I know heat can cause an increase in pressure. My question is, by how much. Say I have a medium warm load that shoots well at 65 degrees. Then I go hunt somewhere and it’s 100 degrees. Is my same load now potentially unsafe? At what point does this become a concern?

Different powders respond differently to specific temperature changes. Some show a very pronounced pressure increase.....while others are relatively stable! memtb

It will vary depending on the powder. Some powders pressure spike more than others in hotter temps. I would imagine a "medium warm" load will be fine. It usually the guys running on the hot side of things that would need to worry. That being said, its reloading and anything can happen.

For this very reason, I pretty much only use the Hodgdon Extreme powders now. I may be able to squeeze another .2 off a group with say Reloader but the lack of temp stability is not worth it. Invest in a chrono and cheap laser temp gun. Leave your gun and ammo in the sun one day and shoot your loads while recording temps. Ive used H4350 and IMR 8208 XBR in single digits up to mid 90s and saw less than 10 fps swing. My factory 45-70 Hornady Leverevolution ammo saw 100fps swings.

In my experience.... temp sensitivity has more to do with load density, than it does with the actual powder in question. The exact same powder can show different velocity swings under identical temp deltas.... depending on the cartridge/load. I seem to remember JB mentioning this same thing years ago in an article on the subject of temp sensitivity.

Interesting. I don’t shoot any compressed loads. Most of my handloads us RL 22, TAC, and H4350.

I bet you'll see a lot of velocity variation with RL22 and very little with H4350 and varying temps

I’ve seen times of both.... with both....

Right, there are no absolutes in this game. Just the probabilities.

The challenge is, I live in Southern California where the temp doesn’t change much at all. But I travel to hunt all over. Got an Axis deer hunt in TX mid summer. Hence my question... should I load some rounds down to be safe? Or is there a generally accepted safe “rule of thumb” already? Say 1-2 gr below max, which is where I am now for the most part.

Some of the old Speer manuals had a chart . This showed the velocity changes at different temperatures. More modern powders have caused these changes to be minimal. Hasbeen

“Available case is wasted space”! If it don’t fit....force it! memtb

Same here, hence why I just chose to go with a temp stable powder. I don't know of any rules of thumb but 1 or 2 grains below max I would imagine would be fine, especially if youre talking about a book "max"

Similar info on the R26 thread. As MD and others have posted all powders will show some increase in hotter temperatures. Many of the newer powders will show little variation in the 0-70 degree range but they all will gain velocity and pressure at over 100 degrees. Most of my hunting is in the 10-80 degree range which is not significant with most powders even some of the worst offenders. That and I don't shoot game at extended ranges where it could make a difference.

It would seem that the thing to do is to develop loads for a given round at varying temperatures (not sure what increment would be best), then segregate them and carry an assortment when hunting. When game is spotted, check the AMBIENT temperature (not some temperature a thousand miles away or in a heated building nearby), get harnessed into your sling, set up your shooting sticks, set wind flags at appropriate intervals between you and the animal in question, spin dials as dictated by distance, then select a round appropriate to the temperature, load rifle, and shoot.

It depends completely on the powder and the load.

Just to understand how bad the situation can be in the worst case, it's entirely possible for a non-temp stable load worked up at 70 degrees F to gain +10KPSI and a couple hundred feet per second fired at 140 degrees which is very possible for a dark colored gun in the hot sun.

To give you an idea, most guns are designed to be proofed with loads that are 25% over pressure. So a .30-06 that normally fires at about 60 KPSI would be proofed at 75 KPSI. That's enough margin that a load that was not over pressure to start with will typically not exceed proof pressure fired hot. So a kaboom is unlikely. However it may very well impede the function of the gun, sticking the bolt shut or blowing a primer for example. A load that was just a "little" over pressure to start with may very well be past the strength of the gun when hot. Which is a good reason to load to velocity with QuickLoad rather than trusting frequently erroneous pressure data from other sources.

