I have been trying this in a 243 with 108 bullet. I shot it at 45,55,and 65 degrees. There was an increase in fps of 60 in this 20 degree change. I was surprised at such a difference and I could see people having issues if they are running on the edge in cooler temps then going to hotter ones. I will continue to test this as it gets hotter, just wondering if others see that kind of difference??
RL26 temp vs velocity results
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cohunt
Well-Known Member
There is usually a drastic jump around 90--- its pretty well known that if you use 26 you should build your load when it's hot and then retest in the cold for accuracy
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Yeah I get that. I had just never seen anyone post results that showed that much difference. I don't think I have used a powder that had that much difference before so I was curious as to others findings. Could easily change your velocity over 200 fps in states that have big temp swings
std7mag
Well-Known Member
How many rounds down the tube?
Sometimes the barrel will speed up in the 100-200 round range vs new.
60fps is more than i've seen with RL26 out of my 7mm Rem Mag for that temperature difference.
But then i've got 1,500+ rounds down that tube.
Sometimes the barrel will speed up in the 100-200 round range vs new.
60fps is more than i've seen with RL26 out of my 7mm Rem Mag for that temperature difference.
But then i've got 1,500+ rounds down that tube.
Make sure it's actually temperature causing the increase or if it's a fouled barrel. I tried RL26 in my .243 with 108s and it powder fouled horribly in less than 100 rounds. I thought my barrel was speeding up but it was actually the fouling. I cleaned the barrel thoroughly with Iosso and the velocity literally dropped over 100fps. RL26 works great in magnums but I think it's too dirty for 6mm's and things like that.
I've never seen velocity swings like that with RL26, even at temps over 90°.
ResearchinStuff
Well-Known Member
In one podcast, Hornady talked about rl26 fouling a barrel crazy fast and raising velocity for constant loads by like 200 fps in ~100 shots on a 6.5 prc.
3 fps per degree seems like way way too much change to be powder temperature changes.
3 fps per degree seems like way way too much change to be powder temperature changes.
entoptics
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Did this test a couple years back...
www.longrangehunting.com
Summary...RL26 performed better than expected, and IMR8133 actually showed inverse T vs V.
Temperature Sensitivity Test: IMR 8133 and Reloder 26
Just ran a fairly rigorous temperature sensitivity test on IMR 8133 and Reloder 26 in my 7mm RM. Equipment. 26" X-Caliber prefit, 1:8 twist, fluted heavy sporter. Sartorius high precision scale for powder charges ( ≤ 0.03 gr ES for charge weights) LabRadar Indoor/Outdoor thermometer set...
Summary...RL26 performed better than expected, and IMR8133 actually showed inverse T vs V.
Testing taken the same day(same light conditions) I would hope....? If not then it doesn't mean much to me. As well with the exact same pieces of brass and same can of powder?
I did some testing with R26 (along with many others) if I can find the info I'll put it up. My tests are generally during the summer heat for one, then come winter when we see some 20-30 below stuff again I give it a go. (same lot of powder, same cases and the gun and ammo in the truck over night)
From my testing, I found this subject to generally be about not much of anything to me. Pretty much all of them will loose in the 60 fps range when the temps swing as much as they here in Montana.
Here's my own experience with RL 26. It is temperature sensitive, especially over 90 degrees, where the velocity increase is no longer linear, but goes exponential and unpredictable. I think its not only a matter of the outside temperature, but how hot your chamber and barrel get if you are at the range. Probably less noticeable if you shoot 1 round only in a cold barrel.
www.longrangehunting.com
Temperature Sensitivity Experience N560 and RL-26
I was recently down in Texas in 90 degree weather, and doing some shooting on our deer camp shooting range there. I had loaded 5 powders to compare in my .338 Lapua Magnum. N560 N565 RL-26 Retumbo H1000 Previously I have had velocities for 84.9 gr N560 in the 2825-2850 range for 250 gr...
Couesnguns
Well-Known Member
I have used RL26 in a 6.5 SAUM with no issues from the early Oct coues hunts to late season elk. There is quite a bit of temp swing between those season and I am sure there is a velocity change but it hasnt been noticeable enough to cause a miss. I do use load data from 82 degrees for my shooting solution.
