270-300 Win Mag now feasible
- Thread starter Big Jake Duke
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Buckammo
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Well, its official, I am done with Alliant powders. I just completed testing my 270 Rem Mag loads with R-26 and the 170gr. Berger. At 78 degrees 65 grains of R-26 produced 2970+/-3fps. At -5 degrees F (Rifle and ammo in the deep freeze over night) the load gave 2398+/-39.6fps and did not produce enough pressure to seal the chamber. And to top it off, the decay in velocity is not linear. While shooting on the 1000 yard range two weeks ago, it was 52 F and the velocity registered 2962fps......
I also tested a load for my .260 AI using R-23. The velocity for that load went up by 86fps and popped a primer. This load had previously only showed 58KPSI. I did not have the strain gauge attached to the rifle when testing out of the freezer. My old load with H-4350 had a delta v/t value of 0.11 fps/degree F.
I am sorry Hodgdon. I will never stray again.
I also tested a load for my .260 AI using R-23. The velocity for that load went up by 86fps and popped a primer. This load had previously only showed 58KPSI. I did not have the strain gauge attached to the rifle when testing out of the freezer. My old load with H-4350 had a delta v/t value of 0.11 fps/degree F.
I am sorry Hodgdon. I will never stray again.
bigngreen
Well-Known Member
Buckammo
Well-Known Member
After my 270 RM warmed back to ambient (69 this afternoon), the velocity returned to 2960+/-4 fps n=6. I am going to place the rifle and five rounds back in the freezer and try again tomorrow. I am also going to add my backup load with Retumbo. I may have to place the rifle back in the freezer between tests.
bigngreen
Well-Known Member
What primer?
Buckammo
Well-Known Member
Fed. 215
Buckammo
Well-Known Member
This time the load with 65grains of R-26 under the 170 grain Berger gave 2416 +/- 94 fps from the deep freeze. I did not get a chance to shoot my load with Retumbo. I will give that a try tomorrow evening. I guess I get to start pulling bullets from the remaining rounds containing R-26.
Big Jake Duke
Well-Known Member
Buckammo
Well-Known Member
The 7mm Rem Mag necked down to .270.
Buckammo
Well-Known Member
I re-did the freezer test with the .270-7mm Rem Mag with a load that consists of:
Nosler 7mm Rem Mag brass (1-fire)
Fed. 215 Primer
72.0 grains Retumbo
170gr. Berger EOL seated to mag length (HBN Coated)
At 65 degrees Fahrenheit the load gives 3155 +/- 9 fps with a slightly flattened primer and easy bolt lift. At -12 Fahrenheit the load gives 3180 +/- 7 fps still with an easy bolt lift. Only three rounds were tested at the cold temperature, simply because that is about all I can fire before things start to warm up. At the cold temperatures, this load gave a clean burn in my rifle.
Nosler 7mm Rem Mag brass (1-fire)
Fed. 215 Primer
72.0 grains Retumbo
170gr. Berger EOL seated to mag length (HBN Coated)
At 65 degrees Fahrenheit the load gives 3155 +/- 9 fps with a slightly flattened primer and easy bolt lift. At -12 Fahrenheit the load gives 3180 +/- 7 fps still with an easy bolt lift. Only three rounds were tested at the cold temperature, simply because that is about all I can fire before things start to warm up. At the cold temperatures, this load gave a clean burn in my rifle.
Well I went out do some range work. It went well. See attached photo. Not my best day at range. But once I settled in I was satisfied. Seeing how I won't be Elk hunting in sub freezing weather in 3 weeks. I'm going to stick with Berger 170, Reloder 33-75.5gr.,215m in my 270wby. Top group is @ 100yds, next 2 are @ 200yds. Bottom was before adding elevation and wind.
Gene
Gene
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Buckammo, so there is published information from Alliant on RL-26 temperature sensitivity:
From accurateshooter.com:
Speed and More Speed with RL 26
Think of Reloder 26 as a high-velocity powder for big cartridges. Furrier explains: "Reloder 26 is produced with Nitrochemie's latest generation EI® process technology. This is the same impregnation coating process used to produce Reloder 17, Reloder 33, and Reloder 50 for us, and it is fantastic. The "so what" on Reloder 26 is great ballistic efficiency, high bulk density so you can get more of the slow powder into the case to harness the energy, and decent, predictable extreme temp response. Reloder 26 is not as flat at temps as the TZ or Australian materials, but it is very manageable, usually in the 0.5 fps/°F range (depending on the application). Just as important, the pressure increases at hot are very manageable. We are using quite a bit of this powder in our Federal factory ammo due to the fantastic ballistics and accuracy.
Not sure how that fits with your testing ....
From accurateshooter.com:
Speed and More Speed with RL 26
Think of Reloder 26 as a high-velocity powder for big cartridges. Furrier explains: "Reloder 26 is produced with Nitrochemie's latest generation EI® process technology. This is the same impregnation coating process used to produce Reloder 17, Reloder 33, and Reloder 50 for us, and it is fantastic. The "so what" on Reloder 26 is great ballistic efficiency, high bulk density so you can get more of the slow powder into the case to harness the energy, and decent, predictable extreme temp response. Reloder 26 is not as flat at temps as the TZ or Australian materials, but it is very manageable, usually in the 0.5 fps/°F range (depending on the application). Just as important, the pressure increases at hot are very manageable. We are using quite a bit of this powder in our Federal factory ammo due to the fantastic ballistics and accuracy.
Not sure how that fits with your testing ....
Longtooth32
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- Mar 9, 2015
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Funny that you should post this...
It has finally started to cool down here and I wanted to go and shoot/ reload for tomorrow.
I was reviewing my RL26 data...and the target...
All I can say is wow...
RL26 gave me velocity and accuracy...Every ES was below 15fps for each 5 shot string
270 Wby, Mausingfield action, 28" Benchmark 1-9 barrel,170 Berger, 3.5" COAL, and .3" off the lands...Magnetospeed v3...
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Longtooth32
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