The more recent Hodgdon Extreme powders, the new IMR Enduron powders, and Alliant RL-16, RL-23, and AR-COMP are the most temp-stable powders that I've got available. I almost always use one of the Hodgdon or RL-16/23/AR-COMP series (the IMR ones are slow and useless as far as I can see). If you load on a velocity node with one of those powders at 70F with a high brisance pimer, you will see essentially no velocity change between 140F and -20F. The velocity node part is key.

Or you could just use a temp-insensitive powder and load on a velocity node.

I think he was making a point that people are overthinking it.

Preach on, in spite of the fact you didn't recognize RL26 as a very temp stable powder. Keep up the good work.

I don't have any personal experience with it but from what ive read, its still not on par with the Hodgdon Extreme line?

I've got limited experience with it myself. Pay particular attention to the posts by Jordan and Mule Deer.

https://www.24hourcampfire.com/ubbthreads/ubbthreads.php/topics/13760085/5/reloader-26

+1

They test THEN report....

DF

I read that thread early on. Also, read a bit more on LRH and Snipers Hide, seems like the guys there also saw upward swing in the 85+ degree range. I typically reserve comments for the powders I use and have personally tested. RL19, RL22, H4350, Varget ,8028XBR, BLC-2. I dont chase max velocities so I typically have no reason to even try other powders unless I cant get one of my go to powders to give me a usable load.

How is that any different than 99% of the people posting here? I say H4350 is not temp sensitive. I shot loads at 5 and 99 degrees, under 10fps. I shot RL19 at the same temps, +90FPS. Not sure what other tests make someone qualified to say one powder is temp sensitive and one is not.

I guess you'll have to choose who to believe then. My money is on MD and Jordan personally.

H-4350 has been shown to be one of the most temp stable powders.

For RL-22, try RL-23, near same ballistics with better temp profile.

Varget is another good one and typically has very low S.D.'s, temp stable and consistent. No wonder target shooters like it.

DF

Not really a matter of who I believe. too many variables when it comes to reloading to say someone is right or wrong. I havent personally used it so I can only go with what I read from other known members who have actually used it. Tejano himself said he experienced a spike. I dont disbelieve him just because MD or Jordan had conflicting reports.
All that being said, I'll get pound here this week and give it a spin and report back what I find. Wont be able to get those super low single digit numbers for a few months but I can get some 40-50 to 95+ relatively soon.

Not even vaguely close. RL-26 is one of the least temp stable powders available. Alliant's temp-stabilized line is RL-16, RL-23, and AR-COMP. RL-23 is the closest Alliant-made temp stable substitute for RL-26, but frequently Hodgdon't Retumbo or H4831(sc) is a better choice. It just depends on the application.

Show us your test results LB, then we can see how you arrived at that conclusion.

Well, I looked at it for the 100gr partition in .264WM since it was a top velocity option. 70.3gr was a velocity node at 3440 ft/s with no more than 10 ft/s variation in mean between 70.0gr and 70.6gr. Velocity SD at 70.3gr was 4 ft/s. This was all done between 60 and 70 degrees F.

With the temp chamber, 140F gave 3620ft/s and a sticky bolt. The strain gauge estimated 65 KPSI. Only one shot was fired. 0F gave 3315 ft/s and a 45 ft/s standard deviation.

Variation over the whole temp range was 2.2 ft/s per degree which is about as bad as it gets.

That's consistent with industry data and everyone I know who's looked at RL-26 serious. It's useless for any application I have.

What other cartridges? Do you have your own pressure lab? So you conclude Jordan and Mule Deer are lying about it?

That's the only cartridge I did a detailed workup on, but there's enough data out there on the temp problems with RL-26 that I don't particularly feel the need to waste any more time on it. It's a fair weather powder, and that's fine. Most applications seem to be between 1 and 2 ft/s per degree F. Even Aliant's marketing department won't claim better than 0.5 ft/s per degree. It's certainly no Varget or Retumbo or H4350 or RL-23 for that matter. RL-23 is great - flat as a strap across hunting temps. More people should use it.

