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View Full Version : How much velocity spread is normal ?


One Shot
05-26-2008, 04:41 PM
I just got my upper and am trying it out. I'm shooting .220 grn, 9.2 H110 and Remmington primers. My velocitys are running from 900 to 975 fps ( one at 1020 ) after about 10 shots. Is that normal ?
I'm still waiting for my supressor.

Thanks
One Shot

Cornholio
05-26-2008, 07:50 PM
What gun and bbl length are you using?

One Shot
05-27-2008, 10:02 AM
It's an AR upper built by a local gun smith. It's a heavy, 16" 1-8 twist.
My powders have all been right on the money.
Thanks

abyssdncr
05-28-2008, 03:40 AM
I got a chance to chrony some AA9 loads from my 8" barrel tonight. I was getting extreme spreads of 35-40 fps with standard deviations of 10-11. If I would have dropped one of my ten shot strings, the SD would be in the single digits. Got to say, that's pretty decent.

120 fps spread sounds a bit high, what other powders do you have to try?

Cornholio
05-28-2008, 05:02 AM
After reading the other thread, maybe it could have something to do with your shooting cadence and residual heat left in the chamber.

One Shot
05-28-2008, 02:35 PM
I've solved part of the problem. One thing I did, or didn't do, was when I made my brass from .221's, I used a tapered die to 7mm, then the .30 cal. From there I loaded them. I didn't run them through a full re-sizer die ( I'm now to non-cowboy reloading ). I loaded up six this am, and had better result. 986, 932, 957, 962, 913, 918
Is that an acceptable spread ?

Thanks