Someone give me the straight information please. This summer in about 85 degree heat I worked up a load of 71 grains of RL-15 and 300 grain Barnes triple shocks in Federal cases that was amazingly accurate and lift the bolt with your little finger so I think I'm going with it. Now I'm hearing from some experts that this powder is temp sensitive and may be an issue in cold or hot weather. Our temps lately here have been hovering around the single digits and I thought about going to shoot this load to see if I'll get poor ignition or hang fire but now some fella's have me thinking I shouldn't shoot that powder.
What do you experts say?
This load is shooting .5 to .75" three shot groups at 100 yards so if I don't have to I don't want to fiddle with it.
Keep me straight fella's........

The US Army chose that powder, RL-15, according to one report I read some years ago, for sniper loads in .308 because overall it met their needs very well, including temperature stability.

It is about mid range on temperature sensitivity in my experience, and gives half the variation that something like IMR-4350 does.

I rank them like this:

H4350 and Varget extreme: 0.5 fps/degree F
RL-15: 1.0 fps/degree F
IMR-4350: 2.0 fps/degree F

This is from looking back at my chronographing and temperature versus velocity records in cartridges like .30-06, .375 H&H and .375 Wby.

I used 72.0 grains of RL-15 with the old Barnes XFB Cannelured .375/300grainer and got velocities around 2530 fps in my .375 H&H with 24" barrel, with 3/4 MOA for 3 shots. I was very happy with that and took it to Botswana. My brass was Winchester, a little roomier than the Federal brass, but my bullet also had greater bearing surface than the TSX. My primer was the GM215M, which is identical to the F215.

Our loads are probably very close to equivalent, assuming you use the GM215M/F215 primers, though there are always rifle differences to consider.

You have an excellent load that will serve well at any hunting temperature. RL-15 is one of my favorites, along with the Hodgdon extreme powders.

Don't sweat it, just go shoot it in the cold and see how good it is. Just check the zero when you get to where you are going to be hunting.

I would use your load with peace of mind.

So unless you are an Army sniper all this temperature sensitivity is another "the sky is falling" issue?

It is commendable that the Army and whomever else determined the need for the data and obtained same, as for hunting it appears that this much ado about nothing.

I use RL-15 in my 375 using 72 grains but with a 270 gr. Northfork SS. I have wondered about this as I have heard that RL-15 is temp sensitive. Good to here it isn't all that sensitive. RL-15 seems to be the perfect powder for the 375 H&H.

I have two 375s and load 71g RL 15 in both with 300 TSXs. I've shot them here in UT from 90 degrees down to -20 degrees. The variation is about 35fps between the extremes. IMO, you could only get into trouble if you worked up a max load at -20 degrees and them shot them at 100 degrees. happy shooting!

I cannot speak on the 375H&H, but, it is most definitely temperature sensitive for me in loadings for 9.3x62 using a 286 Nosler and in 416 Rem using a 400 Nosler. On both, loads that were developed in temps in the 40-50 degree range proved way too hot during temps above 80 degrees. These loads were neither hot thru the chronograph nor showed any signs of excessive pressure during the colder temps. Above 80 degrees, the primers would flatten out and the cases would stick. When reversed by loading for hot weather, the velocities would drop below acceptable levels when the temps dropped.

GVA

Agree with the above for the 416 Rem mag. Developed loads in 42 degree weather which worked fine. By hot summer time, the bolt could barely be opened.

Hello,
Have no absolute/scientific evidence, just suggestions/instructions over the years from those with a lot more knowledge than I regarding powders which serve best w/ varying temperatures and best I have used is Varget.
IMR4064 always provided me with excellent accurcy in the 308 out to the 1000 yard line, but needed to be careful about keeping sun off ammo w/ that powder. It gets quite hot at Oak Ridge, Quantico, Buntner, etc. and "south of the equator..."
Kept bandanna,towel,etc. over ammo no matter what the powder,but Varget always performed nearly as well, but not so temperature sensitive. Have been told by U.S. Army marksmanship unit that RL15 works very well, but also know that previous Palma Team Shooters used Varget (some years ago, not sure what they use now???.) Rule of thumb we used to follow was that for each 15 degree change of temp./upward would result in 1 moa of elevation(upward.)
At 1000 yards that is approx. 10". If you know that and adjust accordingly, you can keep in the "zone" or 10 ring, but the hotter and steamier it gets, shots will do some wierd things. I think back and some of the shots that went astray were due to mirage and my misreading rather than the heat/powder relationship. It's always easy to blame the load, rifle, stock, trigger, etc. etc., but usually the missed shot or near miss is due to the performance of the trigger puller.

If you can use it with your particular load/bullet/caliber, would highly suggest Varget. (extra bonus is that it is easy to load w/ powder thrower!!) Tough to beat if you can use it. Just my experience and sure others may have other suggestions.

I have figured out from experience that I am more temperature sensitive than RL-15.

Seems to me that the difference in velocity/degree F would have something to do with the volume of powder being burned as well. More like a percentage, say.

Jon put his finger on it exactly.

quote:

Originally posted by mrlexma:
I have figured out from experience that I am more temperature sensitive than RL-15.