.223 gel test: Double Tap 77 gr Nosler HPBT

[AndrewWiggin]

Link for phones




.223 Rem Double Tap 77 gr Nosler HPBT fired from 11.5" and 16" barrel AR pattern rifles into calibrated 10% gelatin.

BB: 588.4 fps, 3.7"

11.5" barrel results:

Impact velocity: 2,559 fps
Penetration: 13.8"
Retained weight: 22.7 gr
Max expansion: 0.453"
Min expansion: 0.286"
Neck: 1.8"
TSC: 2.75" x 6.5"


16" barrel results:

Impact velocity: 2,754 fps
Penetration: 12.7"
Retained weight: 41.7 gr
Max expansion: 0.721"
Min expansion: 0.317"
Neck: 0.9"
TSC: 2.5" x 7.5"


The jacket on the first shot stopped in the middle of the block but on the second shot it stayed with the bulk of the projectile all the way. Oddly, the jacket seemed to be "backwards". If you look closely, you can see where the base of the bullet would have been. It seems that it may have somehow separated from the core and then got mashed back against it. This underscores the reason that a statistically valid sample size is important in professional testing.

[markm]

Holy smokes! They're at 2754 out of a 16" barrel??? Wow.

This round came up in another thread where a guy was getting pressure signs or something with this round and another load, but no one had chrono info on the round.

[AndrewWiggin]

I forgot to take pics of the primers but I think I still have the brass at home. I'll try to remember to post a pic.

[fz1boxer]

do you have any rounds you can pull and weigh powder charge?
check to see if its extruded or ball powder.

[markm]

do you have any rounds you can pull and weigh powder charge?
check to see if its extruded or ball powder.

I'll be the ranch it's ball powder.

[fz1boxer]

yea thats what i figured but still curious,more so about charge weight.

[markm]

yea thats what i figured but still curious,more so about charge weight.

It'd be hard to learn much from it since most ball looks pretty similar.. no?

[fz1boxer]

cross referance reloading data to see where it comes close to or if it is off the scale in relation to other powders.
i pulled down some 64 grain SSA marked 5.56 ammo that j-dubya got some low velocities(sub 223) when he chronographed it.
i found it had a ball powder and was 2 grains lighter than anything i could find searching various reloading manuals.

[AndrewWiggin]

do you have any rounds you can pull and weigh powder charge?
check to see if its extruded or ball powder.

These were sent to me by a member over at that OTHER site. I do have a few extra but he wanted me to shoot them over the chronograph for a velocity average.

[fz1boxer]

were you able to locate an ak to test the 7.62 double tap?