Home Forums Reloading Big Game Rifles RL 22 Temperature Sensitivity test

GSSP,
It happend with a Lazz Warbird .308 that I had I would load up some rounds and go to the range and all would look good and then load up some of the same weight and bullet and the dang things would blow the primer right out of new brass. I swithed to H1000 and my problems went away. BUT to be fair I did NOT have a crono at that time and that is one big KEY in reloading.

I thought it was temp change that caused my problem( but could have been do to a cahnge in lot#'s) but now after learing more about reloading and getting a good crono. I now think it was a max( over max) load any how as, I have had this happen to me with my 300 ultra and Retumbo. I was getting 3550 fps with a 180 gr tsx in my 300 rum) with NO pressuer signs and I thought WOW this custom barrel thing is cool but the next time I shot the same load I had primers falling out!!!!!!!

SO as many have learned and as they keep telling me get a good crono and work up loads with it!!! and if you get 200 fps more that a gun should shoot with no visable pressuer signs YOU are OVER perssuer..............................

Allthough I have not used RL 25 since then and right now have no need to.

More test to come.
Thanks!!

I lean this way as well.

GB

Last fall I was working up loads with 160 Accubonds on my 7mag using both RL-22 and H4831SC for an elk trip. They were both giving me about the same group size and the RL-22 was about 150ft/sec faster so I was leaning toward the RL-22 but I was concerned about the temperature issues so I ran a little test. This was late summer so the temps were around 90. I put 3 rounds of each load in the freezer and 3 rounds of each load at ambient and chrono'd each group. Based on the average velocities the RL-22 lost about 100ft/sec due to temp and the H4831SC didn't loose any. This is a very limited test so take it as you will and 100ft/sec would probably have little effect on the POI but I decided to go with the H4831SC due to it's consistancy.

RL-22 is my favorite powder. I don't believe it has any more temp sensitivity than any other powder including the Hodgdon extreme series or IMR powders. I use RL-22 in 270, 280, 7mag, 7 STW, 300 win, 300 Wthby, 300 Jarrett, 338 Win, 338 RUM. It is a very versatile powder that seems to give top velocity and accuracy in most any calibur I have used it in. I do most of my load testing and development in Jan & Feb. usually early in the morning here in Va. The temps are usually in the 15-25 degree range with a few single digit temp days thrown in. I chro each round. When I find a promising load I load up 30-50 rounds and shoot them up in 3 shot groups thru the spring & summer. I specifically save many for the hottest days. Many are fired in 100 degree high humidity! Using this method I have yet to notice ANY significant changes in velocity, accuracy, or pressures during my testing with RL-22. Although my method is not perfect it seems to give me a very good reading on powder performance over a wide spread of temps. I've been doing this for quite a # of years and I'm sold on RL-22 as being one of the best powders available for big game cartridges in temps I am likely to hunt in. RL-22 has proven to me to consistently out perform every other powder I try using this method in accuracy, velocity, and consistency. YMMV, thanks 163bc

Full Draw just told us how he found a 100 fps difference with RL-22 in his 7 Mag and zero difference with H4831SC. Why would you not believe that? His results reflect what many of us have found.

After reading soo much about RL22 and sensitivity, I performed a test about a year ago for a couple pounds I have of the same lot #.

Shot my 300WM @ 600 yds, 3 round group was just under 1/2moa. Put same rounds in a freezer overnight (around 10 degrees I believe). Next day took rounds out of the freezer and fired 1 cold bore shot @ 600 yards. This round went into the same 1/2 min group. Rifle itself was not put in the freezer, so the chamber was the same as the ambient temperature (from memory I think it was around 70 degrees). I dont know if putting the rifle in the freezer would have made a difference or not? Very limited unscientific testing, but it aleviated some of my fears. I agree with many here, RL 22 is an excellent powder for accuracy and speed. I did however buy 5 lbs. of MRP as its supposed to be the "best" lots of RL22. Havent played with it yet.

prdator,

Thanks for posting that. I have moved away from RL22 in the past few years, because I had seen some pretty wide swings in velocity at different temps. I don't recall the exact numbers, but it was in the neighborhood of 100+ fps.

