If waiting for hunting season to open wasn’t stressful enough, my “looniness” is driving me insane about temp stable powders. In my 7mm SAUM shooting the 120 BT, the most accurate & highest velocity load is with Ramshot Hunter avg. 3381 fps. The second best accuracy is with H-4350 a temp stable powder but lags along at the avg fps of 3200. I have a November muley hunt in Colorado where the temps could be cold you just never know. Our typical shots are normally less than 200 yds but you may need to stretch out some… I would say no longer than 400 yds. At those distances is this even a discussion? I would prefer to take the most accurate & highest velocity load but what if the temps plummet? Which load should I bring?

All my hunting buddies do not load and they use nothing but factory ammo. They all do think I am truly “loony” for even thinking about this. My closest partner over the years has been to Northern BC & Alaska chasing caribou, Mtn goat , etc…with his A-bolt & Federal Premium ammo and he says “ my factory ammo killed ‘em just fine” what’s all this powder temp BS you are talking about? It really makes you wonder…..

I would use the Hunter and fogetaboutit.At 400 yards it will mean squato.

What sometimes seems to be missed in these conversations is the difference in point of impact isn't necessarily going to be only a little more drop because of velocity loss.

So does 180 fps at those ranges matter? Are you using an elevation turret?

I'd run what you have the most confidence in. If you developed the load in the 40-50's, I can't help but think you'll be just fine. Before the internet, I just shot whatever I was shooting at or near the temps I was hunting at, and haven't had any issues. Not saying it doesn't matter, but it doesn't matter to me that much!

No dials. I'm still old school "set it & forget it" guy. At either velocity, I am for the most part good out to 300 yds with a center of kill zone hold. Just answered my own question.

Sounds like a smart answer

+1

However, I still don't think it'll matter all that much out to 300-400 yards unless he's getting some anomalous POI shift.

I'd run the Hunter load myself. It isn't going to be a problem for you. I don't know that Hunter is widely known as being temperature unstable anyway.

Test it. Freeze the ammo and gun..easy to do, and run over the chrony. You can check for accuracy then too.

C Roy,
I have experienced same as you with RL 22. During load development it turned in the best accuracy & velocity. Always hunted in the cold, so I cranked up the velocity to max. During my first summer Axis hunt my winter time loads locked the bolt on first firing. When I changed to summer time load work the winter time velocities dropped below my level of acceptance. I subsequently ceased use of temp sensitive powders. Was a lot of work but worth it in the end.

I've gone almost entirely with "Extreme" powders (H4895, H4350, and H4831) for all jacketed bullet loads in rifle cartridges. At least one of these powders works very well with everything from .222 to .300 Winchester Magnum, but I have no "Ultra Mag"-type large capacity cartridges.

I run Hunter in 22-250/75 A-max, 243Win/85TSX, and 270/140TSX. I've taken deer and coyotes out to just over 500yds with these combos. I live and hunt in ND, we get plenty cold, POI shift hasn't been an issue.

What's wrong with 3200 fps?


I once hunted with a box-stock Ruger 77 MK II All Weather in 280 Remington. It was the only rifle I ever fired commercial ammo in & did so exclusively, intentionally. It was so accurate with commercial ammo it surprised me. I swore never to clock the rounds. Doing so would immediately result in load work as I knew they would not be fast enough to suit me. When I quit shooting that gun I did clock the commercial ammo. Remington 150 CoreLokt averaged 2820 fps in the 22" barrel. By that time I had amassed well over 35 dead animals in a 3 year span. Several of those were big bodied Axis bucks. Never required a follow up shot.

The velocity measurement taught me several things. Most important, 2820 fps was fast enough. Anything more is personal preference. And, there are those who are plenty satisfied with even slower.

You are more than entitled to appreciate faster & flatter. But, there is a place for slower & methodical.

If I use a known, somewhat "temp sensitive" powder like RL22, which I love in my 7mags, I develop loads in higher temps around 85 degrees or so. I've hunted the TX panhandle in 0* wind chills, and African temps of 80* with zero issues. Hunting around here this temp sensitivity stuff never enters my feeble mind.

And if it get your drawers in a wad, you could sub RL-23.

DF

At 3200-3300 fps with a 120 grain BT, I think I would be more worried about bullet performance at short distances than whether or not the powder I was using was temp stable. As has been said, 180 fps isn't going to be that big of a difference at your stated distances.

