cold weather and velocities

[wild thing]

Does anyone have an idea about how cold weather affects velocity in black powdes cartridges? I checked the velocity of my loads in 38-55 this weekend and found they were going at 1090 to 1106 feet a second. I should have tried them out last fall but didn't. It was about 8 degrees saturday morning . The groups were about an inch to inch and a quarter larger than in the fall. Of course I blame this on the cold and not being able to hold steady. My home made lube let me down as there was hard fouling in front of the chamber,I tried blow tubeing but ended up patching between shots. There was a 10 foot per shot extreame spread. john

[NickSS]

At that low a temperture I would expect the blow tube to not work as the air was probably dry and the moisture from your breath froze between shots. I alway use a patch dampened with 50-50 antifreeze between shots when it gets that cold. Also you lube will be thicker if it is the same as you warm weather lube. Generally I add some vegitible oil to my lube for winter shooting to keep it soft. As for your group size mine grows a bit in the winter due to frozen fingers even inside a glove.

[Lead pot]

The blow tube will work just fine. And yes you will loose some velocity.

[pulaski]

What Nick said . At our monthly shoot on Sun. I noticed the guys who use blow tubes had larger groups than normal . A couple talked about hard hard the fouling was .
I would guess the slower results were caused by hard fouling and not the result of a cold BP load .
Jusy my .02
Steve

[Boz330]

Density altitude. Cold air is denser than warm air. Add to that the fact you are shooting big boolits very slow and it makes a difference. The lube and fowling will enter into this equation as well.

Bob

[bigted]

wowww so at -40 degrees the boolit may just stay inside the barrel or like everything else it would simply fall to the ground in front of the muzzle. then when the real [-55] cold starts it [the boolit] will just stay inside the case having warmed the rear portion just a bit with the ignition of all that black powder.

i know...smart ass....who needs em? when its that cold i stay in and close to the fire and eat moose stew and dream of nice 15 to 30 degree days in fall when hunting is good.

should have guessed someone was gonna spew some stupid on here huh? oh yea and this.......welcome to the site...i see only a few posts and want to say welcome and pls dont hold the smartass over me for too long.

[Bullshop]

One thing I have noticed in the very cold temps is that the energy of the firing pin strike seems to be reduced. This could be partly due to any residual liquid lube left on any moving parts in the lock or and maybe just the steel itself being more sluggish in the extreme cold.
I found that it was important to remove any trace of liquid lube and re lube with a dry lube such as molly.
In about -50F I did a test with a TCR rifle that was not winterized in this way. The caliber was 22/250 and the ES for the shot string ( cant remember how many) was if memory serves in the 800 fps with some total misfire.
My fear was the barrel steel becoming brittle enough to shatter.
When I was very young I worked in a junk yard and on things like RR rail in order to save cutting gasses we would just nip a notch in the edge of the rail and wait for very cold weather. When it was cold enough you could walk down the rail with a sledge and break each section clean off with a good rap from the sledge.
That memory makes me a bit nervous about shooting in extreme cold.

[August]

The "rule of thumb" we use -- and it seems to hold up well in practice -- is 1 m.o.a. of elevation for every 10 degrees F of temperature difference when shooting at 1000 yards.

There is the double whammy of lower initial velocity due to cold and increased air density due to cold.