Heat affect on black powder guns?

[His lordship.]

Traditionally I have only shot my cap and ball revolvers in the Spring and Fall, the Winter is too hard to put on the caps with gloves, and the Summer makes the Crisco oil liquid and run for plugging up the front of the cylinder to prevent chain fires.


I used to have a Kentucky type single shot pistol and used it in pleasant weather only.  I have a Plains pistol that could use some shooting and this Summer has been especially hot.  Is there any heat related safety issues with firing a single shot muzzle loader?


Thanks.

[Nobade]

I don't think you will find any safety issues, but the hot and dry weather dries out the fouling really fast. In a round ball gun this isn't really an issue, just make sure your patches are moist enough to clean the bore well when you are loading. Since a ball gun is cleaned every time it's loaded, the fouling doesn't really build up. I like to use moosemilk to wet the patches when shooting at the range, I have a little glass bottle of it and tip it up to wet out the patch just before I load. (spit patches work well with my small caliber guns, but I don't have enough spit for a 58 or 73!)  I do think if you used greased patches you might have a problem, you need to water to clean the fouling off.

Now cartridge guns are another matter. Sometimes it is so hot and dry around here that no amount of blow tubing can keep the fouling soft. The result is poor accuracy and a leaded bore. I don't like to shoot much when it is 95 deg. and 10% humidity! But I have never had any problem with roundball guns no matter what the temp.

[coyotejoe]

I use spit patch for the vast majority of my shooting and the only problem I find is that a rifle left in the sun will soon get too hot to handle. One big plus for blackpowder is the fact that it is not temperature sensitive like smokeless. A smokeless powder rifle load developed at 70 degrees may be way over pressure at 110 degrees and substandard at zero degrees. Blackpowder doesn't seem to care about temperature, but of course I do.

[Gatofeo]

I am uncertain about the heat sensitivity of propellants designed to replace black powder, but black powder itself fares quite well in the heat -- as long as it doesn't get hot enough to ignite.
Smokeless powder degrades rapidly when exposed to high temperature. It's affected by it. When the Germans invaded North Africa in World War II, they discovered that their small arms ammunition produced higher pressures because the powder was affected by the high heat.
I've read that German munitions factories began making special ammo for issue to the Afrika Corps, to counter this effect, but can't confirm it on the net. It may be apocryphal.
But black powder doesn't degrade in high heat. As has been noted, the greatest effect is probably upon the lubricant. I live in the remote Utah desert where temperatures can reach 110 Fahrenheit (43.5 Celsius) and humidity can be down to 6 percent. I've shot my cap and ball revolvers in such heat, and found that I have to use extra lubricant to keep fouling soft.
Normally, a felt wad lubricated with Gatofeo No. 1 Lubricant (named after me, but based on a 19th century recipe) between the ball and powder is sufficient. Under such extreme conditions, however, I've learned to put a light grease (composed of beeswax and olive oil) over the ball as well. This keeps the fouling soft and the bore free of fouling.
In a rifle with patched round ball, under such heat, I'd suggest a lubricated felt wad on the powder, with a lubricated patch holding the ball. The lubricant should be water-free if you plan to keep it loaded for more than a few minutes, to avoid rusting. Crisco would be fine.
A felt wad should NOT be used under conical bullets that have a hollow base, lest the wad be driven up into the bullet's hollow base and prevent it from bumping up to engage the rifling. The use of a felt wad under a hollowbased bullet probably isn't dangerous, but it will surely affect accuracy. I base this on personal experience years ago, with my .50-caliber muzzleloading rifle.
Rather than using a felt wad under a hollowbased bullet, simply fill the hollow with lubricant. To prevent contamination of the powder, a thin wad of waxed paper -- the kind sold on a roll to wrap food -- will be sufficient barrier. It will be consumed in the first few inches of combustion, I suspect.
In hot weather, keep your powder and caps out of direct sunlight. Don't leave them in your vehicle, where temperatures can reach 150 degrees or more. If you must, crack the windows and put them on the floor where the cooler air will be found. Cover them with a thick towel or blanket, for insulation. Keep them separate.
A cooler of ice would be good for storing powder and caps in a vehicle. Put them in Zip-Loc bags to discourage moisture and, obviously, raised above the level of the ice or any possible water.
Years ago, on a hot Idaho day, I got into my pickup after it had been parked for hours with the windows up. I immediately noticed green plastic parts all over the interior. My pressurized butane lighter had burst from the heat! Since that incident, I've gained a new respect for the temperatures that can be generated inside a vehicle.