How Much Does Temperature Affect Velocity?

[Quick Draw McGraw]

Hey guys,

I know temperature can affect velocity. It's been in the 50's here, so not too cold. But my reloads have not been reaching the velocities I hoped for as of late. Just wondering if this might be a factor.

[sixshot]

This topic gets brought up a couple times a year & I "think it's about 2 fps for every 1 degree, might be off because I just came in the house & it's minus 9 degrees outside! Some of the newer powders are less temperature sensitive than the older powders.

Dick

[JM]

Depends... Are you shooting into the wind, or with it?

[magnumwheelman]

IMO there are a lot of variables... powder, primer, case shape, and size... as well as bullet weight, as well as the temperature extreme cold and heat...

Pistol cartridges less than bottle neck rifle cartridges...

I've seen as much as 500 or more fps between -5 or -10* and 80 or 90* with cartridges like 223, and 30-30 out of Contenders... also my 338 Winchester magnum

Would suspect a high pressure/performance round like the 454 Casull would suffer more than a cowboy level 45 colt, also the super mags which may have trouble lighting up an Uber case full of slower power

[zeus]

This is an interesting list that was done on Snipers Hide a while back. I've found it to be fairly accurate on the ones I've checked personally.

HS-6 1.21fps per *
H110/W296 1.24 fps per *
Imr4227 1.17fps per *
Lil’ Gun 1.31 fps per *
RL10x .71 fps per*
Benchmark .44 fps per *
Imr3031 .73 fps per *
Imr8208xbr .59 fps per *
H4895 .23 fps per *
Alliant Varmint pro .89 fps per *
Alliant AR comp .77 fps per *
Varget .19 fps per *
W748 1.32 fps per *
Imr4064 .53 fps per *
Ramshot Tac .91 fps per *
Imr4895 .87 fps per *
AA4064 1.11 fps per *
AA2520 .98 fps per *
RL15 1.52 fps per * from 50* and up
PP2000MR .99 fps per *
Imr4320 1.32 fps per *
Ramshot Biggame .98 fps per *
H380 1.44 fps per *
VV N150 1.08 fps per *
H414/W760 1.42 fps per *
Imr4350 .64 fps per *
AA4350 .47 fps per *
H4350 .29 fps per *
RL17 1.42 fps per *
Hybrid 100v .78 fps per *
RL19 1.61 fps per *
VV N160 1.24 fps per *
Imr4831 1.19 fps per *
Ramshot Hunter .86 fps per *
H4831 .36 fps per *
RL22 1.71 fps per *
Imr7828 1.36 fps per *
Magpro 1.01 fps per *
H1000 .21 fps per *
RL25 1.59 fps per *
Ramshot Magnum .87 fps per *
Retumbo .49 fps per *
US869 1.68 fps per *
H50bmg 1.64 fps per *

[Quick Draw McGraw]

Thanks guys. I appreciate it. So much to learn about when reloading. Thanks for the assistance.

[jsh]

That is some interesting info Glenn.
Dang Dick, if your right some of my "cat sneeze"'loads, I may have to drop the hammer today, lay the gun down and come back tommorow, lol. ;-) I have found that the slow poke loads WILL teach you follow through!

Anymore I try my best to work loads up in the summer. Then the first good cold snap I am off with the chrono,guns and ammo to check things out.

[500fksjr]

Jan 4, 2017 22:31:53 GMT -5 zeus said:

This is an interesting list that was done on Snipers Hide a while back. I've found it to be fairly accurate on the ones I've checked personally.

HS-6 1.21fps per *
H110/W296 1.24 fps per *
Imr4227 1.17fps per *
Lil’ Gun 1.31 fps per *
RL10x .71 fps per*
Benchmark .44 fps per *
Imr3031 .73 fps per *
Imr8208xbr .59 fps per *
H4895 .23 fps per *
Alliant Varmint pro .89 fps per *
Alliant AR comp .77 fps per *
Varget .19 fps per *
W748 1.32 fps per *
Imr4064 .53 fps per *
Ramshot Tac .91 fps per *
Imr4895 .87 fps per *
AA4064 1.11 fps per *
AA2520 .98 fps per *
RL15 1.52 fps per * from 50* and up
PP2000MR .99 fps per *
Imr4320 1.32 fps per *
Ramshot Biggame .98 fps per *
H380 1.44 fps per *
VV N150 1.08 fps per *
H414/W760 1.42 fps per *
Imr4350 .64 fps per *
AA4350 .47 fps per *
H4350 .29 fps per *
RL17 1.42 fps per *
Hybrid 100v .78 fps per *
RL19 1.61 fps per *
VV N160 1.24 fps per *
Imr4831 1.19 fps per *
Ramshot Hunter .86 fps per *
H4831 .36 fps per *
RL22 1.71 fps per *
Imr7828 1.36 fps per *
Magpro 1.01 fps per *
H1000 .21 fps per *
RL25 1.59 fps per *
Ramshot Magnum .87 fps per *
Retumbo .49 fps per *
US869 1.68 fps per *
H50bmg 1.64 fps per *

[500fksjr]

What is the starting temp ie: 32 degrees going down?

[bigmuddy]

Jan 7, 2017 21:44:31 GMT -5 500fksjr said:

What is the starting temp ie: 32 degrees going down?

I would say the starting temp would be the actual temperature when you first chrono'd the load. Then it's up or down from there.

Dan

[zeus]

Jan 7, 2017 23:03:43 GMT -5 bigmuddy said:

Jan 7, 2017 21:44:31 GMT -5 500fksjr said:

What is the starting temp ie: 32 degrees going down?

I would say the starting temp would be the actual temperature when you first chrono'd the load. Then it's up or down from there.

Dan

Correct, that's how I've looked at it as well. Your load and temp then an estimate from there will be based on temp change from your benchmark.