Author Topic: temperature affecting accuracy? (Read 511 times)

josebd · « **on:** November 18, 2004, 06:10:01 AM »

had some .243 loaded up with some h4895 38.5,shot great back in warm weather,shot some in cooler weather wont group with a damn. went up to 39.5 groups came back. anybody else experienced this?rifle was a howa 1500 22" barrel.

Willyp · « **Reply #1 on:** November 18, 2004, 11:26:16 AM »

Yep! In a 223 and my 308.Both using ball powders.

dave284 · « **Reply #2 on:** November 18, 2004, 05:52:16 PM »

The way I understand it the cooler temps lowers pressure, which lowers velocity,changes barrel vibrations,etc.. . Hence the reason for temp insensitve powders. Going back up 1 grain probbably put you back to the status quoa in the cooler conditions. You may want to back off a grain when warmer conditions return. Just curious, have you by some chance shot the loads trough a chronograph at the temps that they perform well?

josebd · « **Reply #3 on:** November 19, 2004, 01:39:53 AM »

not yet,but i will

josebd · « **Reply #4 on:** November 20, 2004, 02:41:35 PM »

well i keep messing with it and it still wouldn't group,took the rings off my scope(weaver rings) and noticed the top rings on the inside was shiny. took rings off my remington 700,and put them on it,and my groups are back,finally!!!!!! 3 shots .386 group.next time ill know what to check,couldnt believe i had a powder problem,so know i know!

dave284 · « **Reply #5 on:** November 20, 2004, 06:33:26 PM »

Sorry that I steered you wrong, but I was under the impression that your groups were as good with 39.5 grains in cooler weather as they were with 38.5 grains in warmer weather. Was I mistaken?

josebd · « **Reply #6 on:** November 21, 2004, 02:11:16 AM »

well,at the time thats what i thought,but i think the ring problem was messing with me!