finally chronied my reloads......

Ken

Ken

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Like the title says, I got new chrony from santa

it was finally warm enough to play a little today. which brings me to my question, how much deviation in speed is normal?

The rifle is a Browning A-Bolt in 300wsm, The load is 65 gr of IMR 4350 and a 180gr Accubond. of 12 shots the velocity was anywhere from 3024fps to 2973fps. Accuracy is decent, 1" groups which is about the best I am capable of anyway.
 
crony results.

Set the crony approx 15ft from the muzzle, the muzzle blast can screw things up if too close.
Before using the crony you need 4 or 5 shots just to remove ALL the bore lub you had in there from previous cleaning, things should settle down after that.
Bill
 
10-15 feet should be fine. Bigger charges and more powerful loads need a bit more distance as mentioned - muzzle blast. If you're real fussy with powder charges, case prep (identical as you can make them), seating depth and neck tension (I seem to be using a cheap Lee factory crimp die more and more) you'll tighten up the spreads. I don't like more than 15 fps ES from a 5-shot group. Single digit spread is not too difficult.
 
Now what?

I load for three (mainly) calibers. 260, 308 and 300wsm. With these powders, H414, H4831, H4895, Varget and MagPro (as well as two or three others) in the different loads and with a variety of bullets, the best deviation I have had is about 20-25 fps. Case prep is consistant in all cases. MagPro in the 300wsm gives the 20-25 fps spread and I suspect that it's the best due to being a compressed load and perhaps the powder itself. Without getting into too much detail, most loads are more like 25-35 fps spread, is this normal or acceptable to others? I have all three shooting right near 1" at 100 yds. Some a bit under but on average about 1-1.25" groups.
The chrony has been great for developing safe loads...makes me wonder what I was doing when I never used one?
 
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