I purchased 100rds of Cabela's Herters 115gr Total Nylon Jacket (TNJ) ammo. I put 50 rounds through my G17 Gen4. My G17 Gen4 has the latest RSA. The distance to target was 21ft. At this distance, I can consistently place shots within a 2" bulls eye. The first 10 TNJ rounds hit slightly below the 2" bulls eye. I put out a fresh target, and slow fired another 10 rounds. Again, the shots hit slightly below the bulls eye. I switched to Federal Champion 115gr FMJ's, and repeated the procedure above. Faster pace fire or slow fire, I was able to hit the bullseye. I then loaded a mag with 2rds of TNJ followed by 2rds of FMJ. I put out a fresh target. I took my time, real slow fire, making sure I held the same sight picture, grip, trigger press. Again, the TNJ's hit slightly low & the FMJ's hit the bullseye. I'm not sure if it's the shooter (me), or the interaction between the TNJ & the Glock polygonal rifled barrel. Next weekend, I'll shoot the remaining 50rds of TNJ through my 92fs' traditional land & groove rifled barrel.