If Hunter gives you the best accuracy, then use it.

I have the 7MM RSAUM in a 700 Ti and ran the 120 TTSX for one year only. I killed big west Texas muley with it at about 200 yards, but it took 3 hits to knock him down. Upon inspection, all 3 shots were kill shots, he just didn't know it. I used IMR 4350 for that load. I went back to the 140 TTSX and haven't had a problem.

My load is the 140 TTSX over 59.0 grains of IMR 4350 and a Fed 215GM and runs at 3070 FPS. I've killed a bunch of stuff with it and several, including the above mentioned deer at temps well below freezing without any issues.

I don't think the 120 TTSX was the issue. I don't think I have ever missed a shot due to temperature, but I don't shoot at long ranges. Inside 300 - 400 yards it would take a major shift in point of impact to make a difference. I can't verify it but the most I have seen is a couple inches more drop. I think good barrels and bedding contribute to not getting left and right flyers but again impossible to prove. I do have to be concerned with hot weather where even the most stable powder will show an increase in pressure. Either working up to max loads in hot weather or stopping a grain or so under max is usually all that is needed. In real cold weather I keep my spare ammo in a pocket with a chemical hand warmer and rotate it into the rifle every half hour or so if possible. Or if in a stand I just load one when deer are in sight.

I guess I'm lucky, because living here in the far north......................... of Louisiana, it doesn't get cold enough to have to worry about temp sensitive powders. I use RL-22 for my 270. It pokes along at about 2800 fps, it's accurate, and it kills stuff.

Jordan,

I have seen POI shift as much as three inches at 100 yards with more than one handload that lost considerable velocity from 70 to zero F. It isn't common, but it happens, and you can't tell if it will unless you actually test the load in cold weather. Freezing only the ammo itself is not a reliable test. And the POI can change in ANY direction, not just up and down.

I have never seen any noticeable change in POI at 100 with a temperature-stable powder, and I have tested plenty at 70 and zero.

I've been on a couple of elk hunts when the temperature was right around zero. To me, it's worth the piece of mind to use a temperature stable powder.

Good report from the "far North" of Louisiana.

About the same deal here in Central Louisiana.

I may have to check out that area one of these days...

A man need to get out and explore, don't ya know...

DF

You're welcome any time!

Bingo. I've seen a POI change when the temps change with less than stable powders. The biggest was with RL-22 in a 270 and 150 grainers.

Casey,

Perhaps not so oddly, that was the combo that produced one of the worst POI shifts I've encountered as well. The load was VERY accurate at 70 degrees F.--and was still accurate at zero. But at zero degrees, POI shifted an inch up and three inches right.

And initially I was all excited because RL-22 made this slowish 270 about 75fps faster than H4831.............sheesh.

I’ve never experienced the above POI shifts with MRP in a 7mm Weatherby with loads worked up at 300 ft MSL at 50 degrees and checked at 7,000 ft MSL at 20 degrees. Maybe MRP is not really RL22 or the temp spread is not enough? Happy Trails

7977 for cold OR hot temps.

WAM,

20 to 50 degrees is indeed not much of a temperature spread.

In fact I have yet to encounter a modern smokeless powder that isn't pretty temp-stable at temperatures from around freezing to 80-85. Have also never tested one that doesn't increase noticeably in velocity (and hence pressure) above 85 degrees, though the more temp-resistant don't show as much rise.

Also, even many older powders vary considerably in temp-stability. Probably the worst are double-based powders, whether extruded or spherical--and all spherical powders are double-based. In general, the old IMR single-based powders are more temp-resistant than older double-based powders.

However, there are several factors that I've mentioned frequently in my writings on the subject, especially my chapter on temperature and powder in GUN GACK II. First, even pretty temp-sensitive powders can work pretty well in specific cartridges, or even specific cartridge/bullet combinations. Have seen this numerous times in my tests. In fact some powders specifically designed for certain cartridges are often very temperature-resistant in that specific round, but not so much in others. Ramshot TAC is a good example. It was specifically designed for the 5.56 and 7.62 NATO rounds, so tends to be very temp resistant in the .223 and .308, but not so much in other rounds.

