Carrier Bounce/Failure to go Into Battery

[Nathan]

I’ve started having an issue with my rifle, here’s the long version (sorry):

 

 A while ago, after years of relatively trouble-free operation, my rifle started failing to lock back on an empty magazine. I replaced my bolt catch because that was the culprit last time it happened, to no avail.  After testing many magazines, and adjusting my gas through the whole spectrum and getting nowhere I tried a new buffer spring, and it fixed my problem. I had been running a JP silent captured spring and figured maybe it had gotten past its service life. When I popped into Rainier Arms they were out of the JP’s, so I went with Shooting Innovations’ recoil reduction system spring, similar idea but with some extra doodads.   The rifle ran like a top for about 500 rounds, then I noticed a light strike or two. I replaced my trigger (Wilson Combat to Elftmann), and started getting many more light strikes! I was about to toss the trigger, but then noticed the light strikes were VERY light.   Testing the rifle last night I figured out when it happens the bolt carrier is short of full battery. I’m not sure because I did not have high-speed video capabilities, but my guess would be it is bouncing.  The bolt and carrier will go all the way forward with the rifle empty as slowly as I can move the charging handle forward, so the spring is exerting force all the way in and it doesn’t seem to be gritty when the lugs engage, but when there is a loaded magazine underneath of course it is a different story.   I hopped on-line and ordered the JP LMOS and a captured spring with several spring options, which leads me to my question I guess:

 

Is a lower power spring to slow the carrier return a better way to avoid this issue, or would a higher power spring to shove the carrier back into battery be better?   Usually I am the type that enjoys testing the different combinations, but I have a match this weekend and will have only enough time to ensure my gas is properly tuned :-/

 

 Thank you very much for any advice! 

Nathan

[adamge]

Definitely outside the bounds of your query, but I would suggest you consider new gas rings as well.  And if you run the JP single spiral ring, try conventional rings.

[Nathan]

2 hours ago, adamge said:

Definitely outside the bounds of your query, but I would suggest you consider new gas rings as well.  And if you run the JP single spiral ring, try conventional rings.

 

Thank you for the suggestion.  I actually swapped most of my rings years ago to the single spiral, I think they were Mcfarlane or something.  The new one from JP should be the spiral type as well, but my current bolt will go into my bag as a back-up (assuming I get it to run) so I’ll swap the rings on it to be sure it’s good-to-go.

[NoKimberDave]

Is it a lightweight BCG? Have you checked the firing pin for peening?

 

 

[Nathan]

5 minutes ago, NoKimberDave said:

Is it a lightweight BCG? Have you checked the firing pin for peening?

 

 

 

It is a Young Mfg Lightweight carrier, from probably 4-5 years ago (meaning it is light, but not as superlight as the current generation of light carriers), and approximately 3,500 rounds of use.  It appears visually to still be in really good condition (I can see the points of contact but it’s barely marred the finish), but I haven’t taken the mic to it or anything.

 

I tried a fresh firing pin, same result.  I found approximately 1-2 out of 10 shots the bolt carrier 1/8” to 1/4” out of battery with both firing pins, so I think I eliminated that from my list of causes.

 

Thank you for the response