I have been reloading for about a decade now, but only recently have I really entered the realm of handloading to tailor loads to my rifles. I have become very intrigued with the effects of outside temperatures on the performance of my loads and am wondering if anyone here can give me some good advice on what to look for in an outdoor thermometer, as well as what I can expect to pay, and where I might be able to aquire one.

Thanks for your help in advance.

.300winnie

I just have a standard one like you would pick up at any of the 'marts or a hardware store. Be sure you don't handle it that much as the heat from your hands will cause it to give poor readings. Also keep it out of direct sun too. I think placement is more critical than brand or type.

A diffrence of a couple of degrees isn't going to make a diffrence in velocity that you can see. Now 20 degrees is a diffrent story, and most any thermometer is fine enough for that.

Scout Master 54

Fluke 52II - one lead for ambient air, a clamp probe to use on the barrel. A regular piece of data collection during load development for me. Gives a true insite to heat rejection and how it relates to performance.

Sm54 - I've found as little as 3 degrees affects performance from my single shot handguns. Not so much in the velocity department, but in the accuracy department. Those "fliers" happen for a reason.

Are we talking outside temperature at home while you are reloading or outside temperature at the range when testing loads?

Outside temperature when testing loads.

Sinclair has a digital that is also a hygrometer. That's what I have. Paid about $40. Radio Shack has almost the same thing for quite a bit less. You are dead right that temperature makes a difference. I've not noted much change in humidity but I think there is more effect down range for it while the temperature affects even the internal ballistics.

Remember that your chamber gets hot. I have noticed that velocities are a god bit higher if I've chambered a round in a warm chamber and don't fire it for a little while.

If you want to know how your load will behave in 32 oF (0 oC) temperatures, you can take some ammo to the range in a Ziplock bag in a cooler full of ice. No thermometer needed.

H. C.

I'm not sure that would work, Henry, as your rifle would be the same temp as the surrounding air. But then, I don't think I'm a good enough shoot to discern a difference in my POI that would be caused by a three degree difference in temp. I am sure my shooting buddies have gotten tired of me blaming a varying breeze that only blows when I'm shooting for my shitty performance; now I can blame changes in temperature. Wow!

If a load showed a velocity change of 150 fps from 70 degrees to 90 degrees that would be (if linear) 7.5 fps per degree F or 15 fps for two degrees. Well within the ES and Std. Deviation I often see. My loads must not be as sensetive as some. I'm with Beemanbeme thanks for the excuse!

I would be inclined to think that a cartridge left in hot chamber for a period of time would have an effect irrespective of the ambient temp.

Scout Master 54

Harbor Freight has little general purpose thermometers, sort of styled like little meat thermomenters, for about $5. Plenty good for checking ambient.