How Important is Powder Sability?

[MontanaRifleman]

Howdy all, I'm new to this forum.

I recently found out that most powders are temperature sensitive, ie. if you work up a good load and sight your rifle in at an abient temp of 60 degrees and then go huning when it's 20 degrees out, it will affect your powder's burn rate, and subsequently the pressure and velocity which will in turn affect point of imact and accuracy. For example i was told that Win 760 will loose 2 fps per degree of ambient temp. That would amount to 80 fps less velocity in the hunting situation compared to the sighting bench. That is very significant. Especially here in Montana where hunting temps can easily range from 70 to -20.

Based on this info I plan to stick to temperature stable powders which rules out a lot of good old time proven powders such as all the IMR's and others. Right now my plan is to stick with H4350 wich is one of Hodgdon's Extreme (temp stable) powders for my 270 Win, 7mm Rem Mag, and 300 WSM.

Sooo... why go to all the trouble of so meticulously cleaning, measuring, weighing, trimming, seating etc of our components to eek out our best possible loads and then load an unstable powder in to our case?

Am I missing something here?

Any comments?

[taylorce1]

I think that while temperature does effect powders it is no where near as extreme as it used to be. I think you will find most powders will work in a wide variety of temperature changes. I still wouldn't work up a max load at 60 degrees and go hunting varmints in 100+ degrees. A lot of bullets have been sent down range using W760 with great results, and with the new ways of making powder I'm sure it will be used for years to come. I think you are overthinking things too much if a powder is accurate in your rifle that is the one I'd use.

[Shoney]

MontanaRifleman WELCOME TO THE FORUM!

Having hunted in Montana ALL my life, I have found that loads developed at 60 degress will shoot very well at 20 degrees with little noticeable difference. The difference comes when shooting at zero and sub-zero temps and temps in the 100's.

I try to refine my loads at 20 degrees with the temperature insensitive loads, but still find major differences at 30-40 below. Develop your loads at or near 32 degrees and don't look back. When you get into the sub-zero weather, be sure to sight in at 100, 200, & 300 yards so you know the score.

Good Shooting!

[Sevens]

If you are talking about point of aim changing over a distance of 200-300 yards, I can see a certain amount of concern when hunting in cold temps after working up a load at warm temps.

But in my opinion, where things really matter is if you build for yourself a load that's at or near max and you do it in cold weather. Because when you take that same load out of a hot car or have it sitting on a table in the hot sun, you can put yourself at pretty great risk by shooting it if it was a max load developed in a cold temp. And even if you don't go as far as to damage your rifle with an over-pressure load, you could still get a case stuck in the chamber or have a head separation... either of which could put a real wrench in to a day of hunting.

[MontanaRifleman]

Thanks for your replies, comments and welcome. Some good things to think about.

{A lot of bullets have been sent down range using W760 with great results} This is no doubt true, but my question is, what is W760 doing on a much colder day than the day you were on the range? If your hunting shot is less than a 100 yards, one would probably never know the difference. But it might be significant on a 300 yd or more shot. I'm originally from PA, and most shots there were less than 30 yds. But West of the Mississppi you can get a lot of much longer shots.

{I try to refine my loads at 20 degrees with the temperature insensitive loads} This sounds like a good idea and I will probably try to follow up on it if I get the opportunity. As for extreme cold and hot temps, sub zero and 90+ there are probably other factors affecting the bullet as well as the powder, but then a temp sensitive powder will magnify problems. I'll probably just opt for shorter shots in that situation.

{where things really matter is if you build for yourself a load that's at or near max and you do it in cold weather. Because when you take that same load out of a hot car or have it sitting on a table in the hot sun, you can put yourself at pretty great risk by shooting it if it was a max load developed in a cold temp} Aggreed... I had already thought about that.

My plan at this point is still to work up loads using a temp insensitive podwer, (H4350 for these particular cartridges) at *comfortable* cool temps in the 40 -60 range and then check them at lower temps. If I cant get accurate loads then I'll have to find some other powders. But for now I'll put my time, energy and money into a *stable* powder.

Thanks again for the feedback, I really do appreciate it, and maybe my concern is a little overblown, but I know a guy here who is a serious handloader and he is ALL about accuracy and he went to great lengths to stress this to me. And his powder of choice is H4350.

My guess is that other powders will be developed to be more stable.

Am still open to more discussion, especially from the bench shootin guys.

Load safe, aim well and shoot straight

[Zak Smith]

I use H4350 in my .260 and it has proven to be very temp stable... less than the S.D. over 90*F.

[taylorce1]

Trust me we are all about accuracy if we hand load, and I used H4350 in my load I took to AK to hunt bear. I didn't use it because it was less sensitive to temperature I used it because it provided the best groups in my rifle with the bullet I chose to use. Don't get hung up on one powder because of a recommendation, find which powder gives you the best accuracy and performance in your rifle. Try H4350 if it works great if it doesn't, don't try and make it work, try a different powder.

I've never had a problem with accuracy out of my rifles with cold temps, but I don't hunt very often below zero either. While you are worried about long shots and believe me I know where you are coming from. I find on those very cold days or bad weather it is easier to get within 100 +/- yards than any other because the animals are less active or alert.


