Author Topic: 90 SMK, 20" 1:7 barrel, powder testing  (Read 118 times)

Offline justDee

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90 SMK, 20" 1:7 barrel, powder testing
« on: May 16, 2020, 04:48:12 PM »
Based on what I've read thus far, I wanted to get started with my powder testing using H4350, RL16, and RL17.  They were out of RL16 and RL17.  I opted to go with H4350, StaBALL 6.5, and I thought I'd try Varmint as I have yet to see where anyone has tested it.  There was a recipe for it on their website, so why not try it and see?
I'll post results and details soon, I hope.  8)

My rifle:  Built it from pieces, my first full AR build.

Barrel: PSA 20' SS, non-fluted, with 1:7 twist, no muzzle break/flash suppressor, just an end cap for now.
Bolt Carrier Group:  PSA 224, ordered with the barrel
Upper: Spartan, side charge, non-reciprocating billet upper
Lower: Anderson Lower, standard trigger and parts
Furniture:  Hogue Kit in black
Scope: SWFA fixed 20X scope  (I know, it's a bit much, but I thought "why not?")

Offline Liberator52

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Re: 90 SMK, 20" 1:7 barrel, powder testing
« Reply #1 on: May 16, 2020, 07:53:45 PM »
Good luck with your build. Keep us posted on how she shoots.

Offline justDee

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Re: 90 SMK, 20" 1:7 barrel, powder testing
« Reply #2 on: May 17, 2020, 08:20:01 PM »
Today I made it to the range and shot the ALLIANT PP VARMINT powder.  I had seen that they had a recipe on their website, but could not find where anyone had actually tried it out with the 224.
It started out poorly, but once I hit 2600 FPS, the shots came right in.

24.5 grains Varmint (MAX recommended), CCI SR primer, FC once fired American Eagle brass, 90 SMK bullet
20" SS PSA barrel, 1:7 twist, no brake/suppressor on end of barrel
100 yards

Copied from the software:

#          FPS  FT-LBS      PF
5    2642    1395.16  237.78
4    2620    1372.02  235.80
3    2646    1399.39  238.14
2    2629    1381.46  236.61
1    2634    1386.72  237.06
Average: 2634.2 FPS
SD: 10.4 FPS
Min: 2620 FPS
Max: 2646 FPS
Spread: 26 FPS
Shot/sec: 0.0
True MV: 2638 FPS
Group Size (in): 1.75

Now, I have no idea, why they grouped in two tight groups, but I'll take some blame.  I'm not a sniper, can shoot better than most, but I certainly don't shoot enough to be competitive.  But for the first round of testing, I was pretty worried, now, not so much.  I'm pleased with that group.  Now to try the other powders.


« Last Edit: May 17, 2020, 09:42:21 PM by justDee »

Offline AzCasper

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Re: 90 SMK, 20" 1:7 barrel, powder testing
« Reply #3 on: May 23, 2020, 07:34:09 PM »
FWIW....

I recently shot a load ladder with StaBall 6.5 and 90 grain Federal Fusion bullets. I had a group of three that measured .542" at 100 yards.

Details on the load are as follows:

New Federal Brass
CCI 450 Primer
90 Grain Federal Fusion ( from American Reloading)
27.0 grains of Winchester StaBall 6.5
Seated to 2.285" COAL

Shot through ARP 20" 1:7.7 twist barrel on Aero Precision upper/lower at 5100' and 76 degrees.

This load worked well in MY rifle. Your results mat vary.