Temperature effect on pattern

[55esox]

Went out this morning to run a few Nitros from a new box I just got in and a little confused. Typically my gun (870 Supermag w/Rhino .660) puts around 260 in a 10" circle, but the new batch only put in on average 175. The temp was mid 40's, and I expected a bit of a drop, but that seemed excessive to me. 

Nothing was really changed in my procedure. Gun was cleaned before shooting, and bore snake after each shot.

Thanks

[Gobble!]

I noticed a 50 pellets drop today shooting Hevi #7s.

[learn2hide]

I've shot three days this spring so far...1st and 3rd day were 47/48 degrees.  2nd day was 58 degrees.  Same loads shot 20-30% better on the warmer day and both cold days I got disappointing total results out of loads I have previously shot much better including LBXR, FED HWT, and HEVI-13  Only one small example but there were no other variables.  One notable result: I was shooting LongBeard XR #5 through a swabbed but not perfectly clean barrel with the same .660 Roberts choke.  152 and 169 in 10" in 48 degrees vs 197 in 10" in 58 degrees.  I'm expecting at least 320 in 10" when it's 85 degrees! 

[d.winsor]

Some years I have patterned my gun at 32 degrees, and other years at 75 to 85 degrees.  Never noticed a difference in killing birds.  In any gun I would count # of holes in a 30" circle one time just to see what % of pattern I was getting with a choke combination, the shell was always a Winchester supreme HV #5 shot, 3" or 3 1/2".  As long as the core of the pattern was at poa I didn't worry about it.  After I pattern a gun I don't worry about it anymore.  One time before turkey season I will check the pattern of the gun I am going to hunt with, It might be 45 degrees or 70 degrees, they all kill turkeys at any temperature I hunt in.

[DirtNap647]

I hunt cool mornings

[turkey_slayer]

I hunt cool mornings

Same here. I pattern/sight in around 35-40 degrees as temps usually range from 25-45 here. I shoot in July if I want to see big numbers but that does no good in April

[learn2hide]

Please don't confuse killing turkey's with putting up paper numbers...but picking a load from several choices means evaluating all factors

[turkey_slayer]

Please don't confuse killing turkey's with putting up paper numbers...but picking a load from several choices means evaluating all factors

I'm not but I believe a person should always pattern what the early morn temps are. Test whatever loads in that temp range. Patterns will never decrease going from cold to hot but they will vice versa.

[learn2hide]

Please don't confuse killing turkey's with putting up paper numbers...but picking a load from several choices means evaluating all factors

I'm not but I believe a person should always pattern what the early morn temps are. Test whatever loads in that temp range. Patterns will never decrease going from cold to hot but they will vice versa.

Agree

[gwa]

I patterned this past weekend and temp was @ 40°, I was very satisfied with the results. Thanks for bringing to light this variable that I never considered....