Where would my little 6mm 115 D-TAC {Sierra} bullets go sub-sonic and would they withstand the transition? I launch them at 2650fps from a 1-8" twist 6x222mag.
Where would my little 6mm 115 D-TAC {Sierra} bullets go sub-sonic and would they withstand the transition? I launch them at 2650fps from a 1-8" twist 6x222mag.
Depends on the altitude, humidity, barometric pressure, temp. Quit being cheap, and spend the $10 on a real ballistics calculator.
Figure out what the tail angle is, and you'll have a decent idea. Or go shooting with a decent spotter. If the bullet really tumbles, you can usually see it when you're watching the trace in the air.
You'd drop sub, somewhere around 1380 yards.
The reason I ask is because the club I belong to is talking about putting in a 1000yd range this summer, I've shot the gun at 600yds with no issues, curious about 1000.
Humpy used a barrel that was made from a cut-down Palma rifle barrel that was worn out for its original purpose. 13" or 13.5" twist, IIRC. The 168-grain SMK has a shape that makes it over-correct for any trajectory perturbing influence when it is spun too fast. The 175-grain SMK does not and can handle the 10" twist. But that's not the same thing as saying a 10" twist is optimal for it. It will likely be optimal at some muzzle velocity, but one that is lower than .308 muzzle velocity.
I spent 8 yrs in the Air force in the Radar field. Part of that as a weapons control tech. Used to know what supersonic speed was in relation to say an F4C, don't remember anymore! When I hunt big game I stay within the MPBR, max point blank range, of the load I'm using. Knowing what supersonic is serve's me no purpose at all. I understand that shooting extreme range require's a bullet to stay supersonic to stabilize. Sometime, more than I might admit, I like to plink at target's way beyond MPBR. Don't know if the bullet stays supersonic or not, only know if I hit it or not!
The round i am using right now is 708 rem with a 1 in 10 twist varmint special barrel. I like the 150 ELD x bullet. I I think it goes sub sonic around 1600 yards.
According to Hornady's 4 DOF calculator, which uses their individual bullet Doppler radar-determined drag function, in a standard atmosphere, you'd need to have a muzzle velocity of about 3200 fps to be supersonic at 1600.
Hmm, I think I would have made contact with something way before 1600 yards. Sage rats are pretty tough to see much past 500 plus a lot can happen in the couple seconds between squeeeeeze bang and thwock.
RJ
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