I can measure pressure with strain gauges or multi-point laser vibrometer (basically a fancy strain gauge that doesn't require a sensor on the barrel). Neither is as good as piezo, but they're non-destructive.

I don't spend much time worrying about the correctness of other people's ballistics data. Most of it is in error (just look at the crap in any reloading manual), but I've never known someone to lie about it and have no reason to think anyone is here.

I'm seeing a 1/2 fps gain per degree with RL-26 in my .260 with 147 ELD's fwiw.

Lines up almost perfectly with the Hornady 4dof when using powder temp sensitivity parameters.

The Hornady 4dof app is a great, free reference for looking at powder stability numbers in my opinion.

Hmmm. My 6.5 Swede likes an RL 22 load best. But I also had some decent loads with H4350 that were 1-1.5”. I might load some of those up for this particular hunt.

Anyone have any temp stability comments and experience with Ramshot TAC?

TAC is your basic double base non temp stabilized powder. Temp stability is going to be bad.

If you 6.5 likes RL-22, you should really try RL-23 if you're looking for stability.

Bravo.....

Good to know but I already have H4350 and load data on the Swede. It’s not easy to buy powder here in CA so it’s easier to use what I have already.

What’s your baseline temp?

I’ve used a ton of TAC in .223, both SAAMI and AI, with 75’s, and it’s extremely temp stable in that application. Temps have ranged from about -30 to +90 degrees. It’s a safe bet to ignore pretty much anything LB says.

70

I have for many years always done my load testing on days exceeding 90 F degrees. I place the firearm and the ammo outside, and allow them to reach ambient temps. This pretty much assures me that my loads will not exhibit excessive pressure if used during “hot” shooting/hunting situations! As mentioned, this has been my policy for many years.....as I may use my rifle at any time and at any temperatures!

I will often test these same loads on days with near zero or below temperatures, to verify grouping potential and velocities!

My methods will obviously require 6 months or so to develop and prove a load for all temperatures that may be encountered. But, I shouldn’t have any surprises!


Edit: Once reading all of the postings, I only now realized you were from California.....thought you were from South Dakota! That will pretty much eliminate the procedure I recommended! It “could” still be done.....but very difficult to accomplish! memtb

Ya reckon we being trolled...??

LB is churning out definitive statements that are off the cuff, many over the edge. RL-23 IS a temp stable powder, NOT a sub for RL-26, two different burn rates. He's the only one I've seen declaring RL-26 to be one of the most temp sensitive powders ever. Facts just don't back that up.

Don't think LB has shot much TAC (maybe not much of anything else). Looks like he's reading stuff off the internet, pontificating about stuff he obviously can't authenticate.

Oh well, This is the Fire, after all...

DF

Yeah, Larry Root has come to mind several times as I’ve read LB’s posts...

I dont get it. The guy said he tested the powder with far more specific equipment than I have access too. Are you saying he didn't, in fact test it or that his results are wrong? Or do you think he's wrong because his experience is different than yours? He doesnt seem to be the only one who experienced velocity/pressure spikes with this powder. I understand you and other members havent seen it but does that mean his experience is invalid?

In science, any marked outlier in data, even measured data, is suspect until proven otherwise.

If those cases, means and methods need to be thoroughly reviewed and analyzed.

LB's overall credibility and his outlandish claims puts his "highly technical and carefully measured data" in that category.

In the meantime, I'm going with Jordan, JB and others with credibility proven over the long haul

If wrong, I'm certainly open to review of facts and conclusions, as I continue to work up 7RM, 160 NAB, RL-26 loads for my buds African PG hunt in August..

DF

Apparently this thread brought out all the clowns who think non-temp-stabilized double base powders aren't temp sensitive.

I suppose it's possible that the laws of chemistry were repealed specifically in your rifles, and powders with the least temp stable chemistry in common use (we don't do triple base powders and cordite any more) are somehow stable for you. If so that's great.

