Standard Deviation and Extreme Spread.

[JustAGuy2020]

Ok, so I finally got out to do some shooting and data collecting on my new AR-15 varmint rifle. Rifle is a Wilde chambered 24 inch Wilson stainless bull barrel.

My question is: given this caliber and this barrel, what is considered good, average and poor Standard deviation and extreme spreads on the velocities? I shot some Federal white box XM 193 and some 40 gr V-max over 8208 XBR in two different loadings, 0.6 gr apart.

XM 193 SD: 1.86 FPS, ES: 5.91 FPS, Average velocity: 3619 FPS.
Lower 8208 load SD: 4.87 FPS, ES: 15.09 FPS, Average velocity: 3624 FPS.
Higher 8208 load SD: 3.74 FPS, ES: 11.81 FPS, Average velocity: 3636 FPS

These look pretty good to me especially considering the handloads were NOT trickled but taken straight from the powder thrower.

Thoughts?

 

[Longhorn 76]

Don't know. For 100 rounds, they are both excellent. If you only shot two or three, the numbers don't mean much.

 

[JustAGuy2020]

About 30 rounds each.

 

[Walkalong]

Looks good to me. I have certainly seen worse. I haven't tried my 8208 yet.

 

[gahunter12]

Looks good to me! My SD on my best pet load for my AR's is SD:7.0 for a 10 shot string. There again my AR's are set up as battle rifles for HD, and Tactical matches with 14.5"welded/pinned, and 16" Chrome Lined Barrels, .556 chambered, etc.

 

[Cherokee]

SD's look good to me, lowest I ever got was 5.0 with 55 JSP Hornady.

 

[gahunter12]

What's impressive is the SD for the XM193's. I tested some XM193, PCM, and Dixie Ammo Dump factory reloads this summer. My XM193's had a SD of 18 with the D.A.D factory reloads being the best at a SD of 14.

 

[Dave P]

Those look excellent. Now sell the chrono and worry about something else.

 

[JustAGuy2020]

Yeah, I was surprised by the data on that XM 193 also. I've never had very good accuracy out of any gun I've owned using that federal stuff but not only did it have good numbers in this new gun but it shot pretty accurately too.