Home Forums Reloading Big Game Rifles RL 22 Temperature Sensitivity test

RL 22 Temperature sensitivity test

I have always heard how temperature sensitive RL 22 is and I have had some bad experiences with RL 25 that I assumed was due to temperature sensitivity. So for a long time now I have sworn off RL powders with the exception of RL 15 that I use in my 375 h&h and 416 rem. But alas there was a problem in hodgdonville I could not get the velocity out of my 375 ultra that I wanted with any other powder. So I broke down and loaded up some rounds with some RL 22 I had laying around. And as expected I got 2900 ish fps with a 300gr TSX and excellent accuracy with no pressure signs. But this gun is destined for the bush veldt and big bad Cape Buffalo or may be a Brown bear or big bull Elk. So with that in mind and looking at a possible 50 degree temperature change during a day hunting I wanted to know just how bad the velocity swing would be form hot to cold. A call to my favorite tech support from my favorite bullet maker got a guess of 120 fps loss for a 50 deg temp change so if at 85 deg its going 2900 and at 35 deg its going around 2780 ( yes the animal may not know the difference but I will and more importantly the gun might with a poi change). I just had to know so I did a little experiment. I loaded up 3 sets of 3 rounds with IMR 7828ssc, VV N 165 and RL 22, and for good measure I threw in a few more calibers and powders, these included a 338 rum with H1000, 300 rum with Retumbo a 270 wsm with Magpro and a 6.5X55 with H4350. To do the test I put 3 rounds from each gun / powder combo in a zip lock bag and then put them in the freezer in a small ice chest full of ice. I let them set in the freezer for a day or so and then went to the range. I got to the range and it was a 48 deg that day so I had a set of ammo left out to reach ambient temp and then put a set of ammo on my defrost in my truck and keep it running on high. I had a Fluk temperature gauge the infrared kind to masseur the temperature of each set of ammo and the gun barrel. My plan was to shoot the cold ammo then the ambient ammo and finally the hot ammo one after the other so by the time I got to the hot ammo the gun should be smoking hot. I wanted to get the gun as cold as I could so I rubbed ice on the outside of the barrel ( in this kind of weather this sucked) once that was done I measured the temp of the barrel at 33 deg and the cold ammo at 5 deg, the ambient ammo was 49 deg and the hot ammo was 125 deg. I then shot each gun and powder combo in order, cold ( with cooling down the barrel with ice), ambient and then hot with the barrel now smoking hot.

The results, all velocity was recorded with a 35P and is a average of 3 shots for each temperature.
(As per usually with me I have missed placed my print out so this is some what from memory!!)

Also all the ammo had Barnes TSX except the 6.5 witch was Nosler partitions

RL 22 had 20 fps form cold to hot 2890 to 2910.
Imr 7828ssc had about 40 fps from cold to hot at 2800 to 2840
VV N 165 had about the same form 2780 to 2835

All the other powders and guns had about 40 to 50 fps spread with 6.5x55 and H 4350 being the worst at 60 fps this was a surprise for me as this is an extreme powder.
One other strange thing was Retumbo and the 300 rum Lost velocity with the hot ammo form 3350 ( this is what this load always runs ) to 3290 for the hot ammo???.

I wish I had my print out for this day but I have looked every were for it and can not find it.

I then wanted to just test the RL 22 and the 375 rum so I did the test again with 2 sets of 6 rounds each.
This time it would be the most extreme swing of 5 deg to 125 deg.
The results were about the same with a 12 fps change!!!!!!!!

The hot rounds The cold rounds
2918 + 2894 +
2874 � 2854 -
0044 E 0040 E
2891 M 2879 M
0016 S 0013 S

I realize that I did not really prove any thing statistically but this does make me feel better about using RL 22 in my 375 rum. Next is to do the same thing with my 257 Roy and 264 win to see how much bore diameter may play in this. I do think that each gun also may vary with each powder so the problem may be more complex than just temperature.

I cant wait for the weather to warm up so I can get out in the garage and play some more.



So For the 375 rum RL 22 looks like the powder! Now I just hope that the new lot I buy to load all the ammo I want will be the same!??!?!?

Spence, I'm glad you finally got around to posting your test. Now if we can just find a 55gal drum of RL-22 to split between us......... ...................DJ

First of all....thanks for the results. Appreciate you taking the time to post 'em.

RL22 is my go to powder for several rifles/calibers....several others as well. I've heard alot of other members results which were not so encouraging....some have downright sworn off RL22 and Alliant powders altogether (baby with the bath water thing...). My results mirror yours as do several other members. Perhaps the negative comments came from "strange batches or lots", or other factors we can't know.

