I have a moded mini with a bedded Shilen match barrel and a Boyd's stock. It shoots excellent but about once every 10 rounds it will not grab the casing and the bolt will go back, leaving the empty casing in the chamber. It does this with commercial brass .223, and when I tried to shoot steel case one got stuck in there so bad I had to push it out with a cleaning rod. The rifle shoots brass into the next county so I know it's not short stroking. The problem is the rifle was moded as such when I got it and I have no idea if it was having these problems before. The extractor is clean as is the chamber. Anyone got any ideas?

Would you consider using a wire brush to clean up the chamber.
A purpose manufactured long thin wire brush to clean gunk out of the chamber.
I had the same problem with an ar15, found this brush which also had a wider secondary brush to clean the locking lug recess.
Chocked that brush up in the cordless drill, sprayed kroil in there while twisting at slow speed for 20 seconds while squeezing the upper between my legs.

Was the extractor indeed ripping out of the the case rim when casing got stuck?

Well I agree that the first step is to give the chamber a good cleaning but seeing as it is a great brand aftermarket barrel I would go a bit more gentle . Soak the heck out of it to soften any crud then hand brush with a chamber brush (which should be bigger than a bore brush)

Also clean the bolt to insure the extractor is moving correctly.

Extractor , plunger and spring are available from brownells (ruger factory parts) for about $15

Second step after cleaning would be to inspect the extractor with possible replacement in mind . The extractor might have a bit of wear or chipping that is giving it a less than great grip on the brass .

Not sure how a barrel is fitted on a mini but on many guns it is threaded in and then the chamber needs final reaming to bring it to correct size and shape. If this is the case with a mini that work might have been less than perfect leaving a rough or out of spec chamber .

I am thinking Ruger will not want to do anything to help you except replace with their own barrel .

I guess what I would do after the cleaning and extractor swap is to find a gunsmith with a borescope and have him look at the chamber and possibly do a chamber casting to check dimensions out


Brownells has the ruger factory extractor,plunger and spring for about $15

A bore snake is your friend.  My guess is you have a really tight chamber and any carbon build up causes the brass to stick.  My guess is with time and use, the problem will go away.  kwg

Cool thanks for the responses

Is it possibly overgassed, causing violent extraction(you say it ejects into the next county)?
I think they make different gas port bushings that would allow you to dial down the gas,
giving your fired case a chance to relax or contract, so that it will release from the chamber.

Is it tearing the rim off the case when it leaves a case in the chamber?
Check the chamber for cleanliness and smoothness, and extractor for a good claw edge, as mentioned above.

A chamber brush is a great 1st step and are inexpensive.






 

It doesn't tear the rims off it leaves the entire case in the chamber. I gave the chamber a good scrubbing. Going to take it out and see if that worked. If not I'll probably put a new extractor on there and see how that goes.