Manufacturers design this “short barrel” ammo to balance penetration and expansion at those reduced velocity levels. Here, we’re working with a 7.5-inch barrel rather than a standard 16-inch rifle barrel, so we might see actual velocities from the pistol that are several hundred feet per second slower than the same ammo fired from a full rifle barrel. Performance differs, but you can expect a 30 to 60 foot per second velocity decrease for each inch of barrel length reduction. When a firearm has a shorter than “normal” barrel length, it will launch any given bullet at a lower speed. So, “normal” ammunition is designed to balance penetration and expansion at “normal” velocities. Whether of the supersonic or subsonic variety, 300 Blackout just screams for a silencer, so I used this SilencerCo Specwar 762 suppressor. Lower than expected velocities may not create an expansion effect at all. At higher than expected velocities, a bullet can expand too aggressively and penetrate less. Additionally, both factors are velocity sensitive. Bullets that penetrate deeply generally have slower or reduced expansion. With all else being equal, more aggressive expansion will limit penetration as the bullet encounters more friction and loses velocity quickly. Designing a bullet to perform to very specific penetration and expansion goals is a balancing act. Here’s the thing about “short barrel” ammunition. This year, there are new members of the family, two of which are optimized for short-barrel 300 Blackout rifles and pistols where the 300 Blackout shines. The company also developed a 120-grain supersonic HT cartridge that fired an all-copper expanding bullet. Previously the team at Sig Sauer Ammunition developed a variety of 300 Blackout offerings including 125-grain full metal jacket supersonic and 220-grain full metal jacket subsonic loads. The standard 220-grain load will tumble when it hits an organic target because of its inherent instability, but up until now, a more traditional expanding bullet has been hard to find. Second, while it’s easy to make expanding supersonic ammunition for hunting or defensive use, subsonic loads have been a challenge. First, establishing simple aim points for such widely varying ammunition types through a standard scope requires math and memorizing custom hold-overs. There have been two big problems with 300 Blackout that have inhibited wider adoption, at least in my opinion. I tested out some of the new Sig Sauer 300 Blackout ammo with an Aero Precision 7.5-inch barrel upper receiver mounted on a Springfield Armory SAINT Edge pistol lower. The sound of “thud” comes to mind when the noise of those heavy subsonic bullets hitting the backstop dwarfs the volume of the shot itself. The suppressed supersonic loads are muted, at least for the muzzle blast components of noise, and the subsonic loads are shockingly quiet when fired through a silencer. Adding a suppressor makes the 300 Blackout shine. That’s a lot of performance variance out of the same rifle or pistol. The ability to swap between supersonic and subsonic performance simply by changing magazines the availability of loads ranging from 110-grain rockets to 240-grain bricks is compelling features. I’ve always been a fan of 300 Blackout, mainly because it’s a ballistic geek’s delight. I am also questioning my use of Hollow Points at that distance, thinking the Hollow points in addition to the low speeds at those distance just might be creating condition at the tip of the bullet that may be making it very unstable.Innovative New 300 Blackout Ammunition From Sig Sauer Not being any kind of ballistics expert, I could be all wet, but my thoughts are that the small amount of instability of a Standard/High Velocity slowing down and coming back through the sound barrier is much less then the effects of wind and other effects that may effect a slow traveling bullet's accuracy at those distances. thinking that those shots have a little more to do with learning to read the wind a little better and improving my scope dope/hold over info. I am still using the sub sonic out to 150 yards, not always with great success, but at this point. Since switching, I have yet to fail to earn every point available for those distances. Against the advice of all of the prevailing experts, I switched my 165, 185 & 200 yard shots to the Fiocchi HVCRN 40grn jacketed. I was struggling to get hits and garnish quality scope dope at the longer distances, the 165,185 & 200 yard targets. I Have been using Fiocchi HPSUB 40grn Hollow points to shoot both this competition and Small bore Silhouette. I have been participating in a competition where we shoot from 35 yards to 200 yards, 13 different distances. Click to expand.This may go against what seems to be common knowledge.and I have yet to find the time do any real testing on other ammo.
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