O.k.  I have an Oly PCR 5.  I've had it for about 7 or 8 months with about 2k rounds thru it.  The other day I was shooting Winchester 5.56 thru it and it would try to double feed evert 3 or 4 rounds.  I saw double feed as in not fully ejecting the spent round and trying to feed the new round.  So, I shot it again after cleaning it well.  I fed several different types of ammo with different mags. Ammo:  Winchester 5.56 55 grn
      Winchester .223 55 grn (wal-mart)
      Wolf .223 62 grn
Everything fed well, even the Wolf, without any problems, except the Winchester 5.56.  Again, every 3-4 rounds it would double feed.  Any ideas?

As Olympic produces ARs chambered in both 5.56 and 223, perhaps your PCR 5 is chambered for SAMMI 223 and your running into the 5.56 in a 223 chamber issue.

As 5.56 is minutely larger dimensionally, perhaps it's sticking enough, due to the "tight" chamber to cause your problem.

Mike

Your extractor is letting go.  Need to install a new heavy duty spring.

I read recently,  where a guy went to one of these home building supply stores and  purchased small "O"  rubber ring, and placed it under his extractor spring,and it worked great. So he did all his ARs that way.
I  recently purchased etra extractors and springs and inserts, plus a bunch of other parts for  my AR, just in case I  run into such problems down the road. [:)]

TG

Hey, thanks for the quick responses.  The PCR 5 barrel I have is stamped 5.56.  I'll have to look into replacing the extractor spring.  

The 5.56 being a little hotter than the .223 is most likely delivering a more violent gas pulse than the .223. This is causeing the extractor to lose its "grip" on the spent cartridge as the bolt is moving rearward. An extra power extractor spring will fix this about 90% of the time.

You may want to check your gas rings as well. Just as a maintainance CYA on a rifle with 2K+. Worn gas rings can cause short stroking as well but it is usually the ejector spring.

Oly sells a HTU (HiTechUpgrade Kit) that has everything in you need. Its on their website under AR/PCR accessories. I bought the kit myself, it is a good deal.

[url]www.olyarms.com[/url]