Second, some powders are "accidentally" temp resistant. A prime example is Reloder 26, which was not specifically designed to be temp-resistant, as were RL-16 and RL-23. As a result, 26's temp-resistance can vary more when used in different rounds.

On the other hand, today's powders that were specifically designed to be temp-resistant in a wide range of applications work very well, including RL-16 and 23, the Hodgdon Extremes, and the IMR Endurons. I have yet to test any of them at both 70 F. and zero that show more than about a 25 fps difference in velocity.

Whether all this means anything to a certain hunter is another question. It does to me, since I often hunt in temperatures down around zero, or even colder, and sometimes shoot at ranges over 200 yards--and on rarer occasions have hunted in temperatures above 100.

Wouldn't changes in air density when going from warm weather to frigid weather have a deleterious effect on POI also?

Changes in air density make a HUGE difference in POI at longer ranges. Less dense air causes bullets to slow down less quickly, and thus drop less and hit the target with higher velocity than in more dense air. This is a part of environmental conditions that are factored into ballistics charts though, and I've never seen any noticeable shift in impact at 100 yards that wasn't due to a large drop in temperature/pressure/velocity. I do a lot of hunting at 6k-8k ASL, and the bullets fly a lot flatter there than at the usual 4k-4.5k ASL that I usually shoot at. Of course, during late-season elk hunting, it can be 20 or -20 degrees in the morning, and the air is a lot more dense than it would be at 50 degrees, but it varies less at higher elevation, because there is less air.

Thanks, John

I have read your articles in Rifle / Handloader and Gun Gack, too. I just mention the 7mm Weatherby anecdote as I rarely work up loads when it exceeds 50 F and usually hunt when it is between 10 - 60 F. I never hunt and rarely shoot centerfires if it is above 80F. Any warmer than that, maybe a coyote or other varmint with a .223!

gnoahhh,

Yes, air density has a HUGE effect on downrange POI, as huntnshot pointed out.

But as he pointed out, it almost never has a measurable effect on 100-yard POI--and as I pointed out, temperature[-sensitive powders sometimes do, often major.

Any way we can reduce (or eliminate) the effect of ANY variable helps in accurate shooting. Some we can't do anything about, except calculate their effect--such as air density. But these days we can do something about variations in muzzle velocity due to temperature.

Is this one of those situation that some refer to as "overthinking a potential problem"?

I kinda liked the statement about " I never had those problems" before the internet....
same here....

Runout probably didn't matter before the internet either.

In Internet oddity: Have noticed that many handloaders can apparently "read" pressures precisely by looking at fired primers, yet have never seen any detailed description of how this works on the Internet. You'd think something would have appeared by now.

R19 was the best powder in two .240 Weatherbys I used to have. However, R19 in a heavily compressed 338WM load, using the "slick as snot" older Barnes XLC 185 was perfect...at 60 degrees. When I tried it at 10 deg....patterns. At home, pulled the bullets and powder column was a solid 'cake", had to dig it out w/screwdriver! I jumped on some H4350, worked up a load next day, also 10deg. Nine days later I shot a real big cow elk right at 250yds! Now, this was more of a problem of very, very compressed powder in order to gain any real velocity from that slick bullet! The 338WM case was 'almost too small" for that bullet and many powders, couldn't get enough in there. A LEE FCD would have helped, "maybe", and I was all enamored with R19 for its speed and grand results in the 240W, ha.

I just loaded up some trial loads for my 300WM and the 150TTSX. I'm starting out with H4350 and H4831! ha I was going to use R23, but the mid range load almost filled the case! My Mesa has a long throat, this 150 TTSX touches the lands at 3.50", so set them at 3.45 and crimped them ( I always FCD Barnes anymore...just my thing...) I'm pretty sure I can get one of those Hodgdons to work.

In the early 80's I was probably the only guy in the valley with a chrono. It was not uncommon for shooters to come over and ask to run a couple rounds through my chrono. I met a couple silhouette shooters that way and made friends with them. They educated me to the concept of temp sensitivity of smokeless powder. We would get together at the range once or twice a year and cold test various loads.

Over the years the most stable powders have been H4350 and H4831 in cold weather testing, in a bunch of my own and other guys loads--this was even before the "Extreme" line of powders appeared.

