Ballistic Coefficient extremes in .223

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10-22-18, 10:18
markm

Ballistic Coefficient extremes in .223

Saturday I loaded up some bullets I found on my bench shelf so we would have something to tinker with at the hide. I found these Speer 70 gr soft point varmint bullets that just visually scream LOW B.C.

They shot a decent sub MOA 100 yard group out of the Rem 700 5R, and actually POI'd an inch high. But walking out from 500 yards to a few failed attempts at 1000 yards really highlighted B.C. efficiency.

Our 77s are loaded right around MAX, and these 70s were loaded a little over published MAX with 22.0 gr of XBR.

pictured here compared to the TMK:
https://i.imgur.com/QjHWN78.jpg

Pappabear may have jotted down some specifics on the come ups, but at 1000, the scope maxed out at 16 mils and we weren't even landing bullets on the mound on which the target sits. It looked like they needed another 2-3 mils to get to the target.
10-22-18, 11:02
Pappabear

I think it was a good 5 + mils different at 1000 yards. Pretty astounding. But that 70 grain bullet would throw some hate on a yote.
10-23-18, 20:53
mic2377

Oh I can relate to this, also with Speer bullets. Got a bunch of the 55 gr SP's for amazingly cheap. They shoot quite well for a bulk bullet over a solid load of H335.

But when I shot them side by side against some 52 Amax's and the same powder load and brass, then difference in hit percentage was HUGE. I struggled to even ring steel at 500+ yds at all with the 55's, vs a solid hit percentage with the 52's.

But for 300 yes and in they are GOLD and shoot amazingly well (in several different rifles!) for such a cheap bullet. Terminal ballistics are also excellent.
10-23-18, 22:25
Bimmer

I'm not surprised that the SPs are accurate... The more-forward ogive and consistent QC would make for accurate loads.
10-23-18, 23:55
vicious_cb

Quote:

Originally Posted by Bimmer

I'm not surprised that the SPs are accurate... The more-forward ogive and consistent QC would make for accurate loads.

Yep, thats a common mistake people make just because they see all the long range guys shoot VLDs with sleek secant ogives. They equate fat ogives with poor accuracy, but its actually the opposite. Fat ogives only result in poor BC, not accuracy.
10-24-18, 08:43
markm

Quote:

Originally Posted by vicious_cb

Yep, thats a common mistake people make just because they see all the long range guys shoot VLDs with sleek secant ogives. They equate fat ogives with poor accuracy, but its actually the opposite. Fat ogives only result in poor BC, not accuracy.

I shot the first 5 with an ACOG and it was a dismal 2.5 +/- MOA group. So I didn't have good expectations, but the bolt gun shot them nicely. They are a nicely made bullet, but somewhat useless for what we like to shoot.