Hello all, I've purchased some 165gr Federal HST's (P40HST3) and 180gr Winchester Ranger T's (RA40T) for carry in my Glock 23. I didn't choose the different weights for any reason other than, it is what was available to me at the time. As always, I like to test at least 100 rounds of any SD ammo I plan to carry, for functionality and reliability. This time I decided to do a little backyard ballistics testing just for fun, using four one gallon milk jugs per test, filled with water and paper shreddings from a paper shredder. Each row of jugs was covered with two layers of denim and two layers of an old rag (which I think due to the type of material and thread count, proved to be a tougher barrier than just a normal cotton T or similar fabrics.) First up was the 165gr HST Recoil for this round in my opinion, was just slightly stouter than your average 180gr fmj target round. However the impact on the Jugs from 10 feet away, was quite impressive (lets just say I was covered in wet paper shreddings.) Being a 165gr round, I didn't expect it to penetrate past the 3rd Jug, but it actually made it about 2 inches into the 4th jug, making an approximate penetration depth of 20 inches. After recovering the bullet, it was somewhat apparent why it penetrated as far as it did. I'm not an HST expert by any means, but when comparing to other expanded HST's i've recovered, it appears that this one didn't expand to its full potential, thus allowing it to penetrate a bit further, than one could normally expect, just my opinion. It did however retain all of its weight which is good.