Load Catalog: Subsonic A1680, above 200gr

[StorminNormin]

Nice shooting! What distance was that at? I had to look twice at the FIVE shot group.

Thanks, that was shot at 25 yards. Those 220gr are freaking accurate. They are still just as accurate at 50 yards but have about a 6" bullet drop. I was also shocked that all five shots went through basically the same hole on the unsuppressed group.

[Harbor guy]

16" CMMG WASP barrel, 1:7, pistol length gas
YHM SS Phantom
208 Hornady BTHP, light crimp using Hornady custom die
11.0 grains A1680
Remington 7.5 primer
2.145" COAL
550 ft above sea level, 50 deg./f, 80% humidity
1060 fps (5 shot average), ES 32 fps

[projo198]

Rifle Used: AR-15 SBR (Red X Arms upper).
Barrel Maker, Contour, Gas Length/Port Size: Red X Arms pistol length heavy barrel, port size unknown, YHM Phantom supressor
Barrel Length: 9", 1:7 twist
Magazine Brand/Size: US issue 30 round magazines
Bullet Used (grain, manufacturer, type): Nosler Partition 220 grain
Powder Charge and Brand: A1680 (powder increments listed below)
Case Used: Mixed brass made from .223
Primer Used: Wolf small rifle primer
COAL: 2.120
Chronograph Velocity: Listed below

No issues, all cycled completely. One powder lot failed to read on chronograph, possible chrono problem.

LOT 1: 10.9g A1680, avg. Mv. 886.45 fps

LOT 2: 11.0g A1680, avg. Mv. 854.9 fps

LOT 3: 11.1g A1680, avg. Mv. unknown (chrono error on all 5 shots).

LOT 4: 11.2g A1680, avg. Mv. 883.3 fps

[Cajun Executioner]

Cross Machine Tool (CMT) AR
Barrel - 8.5" Noveske 1-7 Twist
JP Silent Capture Spring
Suppressor - Saker 7.62
Altitude - 25'
Temperature - 70 degrees

208gr AMAX / NO CRIMP
10.8 grains A1680
LC-09 converted (Purchased from WildCat on here)
CCI 400 Small Rifle Primer
COAL- 2.20"
MagnetoSpeed V3 Chrono
5 shot average 1057 fps
SD - 10.1

220gr SMK / NO CRIMP
11.1 grains A1680
LC-09 converted (Purchased from WildCat on here)
CCI 400 Small Rifle Primer
COAL- 2.11"
MagnetoSpeed V3 Chrono
5 shot average 1052 fps
SD - 10.9

Accuracy is so so. I'm using a Leupold 1.25-4x20 VX-R Patrol optic at 50 yards. BHO on last round and no cycling issues but I believe that I have over gassing so I just ordered the JP spring kit for the JP Silent Capture. I will change the springs out until it doesn't hold the bolt open, then I will go up a spring.

[Shaw]

CMMG AR-15
CMMG WASP Barrel 16" 1:7
10 round P-mag gen 2
Palmetto Projectiles 203 gr powder coated bullet
A1680 9.5 grains
Lake City Brass
Remington 7 1/2 primer
2.05" COAL
Avg 997 fps suppressed

The manufacturers recommended COAL of 1.95" caused some feeding issues in my rifle. Extending it to 2.05" remedied the problem. I was consistently getting 1.5" groups at 50 yards with a red dot scope with this load. Perfect for plinking!

[FastMover]

AR-15
CMMG WASP, Carbine Length Gas System
16in 1:8 Twist
Silencerco SpecWar762
20rd Lancer Systems L5AWM
220gr Berry's Plated
10.9gr A1680
New Federal Cases sized via Lee FL Sizing Die
CCI #400
2.10" COAL

Velocity Data
AVG 1076 fps
MAX 1087 fps
MIN 1066 fps
SD 10.7

Load Notes -
MOA Accuracy at 50 yards, No feeding or reliability issues, full bolt lock back.

[ropedrag]

Rifle Used
Daniels Defense DDM4ISR (intergral Suppressor)

Barrel Maker, Contour, Gas Length/Port Size (if known)
Pistol Length

Barrel Length and Twist
9", 1:8

Bullet Used (grain, manufacturer, type)
200gr Sierra Match King HPBT

Powder Charge and Brand
Varies, Accurate 1680

Case Used
New Hornady

Primer Used
Federal 205M

COAL
2.21

5 shot groups using Magnetospeed V3 chrono

10.4, 787 SD=9.4 ES=23
10.5, 803 SD=12.2 ES=32
10.6, 803 SD=10.4 ES=25
10.7, 800 SD=13.7 ES=31
10.8, 813 SD=4.2 ES=11
10.9, 819 SD=3.2 ES=9
11.0, 825 SD=10.9 ES=27
11.1, 842 SD=9.7 ES=24
11.2, 852 SD=7.9 ES=20
11.3, 864 SD=6.5 ES=16
11.4, 871 SD=3.0 ES=8
11.5, 885 SD=5.4 ES=13 (tightest group at 50 yds)
11.6, 889 SD=6.4 ES=17

No issues with rifle function with any charge weight used
I will add another 7 groups taking it to 12.3 next outing

Actually decided to run 10 more loads of 5 each

11.7, 885 SD=2.8 ES=7
11.8, 898 SD=3.9 ES=10
11.9, 916 SD=4.8 ES=12
12.0, 914 SD=13.1 ES=25
12.1, 931 SD=3.6 ES=9
12.2, 936 SD=6.8 ES=18
12.3, 946 SD=3.1 ES=7
12.4, 948 SD=11.9 ES=33 (tightest group at 50 yds)
12.5, 953 SD=5.9 ES=15
12.6, 968 SD=15.9 ES=35

12-23-19 loaded up some more

12.7, 980 SD=19.9 ES=43
12.8, 1000 SD=12.7 ES=30
12.9, 1017 SD=11.4 ES=30 (tightest group at 50 yds)
13.0, 1026 SD=3.4 ES=9
13.1 1044 SD=8.7 ES=23

That's it for crono testing this powder and bullet. Obvious this is what worked for my gun and I've no idea how these loads would perform in yours, USE good judgment

Final = 13.1gr of Accurate 1680, Base to Ogive = 1.77, COL = 2.21, 1044fps