215 gr Berger .30cal stability.

[pondskipper]

Was wondering if anyone had any experience shooting these past the transonic zone in a 1:10 twist barrel at about 2800-2850fps and what your experience was with them. We're they still stable and repeatable, did they impact with any signs of yawing or key holing? Want to try them at 1800-2000 yds from a 300wm I'm building just to see if I'm capable but if the bullets won't work in that twist barrel and maintain stability and tractability there's no point in it.

 

[extreme]

There are hundreds of threads on the 215 gr. Berger bullet on this site. Most have been by the self proclaimed 215 Berger guru BROZ. I think that is what he goes by.
He claims many 1 shots kills with this bullet and has done more testing than most
with it. Try to contact him.

 

[pondskipper]

Thanks, I will try and look him up if I can, in the meantime if anyone else has any honest experience with them at those ranges and velocities I'd love to hear about it, weather conditions, altitude, the works.

 

[bigngreen]

I've shot quite a number of 300's with 215's out in the 2000 yard range and they did well, I've shot a pile to 1535 in my 308 with excellent, excellent results. I'm at 6000 ft elevation.

 

[pondskipper]

Well that's good to know, bad news is I'm basically right at sea level, maybe 500' or so where I plan to try them.

 

[Mikecr]

Berger recommends 9tw

 

[pondskipper]

I know they recommend 1:9 twist on their website but from the experiences I've had shooting other calibers and bullets beyond the max ss range with rifles that had barrels that had a twist rate that was "too slow" for the given weight of the bullets and what the mfg states at a recommended twist for them it got me curious. Other caliber I'm referring to is a 223 shooting 75gr hornady bthp to 1100 yards from a factory 5r Remington 700 milspec with a 24" barrel and a muzzle velocity of 2815fps. Theoretically it shouldn't work but it does, and it does so every time I've ever tried it, from 40-100 deg F, entering the information of each load (300wm and 223) it states my sd being 1.45 and having a 2% loss in bc. If I did the math correctly for the 223 it should be subsonic not even transonic anymore by the time it makes it to 1100 yds but yet I can make consistent hits with it that show no signs of key holing telling me that it's passing through the transonic range and still maintaining tractability. Have photos of the target still, perfect round splatter.

 

[pondskipper]

Where I was checking my loads was on the twist rate calculator on Bergers website.

 

[barefooter56]

I know they recommend 1:9 twist on their website but from the experiences I've had shooting other calibers and bullets beyond the max ss range with rifles that had barrels that had a twist rate that was "too slow" for the given weight of the bullets and what the mfg states at a recommended twist for them it got me curious. Other caliber I'm referring to is a 223 shooting 75gr hornady bthp to 1100 yards from a factory 5r Remington 700 milspec with a 24" barrel and a muzzle velocity of 2815fps. Theoretically it shouldn't work but it does, and it does so every time I've ever tried it, from 40-100 deg F, entering the information of each load (300wm and 223) it states my sd being 1.45 and having a 2% loss in bc. If I did the math correctly for the 223 it should be subsonic not even transonic anymore by the time it makes it to 1100 yds but yet I can make consistent hits with it that show no signs of key holing telling me that it's passing through the transonic range and still maintaining tractability. Have photos of the target still, perfect round splatter.

pondskipper,
Youve just given up some spin rate stability and conditions may have a little greater effect due to the compromised BC thats all. 1.45 SG is just fine.

 

[Mikecr]

With the 223 scenario Sg is going up as velocity slows down range(because travel slows way more than turning). So even though transonic is a hit to stability(amount depending on dynamic stability), your gyroscopic stability is usually high enough by then to handle that hit.

Bad is an Sg approaching 1.0 on muzzle release(biggest hit to stability). This, due to twist rate and/or air density. For marginal stability ranges (Sg of ~1.3) BC can drop a bit, and accuracy can take a significant hit.

Where Berger says 9tw, there is no reason to think 10tw is ok. Even if still stable, due to your air density, you'll be running marginal stability.
And velocity itself, where beyond SS, never helps stability. Even 30,000fps will not make 10tw stability match that of 9tw.

 

[pondskipper]

Well I have 250 of them to try and if they don't work I'll just use them strictly for hunting purposes and find something that works better with th 1:10 twist, probably 208amax

 

[pondskipper]

Either way, I WILL be trying to stretch out to 2k, if I fail, I'll try something else. gun)

 

[Mikecr]

Try 200yds first..
When you can shoot worth a **** there, try 300yds.

 

[pondskipper]

Already well past 200 and 300 thanks