I'm looking for some educated input. For almost a year I've been shooting my Ruger Express with H335 rifle powder. Accuracy has been MOA, extreme spreads have been in the 10-12 fps range w/ corresponding single digit sd values. Well, this last weekend in 90 degree heat and 60% humidity all changed except for accuracy. Extreme spread became 109 fps and sd out the window. All components remained the same, 500 A-franes, Norma brass, Fed215s, same lot of powder. I guess I really don't know the real characteristics of H335, maybe it was a fluke, I am going to shoot it some more. Maybe the chrono had a bad day since accuracy was still moa. Is this characteristic of H335 in anyone elses opinion. Thanks Kigosi anticipation in the fall is mounting. Dr.C

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Originally posted by doccash:
Well, this last weekend in 90 degree heat and 60% humidity all changed except for accuracy. Extreme spread became 109 fps and sd out the window. Dr.C

Did the average velocity go up or remain the same? In other words, did your extreme spread go equally to lower velocities as it did to higher velocities?

One thing I have noticed when shooting through a very hot barrel is that if I chamber a round into a very hot chamber, the amount of time it sits in there cooking before I pull the trigger can affect pressures. This isn't too educated and may have different results with different powders of course.

wink; Velocity went to the high side. I keep the velocity around 2200 fps w/ 500gr bullets and one round out of five jumped up to 2309. Thanks Dr.C

Switch to one of Hodgdons Extreme powders and you won't have that problem.

465H&H

I am loading some H4895 now, it has always shot well in my rifle. Looks like there may be some additional benefits to it as well. Thanks Dr.C

Hello,
Believe you will find Varget as one of the most tolerant powders regarding temperature ranges. Many long range shooters us Varget due to the very feature of the powder for hours on the range in high temperatures can cause problems.

I long ago settled on WW748 in my Lott and .450 Ackleys. Max power with no issues. Try it you'll like it.-Rob

Hi Doccash,
You want to go to a temperature stable powder to have consistent velocities between hot and colder temps. The velocity difference that your seeing is probably too small to change your barrel harmonics enough to noticeably effect your accuracy. WW748 and many of the ball powders are temp stable as well as many of the Hodgdon powders.
Take good care,
Dave

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WW748 and many of the ball powders are temp stable

What about AA 2230 (not for the Lott but in general)? Is it temperature stable?