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Thread: testing loads in the winter.

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    Question testing loads in the winter.

    I've always done load development/testing in the early summer, but note that many on this site mention doing so in the winter. How is your winter testing different than in warm weather? Temperature cutoff? Are some powders not as suitable as others to the cold testing. Temperature caused differences in chronographed velocities? Differences in accuracy or point of impact? Etc .......?

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    Member alaskanmoosehunter's Avatar
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    Default Yes.....

    Bullets do travel slower in colder temps....You may not notice but your chrony will. Your point of impact will be different than when it is 70 or 80 degrees outside. Unless you are shooting competition matches it is nothing really to worry about.

    Most reloading manuals will have a temp. and velocity graph or diagrams in the back of the book in the reference section.....Or shoot a few threw the chrony and average your velocity and check your manual for trajectory.

    I load all my stuff in the winter too. Good luck

    PS: I've never had a powder/primer fail because of cold temps.

  3. #3

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    Rick a big thing to rememebr is that there are normal powders and extreme powders. A powder like H4350 or H4381 is way more temp resistant than the powders that are not considered in the extreme category. Which in turn could mess you up big time, like if you were to make up a load using non extreme powder and shooting it to a max load for your gun at say 10 degrees with a chrono and then shooting the same load at 80 degrees in Aug your velocities may be well over max. Just food for thought if you didn't slready know it.

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    Member Alangaq's Avatar
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    I for one do almost all of my bullet casting, re-loading, target shooting etc, in the winter.........not really sure why other than time constraints with camping and fishing but it just seems to work out that way. I have never even bothered to crono my loads in the summer......until now! Now you have me all parinoid that my loads will be way over max! "darn you, darn you all to heck" (ok, if you dont have little kids in the house you wont get the movie quote...Madagascar) but generaly speaking (other than the guide gun rounds) I stay a grain or two below the max anyway and am thinking 50 to 60 deg change of temp wont make that much of a diff......... if I am being an idiot, go ahead and let me know, I wont hold a grudge..........for long.............
    “You’ve gotten soft. You’re like one of those police dogs who’s released in to the wild and gets eaten by a deer or something.” Bill McNeal of News Radio

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    Member Alangaq's Avatar
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    you know.......as a follow up to my last post, life was so much easier without the cronograph.........I could simply belive what the loading manual said, assume my loads were awsome, and if the cases could be extraced with normal effort, no cratered primers, no head seperation, etc. all was golden! But Noooooooo, I had to go buy a chrono, and suddenly I now have more info that I know what to do with......... turns out, some of my "red hot" loads are actually quite "poopy" and some of my "normal hunting" loads are scary enough to pull bullets and dump powder! What is it that they say......ignorace is bliss.....
    “You’ve gotten soft. You’re like one of those police dogs who’s released in to the wild and gets eaten by a deer or something.” Bill McNeal of News Radio

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    Default winter testing?

    Is Hodgdon the only company producing "Extreme" powders or are there others with a similar line of powders with a comparable profile?

  7. #7

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    I'm not sure I've ever heard anything about extreme powders and normal powders. Been loading and shooting H4831 for over 40 years now, but I've only ever heard it called slow.

    A few years back two different gun scribes did much the same tests on the effects of temp and reported similar results. Because they didn't want to work all year doing it, they put the guns and ammo in temperature controlled environments (chest freezer and a warming oven), then pulled them out and fired them right away before temps could change. Those results were compared with normal range temps, which as I recall were in the 70's.

    Hot temps (100-110 degrees if memory serves) raised all kinds of red flags with max loads that had been worked up at normal temps. Pressure signs and velocities went through the roof. Even a few factory loads caused problems.

    Shots fired with cold rifles and ammo (-20, as I recall) didn't slow much at all, especially with slow burners like H4831 or 4350- less than 100 fps. Not enough to cause any sighting errors or lost game, anyway.

    Some day when I'm rooting around in my library I'll look for those articles. Too much of a challenge this late in the day, though.

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    Member IceKing02's Avatar
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    Default Yup, this happened with shotguns, too.

    Over the last thirty years of reloading and competition shooting shotguns I've seen ammunition that just didn't have the same "pop" as did the same loads in the summer. As a precaution we'd always throw the ammo in the truck to stay warm and then keep a handwarmer in our shell pocket. It was enough of a difference for all of the regular hand-loaders to comment, though we never chronied our loads.
    As it relates to rifles: None of this really concerns us up here in the Great North, unless we're heading Outside to go hunting, right? Heck, I'm thinking that 80-85F is just about too darn hot to do anything but just sit and drink a cold beer! Maybe go jump in the kiddie pool and sun my stark white skin...the LAST thing I'm thinking about doing is heading out to the range to go shootin'.

