Greetings all,

A few weeks ago My hunting partner and I were working on some new reloads in the .204.
We loaded up a few rounds with AA2230 and 32G Vmax bullets. Later that day at the range a couple different loads shot very vell (5 rounds just under 1' inch @ 100).
Being excited that maybe we found the "new"load we reloaded more and yesterday went to ths same place and shot the same rounds.
This time the groupings were 2-3/4 to 3-1/2".
same Rifle, same scopes nothing changed except the outside temp. The first time it was probably 35 degrees, and yesterday 20 at best.
Would the temp have that much effect on accuracy?
Sorry for the lenghty post. just wanted to get all the info in for discussion.
Thanks

I can tell you when I ran some test loads through my new handgun and it was 5 above with a nice strong wind blow.

I really didn't care what size the groups where. I was just glad to know that it worked just fine.

I find it a lot harder to shoot tight groups when I am Shivering.

I do not test group size when the weather is bad.

It just adds another factor that can screw up the testing.

Perhaps some one with Quickload will chime in however, until then, I plugged in what you provided and assumed a MV of 3200fps into my Ballistics program and altered only ambient temp.from 35 to 15 degrees F

Got near nothing in changes in POI at 100 yds .

Logic would tell me that a 15 degree change in the near freezing ranges would alter little.

I remember someone doing ballistic tests over a wide range of temps but cannot pull it out of my limited brain storage at this time.

Gary

Probably: it is not the load that changed, it is the rifle. The temp changed the bedding, barrel, action interaction to get that much shift. You have a bind point somewhere that is radically changed by that cold weather. Just my guess as I have seen that in a couple of rifles with bedding problems.
Or: I could not tell by your note if it was one rifle and scope or two thus; frankly it could have been your resting techniques and hold that was modified. Or it could be a combo of both.
Best regards!

Just another thought. Could the difference in temperature have affected the shooter? I know when it gets that cold I have trouble with the basics of bench shooting. Getting too old to play in the real cold.

muick

Muck,
That is what I was suggesting as possibility 2 above. Even gloves holding a rifle present a different resistance factor I find. I do most of my shooting over sticks with a gloved left hand summer and winter because that is the shot I will have hunting. I might bench one if I have a problem but rarely.

Yes, while I will agree that different rest, gloves or shivers will effect accuracy, I will have to same none were present.

I was not wearing gloves and had no shivers. Had to believe at the temp, but true.

The thing that made me ask was this is a new powder that we are trying. The other "pet" load of AA2520 shot well with almost the same result that we have been getting, which is good. there was not a big variance in accuracy as there was with the AA2230.

Thanks for the replies.