Cold affecting accuracy

[jinxx4ever]

So i did a search and couldn't come up with anything. Don't even know if this the correct place to ask this , but here goes. Does cold affect the barrel as far as accuracy if staying out in the cold all day? I know temps affect powders. The reason i ask is i am trying to work up a load for my Proof Research Carbon Fiber wrapped barrel i recently purchased. 6.5CM, 26" 1:8 Loading Berger 153.5's H4350 42gr. nothing hot. Not setting up the labradar just working on loading depth for a tight group. The loads i loaded last night and shot first thing today were pretty nice. The gun stayed outside on the bench all afternoon. Windchill below freezing. I just went back and forth to my reloading room and worked up 5 rounds at a time, so the powder was never affected by the cold, but by the end of the afternoon, even going back to my first loads that were nicely grouping at noon, are now opened up. I did other things thruout the afternoon, so maybe I'm getting tired by the end of the day? Or does the cold affect the steel in the barrel which could cause groups previously tight to open up? I know steel contracts in the cold like a lot of other things. Thought's? I'll appreciate any imput, thanks

 

[spife7980]

New barrels speed up as they wear in. Should have run the chrono, it might have told you that.
What had shot great brand new may actually be going 100 fps faster now and be out of its node that you thought you found.

 

[rustyinbend]

I'm with @spife7980 ... the Labradar tells you so much. Let "velocity" tell the story here. Otherwise, it's all just speculation.

 

[Steel head]

Brand new Barrel?
I always choose a mild load with a cheap bullet and go shoot it 100 times, also a great opportunity to fire form new brass.
After that barrel is up to speed, I’ll know if it’s a decent barrel and brass is once fired and any load development won’t change on me because of green barrel or new brass.

 

[Squibbler]

Does cold affect the barrel as far as accuracy if staying out in the cold all day?

In my experience....yes.

I have no evidence, only observational data that temperature definitely affects accuracy. In agreement with your questioned observation that colder temperatures lends itself to better accuracy.

My theory would be increased rigidity of the barrel and dampening of the harmonics. Every barrel has it's heating point, when heat lessens rigidity. This is observed after X number of rounds shot, a barrel can start to walk. This is more evident with hunting contours, walking sooner with less rounds. Whereas, bull MTU, target contours are more resistant by increasing rigidity. Shorter barrels likewise increase rigidity. I believe colder temperatures do the same thing... increase rigidity. Anything that increases rigidity has better accuracy potential and/or is typically more resistant to change.

This is at least my observational theories.

 

[E. Bryant]

Are you accustomed to shooting in the cold, and have you proven to yourself that it doesn't affect your performance? Because that's honestly the most likely cause for this variation.

 

[308pirate]

My theory would be increased rigidity of the barrel and dampening of the harmonics. Every barrel has it's heating point, when heat lessens rigidity. This is observed after X number of rounds shot, a barrel can start to walk. This is more evident with hunting contours, walking sooner with less rounds. Whereas, bull MTU, target contours are more resistant by increasing rigidity. Shorter barrels likewise increase rigidity. I believe colder temperatures do the same thing... increase rigidity. Anything that increases rigidity has better accuracy potential and/or is typically more resistant to change.

The kind of temperatures we're talking about here (temps that human beings normally encounter and are survivable) do not affect the material properties of steel to any practical degree.

Stiffness (what I think you mean by rigidity) is not affected by temperature at all until you start nearing the melting point.

Your theory is typical layman's nonsense.

 

[BrienM]

I sometimes wonder how many 100 & 200 yard bench rest matches are shot in the cold.. it seems to me like the people I know that play that game do not play that game much through cold weather.. seems like they shoot April thru September/October..

 

[308pirate]

I sometimes wonder how many 100 & 200 yard bench rest matches are shot in the cold.. it seems to me like the people I know that play that game do not play that game much through cold weather.. seems like they shoot April thru September/October..

For the same reason that all shooting sports in the northern part of the country have few to no events outside of that same time frame: because nobody likes to be unnecessarily uncomfortable doing what is strictly a leisure activity.

 

[Choid]

Guys, if I am shivering, will my ability to hold a quarter minute decrease?

 

[Ledzep]

So i did a search and couldn't come up with anything. Don't even know if this the correct place to ask this , but here goes. Does cold affect the barrel as far as accuracy if staying out in the cold all day? I know temps affect powders. The reason i ask is i am trying to work up a load for my Proof Research Carbon Fiber wrapped barrel i recently purchased. 6.5CM, 26" 1:8 Loading Berger 153.5's H4350 42gr. nothing hot. Not setting up the labradar just working on loading depth for a tight group. The loads i loaded last night and shot first thing today were pretty nice. The gun stayed outside on the bench all afternoon. Windchill below freezing. I just went back and forth to my reloading room and worked up 5 rounds at a time, so the powder was never affected by the cold, but by the end of the afternoon, even going back to my first loads that were nicely grouping at noon, are now opened up. I did other things thruout the afternoon, so maybe I'm getting tired by the end of the day? Or does the cold affect the steel in the barrel which could cause groups previously tight to open up? I know steel contracts in the cold like a lot of other things. Thought's? I'll appreciate any imput, thanks

Two things come to mind; powder/primer sensitivity to temperature, and small sample size.

There is considerable variation of the same ammunition from group to group using only 5 shots per. It can be from the shooter, but even if you isolate the shooter you are looking at a more-or-less normal random distribution of shot radius from the MPOI. Rolling the dice if you will. You're likely to get anywhere from the worst the load combo will ever shoot down to the .1's and .2's. A single 5-shot group won't reliably tell you what a load is capable of. I've made several posts about this subject but the TLDR of it is that 16-18 shots is the floor-- like the bare minimum number of shots to start quantifying accuracy potential of a combination. 20-35 is better. 35-50 never lies. Obviously 35-50 is not reasonable for traditional load development strategy.

I suggest shoot 10-15 in a group, if you're happy with it great. If not, drop powder charge by at least a grain. If that doesn't work switch powder and/or bullets. YMMV.

 

[E. Bryant]

For the same reason that all shooting sports in the northern part of the country have few to no events outside of that same time frame: because nobody intelligent likes to be unnecessarily uncomfortable doing what is strictly a leisure activity.

FIFY

Now that I've got the podium, allow me to lecture the crowd on proper bike tire pressure for riding in powder at 5F vs hardpack at 25F.

I'm reasonably tolerant of cold, but if it's much below freezing, fuck the idea of trying to shoot groups for load development. I'll (somewhat) gladly lay on the ground and ping steel, but that ain't the same as trying to tease out the difference between 0.1gr of powder or 0.010" seating depth. Save that shit for the first nice day of spring (or maybe the second, so I get a trip to knock off the rust).