Perhaps Alliant has changed RL22 slightly in the past few years to make it more temp stable?

Whatever the case, I may have to start using more if it now, just to see for myself again.

Thanks.

I did a little experiment with Retumbo the other day up here in Wisconisn. I have a fussy 300 wby ultralight and found a load that works great (fairly compressed) with retumbo and 180tsx's.
Anyhow shooting in 20-30 degree weather the load was doing 3200-3240. I was worried it might get a little hotter in say 70 degree weather.
I put some ammo in a 6 pack cooler with a zip lock bag of warm water in the cooler. I took a thermometer along and by the time I stopped for lunch and got set up the temp in the cooler was 60 degrees.
It was 10 degrees outside. I got my chrono and gun all set to go. I put the ammo in my pocket and the thermometer in there too. The thermometer said it was 60 degrees in my pocket. I sat by the gun and fired off groups of 3 shots. I'm not sure how fast the chamber of the gun could cool down a shell that was in there for about 15 seconds but by the 3rd shot of the string the chamber should have been at least room temp I would think.
Anyhow....the bottom line in my experiment was that all ammo was still doing right around 3200 fps. From what I saw it would appear to me that Retumbo was pretty temp tolerant from 20 degrees to about 60 degrees. Even if it lost a bit of zip in colder temps or gained just a tad when warmer I think I've proved to myself that in the temps that I would hunt in this powder will be consistant.

My take is a tad different...I believe in the temp sensitivity of R-22, but my experience tells me that the "extreme" powders suffer from it to some extent as well. Its just a contengency to deal with in loading.

I believe what my tests and data suggest over the last 20+ YEARS! I shoot many hundreds if not thousands of rounds out of hunting rifles every year testing various loads, powders, and bullets. In doing so I have shot thousands of rounds over a chronograph with RL-22 in temps from 0-100 over that time period. I've got all the data to back up what I need to know for me. I'm simply passing on my observations. I've seen 100 fps spreads with about every powder made if you shoot em enough. However you get a much better read on temps, acuracy and consistency if you have hundreds of tests to compare instead of a few. I stand firmly by my acessment of RL-22 based on my many years of shooting it in extreme temp spreads. I find it no more temp sensitive than any other powder out there and less sensitive than many. 163bc.

The current issue of "Varmint Hunter" magazine has a great article on the effects of temperature changes. It concluded that the temp of the chamber played a much larger role in vleocity differences than just the temp of the cartridge. It's a great read.

Got mine today.....always a bunch of great articles with useful information.

Not the cheapest magazine around, but sure fits a certain readership niche.

Yep ! First bolt I ever had to hammer open was a 257 AI load with Win 760 .It was a 100 degree day and I inadvertantly let the fifth or sixth shot in the string cook in the chamber .

I burn a lot of RL powders . I've done my own temp tests to MY satisfaction .Only difference I've seen with any powders is that Varget handles the heat better in my 22 250 AI than anything else I've tried . Important in a PD rifle .

163bc,

I agree, my test was not an all inclusive, scientific test that removed all of the variables. It was simply a quick check to give me peace of mind before I chose a powder for my hunt. My goal was to just pass on my limited experience based on what I have seen. I appreciate hearing from someone that has had positive results with RL-22. I may try it again in the future and put it thru a little more substantial tests. RL-22 actually gave me slightly better groups and a higher velocity so if I could convince myself that it was not affected by the temp I would probably switch back to it.

Also, and I realize that these tests could be considered biased because of the source, but he Hodgdon website shows that RL-22 had a velocity loss of 75ft/sec over the same temp swing that H4831SC only lost 10ft/sec.

I have heard that as well from a poster here. However, Stan Watson's tests seem to indicate otherwise.

Regardless, when you are shooting groups on a hot day and the barrel is getting warmer and warmer--along with the ammo--but you are not seeing an increase in velocity, then I think it's safe to say that particular load in that particular gun is not so sensitive to temperature increases.

