Hi! Fairly long time KT owner, but just registered recently. Sadly it's to report a puzzling series of malfunctions and hopefully get some advice on what to do with them.
I had taken my SU-16B out to the range yesterday with the intent of putting it through its paces for a reliability check. Ironically enough it decided to fail massively. My written records from the range note:
1st 10 round magazine loaded, fired, extracted without incident.
2d 10 round magazine, first round failed to fire when chambered, no sign of a primer strike. When rechambered a second time, round fired. No further incidents.
3d 10 round magazine, same incident as the 2d magazine. Brass shavings observed, though recovered casings did not show signs of mangling. No further incidents.
4th 10 round magazine, same incident as the 2d magazine. First round then failed to eject. Fifth round failed to eject. Sixth round failed to eject.
At this point the bolt carrier was held back by the bolt stop. The bolt stop seemed to be stuck and would not let the bolt carrier ride forward. Naturally testing had to stop after less than 40 rounds fired. Very sad.
Some further notes about the rifle's condition:
Had been cleaned fairly well before heading out to the range.
Ammunition used was Federal XM193.
Magazines used were Magpul PMags limited to 10 rounds (poor Californian).
Bushnell red dot mounted to top rail.
Kel Tec compact foreend installed.
Red Lion trigger installed.
DPMS chromed extractor installed.
Bill Springfield trigger job.
Older SU-16B model, without chromed barrel or spec rails.
I would have tried to switch out magazines except that the rifle became inoperable after a mere 35-ish rounds. It's also possible that the DPMS extractor might have something to do with the FTEs, though it hasn't happened in the past and wouldn't really account for all the other things gone wrong. Past performance of the SU-16B over roughly 500 rounds and in its current configuration (minus the DPMS extractor) has been stellar and flawless with impressive accuracy.
Any ideas on what I should do? Normally if there was just a single problem I'd have no issue troubleshooting it (like changing back to the Kel Tec extractor) but in this case there just seems to be a variety of issues cropping up, seemingly unrelated.
If I do have to return the rifle to Kel Tec for work, would it matter that I had done a few modifications to the rifle? I know that in the manual it states that Kel Tec won't cover unauthorized modifications, but in these forums it seems like most people do at least something to their rifle, and Kel Tec did sell me the foreend.
Thanks for your time!