Surprising Chronograph results with .357 mild handloads

[2ndtimer]

Was running some milder .357 hand loads over the chronograph at the range today, and had the most consistent velocities I have ever recorded. The load was a 158 gr RNFP cast bullet a friend gave me, 5.6 gr of Ramshot Zip, some old nickel Winchester cases and the cheap Servicio Aventuras primers from Argentina. Five shots over my Competition Electronics ProChrono DLX measured an average velocity of 1,043 fps, with an extreme spread of 3 fps and a standard deviation of 1 foot per second! This from 5 chambers of a 6" barrel Ruger GP-100. Sadly, my friend has no recollection of where he bought those bullets (he isn't a caster), so I guess I will see if the coated 158 gr SWC's from T&B bullets can come close to those numbers. The 5 shots ranged from 1,042 fps to 1,045 fps. I was shocked.

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[Certaindeaf]

Was running some milder .357 hand loads over the chronograph at the range today, and had the most consistent velocities I have ever recorded. The load was a 158 gr RNFP cast bullet a friend gave me, 5.6 gr of Ramshot Zip, some old nickel Winchester cases and the cheap Servicio Aventuras primers from Argentina. Five shots over my Competition Electronics ProChrono DLX measured an average velocity of 1,043 fps, with an extreme spread of 3 fps and a standard deviation of 1 foot per second! This from 5 chambers of a 6" barrel Ruger GP-100. Sadly, my friend has no recollection of where he bought those bullets (he isn't a caster), so I guess I will see if the coated 158 gr SWC's from T&B bullets can come close to those numbers. The 5 shots ranged from 1,042 fps to 1,045 fps. I was shocked.

Too bad about the 3' groups though?

 

[2ndtimer]

Too bad about the 3' groups though?

Was set up on the 100 yard bench, so didn't have time to shoot for groups. A previous outing punished steel gongs at 15 and 25 yards off hand shooting double action. Next time out I will try them from a rest at 25 yards, single action.

 

[Ben B.]

It's definitely cool, and a good sign that batch has a tight SD, but 5 shots isn't much of a sample and it's almost a 100% certainty that the teeny SD will increase at a repeat test or with larger sample sizes. And don't get me started on possible sources of measurement error.

Sometimes random chance does it FOR you and sometimes random chance does it TO you.

It's still really cool. I've never had a range of 3 and SD = 1 on any loads. Least of all with a revolver.

 

[DizzyJ]

That is pretty cool!