Re: Input needed - Barrier round for SR-25
http://www.m4carbine.net/showthread.php?t=19878
This is an excerpt from that link:
Glass barriers are one of the most difficult challenges for LE snipers. OTM bullets like the SMK’s generally exhibit unfavorable fragmentation and trajectory deviation when fired through glass intermediate barriers, resulting in degradation of terminal wounding effects. Despite gunstore commando lore to the contrary, FMJ bullet terminal performance is extremely erratic against glass. Bonded JSP/PT bullets and true AP bullets like M993 are often able to defeat glass intermediate barriers while retaining their mass, although they exhibit very deep penetration in soft tissue and can be counted upon to exit the suspect and pose a downrange hazard. In addition, they are not always as accurate as other bullet designs. PT bullets, like the Hornady AMAX and Nosler Ballistic Tip, offer better performance against glass than OTM bullets like the SMK, but are not the equal of bonded JSP/PT bullets or AP bullets. The Federal Tactical load using the Trophy Bonded Bear Claw JSP offers superb terminal performance in both unobstructed shots, as well as those through intermediate; it is the most tried and tested barrier blind load, however, accuracy is typically in the 1.5-3 MOA range. Newer barrier blind loads like the BH loaded 180 gr Nosler Accubond bonded PT load offer sub-MOA accuracy along with outstanding terminal performance in both soft tissue and glass. Because of their deep penetration characteristics, plan that barrier blind loads will likely exit the target, so be aware of the backstop. Currently the best .308 glass barrier loads are the Federal Tactical using the 165 gr Trophy Bonded Bear Claw JSP, Black Hills loaded 180 gr Nosler Accubond PT, Nosler 150 & 165 gr Partition, Remington loaded Swift Scirocco II 150 & 165 gr bonded PT, Swift A-Frame 165 gr JSP, Remington Core Lokt Ultra Bonded 150 & 180 gr JSP, Hornady Interbond PT, as well as Barnes Triple Shock & MRX; all create similar deep penetrating wound profiles. Be aware that while the Barnes all copper TSX bullets are great projectiles and offer good penetration through barriers, when first hitting a laminated automobile windshield intermediate barrier, the TSX bullets exhibit less expansion than other “barrier blind” loads, as the Barnes jacket either collapses at the nose, the jacket "petals" fold back against the core, or the "petals" are torn off. This phenomena has been documented by the FBI BRF, as well as being noted in our testing.