Some powders I 've had good luck with (at all temps) and still using are:

IMR & H4350 (.30-06)
IMR & H4831 & H4831SC (.270 & .280)
RL15 (.338-06 & .35 Whelen)
IMR 4064 (.243)
H4895 (8mm-06)
H4198 (.223 & .30-30)
H380 (.30-06)
H335 (.223)
TAC (.223 & .30-06)
Big Game (.30-06, .338-06, & .35 Whelen)

I got a smoking deal on some 8lb canisters 1 each of H414 and W760 $160 for 16lbs. I figured at that price it was worth trying, haven't done it yet though.

[freakshow10mm]

I use Varget in all my rifles and some get IMR4198. No ball powder.

[MontanaRifleman]

Taylorce, I agree and I'm going to focus on H4350 to begin with because it seems to have the best reviews but if I cant find a good load, I'll try another powder. Varget and H4831 are a couple of temp stable powders that might work. I also came accross a load with from a guy with my rifle and bullet using A4350 with very good results, but a tech rep for Accurate said I could expect a 1 - 2% change in velocity with temp change at more extreme temps.

Freakshow, I agree on *no ball powder*

Thanks guys

[taylorce1]

I've never found there to be much of a problem using ball powders in fact a few of my favorites are ball powders. When reloading bulk ammunition and using a thrower to meter out the powders I don't get the crunching of the stick powders. Sierra did a test on temperature sensitivity and came up that there wasn't much of a difference between the extruded and ball powders they tested.

(2) The muzzle velocity sensitivity to cartridge temperature for the two ball powders used in these tests does not appear to be much different than the sensitivity for the extruded powders used.

http://www.exteriorballistics.com/eb...ned/4th/56.cfm

[freakshow10mm]

In velocity comparisons, not really. In pressure comparisons, yes. Load up a 375 H&H Mag with some ball 760 with a load developed in the winter in Montana they go shoot it in Africa when it's 115 in the shade and see how much your case bulges.

[taylorce1]

Load up a 375 H&H Mag with some ball 760 with a load developed in the winter in Montana they go shoot it in Africa when it's 115 in the shade and see how much your case bulges.

Did you not read the whole test? With an increase in pressure you get an increase in velocity as well they are very much related. The temperature varied from 20-135 degrees granted they were not max loads (accurate loads rarely are). I'm not saying that there are not powders out there more temperature sensitive than others, just that many powder companies have tried to address this problem in all of their powders.

Hogdon produces IMR and Winchester powders anyway and you are saying that they don't share the same powder manufacturing processes between brands. Granted W760 has had a bad reputation for temperature sensitivity in the past but have you tried it lately? I haven't tried it either but I wouldn't go on any out of State hunting trip without doing extensive load development. I would still choose the powder that gave me the most consistent accuracy regardless of it was ball or extruded powder.

[freakshow10mm]

With an increase in pressure you get an increase in velocity

Not always.

Hogdon produces IMR and Winchester

No, they market them. Big difference. Hodgdon makes most of their powders in house but a lot of other powders are made overseas and marketed by Hodgdon.

Granted W760 has had a bad reputation for temperature sensitivity in the past but have you tried it lately?

I don't use Winchester rifle powders for this very reason. I don't care if they made it better or not. From the people I've talked to that use it extensively, they said it hasn't bettered.

[taylorce1]

With an increase in pressure you get an increase in velocity

Can you explain this better to me? I'm no physics major or anything but I've always been under the assumption from reloading data higher pressures increased velocity. I never said that there would be a signifigant gain in velocity but that you should get a change.

We know that as pressure goes up, so does velocity. Pressure goes down, so does velocity. If you are worried about pressures, and don't have access to pressure equipment, develop your loads using a soft primer like CCI and a chronograph and find the top node or stop when you get flattening or cratering. Then switch to a harder primer and adjust your load to give the node velocity.

http://www.frfrogspad.com/intballi.htm

[freakshow10mm]

Certain powders get hinky. HS6 and Blue Dot come to mind. I've had certain loads during workups that an increase in powder charge flattened primers (increased pressure) but the velocity dropped by 75fps. I don't know what goes on, but my experience has shown it not to be true 100% of the time.

[Pathfinder45]

......YOU'LL GET MORE velocity with more pressure. But all else is seldom equal. This is why we often change powders with different weight bullets because one powder is more, "efficient", than another for a given weight, etc. A significant change in powder, [as in burn rate], will show a big difference in velocity when both powders are loaded to the same pressure, again, A.E.B.E. But getting back to temperature stability...... I read that the powders H-110/W296 can show quite a bit of velocity variance in relation to temperature change and that at extreme cold conditions H-4227 is a better choice, [This from a Hodgedon magazine at Sportsman's as I recall]. But that was for magnum pistol loads. For the calibers MontanaRifleman lists, I think H-4350 should be a good choice but if the choice of bullets are heavy for caliber then perhaps a slower powder like H-4831 might be a better choice. My .270 prefers 150 grain Partitions loaded over a hefty charge of Norma N-205, a powder that has been discontinued for perhaps 30 years. Y'all got any ya don't use? "I like ball powders 'cuz of their metering uniformity; I like stick powders 'cuz of they seem to be the best for every thing else." Oh, we poors souls,.......hopelessly experimental!

[scsov509]

Oh, we poors souls,.......hopelessly experimental!

I love that about reloading though! There's just something so fun about sitting around and saying, "I wonder if..." and then getting to go out and actually test those speculations. That's part of what makes reloading downright addictive