Cold weather grouping problems updated with pics post #25

Shooting at cold temperatures is much more demanding than shooting during the summer. When you are all bundled up, your cheek weld has changed, the LOP has changed, you don't have the same sensitivity to the trigger, and when your body begins to cool off because you are shooting prone in the snow, you'll start to shiver. Now add in to this the fact that typically velocities are lower, barrel harmonics have changed, the air is denser, and where you might be more used to soft light in the summer, the winter produces harsh light that reflects off the ground and you might be experiencing mirage. I submit that if your 100 yard groups have gone from dime size to 4" there is more going on than the effects of temperature on your load.
 
Boomer said:
I submit that if your 100 yard groups have gone from dime size to 4" there is more going on than the effects of temperature on your load.
Click to expand...

200 yards . I only shoot at 200 yards with this rifle.
I am getting ready for another range visit now. I loaded a few round to max load. I also got a new trigger for Xmas. I cleaned the rifle in deep, Used oil . instead of grease.

Tonight I will have pictures :stirthepot2:
 
I am back from the range, my fingers are still numb. My Guess is was around -15 without degrees the wind factor.
I did not warm up the ammo like some of you suggested.
I think my issue was more behind the trigger, than the actual gun of ammo.
I got a new trigger for Xmas and I think this was great help.

So here are the results
IMG_0222.jpg

IMG_0223.jpg


Gotta love Quebec Safety tunnels. Feels like shooting from a cave
IMG_0224.jpg


This was as suggested Shots to warm up the barrel at 100M with cheap FMJ 55gr Winchester
IMG_0225.jpg



Upper left is 5 rounds Max load 24.8 I think 3 almost touching and 2 flyer almost touching. I know what happened here. It was my reloads, I did them yesterday night and 2 bullets did not seat like the other 3 they were about .010 higher and I readjusted the seating die. I think maybe the brass was shorter. That could explain why the flyers went to the same place.

Upper right 5 rounds with 24GR not much to say there looks like last week grouping .

Lower Left 4 rounds with 23.6gr

Lower Middle 4 rounds with 24.2gr

Lower right 4 rounds with 23.3 gr 1 flyer which was my fault.


IMG_0226.jpg


So I am not sure what to think now. Since the 4 rounds group were done with last week ammo that couldn't group last week and seems better now. I am saying it's probably the Shooter the problem and me Struggling with the 10 LBS factory trigger with frozen fingers and watery eyes. RRA 2 stage trigger is must for winter shooting Thank you Questar

I need more Ammo and more trigger time to really pin point the problem. One thing is sure my summer recipe is not working as good in cold weather
 
Bryan Litz has a guide in the back of his book (Applied Ballistics of Long Range Shooting) that has a farily comprehensive list (Actual G1 & G7 BC and a host of others), tell me what bullet you need data for and I'll see if it on the list.
 
Take a look on JBM, there is a list of bullets with lengths, you can also submit your measurements for any bullets that are not filled in on the list.
http://www.jbmballistics.com/ballistics/lengths/lengths.shtml
 
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