As reported at The Gun Zone:
Go to the link provided below to see a stop-action display of the below from exit of the gun to penetration of the as noted ballistic gel
A Federal .45 ACP HST bullet (P45HST2) emerging from, but still in, the 5" barrel of an S&W Model 4506, complete with gas being blown ahead of it. (Average muzzle velocity 900 fps, 414 ft-lbs of energy, and 21,000 psi.) Note the amount of infrared light that's being emitted around the bullet, and the little smoke plume above the ejection port. The action was caught using an invisible infrared trigger beam system (1,000,000th-second response time). Flash duration was 1-2,000,000th-second.
Note also the dramatic projectile deformation and expansion to approximately .90 caliber(!)
in the 6-inch x 6-inch x 2-inch block of calibrated 10% ordnance gelatin. When Federal/ATK blurbs that "HST is engineered for 100% weight retention and impressive expansion," it's not just "press kit hyperbole." The 230-grain HST typically penetrates between 12¾ and 13½ inches in 10% gelatin. Most of the well-designed bullets of today will exhibit mature or near-mature expansion when fired through two-inches of gelatin.
Sale of P45HST2 ammunition is restricted to Law Enforcement agencies at this time.
Photos courtesy of Tom Burczynski.
Source - http://thegunzone.com/45hst.html