Non fluff and buff P11
I have not have trouble with any RN bullets in any weight. RN target loads usually end up around a COL of 1.150. I usually stick with Montana Gold, Hornady and Zero bullets.
No issues feeding any RN or HP 100gn or less 0.355" bullets - 380 weights which always end up with short COL.
I could not get Hornady XTP #35571, 124gn bullets to feed. Stopped with 1.065 COL. Possible to squeeze COL more, but i wasn't interested.
Nosler #44848 115gn tmj hp's at 1.056 COL feed all day without any issues.
Hornady #35580, 147gn XTP @ 1.085 COL feed without any issues
Remmington 124gn HP, made by Black Hills feed without any issues at 1.110 - 1.120 COL
I am not going to post load data. Typically i load with Hodgdon or N320 and load data for these powders can be found easily. Midway published a dedicated 9mm load map manual which is still an awesome resource if you can find a copy. It has been out of print for quite a while, but worth looking for. Digital copies can be had with some google searches.
If you have a lot of keyholes that cannot be resolved with a change in crimp or verified with BUG P11, send your barrel back to Keltec. My 8/2011 build p11 flipped bullets out the end.