Glad to hear that it works for you....have often said it's the most bang for your buck in the velocity department, while giving excellent accuracy as well.

Buy it in bulk in the same lot#. I do as I say....my last purchase was five 5 pounders of RL22 in the same lot#.

375RUM's have a big appetite.....grin.

Magnumb,
Man great minds think alike Iv been looking for 5 five pounders!

I wounder why they dont sell it 8 or 10 lbs kegs??

I just really hope that the large lot I buy will have the same results

have you every tried it in small bores?

Thank's

Thanks for taking the time to run the tests and post the results. There are a lot of "truths" that circulate on the internet that don't seem to hold up to well to testing. I look forward to seeing if you find many differences in other calibers.

Thanks for the data. I trust your test over that of the ones who make claims or get paid to write about it.

The way I hunt I can check my zero in a similar temp to what the rifle hunts at not that it can't vary anyway. I bought two five pound jugs of RL 22 a couple of months ago.

That's some good info. Alliant RL19 has become a favorite of mine, as have their pistol powders. And yes, I've tried many of the Hodgdon and IMR powders. I haven't had a chance to do any temperature sensitivity tests so your data is encouraging. Thanks.

prdator,
Thanks for doing the test and posting the results. I really appreciate you sharing this info with us.

I used to use RL powders almost exclusively. Then I began to hear about the temp sensitivity issues. I swithced to Hodgdon, but have recently started using RL 19 and 22 again. Like you, I really like how they perform. I have always gotten good results with them.

I'm kind of wondering if Alliant didn't change there formulations to make there powders less temp sensitive. I recall seing some data that showed their powders had the widest swing at changing temperatures. Or, like someone else said, maybe it has something to do with the many other variables that come in to play concerning ballistics.

I also appreciate the 6.5x55 test with H4350. I recently changed from RL 19 to H4350 in my Swede. I may have to rethink this change. RL 19 with 120 to 129 gr. bullets has always been freaky accurate in my 6.5x55.

Thanks again,
Steve

Oh one thing I forgto to say was i saw No poi cahnge with the RL 22 or for that mater any of the others.

The search feature doesn't seem to be full up just yet and I don't have time to re-create the post. However, Stan Watson did a the most scientific test I have seen on this topic several years ago and published it in his reloading book. Stan used a 30-06 with a 165 grain bullet and an Oehler 43 PBL to gather his data. He tested at propellant temps of zero degrees, 70 degrees, and 110 degrees.

With standard primers, IMR 4350 had a 63 fps increase between zero and 100 degrees, VV N-560 had a 51 fps increase, WW 760 had a 57 fps increase, and H4350 had a max variation of 5 fps, and the 70 degree load was 5 fps faster than the 110 degree load.

I think if a guy has worked up his load properly--which means using the most consistent load vs the one-time best and not using a hot load, the sweet spot ought to be big enough where a 63 fps difference in velocity wouldn't meaningfully change the POI or group size out to 500-600 yds. Of course, the only way to know for sure is to actually check the load under various temperatures.

I think the relative "hottness" of the load, the speed of the powder, the condition of the barrel, and the chambering itself will have a large play in how much velocity increase or decrease one would see as the temperature changes. I would speculate that a 375 H&H loaded with a 270 grain bullet at 2650 fps would be much less sensitive to temperature extremes than a 300 RUM shooting a 220 grain bullet at 3200 fps. I also think that as the the load gets hotter and hotter, small changes in propellant temperature will have larger and larger effects on pressure and velocity.

I do not know of anyone who has done a complete enough test to fully check this effect, but it would be fun to have enough time and resources to do such a test.

In most cases, I think lot-to-lot consistency of a powder probably is a bigger concern than than the actual level of sensisitivy to temperature. In my experience, Hodgdon Extreme powders seem to have very good lot-to-lot consistency.

I don't have my info with me but my memory is close enough...

In 2003 I worked up new loads for a pair of my 270W's with 150gr Partitions. Velocity was about 60-70fps faster with RL22 compared to my tried and true loads with H4831. Accuracy was as good as before. Then I read more and more about the temp sensitivity of RL powders.

I had fired a goodly number of my final loads through my chrono that previous summer and always note the temp when I chrono.

So the following winter, I put of batches of the same ammo and both rifles in the back of the truck to "cold soak" overnight when the temps were down to about 5 degrees.

Early next morning I went to the range. I parked the truck tight along the shooting bench (we can do that in the middle of the winter at my range) so I could keep the Oheler timer in the cab and warm. At shooting time the temps ran 9-14 degrees.

I also borrowed a Fluke temp "gun" from a friend (I gotta get me one of those). I kept the ammo in the shade and I would fire two rounds and let the rifle sit outside in the shade to cool while I shot the next rifle, letting the rifles thouroughly cool each time.