But reality is that there's a hierarchy in terms of powder stability by chemistry from most stable to least:

Temp stabilized powders (recent ADI series, IMR Enduron, and the RL-16/23/AR-COMP series)
then
Single based IMR-type powders
then
Double base not temp stabilized (which includes the RL series with the exception of 23 and 16, TAC, and a bunch of other powders like H335 etc.)
then
Triple base powders, cordite, and certain other obsolete powders

There's really not all that much to it, but of course lots of marketing chaff being blown by companies with an interest in selling non-stabilized powders. In the end I don't give a flying [bleep] what you put in your rifle, but the facts are the facts.

See Dirtfarmer's response above.

I don't have a problem with other people having legitimate experience which runs counter to my own, but I always consider the source of any such info. Some sources of info have earned more credibility, and are more deserving of trust, than others. In this case, LB has posted enough non-sense in other threads that his "experience and measurements" are suspect. I question whether he personally has tested RL26 at all, or is just regurgitating something he found on the internet, as with most of his other posts.

+1

Some of us don't have to pontificate about the theoretical behaviour of these things, because we've actually tested them in a variety of circumstances. We KNOW that certain powders are temp-stable in a wide range of applications, despite what your assumptions or Google results may say.



In the end theory is theory, and facts are borne in experimental results.

Them some nice clown shoes ya'll are wearing.

Now, explain why chemistry works one way in my rifle, every other rifle, and the chemistry lab, but DIFFERENT in a couple people's rifles. You could imagine that I, the lab, the chem books etc. are all in error. You could imagine those couple rifles are magic. Or you could imagine that a couple of people who lack temperature chambers and just guessed their way through it made errors. It's up to you. I really don't care what the [bleep] you shoot. But realize that chemistry is chemistry, and no amount of backslapping and clown show wearing on a forum will change that

There's a REASON none of these double base non-stabilized powders are used in accuracy disciplines any more - because they're not stable That's why you almost can't buy an 8-lb keg of H4350 or RL-16, but there's all the RL-26 you want to buy waiting there for just he right sucker to come along

Good thing I've got far more experimental results than you. Call me when you're using a temp chamber rather than clown shoes to heat and cool your rounds

Also, if you knew jack [bleep] about propellant chemistry you'd know the "theory" on this is old, well understood, and really not up for debate This is almost 100 year old news we're talking about here

You clearly don't even know what you don't know.

What chemistry labs? What chem books? Perhaps you don't realize that temp-stability of ALL powders is dependent on the suitability of the application to the burn rate of the powder. Some powders are more sensitive to this than others, but all are affected. Even if you did test RL26 (which I doubt) in one rifle, using one or two bullets, that is a far cry from sufficient experimental results to come to a general conclusion with any validity. Yes, there are a couple of other people who have experienced temp-dependent velocity variation using RL26 in a particular application, but the majority of credible sources have reported the opposite, at least below 90 degrees.

There are far too many internal ballistics variables at play in a given rifle/cartridge sample for you to make a blanket statement about "chemistry is chemistry", and have anyone with half a clue believe that you know what you're talking about.

In the last few months RL26 has been far harder to find than H4350....

Then post them.

Yes, I can Google "temp chamber" too.

I hear reports of RL-26 being hard to find, so where is LB seeing all this RL-26 for sale?

If he would be so kind to reveal those sources, many here on the Fire would be very grateful

DF

The reason that we lose velocity in cold weather is that cold steel, lead, and brass rob heat energy from the propellant gas more than hot metals do.

Temperature insensitive powders compensate for this by burning a little faster than other powders when pressures are lower. This offsets the loss in MV.

In the cases I've tested, temperature compensation only works really well in a particular case geometry. For example, Varget is wonderfully stable in the 308, but not stable at all in the 223. H4350 seems to be optimized for stability in the 30-06.

Precisely. The temp-stability of a given powder is dependent on the application. Bore volume to powder volume ratio, bullet weight to powder volume ratio, etc, are factors in a given application that affect the stability of the powder in question.

