Home Forums Reloading Big Game Rifles Is my ProChrono lieing to me? .257 Roberts

ProChrono Digital Chronograph. 7-10 years old.

120 Partition, H-4831SC, Nosler +P case, Federal 210M, COAL 2.955, Ruger No.1, 26" barrel. 65* sunny, sea level.

46.5 = 2898, 2867, and 2867fps
47.0 = 2923, 2904, and 2904fps
47.5 = 2936, 2909, and 2936fps
48.0 = 2956, 2956, and 2956fps

I also shot some 100 Partitons, H-4350, Remington case, CCI BR2, COAL 2.910. I had reloaded these for my Ruger M77UL 20" barrel. 65* sunny sea level.

47.3 out of the 20" barrel was 3130fps. Same load out of the No.1 26' barrel 3236, 3228, 3236, and 3228fps.

Just curios if this data is inline with others shooting similar loads.

Change the battery and try again, just to make sure.
Very common to see very different results from different guns. Chamber and bore differences.

For your #1, FYI, punching your info into QL gives me this:

47.0 - 2937 fps @ 54K pressure.
48.0 - 3003 fps @ 58K pressure

M1, thanks for the QL lookup. The load seems to be inline with QL. Thanks.



WS, I do keep up with the batteries, been there.......always keep a new battery handy.

In my 257Ackley Improved 51gns of H4831sc & 120gn Speer produced a 10 shot average of 2930fps from a 23" bbl and 50gns of H4350 & 100gn Core-lokt produced a 5 shot average of 3210fps


I wouldn't be taking too much notice of Quickload, I've seen it out by 150fps - 200fps in some instances and spot on in others. A decent chronograph and a few range sessions is the only way to get a proper feel of which powders perform the best in a particular rifle.

dingo, I agree 100%, it's just a prediction and a guide. QL can be off sometimes, but the burn rate can be changed to match the velocity and hopefully give a better prediction. Nothing replaces pressure measuring equipment so chrongraphing, watching for signs and QL is the best most of us can do.