I never worry about it I just load to accommodate the possibility.
How do you do your temperature sensitivity testing for your loads?
- Thread starter David Milisock
- Start date
Does the temperature change there?
Kind of a drive it like ya stole approach
I love it !
tom
Gold $$ Contributor
I like to collect data over the natural changing of the seasons. It takes longer, but is a true representation of what to expect. And just FYI to those concerned about groups/tune vs muzzle velocities only. It is possible to have a powder that doesn't change velocities AT ALL, from 90s down to single digits,. And STILL have it capable of winning group title at a 1,000 yard national(this example did exactly that). And then with no change in velocity, shoot unacceptable/non competitive vertical groups when temperatures drop to the 30s. It's also possible for your muzzle velocities to change, but the rifle stays in perfect tune. I've gone from here to Georgia and had the same exact load, to the kernel be the tune, but the velocities were lower down there. I've gone from here to Missouri and had the velocities increase, but the tune came in with an increase in powder a couple tenths. I've went from here to Missouri and had the velocities increase, and the rifle needed me to drop down the powder a following year. If we're concerned with groups, we're not done tuning ever, no matter what it says on the powder can.
Tom
Tom
tom
Gold $$ Contributor
No tuner. Yes I agree about the elevation changes. I've been told by smart people that part is calculatable, but I'm dumb. I do make it a point on the hunting guns to always go to my same range as I collect the data. I shoot 3 from a fouled barrel on paper, besides collecting the numbers.
Tom
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All powders are temperature sensitive...some more than others. I'm too old to worry about sensitivity...but sometimes adjusts my shooting to keep things intact. I've shot many thousands of rds of Varget in 308 for many years...had to get the shot off in 5 seconds to avoid an overpressure round in a hot barrel, smell the hot steel, adjust for change in impact, still hitting a pop can at 1000 yds...the only thing that stops me is the heat waves off the barrel are so heavy they distort the target. Today I shoot more ball powders than stick powders, in a large variety of cartridges. I never test a powder at -32 to 110 degrees and see the velocity difference. So I'm not concerned about my powders sensitivity as most of my shooting is between 55 and 85 degrees, outside. And when the barrel is allowed to get, or really hot the impact will change... make the adjustments, never found it difficult, as you spot your impact changes ...But Even Slight Wind Changes will always be the problem child to be Concerned about...it's the ever-changing wind, flowing down the canyon or up the mountain, swirling, stopping, sudden increase, left to right here, but right to left way over there, or changing direction. The hardest part ...for me, powder temperature sensitivity not so much...how does it shoot for the intended purpose? If "stick" gives you more confidence stick with "stick." Confidence is very important.
MGYSGT
Silver $$ Contributor
It does change. High of 118 to a low of 65 at noon throughout the year. Our range is only 300 yards, but the changes on target due to heat/loads are very small. The biggest problem is mirage in the summer. Even at 300 it can put you out of the 10 ring and really put you out of the X ring. That darn target just wiggles like it was at a dance.
My mother lived in Arizona for a while, learning to play in mirage is challenging to say the least.
For a well prepared person there's alot to love about the desert.
^^^^This^^^^
Smokeless powder converting from a solid to a gas is a chemical reaction and all chemical reactions are temperature dependent, to varying degrees. Bottom line, as temp increases, they make more energy and hence, velocity. Yes, some are more sensitive than others but temp affects all chemical reactions and in bore time of the bullet, which affects tune. It nearly defines what tune is in that tune is about timing bullet exit with muzzle position. Before tuners, we altered exit timing. With tuners, we affect muzzle position relative to exit time. Both methods work and work similarly due to this correlation of exit time and muzzle position.
Once you're familiar with either method, it's a matter of staying on top of that timing. Tuners make it easy, when used properly and, they're literally at your fingertips. Ultimately, group shapes tell us a lot about relative tune, both ways. Moving a tuner or changing powder charge is best done with a method to the madness, not randomness. So, learn to read group shapes relative to powder charge and/or tuner setting../and you're on the right path.
The point of all of this is that with a tuner, powder sensitivity is not a huge deal. Sure, I like when there is a nice wide tune window but as long as I know what the groups are telling me, I simply move the tuner or change the load accordingly.
I try out loads for everything year round, but concentrate more on small stuff (varmint calibers) in hot weather & bigger stuff in fall & winter. The only thing that has ever caused a real problem was a warm load in 22-250 from spring to a locked bolt in July or August with H-380 which is longer in the powder inventory. Where I live now, the temp rarely goes below freezing, even at night, & isn't often above low 90s during the day year round so not a lot of concern.
Even without the large temp swings some of you all have, I wonder if temp. is the reason for my love/hate thing with RL17? Some days it shoots well. Some days it flat out sucks. Good velocity though. There are other options. When it's gone, it's gone.
Even without the large temp swings some of you all have, I wonder if temp. is the reason for my love/hate thing with RL17? Some days it shoots well. Some days it flat out sucks. Good velocity though. There are other options. When it's gone, it's gone.
If a fella knows how wide of a node he’s working with the temp swings should be manageable.
@gunsandgunsmithing
Mike
How do guys take advantage of a tuner during lr br ?
We can’t see our groups forming, pit crews only spot the sighters, we don’t have cameras and we can’t run down to the targets for confirmation ?
@gunsandgunsmithing
Mike
How do guys take advantage of a tuner during lr br ?
We can’t see our groups forming, pit crews only spot the sighters, we don’t have cameras and we can’t run down to the targets for confirmation ?
It IS tougher when you can't see bullet holes or sighters, but it's no different than before tuners. Good notes help a lot as does falling back on your last target, but your point is valid. With a tuner, you simply have a tool at your fingertips that without one, you simply don't have. There's a learning curve to tuning by either method. As a general rule, as temps go up, I move the tuner inward and the opposite for temp going down. That's just a general rule though and there is more to it than that. Relatively, to me, it was a WHOLE lot easier to learn how to maintain tune with a tuner than by changing the load, but both ways do work.
Bottom line is, if you never touch it, it has the small benefit of the tune window being very slightly wider, but otherwise, it'd be like it was before cf started using tuners. Gene Bukys used his tuner that way, just for the benefit of a mass on the end of the bbl making it hold tune a tad better. He and I never agreed on this. I always felt he was leaving the best part of a tuner on the table...being able to tune at the bench.
In long range, electronic targets are becoming very popular and they give the instant feedback that makes tuning at the bench so much easier. But again, it's no different than it would be if you didnt have that tuning tool on the bbl at all. Once you learn how to use it, life gets a lot easier. Still, by far the most common mistake with a tuner is moving it way too far at a time. I have a test/system that helps you to quantify the value of each mark and group shapes. Typically, there are only 4-5 marks between tuned to the hilt to completely out of tune. That said, you really just have to recognize what each of those 4 or 5 marks looks like on target. You can hopefully see where that alone breaks things down into an easy and workable thing, rather than twisting it and hoping for the best.
JEFFPPC
Gold $$ Contributor
What was the effect on your groups? Was a tenth enough to get you back or was more required? Or should I quite asking personal questions, lol.
On the 6PPC
200 Yards
1. 0.337
2. 0.271
3. 0.374
4. 0.264
5. 0.483
I dropped a total 3 tenths to keep it shooting. I screwed up the last group by fumbling the the case on the fifth shot. The first 4 we’re in a .250 or less. That cost me the yardage.
Bart
Clancy
Silver $$ Contributor
He may just be “pretending” to be human
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