competition master bolt locking back

[AR15]

Hello! I have a Competition Master with and EZ-Loader that locks back when there are still shells in the tube. It will drop a shell on the carrier but the bolt will lock back anyway. Could this be my tube spring being weak? Is there a good place to get new ones or extra power springs?

[ERIC]

That sounds like a weak mag tube spring. It is not throwing it back hard enough to activate the lever to close the bolt. ISMI and Wolff makes good springs. Try Brownells.

[Fullauto_Shooter]

Hello! I have a Competition Master with and EZ-Loader that locks back when there are still shells in the tube. It will drop a shell on the carrier but the bolt will lock back anyway. Could this be my tube spring being weak? Is there a good place to get new ones or extra power springs?

I was having an almost identical issue. I called Nordic Components and ordered their replacement spring (it was like 44" long); cut it so it was 15" longer than the total length of the tube, and installed it. Took the gun to the range yesterday and tried my best to choke it by running several 9 round bursts through it (.16 to .18 splits - as fast as I can shoot a shotgun) - function was perfect through two boxes of shells. Looks like the new mag tube spring fixed the problem.

Doug

[ShooterSteve]

Hey Full Auto, Were your splits done with a timer? I'm assuming they were. I'm asking because it will help answer my question on another thread about cycle time of the different shotguns out there. That is a pretty fast cycle time from shot to shot, and helps tell us how fast we really have to go to out run our shottys, regardless of brand.

[Fullauto_Shooter]

Hey Full Auto, Were your splits done with a timer? I'm assuming they were. I'm asking because it will help answer my question on another thread about cycle time of the different shotguns out there. That is a pretty fast cycle time from shot to shot, and helps tell us how fast we really have to go to out run our shottys, regardless of brand.

Steve,

Yep - used a timer to get the splits. Most were .17 to .18 with a few in the .16 range. I've heard that some guns will choke at .13 or so but that's never been an issue with me because I can't shoot that fast.

Doug

[StealthyBlagga]

I agree with the advice above that it is probably a weak magazine spring - try installing a new Wolff Extra Power spring and see if it solves the problem. Run it full-length first, then you can play with shortening it if it solves the problem.

If you still have the problem with a new mag spring, then look at the "springy finger" on the carrier where it engages the carrier release. There has to be a "Goldilocks" amount of engagement - not too much or the carrier release may not get pushed past the springy finger by the shotshell, and not so little that the springy finger slips off the carrier release. The photos below show what I mean:

Edited December 31, 2009 by StealthyBlagga

[DaG]

Hello! I have a Competition Master with and EZ-Loader that locks back when there are still shells in the tube. It will drop a shell on the carrier but the bolt will lock back anyway. Could this be my tube spring being weak? Is there a good place to get new ones or extra power springs?

I had the exact same problem with my CM and also thought it was the tube spring. Turns out the carrier dog had a small chip missing from it and it turned into a single shot also. The bolt was hanging up on the chipped out area (I think). Anyway replaced the carrier group and all is well.

DaG