Just got back from Oregon from a deer hunt, didn't get anything but still had a blast hunting with my buddies. Anyhow Before I left here in Arizona I worked up a load for a 300win mag using RL-19 it shot 1/2 inch groups here in Arizona the Temps were aound 92, 93 degrees. I get to Oregon and it is 70 degrees I shoot the 300 win mag with my handloads to verify zero holyshit shot gun patterns at 100yds. So I try some facotry stuff and less the 1/2 inch groups. Is RL-19 that sensitive to temp changes?

John

quote:

Is RL-19 that sensitive to temp changes?

Yep, all the Alliant powders are although I've been told that RL15 has been made temp tolerant because of its military use.

You face much the same problem I did for years in developing loads in warm/hot weather then expecting them to be the same in the cold. Any time your temperature is over 70° ANY propellant goes up in pressure. That affects accuracy and velocity in colder weather. For years I used to use RL22 in a 338 Win Mag. I chronograph everything at the range and I chronographed those same loads near the site of some late season hunts in Montana and Wyoming. I was shocked to see that the loads in cold weather lost over 200fps in velocity. The groups were larger though still "good enough". Since that time I've gone to the more temperature tolerant propellants as made by Hodgdon and Ramnshot. I've also given up developing loads when the temperature rises above 70°/75°. Loads WILL NOT perform the same.

For a good while when still using Alliant powders, I increased the charge by one grain when going into colder conditions but that was just a guess though a successful one. Now my hunting loads are all using the Hodgdon or Ramshot powders, and I don't alter the loads based on performance when the temperature rises above the mentioned threshold. The temperature tolerant powders don't lose much in velocity and performance in the cold providing you don't develop loads in weather above that threshold.

How do you know for sure it was the powder. Does your rifle have a wood stock? Could the wood stock swelled do to the damper air in Oregon vs dry air in Arizona and put pressure on the barrel? For all I know you may have a fiberglass stocked rifle.

It has a fiberglass stock. Like I said I tried some factory stuff to make sure it wasn't the rifle and it shot them just fine.

I have experienced the same issues with the alliant powders, specifically RL-19, 22 and 25. I had some fantastic groups in three different rifles/calibers - 30-06, 7mm Wby and .300Wby in warm weather and had them all fall apart in the cold. I have gone to Varget, H4831SC and H4350 respectively and have managed consistency and accuracy across the board now. All with Barnes TSX and or Sierra SMK's.

Hey 323, Back when RL-15, 19 & 22 came out I tried about 3 jugs of each. Always had Pressure Fluctuations as I approached a SAFE MAX Load.

Gave them to a buddy and he gave me a jug of RL-25. Same Pressure Fluctuations for me.

After he messed with the partial jugs I gave him, all the Powder went on his garden.

It may have just been the "Early Lots" we had, because I see people speak well about the various RL Powders all the time. Then again, perhaps they just haven't shot enough of it under different conditions to know how it really performs.

I am having the same issue. Loaded my 25-06 with 54gr of RL19 behind a Barnes 100gr TSX on a nice sunny 85-87 degree day and was shooting half inch at 100 yards. Go home clean the rifle and go back the next morning and it is sunny but 55-57 degrees and the same load will not shoot better than an inch and a half at 100 yards now. Look like I may be looking for something less sensitive since it is only going to get colder as the season progresses.

I use R19, R22, and R25 extensively, and I haven't noted accuracy differences at temperatures usually encountered at the range (~85oF) vs. those usually encountered while hunting (~40-55oF). But, as ambient temperature rises, pressures and velocities will increase. Sometimes unexpected high temperatures occur while hunting, and for these periods, I carry ammo loaded one grain less. Not because I'm worried about accurracy drop off, but because I don't want a blown primer or stuck case in the chamber, while the big buck walks over the hill.

If ATK/Alliant could make RL-19 and especially RL-22 significantly less temperature sensitive I wouldn't need any other powders besides RL-15 for all my hunting ammo.

I've been using RL-22 in my 7mm Rem. Mag. since forever. I have had no problems with temperatures as low as 35 below to 98 above.

I use RL 15, 19 and 22 for about 80% of my rifle reloading. I have never had an issue of pressure or accuracy due to a temperature change.

I went through the period of trying to ring every FPS from my rifles. After 30 + years I've concluded that the animals I've killed never knew the were hit with a load 50fps faster or slower. If I really need that extra speed I grab a magnum.

This load was not even a max load.

I'm w/ Steve, Never had any difference w/ R22 in my 7RM from cold too hot. If anything, it shot alittle better in the cooler temps.

Reloader