Which makes all encompassing, overly broad statement of "fact" not factual...

Experience leads to caution, the lack there of tends to lead in the opposite direction.

Not too hard to spot the difference.

DF

denton,

All excellent points--which the head guys at more than one professional labs have mentioned to me more than once.

Even the most temp-resistant powders don't work as consistently outside their design parameters, which one of the guys who's been working in the business for around 40 years also called their "comfort zone."

The .264 Winchester Magnum with 100-grain bullets and Reloder 26 would obviously be outside those design parameters, but LB cites it as his primary example of the abject failure of 26. Which he also tested in an indoor lab, without the rifle at the same temperature as the ammo.

I have tested 26 with the 150-grain Nosler Partition in the .270 Winchester outdoors, at temperatures from -10 to 90, one of 26's definite comfort zones, in fact one of the combinations it initially became known for. The variation in average muzzle velocity was 45 fps, .45 fps per degree. Point of impact never varied.

But of course LB will tell us that the testing was faulty, because he got different results firing 100-grain bullets indoors from a .264.

Funny you should ask that, because if you knew jack [bleep] about propellant chemistry, you'd know that temp stability and nitroglycerin content has been an issue all the way back to Alfred Nobel trying to pawn Ballistite off on the French government in the 1880s. They were't as foolish as he'd hoped, spotted the stability problem, and stuck with the single base nitrocelulose Poudre B and thus got the first working smokeless cartridge. The Italians were more gullible and bought Nobel's mistake and lost 5 years jacking around with it until they invented Solenite which is still laughably unstable by modern standards but at least could be used.

So the role of nitroglycerin content has been understood for right at about 130 years now. Except by you. I guess some subjects just aren't covered in clown college

How'd you come to that conclusion? Provide calculations please.

Why don't you provide some contrary evidence?

One way to "calculate" the highest and best use for a certain powder is to look at pressure-tested data where that powder provides higher velocities in a certain cartridge/bullet combination. Since even with 140-grain bullets, Reloder 26 velocity lags far behind several other powders in the .264, a reasonable guess (no calculation needed) would be that with 100-grain bullets the pressure wouldn't be anywhere near optimum for the powder's design parameters.

But since you're apparently the only person on earth who knows anything about pressure-testing, that wouldn't mean much to you.

Apparently they're covered very well in a**hole college.

So there are no chemistry labs that you’re affiliated with that have any evidence of RL26 or TAC generally being terribly temp-sensitive. Roger.

Thanks for the history lesson, which contains nothing new. Not sure why you’d assume I was unaware of the history of smokeless powder. Then again, you make a lot of faulty assumptions.

Well for starters you might run the .264WM/100gr partition in Quick Load at which point you would find that RL-26 is in the 5 fastest powders, load density will be close to 100%, and it'll burn 100% in a 24" barrel. That combined with Alliant's recommending it for use in magnum rifles might get one thinking about whether it was an ideal powder for that particular bullet/cartridge. And it is, producing excellent accuracy and velocity. The only problem is that it's too temp unstable for all-weather use. Were it not for that, RL-26 would be great. As it is, RL-23 is a better choice despite being slower in that application and no more accurate.

Because you've exposed your ignorance on the subject repeatedly in this thread. Why exactly would I expect you to know literally anything given what you've failed to know so far?

I deal in facts. That makes some people uncomfortable, which is perfectly fine by me. That's the great thing about facts - they're still true no matter what a clown like Jordan says. He can flop around in his big shoes and red nose all he likes, and the combustion chemistry of double based powders doesn't give a flying [bleep] what he thinks. It'll just be what it is, I'll be right, he'll be wrong, and life will go on.

Goonga la goonga...

You deal in facts. So "clown college" is real then?

Apparently...😎

https://www.theclownschool.com/

Looks like we've got the Valedicktorian in our midst. And I don't mean Jordan.....

Wow did this thread ever go south! I don’t even remember what my original question was, or if there’s any valuable information to be gained from this post anymore.

