308 Load data - temperature variances

[vooduchikn]

I've been loading a while, finally got myself a bolt gun in .308 and cooked up some hopeful deer hunting loads on the ole 650 along with a paper puncher (had a box of AMAX on the shelf).

Here's my data for the batch I shot today:

RIFLE BARREL TWIST
TIKKA T3 22 7/16 1:11

CALIBER BRASS BULLET POWDER PRIMER OAL FPS (AVE)
308 REM 165 Nosler Partition 44gns Varget CCI 200 2.80 2640 (HUNTING LOAD)
308 REM 168 Hornaday AMAX 42gns Varget CCI 200 2.80 2480 (TARGET ROUND)



Accuracy was great in both loads out to 200 yards (furthest I felt I could shoot accurately today with the insane wind). No signs of over pressure. It appears that I could get another ~200fps or so, but I doubt deer or pigs would notice the difference inside 500 yards. The 165s had very low recoil and that was a bonus. I can go up 2 more grains on both per the book, but I am looking for an all around load that I can also shoot in the summertime.

It was ~40 degrees today and my concern with going up in charge is a possible over pressure condition in the summer. The last place I lived (Hawaii) I didn't have to worry about extreme temp changes.

Can anyone chime in here? I have read and have been told that Varget plays well with temperature changes, looking for more opinions on that.

I know this load requires further development to truly get the most out of it, but I may just leave well enough alone for this trip. Looking for any other pet loads you may have for this caliber.

Thanks



Vood

 

[ASP785]

Varget is pretty temperature insensitive. I have seen around a 1% change in velocity from the low 30's to the mid 90's in my 308 loads.

I have seen more lot to lot velocity variation with Varget than temperature variation. Follow published load data and you should be good.

 

[Shadowrider]

If you are worried about temp variation try IMR 8208XBR. Supposed to be utterly temp insensitive. I haven't chrono'd loads in the cold yet but the benchrest guys back up the claims and they know their stuff. It also meters decent out of a Dillon measure. Not benchrest perfect, but a darn sight better than Varget. It's also close in burn rate to Varget. I was getting some insanely consistent .223 velocities with it.

 

[vooduchikn]

If you are worried about temp variation try IMR 8208XBR. Supposed to be utterly temp insensitive. I haven't chrono'd loads in the cold yet but the benchrest guys back up the claims and they know their stuff. It also meters decent out of a Dillon measure. Not benchrest perfect, but a darn sight better than Varget. It's also close in burn rate to Varget. I was getting some insanely consistent .223 velocities with it.

I may give that powder a shot after I burn through my Varget. 5.56 is what got me into varget, very consistent provided metering was good.

My main concern was working up a max load during the winter months and then having it be over pressure in the summertime. I am trying to get consistency in my hunting rounds. I haven't got into bench rest shooting, but it sounds like fun.

I hear you on the Varget and metering, its not to bad, but I have noticed some variance. A trick I was told by a Dillon tech was to attached a vibratory device, to the top of the powder measure and turn it on while you are loading, this vibrates the poweder measure and keeps the powder moving. Apparently like stacking logs in a truck vice just throwing them in. He uses a vibrating denture cleaning device, but you can use your imagination.

I am pretty sure the 26XX FPS I am getting out of 44gnrs Varget is plenty for whitetale, hogs, and the occasional coyote. Being a relatively softshooter is a bonus as well.

I may load up some more up to the max and try them at the Georgia range to see how they do because I would like to get the most out of my reloads. I have a bunch of Sierra 165 Gamekings and some Lapua brass that should be here today. I have heard great things about the 165 SGK.

 

[vooduchikn]

Follow published load data and you should be good.

Thanks, and that's what I intend to do. Funny how so many people want to go over the max because they believe FPS equals accuracy.

I saw a guy at the range once who was shooting 270 and his spread was about 4-5". He seemed very perplexed given it was a relatively new rifle and asked us for a recommendation. I recommended that he clean his bore real good and my buddy then offered up his some medium-high reloads. His rifle then shot sub MOA at 100 yards. Guy said he must've had some bad powder....

We looked at his load data when we got home and the guy was over max recommended load, but the cases that I saw didn't any pressure signs that we noted while we where there. He also had never chrono'ed the loads, so he really had ZERO idea what he was shooting.

I think the guy got lucky that he didn't damage his rifle.