    Sounds like the best plan is to actually chronograph the loads like Alangaq said. And to think that we kid ourselves thinking that we might actually be saving money with all of this handloading the "right" way. Shhhhhhh, don't tell my WIFE!

    Cheers,

    IceKing02

  9. #9

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    Interesting point on the shotgun ammo, IceKing02. I've done a lot of muzzleloader shotgunning and some black powder cartridge shooting. While I've seen what you're talking about with the modern ammo, I've encountered nothing similar using either form of BP. I always wrote it off to the plastic wads in smokeless versus fiber wads in BP, and to the burn profile of smokeless versus BP. It would be interesting to chrono both, as I've never seen it done.

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    New member George's Avatar
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    Default cold vs hot testing

    For sure there will be differences. Since most of us don't have pressure testing equipment, guessing about it is just that. Everything I've seen/ read and experienced indicates increased pressures in high temps relative to decreased pressures in low temps. How that affects load testing is wide open. If you are testing for accuracy at reasonable pressures may not matter too much. If you are like so many and have to get the last 50 fps out of any gun then red flags are popping up all over. I generally shoot well below max in all my guns- so accuracy and reliability, not pressure and velocity, are what drive my testing. The suggestions about using the chronograph to detect differences in velocity as it relates to temp changes are good ones. Still back to the pressure question?? Higher but how much higher?? That's the advantage of the conservative approach I use. So far all the discussion has primarily related to the ammo. The next problems are the mechanical issues with the firearm. Barrel vibration/harmonics are bound to change with temp change. Bedding is bound to change. I've found that a load developed in summer temps will not act or group like one shot at -10' and vice versa. I've found that very low temps make it hard for the shooter to do the best job with shooting technique. The trigger/bolt lock times slow down- this is well documented. And so on. Pin pointing the cause for changes in how guns/ammo shoots in hot vs cold is wide open and the variables are near endless. The only for sure I know is that increase in temp equals increase in pressure.

  11. #11

    Default Extreme Powders

    Quote Originally Posted by Rick View Post
    Is Hodgdon the only company producing "Extreme" powders or are there others with a similar line of powders with a comparable profile?
    Its not so much that they are referred to as extreme powders , thats what Hodgdon calls there non temp-sensitive powders. H4831 and H4350 being two of the most popular. In the Alliant line I think its RL-15 and I think in Ramshot its their Hunter powder. Its just the specific powders that the different manufacturers make for those who load and hunt in places that the temp can fluctuate drastically, keeping your shots and loads consistent. This is something that would really affect Alaskan hunters where you could be hunting sheep in Aug in 80 degree temps and a couple months later be hunting Caribou or Moose in -10 or colder temps.

  12. #12

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    I'm with you Alangaq, I just dont want to know that little piece of info...
    If people are loading under the max loads "according to the books!" then they 'should' be okay with temperature differences and preasures, right? Because max load is really only 80% of actual max, right? I would think they do that for safety and situation such as the temperature differences, chamber dimensions, bullet construction (in terms of using barnes book/data on 90grn load for a 90 grn sierra bullet to load)

    and just for fun from physics class: all matter expands with heat and contracts with the lack there of. metal is matter. your barrel is metal. if the hole through the barrel is 'x' diameter at 90 deg F and your bullet is 'x' diameter as well, then what happens when your barrel is -10 deg F and has "shrank" and you still push that 'x' sized bullet down it?

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    New member George's Avatar
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    Default physics- uh oh

    Yep the expansion/contraction thing with both the bullet and barrel will happen. Qualifying it is easy, quantifying it is more than my brain can wrap around. Also, the coefficient of friction between bullet and bore surface will change with temp. change... thinking about that is as bad or worse than thinking about the differential thermal expansion coefficients between the bullet and barrel

  14. #14

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    Feeling low? Just call the Psyshics Hotline at 1-900-234-5678 for a psychic reading.

    Oh, you're talking about physics and not psychics. We'd probably be just as well off using a psychic hotline as trying to translate physics textbooks into ballistics on our local range without the help of lots of instrumentation and testing.

    Fun to speculate on the physics, but worthless to get religious about citing it. Too many variables and just as much guesswork involved as with traditional ballistic methods.

