Reloader 22 - How temp sensitive is it?

[rg1911]

Some time back, I had worked up a load for my 6.5-284 using RL-22, Berger 140 VLD, Federal Match primers, and Norma cases. Rifle is a trued Remington 700 with Pac-Nor barrel. The load was on the stiff side.

Finally found some Lapua brass and did another load work-up using the same set of components. At .6 grains less than the previous load, I got some subtle pressure signs -- smoke from action and primer in the magazine well.

Back home, I checked:

1. Powder charge. It was right on the money. Also the same lot of powder.
2. Seating depth. Also right on and set back from the lands.
3. Neck diameter of loaded round. Exactly the same as the Norma loads (of which I still had a couple for comparison).
4. Case capacity. Almost the same between the Norma and the Lapua. (About a 1/10 grain difference with the Lapua having a touch more capacity.)

The only difference of which I can think is I tested the Lapua loads on a day that was about 95 degrees F, or about 25 degrees warmer than when I developed the load using the Norma brass.

Is RL-22 that temperature sensitive?

Thank you,
Richard

 

[BuzzBoss915]

This is a personal opinion, based on my experience with R22 in my 25'06Ackley, 210M and 100gr. Nosler BT. Hunting northern Nevada winter conditions and southern Arizona in the summertime. I think R22 under the conditions I have encountered IS (surprise!) temperature sensitive. Bearing in mind that I always check my zero under local and ambient conditions, point of impact changes; can change. THEREFORE: I always use a slightly under max load, (1.5gr.) to avoid things like pierced primers; a prudent thing to do.

Secondly, don't just blame the powder. If the rifle is out and exposed to midday sunlight conditions (including chambered rounds), these things will affect the most temperature stable propellants you can find, it's simple physics. My opinion is that ambient temperature is reality, and temperature stable powders, and the consideration of such, is overrated. BB

 

[mclevela]

RL-22 is a great powder but it is temp sensitive. Keep your ammo and rifle out of direct sunlight before shooting on warm\hot days will minimize the temp problem.

 

[rg1911]

Thank you for the information. I've worked up a lighter load that is giving only very slight pressure signs at 95 degrees ambient temperature. It doesn't group quite as tightly, but I won't worry about spontaneous disassembly of the rifle.

Richard