Queston about a load and Chrono speeds

[CooperRandall]

I am fairly new to reloading and I am finding it extremely fun. I am working on finding a good load for my DTECH AR 204. It has a 24" Shilen barrel with a 1 in 10" twist and so far I am extremely pleased.

I have gone through the following steps in my reloading process. Sized the brass - uniformed the primer pocket - de-burred the flash holes and chamfered the inside of the necks.

I am using Benchmark powder and 39 gr Blitzking bullets and Federal match primers.

I have sized the brass to 1.549" to the shoulder and the loaded rounds are 1.867 to the Ogive. There is so much freebore I can't get anywhere near the rifling and my magazine renders that as a no go anyway.

So I am pretty pleased with results and I found that the gun likes 25.1 grains and 25.5 grains of powder. The confusing part is that my Chronograph showed the following for the 25.1 grains loads.

low - 3320 fps
high - 3496 fps
Avg -3429 fps
spread - 176.4

group size for three three shot groups of this load were 0.413" - 0.395" - 0.204"

the conditions were not the greatest. Wind 20+ mph gusting out of the NE (I was shooting due south) and temp of 52 degrees.

I wouldn't figure the groups would be that good with the spread in velocities I was getting. Any ideas or thoughts? Pics below of some of my targets.

[Ahab]

I'm thinking that's not too bad of a spread for a gas operated semi-auto and the groups aren't that bad either.

[WHISTLEPIG]

Try moving your chrono out further. If you are setting it to 10 ft. go to 12 ft.

[glenn asher]

I think I'd try H4895, too, while your groups are good, the velocity is pretty low compared to what you can achieve with 4895, and accuracy is usually pretty good with it. If you can get more speed AND accuracy, why not go for it?

[CooperRandall]

I read that if you are getting consistent or small groups but a large spread in velocity a primer change might help. The info came from Hogdon's reloading magazine.

[joghotrod]

Hi Cooper,

I have 2 Dtech .204's and I use 27.5 grs. of H-4895 behind 39 SBK's and get around 3800 fps out of both of them. When I shoot 50 gr. Bergers out of the 1/9 twist it will be around 3400 fps. I use Varget with the Bergers. I shoot 39's at mag length and they work pretty good.

Jimmy

[CooperRandall]

H-4895 it is. I will pick some up tomorrow. Thanks for the help. Would you stay with the Fed205m primers or try something else?

[joghotrod]

I use BR-4 primers but the 205's are probably ok.

Jimmy

[jo191145]

Coop
Don't know diddly about gas guns but make sure you edit your first cold clean shot from the chrono. Its usually quite slow. Not sure if this applies in your case but I figured I'd throw it out there.