    I'll use the standard pressure indicators that have worked so long and watch the chrono for velocity changes. If pressure signs or velocities climb, I'm backing off on the loads. If they drop in cold weather testing, you can bet I'll change powders and do more cold weather testing before going on a hunt.

    Can't see any other way to go about it.

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    Member Kay9Cop's Avatar
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    Quote Originally Posted by BrownBear View Post
    I'll use the standard pressure indicators that have worked so long and watch the chrono for velocity changes. If pressure signs or velocities climb, I'm backing off on the loads. If they drop in cold weather testing, you can bet I'll change powders and do more cold weather testing before going on a hunt.

    Can't see any other way to go about it.
    BrownBear,

    The problem is if you go by traditional pressure signs while developing a load in the winter and then don't shoot that handload again until sheep season you may find the pressure drastically increased in the warmer temps to the point of not being able to extract the empty casing or worse. That's why some people, me included, caution against working up a load in the winter that may be used in the summer. I try to do all of my load work-up and testing in the spring/summer and then stick with that load through the winter.

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    Member Big Al's Avatar
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    Default

    Did I miss it in a post? Has anyone brought out the fact that all of the manufactures of ammo have had to deal with this same problem since day one?

    If we are going to set down to load ammo for Africa we might want to be a little more conservative with the powder, than we would be for our Alaskan winter hunt.

    We can not get around the physical laws that requires us to remember that temperature and pressure have a relationship.

    So we all know about this problem and we also know that we have the control. So then what would be the most logical conclusion?

    That would be to load the ammo for the broadest temperature range and make sight corrections in the conditions we will be using the ammo in.

    There are monkeys in the works due to modern chemistry that will throw us a few curves. But for the most part we will not see many people here using these powders. It is true that contrary to the normal laws of physics that some (a few) powders show an increase of pressure as the temperature goes down. I will add that this manufactures representative denied that such could happened.

    Please remember that all military ammo must be loaded to take into account all these different temperature ranges that might place this ammo under any condition around the globe.

    Only one logical way to beat the problem is to sight in for the conditions.
    "The tree of liberty must be refreshed from time to time with the blood of patriots and tryants." (Thomas Jefferson

  17. #17

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    I'd NEVER develop loads and load ammo in winter, then leave it hangin around till sheep season. There's absolutely no sense in betting a long hard hunt on ammo that hadn't been tested in the conditions of the hunt. That's the point.

    I'm not worried about using summer loads in winter and losing power, cuzz I've never seen that to be a problem.

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    Quote Originally Posted by Northern View Post
    and just for fun from physics class: all matter expands with heat and contracts with the lack there of. metal is matter. your barrel is metal. if the hole through the barrel is 'x' diameter at 90 deg F and your bullet is 'x' diameter as well, then what happens when your barrel is -10 deg F and has "shrank" and you still push that 'x' sized bullet down it?
    Not quite: water expands when freezing, and contracts when melting.

    Velocities fall off as the temp gets colder due to the slower combustion of the propellant. Chemical reactions, as a rule, slow when cold, and speed up when hot.
    Air density will slow the bullet also, but 99.9% of the people shooting today are not good enough to really notice.

    This was covered pretty well in Alphin's "Any Shot You Want" reloading manual, where he tested .30-06 velocities and pressure from -160*F to +140*F.
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    This was covered pretty well in Alphin's "Any Shot You Want" reloading manual, where he tested .30-06 velocities and pressure from -160*F to +140*F.
    Man I'm glad I don't live where that guy lives!

    Temperature of ignition, that is the temperature the powder is at ignition and what the primer has to bring the temperature to for ignition to occur.

    Needless to say, primer energy falls off at the lower temps, combustion of the powder is at a lower pressure and therefor velocity falls correspondingly.

    ACKELY's vol. I) has a great chart that shows the relation of temp to velocity loss.
    "The tree of liberty must be refreshed from time to time with the blood of patriots and tryants." (Thomas Jefferson

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    Quote Originally Posted by BrownBear View Post
    <snip>
    Shots fired with cold rifles and ammo (-20, as I recall) didn't slow much at all, especially with slow burners like H4831 or 4350- less than 100 fps. Not enough to cause any sighting errors or lost game, anyway.
    <snip>
    Then the corollary for H4831 or 4350 is that loads developed at -20 won't speed up much when heated to +70.

    Anybody know if Lil'Gun changes much with temperature?

    Brian

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