So without getting into a pissing match and attacking somebody else personally, can we please be adults and just answered these questions?

I need temp resistant powders for 6.5 Swede and .358 win. The 6.5 Swede I think I have covered with H4350. What is a good temp resistance powder to use with the 358?

Your credibility up against those guys is a joke...

As in nonexistent...

DF

Give LB some credit. Clown school was the only thing he got right 😎

What bullet weight?

Hey bob, by asking that question you seem to be acknowledging that temperature sensitivity depends on bullet weight?

Nope. I didn't say anything of the sort - address your comments to whoever did.

However, correct powder choice does most definitely depend on bullet weight.

It was mule deer and Jordan. When those guys are making a point you'd do well to listen. And yes, I know you won't. my comment was for the OP.

Humm, so that's why you quoted me. You're as much of a clown as Jordan is.

And the facts of propellant chemistry are still the facts. They really don't care who thinks what, they just keep on being what they are.

H4895

LOL, coming from you that's a huge compliment, it's nice to see I'm in good company.

Your "history lesson" sounded like something off the internet.

So, I Googled the topics and guess what... http://firearmshistory.blogspot.com/2017/02/smokeless-powders-cordite.html

You took credit, didn't give any. Not surprised.

Generally with "scientific" discussions, one footnotes or gives credit for quotes.

DF

What some fail to realize, is that aside from the well-established smokeless powder chemistry being so flippantly thrown around, powder geometry also plays a role in temperature stability. Recent advancements in smokeless powder include new geometric approaches (like cylindrical shells), as well as modern chemical additives such as different and perhaps more effective de-coppering agents.

It is certainly an overly simplistic and narrow-minded approach to make all assertions of the temp-stability of various smokeless powders based solely on the basic chemical composition of a particular powder (the standard nitrocellulose and nitroglycerin bases), without also considering powder geometry, bore-to-powder volume ratio, pressure curve characteristics, bullet weight, etc.

About as much physics as chemistry.

And powder coatings have come a long way.

Technology has advanced a bunch since Cordite.

DF

Jordan if I'm not mistaken, his assertions weren't based solely on chemistry, there was that extensive testing he did using a single bullet in a single chambering.

My issue with LB is his over reaching, didactic, authoritarian statements and claims that are outliers from accepted norms.

That RL-26 is the most temp sensitive power doesn’t square with conventional knowledge. Now temp sensitivity, from what I understand, can vary a great deal depending on application. I agree that the Extreme series is very temp stable, no doubt better than RL-26, but there are more temp sensitive powders, IMO.

Then there was LB’s historical treatise on early smokeless powders, regurgitated thought for thought from the internet link I posted with no credit given. So, how much of his other stuff is of similar origin. We’ve seen that kinda behavior here before.

So, based on style and content, I’m not convinced until shown otherwise. Mark me as skeptical.

DF

These days it's easy to look like an expert, with the Google-machine close at hand...

Evidently...

DF

The one I really like is "proving" RL-26 was really temp-sensitive, first by simulating results indoors with a really light bullet in the .264--when a bunch of shooters have found 26 very stable when chronographed in ACTUAL field conditions with heavy-for-caliber bullets in cartridges from the .243 on up.

Then he "backed up" his claim by citing QuickLoad. Now, I have nothing against QL, having used it since it appeared. But even the directions for QL state that actually testing is preferable.

Damn John, thought you were above petty sh*t like this. Sad

What's wrong with stating a fact Swifty, which is all MD did there, and he's 100% correct. Everyone knew LB was a dumbass so MD was actually being nice about it. Just like he was to you when you became one of the only people on the planet that couldn't figure out how to use Bore Coat.

Swift, this was not even close to “petty”, but rather furthering a point that the poster in question was narrow, biased, and conceited. 😎

No, what's sad is your tirades about your "negative experience" and unanswered emails on a discontinued inexpensive bore coat product. Ironic that a guy who's been pissing and moaning for weeks about such a trivial thing would take someone to task for being petty.