[9x19]

Single extractor models are notorius for this.! I would opt to replace the bolt for a dual extractor.. FWIW,You can also try a titanium extractor which will help some but may or may not be to your satisfaction, it will still likely jam after 10-15 rnds..

Interesting... I have two early single extractor models and they both run fine... and both have their factory extractors.

Of course I am using factory barrels (one .17 HMR, one .22 WMR) so their chambers are likely not as tight as on the after-market barrels.