300BLK/H110 Temp Sensitivity Issues [Archive]

Onyx Z

11-10-13, 22:05

A few months ago, I was just about to give up on my 300BLK until I found a load that gave amazing results (125gr SMK/H110 @ .394moa). I took this load to the range a few days ago and was getting 3-4" groups. This gun now has a new lower with a different trigger, which I built to stay on this gun permanently instead of swapping uppers. The first lower was a Noveske GenII w/ a SSA-E, now this gun has a Northtech lower with a JP EZ Trigger. I was not expecting the same results as the previous range visit, but I wasn't expecting THAT much of a difference. Either H110 is very sensitive to temperature changes or the trigger is hitting the firing pin and striking the primer at a different pressure. Anyone know of a powder used in 300BLK that isn't as temperature sensitive? Or could the trigger make THAT much of a difference?

bigedp51

11-10-13, 23:35

Google H110 temperature sensitive in 300 blk

https://www.google.com/#q=h110+temperature+sensitive+in+300+blk

You didn't state powder charge or type primer "BUT" a magnum type primer would be to your advantage.

Onyx Z

11-10-13, 23:50

I did Google it shortly after the most recent trip to the range and found that it is somewhat sensitive. I also had first-hand experience to it's sensitivity to changes in temperature, which is why I'm inquiring about a powder that is not as bad.

I've been loading 18.2gr H110 w/ CCI 400 primers. I was just about to try some CCI450 until I got these results, so I stuck with the CCI400's.
http://i39.tinypic.com/11jw1eq.jpg

bigedp51

11-11-13, 00:26

Look at the photos of the primers igniting at the link below, I don't think the Remington 7 1/2 would have any problem in cold weather lighting off H110 powder.

Primers - Small Rifle Primer Study
A Match Primer Study in the 6BR Cartridge
By Germán A. Salazar

http://riflemansjournal.blogspot.com/2009/06/primers-small-rifle-primer-study.html

matemike

11-11-13, 05:41

Likely a combination of the different lower and trigger AND temp. Any one of those things could make a difference. All three together...? 3" group size change is possible.

Hand loading is like a science experiment, only change ONE variable at a time. Otherwise you'll always be back a square one.

I assume everything else was the same? Bullet weight. COAL. Crimped. Etc?

GunnutAF

11-11-13, 13:06

The fact that none of the data for 300Blk called for a Mag primer always sat badly with me as all data for other calibers call exclusively that one useing a Mag primer. I may have to revisit H110/W296 laods in the 300 Blk with Mag primers. I stopped using it cause accuracy wasn't there and case life sucked big time.:D

Onyx Z

11-11-13, 19:57

Likely a combination of the different lower and trigger AND temp. Any one of those things could make a difference. All three together...? 3" group size change is possible.

Hand loading is like a science experiment, only change ONE variable at a time. Otherwise you'll always be back a square one.

I assume everything else was the same? Bullet weight. COAL. Crimped. Etc?

These were left over from the same batch, so yes, everything was the same as before.