What Could Cause Brass to get “stuck” on the bolt/extractor when manually cycling the action on 6 arc gas gun?

[WeR0206]

The below happened when I was at the range today and manually cycled the action to make sure there wasn’t a sticky bolt close/open. It closed and opened fine but when the cartridge got to the point where it should have shot out of the upper it didn’t and instead it just clung to the extractor claw. I had to pull it off by hand. It didn’t happen for every round in the mag but it did happen maybe 2-3 times out of 10. I checked and the ejector plunger moves freely/isn’t sticky. Mag being used was a duramag 6.5 gendel 10 round.

This is a rubber city armory bolt with sprinco 5 coil extractor spring (with insert but no o-ring) and sprinco ejector spring with only 100 rounds on them.

 

[Edsel]

Issues with the ejector and its spring, perhaps?

Resistance should be significant even when using the cartridge as a lever.

 

[WeR0206]

Issues with the ejector and spring, perhaps?

That was my first thought but the sprinco springs in the bolt are still practically new with only 100 rounds on them. I can swap the springs out pretty quickly or I actually have a spare bolt I can try to see if that narrows things down.

 

[bfoosh006]

Also...check the claw of the extractor... it wight be holding onto the case rim.

 

[WeR0206]

Also...check the claw of the extractor... it wight be holding onto the case rim.

View attachment 8721315

The claw definitely seems to be holding onto the case rim. I can see two parallel claw marks on the heads of a lot of brass. I will switch to a weaker extractor spring I guess?

Pics of extractor:

 

[45-90]

Probably the extractor...just switch out with another brand of bolt that works from your 6.5 Grendel or from another 6mm ARC, or any type 2 bolt or complete bolt carrier "that's working" in your collection or from a range friends gun...probably work flawlessly in yours too.
Throw your current bolt in an emergency parts drawer tagged to be fixed later... or not.
Bolts are fairly cheap and an expendable part, no need for an expensive one.
They all come from the same few manufacturers.

 

[padom]

My Rubber City 6 ARC BCG works excellent without issue. Did you swap springs on it when you got it?

 

[WeR0206]

My Rubber City 6 ARC BCG works excellent without issue. Did you swap springs on it when you got it?

Yes i swapped the stock extractor spring/donut out for a sprinco 5 coil with insert and no donut (I think I also swapped the ejector spring out to sprinco as well). This is something I usually do for all new bolts if im unsure on spring quality.

Swapping the stock spring out may have messed up a very specific spring tension that was calibrated for their particular extractor.

I still have the original RCA bolt springs I think so I can put them back. Or I do have a spare lantac 6 arc bolt with all its original springs that I can use to see if the issue goes away and if so that would indicate an issue with RCA bolt/sprinco 5 coil.

 

[flogxal]

How is the extractor plunger? Smooth radius?

 

[WeR0206]

How is the extractor plunger? Smooth radius?

Yeah it’s smooth, there’s no binding when I plunge it up and down. Spring is strong

 

[flogxal]

Sometimes they can dig into the case head and some folks will bevel the top radius. Have read reports of folks finding that step helpful, but never done it myself. This would be different from its cylindrical trueness, and more about its top edge that contacts the case head during extraction.

 

[WeR0206]

Sometimes they can dig into the case head and some folks will bevel the top radius. Have read reports of folks finding that step helpful, but never done it myself. This would be different from its cylindrical trueness, and more about its top edge that contacts the case head during extraction.

Yeah good point. The top edge of the ejector does have a bevel. After looking at the brass some more and reading comments in the thread im pretty sure the extractor is the culprit but Ill be doing a few things to narrow that down (put original extractor spring back in, use completely different bolt, etc.)

 

[Cascade Hemi]

Break the extractor claw corners. The only brand Grendel extractor I've ever seen that didn't need dressing is the Monster bolt.

 

[WeR0206]

Break the extractor claw corners. The only brand Grendel extractor I've ever seen that didn't need dressing is the Monster bolt.

I think this is what’s causing my issue. Thanks for the tip, just got some diamond needle files to do some work on the claw corners etc

https://a.co/d/dXfsB31