Data for AR Comp and 123 sst's in my new 18" GB barrel

[grayfox]

Today's range trip had a couple of objectives for my 18" group buy Faxon/BFT barrel.

1. Gather some data on Ar-Comp for the 123 sst.
2. Try some loads with 1x fired federal cases... even though they are softer and the primer pocket may not last very long, maybe I can get 1 or 2 loads to use at the 1x stage, after firing the AE-90 TNT's and/or 120 MSR ammo I get.


Both objectives were met with some decent MV's IMO, so here goes.

At my indoor 100 yd range, 328' elev, a moderate 72*F and no wind (a little humor there!). Using my Magnetospeed.

1. AR-comp and 123 sst's, Hornady 1x fired, cci450's and 2.250 Coal.
27.6: 2366, 2406, 2399, 2411; avg 2395, sd-20
27.8: 2424, 2414, 2433, 2424; avg 2423, sd-7
28.0: 2442, 2433, 2442, 2451; avg 2439, sd-4

For comparison on the 123sst's, Hdy factory sst loads out of this tube fetch ~2425, and my CFE load (30.8) is 2466, sd-2. Would I like zippier speeds? Heck yeah but the rifle tells you where the node is, not the other way around... so this will be just fine.


2. Using FC1x brass, Fed 205M primer, H335 powder.
a) 107SMK, 2.260:
--- 29.4: 2619, 2606, 2605, 2609; avg 2609, sd-6
--- 29.7: 2641, 2639, 2632, 2651; avg 2640, sd-7

b) 95 Vmax, 2.240:
--- 30.2: 2699, 2705, 2692, 2717; avg 2703, sd-10
--- 30.5: 2714, 2717, 2721, 2732; avg 2721, sd-7
--- 30.7: 2726, 2739, 2726, 2739; avg 2732, sd-7

I caught all but 1 or 2 pcs of the Fed brass, so I'll be examining it to see how loose the primer pockets are from firing the 2d time. If too loose I'll just chuck 'em, otherwise I might get 1 more out of them. This is ok, at least I have some extra use and if nec, I can just not worry about finding them in the field.....

Why, you might ask, did all 3 bullet types wind up with good sd's? I. Don't. Know!!! This was a lucky day is all I can figure. I've definitely had days where the opposite was true.

So the 18" GB barrel is shaping up very well. I'm about 120 rounds downrange for it. It cleans up quickly and with the Nitrided bolt and BCG doesn't seem as dirty in between cleanings.

BFT you're definitely Da (designer) Man!!

[mdewitt71]

Lucky you for an indoor 100 yard range......
I am stuck in the mud and rain this week.

Thanks for posting info.... and Chrony speeds as well, I really like to see the Velocities.

[BluntForceTrauma]

I like your 107SMK results.

Hodgdon's online reloading data shows that bullet in a 24" test barrel doing 2,677 fps with 30.0 H335 at 49,500 psi.

Sierra's online data shows their 107 SMK in a 24" doing around 2,650 fps with 29.2 H335. (Shows it 100 fps faster at 2,750 fps with Exterminator, PPV, or TAC!)

If you're getting from an 18" 2,640 fps with 29.7 H335 you're doing pretty good!

And your barrel may disagree, but LRRPF52's testing says a 123 A-Max, for example, with 32.0 CFE in a SAAMI chamber at 2.275 COL is at 50,500 psi. So there just might be room for a bit more "zip."

[grayfox]

take a bow! ... this is your 5r-ee barrel.

[CVCOBRA1]

I like the looks of both the lighter bullet loads. I have always been more interested in a 400 yard coyote load than ringing steel at a 1000 anyway. I did pick up 500 123gr. ELD's but also grabbed 200 of the 107gr. TMK's too. Looks like I'll have to pick up some sub 100gr. pills.

[grayfox]

lots of choices with a bit of BC... 100 eldm, 107 smk, 95 vmax. Cost-effective too. None of them are 0.500's but still better than any of the 90 gr pills.