Technical question regarding temperature and powders.

[jtoews80]

To my understanding and experience, subzero temperatures will affect and decrease velocity with most loads to some degree. Particularly if you’re using a temp sensitive powder. However, what happens if your powder is at a conventional temp of something like 65-70F( 15-20C), but your bullet is travelling through air that is subzero or in the 0 to -30F (-15 to -25C) range?? Theoretically, ie according to Google, the cold air would be more dense and will also lower your BC, but you won’t have the 100-150 FPS velocity drop caused by cold components and barrel.

I’m thinking about modifying a small single axle atv trailer (6’x12)’ into a heated shooting blind for hunting coyotes and target shooting in our cold winter months. An Amazon diesel powered space heater that’s worth $300 can throw 8000 BTU and will easily keep a body comfortable when lying prone, likely for several hours if a person wants to be out there that long. Add in a couple layers of silver bubble wrap insulation underneath and a tarp and/or tarp with bubble wrap liner you’ve got a pretty decent chance of keeping rifle and ammo at summer temps and only having to fight with the BC differences. The biggest variable I can see will be keeping the barrel almost completely inside the heated environment and the temps semi consistent because having any part of the barrel exposed would tighten tolerances and throw your velocities all over the place.

Has anyone done something like this before??

 

[xphunter]

How far will you be shooting typically?
The best thing is to just put a target at your max distance, and shoot it, under the same similar temperature conditions.

 

[RL338]

Best thing to do is download a good ballistic app and enter your environmental conditions.

 

[salmonchaser]

Go for it, why not. If the rancher who swore he would never sell to the yuppies had never sold to the yuppies I’d have a winter shooting shack at the back of the barn, but now it’s just not a safe thing to do.

 

[jtoews80]

How far will you be shooting typically?
The best thing is to just put a target at your max distance, and shoot it, under the same similar temperature conditions.

If I stick to the local range I’m capped at 300m or 330 yds, once the pastures are empty, I have access to 800 yds, but that’s always in winter.

 

[300WSM]

If I stick to the local range I’m capped at 300m or 330 yds, once the pastures are empty, I have access to 800 yds, but that’s always in winter.

I don't mean to sound malicious as I am saying all this in the most mild of ways...
but the climate ordeal always makes me roll my eyes.

Our industry..possibly more than any other is the trendiest industry I swear on it.
In other words if the right author makes an article in a gun rag about something then you better believe it will catch fire and thus the industry must respond.

Realize how many matches, game harvested, and just good shooting groups have happened over the years decades and moons ago...well before any chatter went on about the weather and ammunition performance.

It's just funny to me because to me the climate impact is negligible at worst. A non phenomenon at best.

But hey...the moment someone said this powder is "impervious to the weather"...look out. Everyone started thinking their gun shot around corners and couldn't hit the ocean from the pier if shooting in unfriendly weather.

Again...all the game harvested and decent groups shot in bad weather be damned over all the years. I guess that just didn't happen.

As far as your shooting blind...

That is a great idea! I'd love to see some pictures of that

 

[PJGunner]

"To my understanding and experience, subzero temperatures will affect and decrease velocity with most loads to some degree. Particularly if you’re using a temp sensitive powder. However, what happens if your powder is at a conventional temp of something like 65-70F( 15-20C), but your bullet is travelling through air that is subzero or in the 0 to -30F (-15 to -25C) range?? Theoretically, ie according to Google, the cold air would be more dense and will also lower your BC, but you won’t have the 100-150 FPS velocity drop caused by cold components and barrel."

The last few hunts I've done have been in northern New Mexico near the Colorado border. One hunt was done at 14 above zero and another at 4 above zero. None of the hunts were warmer than about 20 to25 above at the hottest part of the day. The hunts were cull hunts for cow elk so mostly one stepped out of the truck and took a shot at the game.

Usually on the day of the hunt, I'd stop at the NRA's Whittington Center to check the sights on my rifles. Shooting at 100 and 200 yards I saw no change in point of impact from any of the rifles tested. Cartridges tested were the 30-06. .35 Whelen, .280 Rem. and .270 Win. Normally I take two rifles on a hunt, the main one for the hunt and a back up. The main for those cull hunts has been the .35 Whelen and one of the others as back up. Only had to use a back up once when a scope crapped out at the range. The 30-06 got todo the honors.

Powder for the Whelen was RL15. W760 was for the 30-06 and WMR for the .280 and 270. I did bring a .300 Win. Mag to check out on one hunt and I used WMR in it as well. WMR which stands for Winchester magnum Rifle powder was another flop in Winchester's strggle to find a slow burning ball powder. It worked great in the cartridges I mention but was a disaster in the 30-06. I just happen to have a greater than lifetime supply.

Dunno if that answers your question but I think that if the ammo is shot withing a reasonably short time after being removed from a warm truck cab to very cold temperatures, ballistics probably will not be affected. Probably would after an hour or so but before then it think ballistics would be fairly normal as tested during warmer days.
Paul B.

 

[RL338]

I try to develop loads for hunting in spring or fall when temps are 50 - 60 degrees. Hunting season usually start out in the teens in the morning and warms up to the mid 30’s by afternoon. I’m not too concerned about 20 - 40 degree swing.

 

[grry10]

Maybe if I were shooting at extreme ranges all this might be relevant, but where I hunt it is rare to get a shot at predators beyond 300 yards. Even when we go prairie dog hunting/shooting I'm shooting a .22-250 (H380), .222 Remington (IMR4198), or .17 Remington (W760) with loads that were developed mainly in the fall, but do keep my ammo out of direct sunlight. These same rifles and loads are shot year around. I don't find powder sensitivity to be as much of a factor, but the wind OMG! When I do ladder tests looking for nodes, I don't see big swings in elevation. I'm not saying that velocity changes can't have an impact in competitive shooting, it can. But in my opinion, when it comes to hunting and shooting at reasonable ranges we have gotten anal and sometimes are try to pick fly sh*t out of pepper.

 

[jimbires]

I've never tried to test warm ammo shot in cold temps . I don't know how I could have repeatable conditions .

I have tested cold , and very cold temps with my labradar . I put everything in the truck and let the truck set out over night . go to our range set up and shoot . I needed to do this in cold temps to calibrate my rangefinder . I did this a few different times getting data points . I did this on an extremely cold morning , if I remember right about -30*F . this temp gave me hangfires , the labradar didn't want to work . it was a no info day . I did learn that in these temps things don't work right .

cold temps will affect velocity , and trajectory . a few years ago during rifle deer season I sat on our long range watching for a doe . it was snowing , if I remember right about -10*F to -20*F . it was cold enough I kept getting back in the truck to warm up . I kept my ammo in a outer pocket , thinking it would function properly at that temp . a couple doe showed up right at our one target . I tried to range them , but the snow in the air goofed up my rangefinder . it was giving me readings around 30 and 50 yards . I went to the truck and grabbed my dope book . I looked up dope for that target distance , dialed the scope , corrected for spin drift , settled in and thought this is nuts . I have never shot long range at this temp , so my dope book is useless. I watched the deer waiting for the snow to stop so I could use my rangefinder . some time after the deer wandered off , the snow stopped . I ranged the target the deer were feeding by , and my corrected dope for the weather conditions was 17 MOA different than my dope book . meaning my bullet would have landed 272 inches short . I probably would have never seen that miss , splash in the snow . I loaded my stuff up and came home .

 

[clearwater]

My best groups have been in the cold. Only when the temps are over 90F do i see variations. I am not a 600 yard hunter however.