on the ground. The bolt releases and cycles forward. Do they make different weight springs? Any thoughts would be appreciated.
 

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Sorry I can't help you with an answer but if you don't get one here, the folks over at Militaryfirearm.com are good with CETME's. Welcome to the boards!
 

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I stepped out to the shop and found the weakest Cetme FP spring I could find. It was in a Cetme Model B (light weight) carrier. Then I grabbed an HK FP and spring and played around for a few minutes. Here is the difference between them for those that haven't seen a cetme model B FP spring:



The FP spring is held captive between the carrier and the rear of the locking piece. It does nothing by itself to affect function of the carrier. I interchanged the parts just to satisfy my own curiosity and the difference in the force needed to move the FP is about 3-fold. Is the spring the only part you are swapping out?
 

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Discussion Starter #4
The spring is the only part i switched out. I even put the old spring back in after the bcg malfunctioned. With the old spring the bcg worked just fine. The new spring is a few turns longer can i just clip it, or would it be a better idea to locate a lighter spring, do you know of a place where i could find a lighter weight spring? Thanks
 

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The usual advice is to replace both the Cetme FP and spring with HK91 parts. The FP spring in not the source of your problems. I posted on another forum where your situation was described by you or a friend of yours that the problem can be caused by several different things, but the FP spring isn't one of them. The usual cause for this problem in a Cetme is the shelf inside the trigger pack getting bent open slightly allowing the ejector to wobble enough to miss it's slot in the bolt head and jam the bolt open. If that was happening you would be able to see it looking through the ejection port.

The only scenario that I can dream up where the spring would "cause" a problem would be pretty far fetched. That would be that the lug slot inside your carrier (that the locking piece rotates into) is so horribly worn that the extra pressure from the HK spring forces the locking piece to sit crooked (causing the bolt head to sit crooked - out of line with the carrier) and drag on one of the rails. If that was the case you would most likely be ble to see it visably outside of the rifle. If you want to test the theory, go over the bolt head with a black magic marker and put it back together in the receiver with the light Cetme spring and the heavy HK spring. See where the rub patterns are after it hangs up with the HK spring.
 
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