I have seen some post about Reloader powders being heat sensative, but wasn't sure if RL22 was one that was or not. I am working up a load for my 6.5 swede and some TTSX's. Seems to shoot well, but i notice a change in point of impact from my morning string to the later string when both BBL and day were hotter. Anyone have experience with this? I know that some might say the bbl being hot would do it, but the gun is well bedded and floated and was not overly hot. The air temp, and thus the ammo temp, was the main change. Thanks.

Various powders are landed with a bad reputation for this or that attribute from time to time. It is hard to get a handle on what is reality and what is hearsay. Even on forums such as this, offering unprecedented access to a large audience of shooters with personal experience, it is hard to get a clear picture. Experience seems to differ.

But, yes, RL22 is also one of the powders with a bad rap for being temperature sensitive. Depending on who you ask, you may also hear that RL22 varies quite a bit from lot to lot. Both attributes from time to time are also associated with other powders.

If changing POI with varying temperatures is the criterium, then a LOT of (all?) powders qualify, not just RL22. IMHO, there is a clear correlation between temperature and POI, I see this all the time on the range. The change may not be dramatic at shorter range (1-2 clicks @ 110 yds are typical for me), and not all types of shooting make the POI shift obvious. I observe it in shooting for points in target type applications - probably also because that is the type of shooting I do regularly (every week), and because it is a discipline in which POI is easily observed. Typically, I observe it with powders such as VV N130 or N133 - but I'm sure other powders would produce equivalent results.

In the calibers where I personally use RL22 (mostly for hunting), it is rare I shoot my guns regularly enough, nor do I require an unchanging POI to the extent that change in POI is easily observable. YMMV...

- mike

I have shot RL-22 in Africa at 100 degrees and in Alaska, Colorado and Alberta at -22, with no noticable difference in performance. Good shooting.

I was thinkin it might not be a big deal for hunting loads but wanted to clear up what i had been seeing. Thanks fellas.

This topic has been chewed on quite a bit at 24hr campfire. One of the guys that posts there did some hot weather/cold weather chrono work in the past year or two with new powder and found no difference. Another poster also did the same type of testing a few years ago and showed a somewhat significant (I can't recall the numbers) change in velocity.

I have yet to see someone do this with dated lots of powder. I suspect that perhaps Alliant has quietly reduced rl22's temperature sensitivity.

FWIW, I have found RL22 to be pretty consistent lot to lot (something I cannot say regarding RL19).

405wcf

I have no doubt that there is a difference in the cold weather performance of bullets loaded with any powder, giving extreme differences in temperature. My field experience has shown no perceptable difference in performance on animals, meaning Deer, Elk, Moose, Bear and Caribou, Cape Buffalo, Kongoni, Impala, and Zebra. I could see a slight difference on paper, say perhaps a fraction of an inch at 300 yards, but recognizing that difference on the animal would be impossible in my opinion. The difference of 50 fps on a 3000 fps bullet being discernable in the field, under field conditions would be neglidgable. On the target range with excellent Chronographs you might manage some slight differences, but in hunting conditions, not to worry, unless you want to, then go to it. Good shooting.

guncurtis2

As mentioned this subject gets some discussion. Loads developed with many powders (the "Extreme" type powders being the exception)are temperature sensitive in as much as pressures are lower in colder weather and higher in hotter weather. I've been using a chronograph since '75 and have chronographed many loads in hot, medium and cold temperature ranges over the years. Specifically I have used RL22 quite a bit in a 6.5-280 for long range rock chuck shooting in temperatures upwards of 90 degrees and to shoot coyotes in temperatures down to 0 degrees (both are "F").

The load specifically used was a 129 gr Hornady SP over the RL22 and was developed in 60 - 70 degree temperatures. Velocity was 3100 fps (+/- for the usual test to test variences). At 85 - 90 degrees the velocity increased to 3145 fps with the ammo at ambient temperature. I learned real quick to keep the cartridges out of direct sunlight as at that temperature if I did not the primer pockets would blow.

I also managed a chronograph test at 15 degrees with the same load. With the ammo left out in the cold for several hours before the test the velocity dropped to 3020 fps. Another test at that temperature of the same ammo except it was kept in my shirt pocket under my coat and then put in the rifle for 30 minutes before firing to simulate getting out of a warm rig and going on a coyote call for 30 minutes before shooting. The fps extreme spread of that test (5 rounds) went from the usual 35 - 45 fps up to 134 fps. This showed the low temperature was having a varying effect on the loads.

So from a practical stand point what did id matter? I already knew as a long range high power competitor that at long range the temperature does have an effect. However, as phurley5 mentions, over practical hunting ranges (perhaps as far as 300 yards) of big game in cold, moderate or hot temperatures there is little practical effect to point of impact. The exception I found was with coyotes beyond 200 yards as the point of impact was effected by the lower velocity. I simply began adding additional sight correction for longer range shots; 1/4 moa for each 15 degrees of temperature change +/- 65 degrees. That worked for me, much to the demise of numerous coyotes, with the 6.5-280.

You don't mention how much the change is in POI with your 6.5. As the temp gets hotter with an attendant increase in velocity the harmonics of the barrel may change enough to alter the POI also. My 6.5-280 had a light varmint 26" barrel so it was fairly stiff so that wasn't an issue with mine. Also as the day gets hotter the mirage acan cause upwards of 1/2 moa change in POI. Several things at work there but the big question is; Will it matter over effective hunting ranges? BTW; keep those rounds out of direct sunlight as it warms up.

Larry Gibson

I use R-22 alot and have seen no difference in POI when using it in 90+ weather or teens in the winter. I have found it to be a pretty consistant also from lot to lot. I have heard about r-19 problems also but I have not expirenced any problems.

Thanks. Interesting. I guess it gives me a good reason to do more shooting! Just to do my own testing.