Has anyone had issues with regulation done in warm weather going bad when shot in cold weather ? If so what were the issues & how did you address it ?

Clayman:
Now that temperature sensitive cordite is no longer used (no more tropical loads) I don't think it is much of an issue. I have not noticed any difference in my shooting from temps in the teens and 20s up to upper 70s (as hot as it ever gets here). It will be interesting to see what others say. Also, in Africa, my rifles seem to shoot OK in the 90s--but this not off a bench, but at critters.
Cheers,
Cal

No, no problems.

I have loaded in the middle of winter here in Aus - 0 - 15 degrees during the day at worst - and then hopped on a plane to the other side of the country and shot in 40 - 45 degrees (at worst) (over 100).

No problems whatsoever.

I don't yet have experience with doubles, but with my long range stuff I do, I have doped a difference between shots at 10 below and 60 above. For example, to get to 1000 yards on my 20 inch 308, I need 9.6 mils of elevation at 60, but at 10below, that changes to 10.9 mils. Cold makes the are much more dense.
Hope this helps.

I have experienced negative effects on regulation of my Searcy .470NE double in cold weather. A few winters ago, I went to the range to shoot. The temperature outside was in the 30s. My ammo is always stored in my outside unheated garage, and it got down into the teens the night before. So, the ammo was very cold. At the range, I found my Searcy double, which usually shoots the width of the barrels for 2 shots at 25 yards, was now shooting a 6 inch spread at that range. My load was, and still is, 106 gr of IMR-4831 with a 500gr Woodleigh soft or solid bullet. When I called Butch Searcy to ask him about what was going on, he was not the least bit surprised. He said the colder temperature meant the poweder was burning at a different rate and producing a bullet velocity slower than when the rifle was regulated. The next day, with the same temperatures outside, I kept my 470NE ammo inside the house where it was nice and warm. That morning at the range, with the outside temperature still in the 30s, my double shot the width of the barrels at 25 yds. The "warm" ammo seemed to make all the difference.

SS74; Sir, the issue is IMR 4831 in my opinion. H-4831, albeit a slightly different powder is much more temp INsensitive than the IMR.

How close is H 4831 to IMR 4831 in measurement for loads? Is there a formula for measure ?

Alaskaman:
Interesting. On my 4-bore I use 9.8 mils at 1000 yards but only 9.4 on my .600.
Cal

H4831 is the powder I've had the best success with in terms of temperature stability (in the .470) but even with it, there is still some variation.

I've posted about this here before, but a six-sigma math genius ( Denton ) and I did a fairly rigorous experiment on the subject a couple years ago and found (at least in the .470)

H4831 has a varition of 1.4 fps per F* (tested from 10* to 102* F).

For me, a load of 106g covers about 10-70* and a load of 104g covers 70*-110*.

I don't see a way to attach a file here, but pm me if you're interested and I can e-mail you a spreadsheet with the formula(s).

-matt

I’ve shot my double rifles in temperatures from the low 20s F, in snow, to 105 f . in Texas July heat. This shooting in that range of temperatures was in the same place which means the same altitude of 600 feet above sea level, with no perceivable difference in impact on the target or change to regulation.

I think the older ammo loaded cordite and some of the flake powders used up through the early years in Africa was so temperature sensitive that reduced loads were necessary in those tropical climates. The ammo made today with modern powders is not a problem in my experience.

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I have completely solved any problems associated with ammo temperature; I do not go to the range if the temp is below 30, nor above 100. When I am hunting and the weather is outside those extremes, I have not found a problem with hitting game at any distance that I shoot game, with a Double Rfle.

quote:

Originally posted by cal pappas:
Alaskaman:
Interesting. On my 4-bore I use 9.8 mils at 1000 yards but only 9.4 on my .600.
Cal

LOL! Dork! You know with your rifles, its called a fire mission, and what you shoot is not called a rifle its call artillery!

I have had where the groups in my 450/400 opened up on a colder day,I was using IMR4831,where as H4831sc showed no change,both the loads had been tested on a warmer day.

quote:

Originally posted by jorge:
SS74; Sir, the issue is IMR 4831 in my opinion. H-4831, albeit a slightly different powder is much more temp INsensitive than the IMR.

Jorge - that could very well be. I have never shot H-4831 in my .470. Butch regulated it with IMR -4831, so that is what I shoot. In any case, I have no plans to hunt with my 470 in really cold weather. One can argue it is very cold in Zimbabwe on those crisp July mornings, and I would agree with them. But then again my cartridges are fairly close to my body and no where near the ambient temperature. In other words, no problem to solve.

Correct sir, you'll have no problems in Zim! good luck!

ADI Powders which are made here in Australia and who I am pretty sure make the H4831 and other powders used in the US are made so they are NOT sensitive to temp changes, which is a good thing considering the wide range we have here.

That is why some people get changes in regulation and some don't, IMR vs H powders.

quote:

Originally posted by cal pappas:
Alaskaman:
Interesting. On my 4-bore I use 9.8 mils at 1000 yards but only 9.4 on my .600.
Cal

See guys I told you a double rifle is not just a short range rifle!

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I use H4831 and consistently see velocities drop and groups open up as you might expect. Don't buy the purported temp insensitivity marketing.

quote:

Originally posted by Antlers:
I use H4831 and consistently see velocities drop and groups open up as you might expect. Don't buy the purported temp insensitivity marketing.

I agree. We get some pretty good temp spreads in Texas between Feb and Aug, and I've seen it with a variety of caliber and powder combinations.

Here in Norway I have tempratures from 25c (77f) and down to -25c (-13f).

My regulation seem to move further apart in really cold weather. Tested in -20c (-4f) and found my regulation 1" more apart than usually @ 100m.

From my hunting point of view it is not a problem.

The caliber is 9,3x74r

quote:

Originally posted by Schlum:
Here in Norway I have tempratures from 25c (77f) and down to -25c (-13f).

My regulation seem to move further apart in really cold weather. Tested in -20c (-4f) and found my regulation 1" more apart than usually @ 100m.

From my hunting point of view it is not a problem.

The caliber is 9,3x74r

From +77 degrees F down to -4 degrees F is an 81F degree spread, a very wide spread in temperature, and showing only a 1 inch difference in spread on the target very small. One inch is tighter then the average double rifle shooter can hold at anything farther than 10 yds under hunting conditions and is, IMO, a non-issue!

I can assure you, given the same temperature spread with Cordite would be a lot wider, and with a temperature above 77degrees F to 110 degrees F with cordite would be disastrous not in spread but in chamber pressure and horrendous recoil if the rifle stayed together that is.

Considering the slight difference in spread, with modern powders being so small, and rise or fall in chamber pressure for all practical purposes the modern powders are basically immune to temperatures.

With modern powders like H or IMR 4831 if one works up a load at between 70gegrees F and 80 degrees F he will be in the ball park for hunting from 30 degrees F to 110 degrees F for all practical purposes in the hunting fields!
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I have seen it in my Chapuis. Loads worked up in summertime heat spread father apart in colder weather.

quote:

Originally posted by MacD37:
From +77 degrees F down to -4 degrees F is an 81F degree spread, a very wide spread in temperature, and showing only a 1 inch difference in spread on the target very small.

I would however add that when I did my test I had not exposed cartridges and rifle to this freezing temprature more than half and hour before I started shooting.

I supose regulation would have been further apart if I had exposed cartridges and rifle outside for a longer period of time before firing..?