Problem with M3K feeding after two years of error free use

[3gunDenver]

My 3-gun shotgun is the M3K, and for the most part I have had very little issue with the gun over the past 2.5 years. At yesterday's match the shotgun started jamming rounds into the side of the barrel when feeding. I had some Federal, RIO, and Winchester in my bag and could duplicate this with each shell. I did not have any AAs with me at the time, so I am not sure if those shells would make a difference. It was suggested that I knock down the sharp edge of the barrel and round it off a bit to solve this problem. Question is... why did this start happening out of of the blue? and what can I do to fix it?

 

Thank you!

[sbfcolina2]

Have you polished the mag tube. Also the recoil spring could be wearing out

[kurtm]

Suddenly.....after 2.5 years!

The preamble.....do you have a knife set in your kitchen? Does it have a sharpening steel? You know that round steel rod with ridges that is just slightly harder than the knife steel, so when you run the knife over the sharpener.....it gets sharp?

 

Well, your extractor is a hardened part, your extractor recess.....well not quite as hard. By now I know you see where this is going. Occasionally this is an area that will need to be lightly sanded, until you hit the Ballance point.....on my M1 that was around the first 50,000 rounds. Till then, it seemed that I had to do that about every 10-20 thousand. Also watch those shell crimps, even real high end shells can have batches with belled out crimps. But with 3 brands doing it, I'd say it's time to "DULL" your knife.

 

Also a new stronger lifter spring maybe in order as well. It tends to help with this, as well as knocking off the edge.

[3gunDenver]

As it turns out, the lifter was bent causing shells to run into the chamber slightly off center. After fixing this issue I cleaned and deburred the edges and the problem seems to have gone away.

 

Comment on shells is a good one. I have run into some real junk from many major brands. I was glad I had a bag full of ejected end of stage rounds in the truck so I could run as many as I could through gun.