Short story: From summertime data derived at 89-99 degrees, one rifle GAINED about 12fps, the other rifle lost about a 100fps in the cold weather--go figure. More importantly, my ES in one rifle opened to 86fps, the other 104fps. This is from summertime ES of <25fps for both rifles/loads.


All of this data was derived from 10 shot strings--something I think is important when getting serious about ES, average velocity, measuring pressure with Ballistics Lab or Pressure Trace.

This is consistent with info from some whose knowledge I have faith in. The temperature sensitivity is as much about inconsistenty from shot to shot as it is about velocity loss.

Accuracy was not nearly as good, but at least some portion of that can be attributed to chattering teeth

I went back to H4831. At a tad under 2900fps with a 150gr, the 2950+ I gained with my 270W's wasn't enough be concerned about. I would not be surprised though to see a lot of variation with different cartridges, loads, and even different firearms.

I have read, and have one friend, who is claiming phenomenal velocity with RL22 in their 30-06's. I would really like to see what is happening in really cold temps.

Obviously, Only a small segment of big game hunters hunt in temps near or below zero.

I have been thinking about trying RL in my 30-06AI's. But I WILL test the load in cold weather (I mean really cold) before I would officially designate it a hunting load.....

Casey

prdator, In reading this post your comments on the 300Rum and Retumbo caught my eye. I had a similar experience last year where in the spring 40's I was getting 3350 fps and in the summer high 70's to low 80's I was getting 3320 fps with same powder lot. Thanks for posting

I love RL22. Second comes Imr7828 & I wish I could find some 7828SC.

RL22 is like an old faithful dog. Wish I could buy an 8 pounder.

Prdator,

Please enlighten me about your less than favorable experiences with Rel 25. I just developed an awesome 180 gr load for my 30-05 Ackely with it.

I've had nothing but good luck with reloder 22 and reloder 15, but had very inconsistent results with 19.

prdator - Yeah.....I wish they sold 25 pound kegs.

In answer to your concern about the next lot of RL22 that you buy.....find a gunshop that has as many 5 pounders as you'd like to buy with the same lot#. Purchase one of them and have them hold the other's. If it gets you what you want (consistency and accuracy...whether the same POI as your last grouping with RL22 or not), return to pick up the remaining kegs. I do that all the time....my gunshop is rather large and they order in large quantities...they also love seeing me darken their door....grin. Appreciate them doing that for me, but they also are all shooters and understand the drill.

I use RL22 in my Sako 25-06 and it gets me nearly 3,300 fps with the 110 gr. AB. Very accurate. Both my 300 and 270 WSM's are also quite fond of RL22.....great combinations....made for each other.

It's amazing how fast five 5 pounders vanish loading several rifles/calibers with any powder. I'm at just less than half my original RL22 purchase and that was only 2 years ago.......lots of trigger time.

Good luck to you on your quest for the "bulk buy". It'll happen....

Let us know your results with the new lot# of RL22..

Yea at 7000 grains a pound and all most 100 gr a round thats 70 rounds a pound or 350 rounds a keg ( 5 lbs). it dosent take long.

Thats a great idea on having the store hold some powder I guess if a guy could get it worked out you could buy a 1 lb can and test it quick and then go back and buy the rest if it worked out.

I do think RL 22 is some what magic as how could the same powder work in the 25-06 and the 257 wby ??? with top velocity in both.

I'll keep yall up to date with what I find out on the other guns and lots.

I own and load for .243W, .270WSM, .280Rem, 7mmRM, 30-06, and 300Winnie. If I was forced to choose one powder, R-22 would work in every one of them. In fact, I have a R-22 servicable load for each of those guns even if its not my go to load. However, if you ever start Using VV-N160, N165, or N560, you'll have another old standby powder that is more consistent. That being said, I have a theory on R-22 and some loaders inconsistent results. IME, R-22 does its best work behind heavier for caliber bullets. IE. 160s in .284 calibers, 180s and 200s in the 30s, etc. IOW, it needs pressure to burn more consistently, and lighter bullets don't work as well. Not at all saying there are not good light bullet loads...but just my general experience. YMMV. On the whole, I agree with those that are R-22 fans...its a great powder.

I'm a bit of a "heavy for" guy and most Reloder offering do as you suggest with "plumper' pills......always top velocities.

Happy the 25-06 eats it up....makes life a bit easier.

prdator

EXCELLENT POST & THANK YOU! RL-22 is my go to powder for 270, 280, 30/06, 7mm Mag, & 338WM.

Always had the same question about its temp sensitivity based upon all the negative stuff I saw written about it...but never really had any first hand experience with significant velocity swings and POI shifts at varying temps.

WN