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varget & IMR8208 questions

So I have a load worked up with my .308win, with Varget, that shoots great when it's a certain temperature zone outside. when it gets hotter or colder, the groups really open up. This past weekend I tried a load of 8208 with same bullet and it shot great again. Temps were in the upper 30's. My original load using varget was up around the 1" size since it was cold. now to my question. Is the new IMR8208 more stable in temp differences than varget is? If 8208 is less temp sensitive I guess I am going to have to change powders. please let me know what you guys are running into.
 
Hmmm well not a 308 but Ive shot both powders in my .223, only thing is they both shot great regardless of temp. What primers are you using? When I was shooting varget in really cold temps with CCI's groups went to hell. Switched to Rem 7 1/2's, problem solved.
 
I've used Varget for years both in my 308 and 223's. I have not noticed any significant changes in group size with changes in temperture but point of impact does change with significant temperature changes (i.e approximately 30 degrees and over).

I'm not sure but I believe this is due to changes in air density rather than powder sensitivity, the colder tempertures having higher air density and producing greater drop. For example, my varmint rifle sighted in during early spring with temperatures in the low 50's shoot noticably lower than when sighted in during mid summer with temperature in the 80's and above.

This is less of a problem with my 308 since I used it for deer hunting and most of my shooting is done from October to December where I don't experience wide swings in temperture.
 
Sounds like you might be outside the node of your load. I've shot both Varget and 8208 in several 308's in temps from 100deg F to 25degF. The only thing I notice, which was mentioned above, is the point of impact difference between hot and cold weather. Group size remains relatively the same. Temp sensitivity seems pretty close between the two. 8208 is a good bit faster than Varget and depending on the weight bullet you're shooting may limit the efficiency of 8208. YMMV... Good luck!
 
It's supposed to be, at least if you believe the marketing hype. I used Varget for Palma for years with decent results, switched to 8208XBR this past season after some basic testing. Much prefer the latter, in fact use it in my 6XC long-range "any-any" rifle and a 6mm spacegun too. Burns cleaner, seems to be more consistent batch to batch (on 3rd batch now, went thru 16 lbs split between 2 different batches so far) with higher velocities and lower SD's. Takes some care in testing though as it's dense stuff, there's always room in the cases when I start seeing pressure warnings.
 
Thanks for the responses so far. the load I used for Varget was a pretty stout load. To me that explain why the groups open up when it's really hot outside, as I delveloped the load for it a few years ago in the fall, just before hunting season. I am about out of that lot of powder. I am using CCI primers too, I might just give win primers a try this weekend. I also might just give this 8208 a try soon. it's hard not to when the very first and only load I tried with it shot a .265" group. I guess it gives me some reasons to go to the range!!
 

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