Finally bought a chronograph

[aandabooks]

After almost 3 years as a reloader I finally broke down and bought a Caldwell chrono. Got the IL Sectional tomorrow and wanted to make sure my ammo is good. I've been using the same recipe since last year on my 9mm and last sectional they went over at 133PF.

Got the Caldwell all setup and they are reading average 141PF. Yesterday here in Central IL was 88. Tomorrow will be 68. I'll be interested to see how much the PF changes. If there is a diiference will it be attributable to the temp or difference between using 2 different chronos?

I look forward to using this much more for load development.

My load for 9mm is S&S 147gr, 4.6gr AA#5 @ 1.110" OAL.

[Braxton1]

I would think that you'll be in good shape with that load.

There will be too many variables with the weather and the different chrono to be able to attribute changes to one or the other.

[Bkreutz]

My normal load is 172PF, I'm at sea level, I was wondering what effect altitude would have on my loads. At Area 1 (4700 ft) my load chronoed at 172. Conclusion, Autocomp doesn't care what altitude it shoots at. (or maybe I trapped the dense sea level air in my ammo )

[AzShooter]

I'm lucky. They say you should chrono on the hottest days you can. I recently chroned a bunch of loads in 110 degrees. They should be good all year long.

I still have a lot of loads to test but it's still in the 100 degree days so I'm good to go.

You have a decent Chronograph. Now you can tell what your loads are really doing instead of guessing.

[Bamboo]

Congratulations! For folks shooting the games (especially those making major in any of the 38/9mm guns) I consider a chronograph to be as essential as a powder scale. Without one you are just guessing. They used to be crazy expensive, but now they are very reasonably priced and there is no excuse.

Also, altitude in itself does not affect velocity at the muzzle (or 10' from the muzzle) significantly. However, if you are shooting long distances it does affect the downrange velocities (air density).

Temperature is by far the biggest contributor to velocity variations (some powders are more sensitive than others)...that and using different chronographs (yours vs. the Match Chrono).

[aandabooks]

Loads went over at Sectional at 141PF. Right in the same ballpark. Now I'll back off the powder a little and get a little closer to 130-132. Probably won't be able to tell the difference but maybe.

[MarkCO]

I can barely tell the difference of 5 PF, 10 PF I can feel, 15 PF is noticeable on the timer with minor.