temperature and testing reloads

[anweis]

It's 0 F outside and i was wondering if this is too cold to effectively try some reloads that i have? These will be used at about 40 - 50 F, actually. IMR 4350 powder (41 gr.) and CCI BR-2 primers...?
Would the cold affect the burn rate and cartridge performance, or just me?

[Graybeard]

Dunno if it's too cold for the powder but it's dang shore too cold for me to go out and shoot. Such extremes to have some effect on both primers and powders if they are not made to be temperature insensitive. How much effect only testing in both temp ranges can say.

[drdougrx]

I notice a definate vibration when the temperature gets a bit under 32 degrees.  It does have an effect of group size...usually I go into the range house and the vibration stops.....

Seriously....I've been told but have not experienced any noticeable change in group size.  As to effect on components...they say in really cold temps, velocity decreases and visa versa in the heat.....a temp stabilzed powder should help, but, I haven't seen anything specific....


Anyone?

[gypsyman]

Talked with several hunters that hunt extreme cold. Will use nothing but magnum primers, as they have had problems with standard primers at low temperature's. But I know if it was me, I'ld make sure the load I was hunting with, was tested at the temperature I would be hunting in. Or, at least as close as I could get. If I shoot at a much warmer temperature, would definetley watch for pressure signs. gypsyman

[Larry Gibson]

Yes the burn rate does change (gets slower) as the temperature gets colder.  How much depends on the powder used and the cartridge. With most extruded powders (excluding Hodgdon's Extreme powders) it is not a good idea to develop loads in cold weather for use later in hot weather.  What may seem to be a safe load developed at 30-40 F temperatures may be over the top in 80-100 F temperatures.  Best to work up Max loads in the max temperatures they will be used in.  I use 4350 in my '06s.  With 180 gr bullets I get right at 2700 fps at 70-75 F.  At 32 F I get right at 2660 fps. 

I've not chronographed the '06 in colder weather but I did my varmint rifles in .223 and 22-250.  In the .223 I was using BR primers with 4895 and H335.  In the 22-250 I was using CCI 200s with 4895.  On a cold day at 10-15 F many years ago I got severe hangfires with both cartridges and ES over the chronograph of almost 300 fps.  I switched to Winchester primers because they are hotter and made to ignite ball powders and never had the problem since.

The BR primers may also give an ignition problem with 4350 when that cold.  This is mostly the case with slower burning ball powders.  That's why most use magnum primers or Winchester primers (made for ball powders) for use in cold weather.  I've not used the BR primers with 4350 in cold weather but I have shot lots of elk in down to -8 F with WLR primers under 4350 in my '06s.

Larry Gibson

[wncchester]

" It's 0 F outside and i was wondering if this is too cold to effectively try some reloads ..."

That would be more fun than I could stand. 

But, while it would make some difference in powder burn it wouldn't be vast. 

We work on an artifical temp scale but chemical/physical things work on an absolute temp scale.  In absolute, 0 F is actually 460 degrees while 70 F is 530 degrees, or 15% warmer.  That makes a LOT of difference to us but it's not a lot of change to most inanimate stuff.