It's not the temp sensitivity that has caused me to question my relationship with RL-22, but lot-to-lot variation. Otherwise, I love it. It does make my .270 Win. sing with 140-gr. InterLocks.

rsy

[quote=Full_Draw]163bc,
I agree, my test was not an all inclusive, scientific test that removed all of the variables. It was simply a quick check to give me peace of mind before I chose a powder for my hunt. /quote]

Full Draw, Your tests are fine and they are exactly what you should do. Especially for a hunting load. You are stating what your tests reveal to you. I am doing the same in stating what my tests are telling me. I use lots of RL-22 I also do a lot of big game trophy hunting. I had heard and read of problems with RL-22 many years ago and set out to make my own determinations instead of just accepting what I had read as fact. I continue to do tests including this coming week with 3 custom rifles and severasl different bullets & powders including as usual RL-22. I have also spent quite a bit of time on the phone speaking to Alliant/Hercules technicians and asking lots of questions. I learned quite a bit from them during my conversations. I can tell you that their tests are far more thouough than yours or mine!! A Hercules quality control tech in Radford, Va. told me a supplier in Europe makes RL-22 under very strict and controlled manufacturing tolerances. BEFORE accepting a shipment it is tested in numerous ways to make sure it is exactly per the tolerances & specs. If not it is not accepted. The long and short of it FOR ME is that I cannot see any significant difference in RL-22 vs. any other power I tried over wide temp ranges and over lots of load combos over lots of years. In addition just to be clear I have tried damn near every powder you can think of including Hodgson. I use and am happy with quite a few other than RL-22. Again BASED ON MY EXPIERENCE I am quite confident and happy with RL-22 anywhere, any time, and any temp!! Good hunting, 163bc

I have seen up to 6% variation from lot to lot in powders I was told were kept to 2% variation.(At that time, the industry standard was supposed to be 4%)(+2-2%)

These days I simply don't care about velocity variation as much as point of impact variation, which is the single most important factor when I am hunting with loads made prior to the season.

100fps is nothing in the field and when you are talking about magnums shooting with velocities over 3000fps, it really doesn't matter. The deer simply won't care.

AGW

Over the last year or so I've been working on a 338 RUM. I tried several different bullets and loads but eventually settled on 225 Swift A Frames over RL-22. I got very nice accuracy and velocity. My notes show that in March of 06 (temps in 50-60s)I got 3140 avg velocity for 9 rounds fired. In August of 06 (90s high humidity) I got 3130 avg for 9 shots fired in 3 shot groups with no pressure and excellent accuracy again. Just last week in 10 degree weather my friend hicountry fired some of this same load out of my gun over his chrony at 3134 fps and again no pressures and excellent velocity. I have done this enough times with this rifle and load as well as loads with RL-22 in other rifles from 300 Win, 300 Wthby, 300 Jarrett, 270 Win, .280 AI and a few others to be totally confident in RL-22. Thanks, 163bc

Some of the "tests" listed here are not variable enough in the temp swings to really matter anyway. "Temp sensitivity" is not going to swing things worth a hoot if the variation is only 50 degrees or less. When you start talking 100 degree swings, then you're getting something more significant. Also, the valid tests for "hunting" must include the gun either hot or cold, since most of us carry our rifles out in the weather as we hunt. Some before have noticed that it is chamber metal temp, not simply powder temp that matters most.

Overall, I agree with Aussie, that what really counts is POI, whether velocity or ES varies or not. Even the worst of the worst powders are only going to vary maybe 100fps, and that only if we worked up our load at 100 degrees in the summer, then hunt at below zero, which is quite doubtful.

My strategy is to work up loads at temps somewhat close to what I might be expected to hunt with that cartridge. Big game and coyote loads, for the Dakotas, have to work in the cold (it was -24 this morning). Prairie dog loads have to work in the heat (it was 112 one day last year). I usually don't hunt quite to those extremes, so most often pick a nice medium-temperature day for working up loads, then force myself to test them in either the hot or cold environment later in the year. If the POI is good, and no noticeable pressure signs, that load is good to go no matter what the temp sensitivity is.

The only time I ever had any noticeable variation, was on a very hot summer day when I stupidly left the box of ammo and the rifle sitting in the truck window, grabbed a couple rounds, and started firing. No stuck bolt, but I knew something was wrong. When the gun was shooting an extra foot high, I went home to think it through.