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7mm-08 Fans

Great write up Buzz. Really makes me like this round that much more. When people ask me for a caliber recommendation I always recommend this one.
 
FWIW, R19 has a reputation for being much more sensitive to temperature than Varget. Be interesting to hear what results you get if you test it. Do you get temperature swings there? ;)

Here's a link from Hodgdon's website where they tested a few more common powders along side their extreme powders. RL 19 wasn't as bad as some, but showed about 0.75fps lost per degree of temp change. I'm sure there are a gazillion variables that I don't know to account for, but that was their testing. I'd be all sorts of interested to see how it goes in the real world done by real people... See the top chart for RL-19.

https://www.hodgdon.com/smokeless/extreme/page2.php#top
 
Here's a link from Hodgdon's website where they tested a few more common powders along side their extreme powders. RL 19 wasn't as bad as some, but showed about 0.75fps lost per degree of temp change. I'm sure there are a gazillion variables that I don't know to account for, but that was their testing. I'd be all sorts of interested to see how it goes in the real world done by real people... See the top chart for RL-19.

https://www.hodgdon.com/smokeless/extreme/page2.php#top
Thanks for that chart. According to John Barsness the cartridge plays a role in the temperature sensitivity as well. The order of sensitivity could change for a 7-08 vs the 30-06 used in the test you showed. I do agree that it'll be interesting to see the results.
 
According to John Barsness the cartridge plays a role in the temperature sensitivity as well..

I would expect it to change some with a 7-08; but, I don't think the change would be dramatic. I don't know of a good way to predict that. Way more variables than I want to think about... I'd be real interested to see results though.

That being said though... 0.75fps/degree isn't that bad to start with. I tend to consider a change of 50fps worth adjusting for when it comes to hunting. So... if you chrono and zero at 40 degrees, you should be +/- 50fps from -25 to 105 degrees. That should cover the majority of hunting... But the only way to be sure is to load 'em and shoot 'em.

I did have similar results to Hodgdon's with H4350 out of my .325WSM. I chronoed it at 85 degrees and at about 35 degrees, there velocity change was less than the standard deviation of the loads. I think it was like an average change of 4 or 5 fps. SD is 7fps for this load. I'll have to go back through my notes to be certain, but it was amazingly small...
 
That being said though... 0.75fps/degree isn't that bad to start with. I tend to consider a change of 50fps worth adjusting for when it comes to hunting. So... if you chrono and zero at 40 degrees, you should be +/- 50fps from -25 to 105 degrees. That should cover the majority of hunting... But the only way to be sure is to load 'em and shoot 'em.

You have to consider pressure issues in the heat though, I had it with RL22 in my 7RM. I was under max load, but when the temp got north of 75 I was seeing pressure signs. That's the major downside to temp sensitive powders IMO.
 
Chrono first, and the calculated come-ups were verified as being nearly on the knats-ass to the 700 yard line, with the varget load. Havent stretched come-ups beyond 700 with my 7-08, maybe now that things are settled down, I will see whats up at 1k.

Chrono only with the rl19.
 
Well, it took some time, some HT hero's, and no shortage of plain dumb luck, but I've managed to get a box of 140 Accubonds, 140 BT's, a can of Varget, 4064, RL-15, primers, and brass all together at the same time !

With all the snow we have coming down right now, and the public ranges closed for another 4 weeks, I'll have at least a couple free nights to mix up a few batches of fodder.

If I can chrono 2850fps, or better, and still cover 3 shots with a quarter, I think I'll be set.

Load work up and fine tune with the BT's , then zero with the Accubonds.
 
I've been shooting it in mine, looking good at the range but that's all so far. I had some brass related pressure issues so it's on hold for the moment. The published BC was good to 600.
 
I tried varget and h4350, h4350 gave me slightly better groups. I'm out of town so I can't look at my load book on charge weight but COAL was 2.805". I was around half a grain under max on the hodgdon data site if I recall.
 
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