Nicely done as always Molon! Thanks!!
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Nicely done as always Molon! Thanks!!
Another amazing series of posts.
Have you experienced a marked difference in group sizes and/or terminal performance between the NATO pressure XM556FBIT3 and the SAAMI pressure TBBC round referenced here?
I'm a little underwhelmed with the velocities of this round out of a 14.5" barrel. Excellent presentation as always Molon but I can get faster velocities out of my 14.5" AR and 77 gr Sierras.
sometimes to much velocity undermines the design and purpose of the round/projectile.
just talking out my ass here but IIRC, the reason for the lowered velocity with soft point bullets is that they dont need the 5.56 velocity to get the job done and the bullets tend to under perform at the high velocity.....does that sound correct?
where as the copper solids need the extra velocity to get that tip opened up.
As to the first, thats what I understand as well. The soft points will open up pretty well and arent relying on blistering speed to tumble and what not. Slightly different wounding mechanism. From what I understand the 62g fusion is supposed to expand down into the 1700 fps range(unless I heard the number wrong, but I believe that is what I saw).
As to the second i.e. copper solids, maybe, maybe not. Take the 110g Black Tips designed for 300BLK and they are reported to open reliably down to 1400fps with reports of guys saying they opened up at even slower speeds(guestimating speed with ballistics software I believe). Or the couple subsonic expanders from LeHigh Defense that open down in the 700-800fps range. I think the manufacturers can do a lot with the alloys and hardness's and what not that they use with the copper solids.
Great thread thank you.
Really liked the comparison of the 3 similar rounds.
Here is a recovered 75gr Gold Dot from gel. It impacted at roughly 1850fps, flipped twice, and penetrated roughly 21".
http://i64.tinypic.com/ririfd.jpg