stubblejumper

I purposely look for loads that show consistant accuracy if the powder charge is increased or decreased by a grain.They seem to be the most consistant in changing temperatures.The loads that change dramatically when the powder charge is varied by only 1/2 grain or so,tend to be erratic when the temperature changes.A load that shoots sub 1/2" at 70 degrees is pretty much worthless if it opens up dramatically at 20 degrees.Since my hunting weather varies from -30 to 70 degrees,I want a load that will perform well throughout that range.

racowboy

How does that temperature affect speed if any? I chrono'd my 300 RUM yestarday and am barely hitting 3200 with the 180 TSX with 92 grains of RL25. That's 1 gr. over what barnes said is max and I'm still not seeing any pressure signs. Was 43 degrees and out of a 26in barrel Sendero. Today I'll shoot 92.5 and 93gr. I want to hit 3250-3300 fps. I have pretty much shot one whole with all the loads I've tried starting at 89gr and increasing at 1/2 gr. increments at 50yrds just trying to get my speed.

bigcountry

One hole huh?

racowboy

Yes, one hole...12 shots touching all together....it was at 50 yrds and shouldn't be a big suprise to someone who gets out and shoots.I didn't say how big the whole is! Why is it that people think they have to get on here and give other people crap instead of just help and answer the questions?

bigcountry

I don't know RA, I have pretty much answered every question you ever asked.

Your probably the exception, but we get alot of internet one holed groups on here. But 50 yards is probably understandable. Most test out thier reloads at 200yards or even longer. It is highly unusual to do it at 50. At least for me. Too hard to tell the tale on a load.

congrads on your one holed groups.

stubblejumper

The top group is what I consider a 100 yard ,one hole group.I will admit that I have never shot another group as small as this one with a hunting rifle and hunting load.It is anhonest.080" group.The three groups were fired consecutively with one of my 300ultramags.A fellow thathad beenbragging about the accuracy advantages of his 300wsm,refused my offer of a wager for a three group average after witnessing me fire these groups.

http://i34.photobucket.com/albums/d128/stubblejumper11/300ultramaggroups.jpg

As for velocity,I see a difference of about 2 fps per degree with my 300 ultramag loads.My 180gr tsx loads produce 3360fps and 3380fps in my two rifles respectively at 70 degrees.At 40 degrees the velocities would be about 60fps slower.

racowboy

Thank you Stubble, you answered my question. All I was doing is shooting over a chronograph to try to get in the ballpark of what the gun is suppossed to do with reloads. All said and done I had about a 1 inch hole in the paper at 50 yrds. The info from Barnes wasn't even close to what they say. According to Barnes I was suppossed to get around 3359 at 91 gr. I finally got 3285 with 93gr. RL25 and was trying to figure out if I would be increasing or loosing fps with temperature.

stubblejumper

Just be aware that a load that is safe at 40 degrees may not be safe at 70 degrees.Accuracy may change as well.