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Posted: 10/21/2006 12:09:20 PM EDT
| I have some subsonic loads I want to try out and the gun is zeroed for 100 yards with some super sonic loads. Anyone have any idea how much drop difference there will be between the subsonic and the super sonics? |
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Using ballistic calculator software, ,308 168gr BTHP at 2700fps drops 2.7" at 100 11" at 200 25.6" at 300 same bullet at 1050fps drops 16.4" at 100 68" at 200 156" at 300 So I would expect about 13" low at 100 56" at 200 and 120" or 10' at 300yds Now you see subsonic 308 is a rock from a slingshot. |
The 220 ge bullets at subsonic velocities generally need a 1:8 twist barrel to stabilize properly and yaw excessively in barrels with 1:10 or 1:12 twists. This is why most US manufacturers of quality subsonic .308 ammo use 165-170 or so grain projectiles. The Europeans, who use the 220 gr pills are generally loading for the AI rifles with a 1:8 twist. |
Couple of problems here. A .45 ACP handgun bullet has the Ballistic Coefficient of a brick. A .30 cal subsonic actually has a very high BC, higher than it would have at supersonic velocity. Thus rifle caliber subsonics do have a much greater effective range than pistol bullets. Pistol bullets are actually designed to expand at subsonic velocities. Rifle bullets are not and do not expand at subsonic velocity. A long pointed subsonic rifle bullet will simply push its way through tissue without creating a large wound thus they are not good for hunting. There is no need to use excesively heavy subsonics. Kinetic energy is meaningless in the subsonic realm. Penetration by subsonics is impressive to say the least. A 150 gr spitzer type subsonic will easily transit all the way through a typical deer. How does a heavier bullet increase such terminal performance? Lighter subsonics fly flatter making them easier to get onto distant targets. And as Phil noted they are easier to stabilize and thus safer to use through a suppressor. |
True. However, a subsonic .30 still has a rainbow trajectory. I've had a difficult time trying to decide where to zero my .300 Whisper, because going from 50 to 100 yds creates such a wide change in POI. |
| I measured the drop at 200 yds from a subsonic zero at 100 yds. It was something like 40 inches. hock.gif |
| a long bullit will slice a wide path if/when it yaws & gets sideways or more likely end over end vertically as it tries to go base foward, especally if it's a flat base projectile. cutting a butcher knife like wound not counting any energy release. if it hits bone or a major blood vessal the critter will have some serious problems. that's to many if's to rely on but it does alot more than just a .30 hole |
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