Alliant powders have been claimed to be temp stable but I have seen some velocity loss even in the powders Alliant claims to be temp stable. And I mean every time that I can recall. When JB cold weather tested RL-26 in a 270 and found no velocity loss I had to try some--especially given the velocities RL-26 was getting. When I got around to testing RL-26 I lost 20-30 fps in two 270's and two 243's from 80-85 degrees down to about 15 degrees.

A call to Alliant and it was explained to me the "controlled response" of RL-26 means there most likely will be a smallish velocity loss with RL-26, but it will occur in a linear, and predictable, fashion. My experience has been at roughly 15-25 degrees is where a quick drop off of velocity occurs. I think JB has mentioned this before. The only way to confirm what the Alliant rep described is to test RL-26 at three different data points--80+ degrees, then at around 25-30 degress, and then in the low teens or single digits.

Casey,

In my 70 F./zero test with RL-26, using the 150 Partition and a max charge, 26 actually gained around 50 fps.

My "zero" tests are actually at -5 to +5 degrees, which is as close as I can come to zero under actual outdoor conditions, given the vagaries of weather. This is explained in my chapter on temperature and powder in GUN GACK II, which includes a bunch of tests in cartridges from the .17 HMR to .375 H&H. In fact in the tests with Extreme, Enduron and RL-16 and 23 powders usually show around 25-30 fps difference in velocity from 70 to zero, sometimes plus and sometimes minus.

One of these evenings I'm gonna have to read that chapter!

MD What do you attribute the gain in velocity in cold weather too? Are the barrel harmonics changed or does the steel contract in cold weather?

How forgiving is the hunter node you've found? Load to the highest velocity that your load will produce NOW and not open up. That alone could keep you in the sweet spot when it cools off. You could also adjust seating depth to the shortest length that doesn't open your groups up. Lastly, you could load some extra rds long, and ( if you use one) take a arbor press along . You could quickly try three different depths, and one should shine without committing to loading another charge weight that may not. Good luck.

I experienced this dilemma earlier in the year when I was deciding on a load for my .308 Winchester for a Colorado Elk hunt. The bullet I selected was a Barnes 168g TTSX. I noticed impressive velocities in Barnes Book with the CFE-223 powder which I know is a double base and I also tried Varget. I really wanted Varget to work but best accuracy was at about 2500 fps and even so it was notably less accurate than CFE-223 from the start charge to the point I couldn't believe the numbers I was getting from a 20" tubed .308 Win. I tested it in 30, 60, and 90 degree weather and found the velocities spead to be less than 30 fps from 30 to 90 degrees.

Anyway it worked and I plugged my 6x6 elk at 294y

The radical horizontal spread MD reported...3 moa?...Anybody care to opine where that comes from? Kinda makes one wonder if powder temp ain't the (w)hole story. I've had some horrible things happen to barrels in the hot blue tanks and in the lathe while profiling. There are inherent stresses in rifle barrels, button rifled barrels for sure. Just wonderin'.

flintlocke,

I sincerely doubt the 3 MOA horizontal shift in POA was due to barrel stress, since the rifle would group very accurately when shooting one shot after another until the barrel was quite warm.

Instead, as hinted at in the chapter, I would say its due primarily to the radical change in muzzle velocity. As mentioned, what I have noticed over years of testing is that rifles showing considerable change in POI when testing various handloads during the SAME range session, from cool barrels, will often show the most POI change when shot with temperature-sensitive powders at widely varying temps.

I've come to the following conclusion; each rifle is a world onto itself. yesterday I was running some loads through my 416 Rigby. Outside temp was about 50 degrees. 410 Woodleighs with 90.2gr of IMR 4350. One curious thing happened. The day before I shot the same loads when the temp was about 75 degrees and mv was about 50 fps faster but POI stayed the same. I then switched to 89gr of H-4350, same bullet, MV was about 40 FPS slower but it grouped 3" high and 1" left than those with IMR. there it is.

Yep, and that sort of thing will vary with the cartridge, barrel contour and stock bedding.

I tune the load to expected temperatures. For hunting it's ~40 F because I can encounter freezing to 60F. For competition look at the forecast for that day.

Using H 414 in a 30-06 has caused no issues, even though it is deemed temperature intolerant.

MD

Do good barrels show less temperature variation or POI changes? They seem to especially with cartridges that are well balanced and seem to shoot just about any load well, but I have no way of proving this theory.