Was out plinking the other day and my rifle started jamming about every fifth shot.  It would eject the empty shell, but the loaded round would be jammed under the bolt face with it's tip just started up the feed ramp.  Does this sound like short stroking?

I was shooting the newer Wolf 62gr ammo and didn't bring any other brand to cross check with (the rifle has always shot Wolf without problems in the past).  My troubleshooting found the gas tube open, the carrier key tight, but the bolt gas ring slots were aligned.  Could it just be a combination of ring alignment and slightly underloaded ammo?

Thanks

Hoppy

One problem with Wolf ammo is the laquer coating.  When the gun gets hot it can make the chamber sticky.  Getting the empty out of the chamber can use up more of the energy available to cycle the gun than normal.  

Rough sticky chambers can cause short stroking.

I would clean the chamber well with a chamber brush.

There are three possibilities...Gas pressure problem, tight chamber, or magazine problem. I have a mag that would pop up another round prematurely and the the carrier would slam into it bending the case. Try a different mag and clean the hell out of your chamber.

It could be that a dirty chamber is causing the problem, especially if you haven't cleaned it for awhile.  Could also be the mags, if they get dirty or the spring start to get soft you can get the same problems.  May want to switch around mags to see if that is the problem.  I severly doubt your problems have anything to do with gas ring alignment.  The whole ring alignment thing is sort of a myth.  I beleive a properly functioning rifle only needs one ring to function, the other two are just there for backup.

Since the problems just started happening I would guess it is a dirty chamber that needs to be cleaned properly with a chamber brush.  My second guess would be a dirty mag or weak mag spring.  If this was during the winter, my third guess would be low gas pressures due to ambient temperatures.

Thanks for all the suggestions.

I forgot to add that I had six mags with me, three SA-80's and three USGI.  The SA-80's were new and the USGI's recently rebuilt and have always functioned flawlessly.  The problem started with one of the new SA-80 mags so I stopped shooting that one and switched to one of the USGI's and had the same jamming problem.

I clean my weapon religiously after every shooting session and lube with CLP.  I clean the chamber with a brush soaked in CLP (or Hoppe's) then chucked in a battery powered drill motor.  I will say that I did not lube before shooting that day and the rifle had been in the safe for a couple of weeks before this trip to the range.

This rifle has had about 700 rounds of Wolf put through it (mostly the older type with the red sealant) without any problems.  This was a first trip with the new Wolf without the sealant.

Since that session I have: recleaned, staggered the gas rings, checked the carrier key screws (tight) and cleaned the grease off the buffer spring (back to basics and CLP only here).  I will probably disassemble, clean and replace the followers on the new SA-80's, just because.

Won't be able to get to the range for a couple of weeks though for a function test, but it's gonna bug the hell out of me until I do.

Thanks again.

Hoppy