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Campfire Tracker
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OP
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I also wonder if the change in barrel harmonic is a factor in very low temperatures changes point of impact? Both due to velocity change and metallurgical changes.
Elasticity, expansion, hardness, bore diameter, and other things would change very slightly with extreme temperature shifts. I would discount this except for the photos of blown stainless steel barrels in very low temperatures confirm something is changing.
"When you disarm the people, you commence to offend them and show that you distrust them either through cowardice or lack of confidence, and both of these opinions generate hatred." Niccolo Machiavelli
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Campfire Outfitter
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I have found Retumbo to be fairly tem stable. At least down to 10 degrees.
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Campfire Regular
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MD and friends,
My experience mirrors that of Bigwhoop with H4831sc being my top cold weather performer down to -10 which is about as cold as it has ever gotten here. Currently, I am playing around with AA2230 & AA2250 in .223 and other sub 30 caliber rounds vs Varget in different temperature extremes. So far Varget is better in heat but I still have to do the cold weather tests for each rifle this winter.
Flower Child
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Campfire Ranger
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Campfire Ranger
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How stable is Varget in hot/cold swings?
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Joined: Oct 2000
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Campfire 'Bwana
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Campfire 'Bwana
Joined: Oct 2000
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I wonder how Varget and RL15 compare in cold... I've hunted with my 308 in -23F weather stoked with RL15 and have always wondered about it but have never tested it... I'm not as motivated as Sammer (grin).
Just looked over the Barnes article... seems, at least within their testing parameters, Varget is quite a bit more temp stable than RL15...
Last edited by Brad; 07/05/10.
“Perfection is Achieved Not When There Is Nothing More to Add, But When There Is Nothing Left to Take Away” Antoine de Saint-Exupery
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Campfire Tracker
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Campfire Tracker
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How stable is Varget in hot/cold swings? I have used it in my .308's up here in temps as low as minus 40F with good results....even at long range.(MV has stayed consistent)
Luck....is the residue of design... ![[Linked Image]](http://i423.photobucket.com/albums/pp311/patrickgsinclair/96zvyt.gif)
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Campfire 'Bwana
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Campfire 'Bwana
Joined: Feb 2006
Posts: 43,906 Likes: 11 |
Brad, didn't hear the phone ringin' in the tractor, just got your voicemail. I'll be up here for another week or two.
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Joined: Mar 2008
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Campfire Tracker
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Campfire Tracker
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I've tested Varget down into whatever temp that 9V batteries no longer work. 46 grains of it under a 165 Hot-Cor still goes 2740  It goes closer to 2780 if you leave your loaded rifle on the dash in the summer. Of course I buy Varget by the 4 pack of 8 pound jugs so I can deliver this kind of info to the Campfire (that and I don't have to guess if 40 FPS swings over the year are caused by different lot #s)
I'm Irish...
Of course I know how to patch drywall
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Campfire Tracker
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Campfire Tracker
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Brad, didn't hear the phone ringin' in the tractor, just got your voicemail. I'll be up here for another week or two. LMAO Only in Montana 
I'm Irish...
Of course I know how to patch drywall
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Campfire Kahuna
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Campfire Kahuna
Joined: Jul 2001
Posts: 60,156 Likes: 13 |
A couple weeks ago I spent a day at a pressure lab, and the guy I interviewed said that Varget typically acted very reliably in the .308 Winchester at extreme temps, but when
"stressed" (the word he used) it could get a little wonky. The specific example he used was the .260 Rem. with a 140 at top pressures, a place where a somewhat slower powder would work better.
Which goes along with what I have found in cold (and heat) testing over the years: The particular case and bullet can affect how well a certain powder is resistant to temperature change, yet another reason to actually test our loads in the temperatures we might encounter when hunting.
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.”
John Steinbeck
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Campfire 'Bwana
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Campfire 'Bwana
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Brad, didn't hear the phone ringin' in the tractor, just got your voicemail. I'll be up here for another week or two. LMAO Only in Montana Ha, too true! Sammer, I'll be down at the ranch during the week but home weekends... give a jingle when you're in town. BTW, ran into a Sow grizzly with two cubs in tow making a kill on an elk calf a few weeks back... was pretty exciting (grin).
“Perfection is Achieved Not When There Is Nothing More to Add, But When There Is Nothing Left to Take Away” Antoine de Saint-Exupery
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Joined: Dec 2002
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DakotaDeer & Brad,
The only way to know for sure is to do the work. As MD hinted at, powder is just one variable to the equation among at least 10 others that I can think of, which makes for a lot of miserable combinations to test. Once in a while you get lucky and find some that shoot well in a variety of conditions but usually this is not the case. I have a whole shelf full of loaded ammo marked for different temps, climates, and conditions for specific rifles. Then I have a bunch of GP ammo that I use for everything else. I always seem to have something on hand that fits the bill but only rarely do you find a load that does several different conditions well. Consequently, my rifles are divided into three temperature extremes -10 to +30, +30 to +60, and +60 to +105 all of which represents the spectrum of temperatures where I live. This is not to say that I have a lot of rifles, but rather that through experimentation, I have found a lot of loads for them that work under certain conditions.
Flower Child
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Campfire Ranger
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Campfire Ranger
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You are far more "into it" than I am FC. I like to find one load that I can use everywhere. Now, I am guilty of using different bullets for different critters.....
Don't even like to do that. Hard enough to keep my rifles stocked with enough good, reliable ammo. E
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Campfire Regular
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Which goes along with what I have found in cold (and heat) testing over the years: The particular case and bullet can affect how well a certain powder is resistant to temperature change, yet another reason to actually test our loads in the temperatures we might encounter when hunting.
The biggest problem I encounter with this is I don't hunt near where I live and conditions can vary greatly between the two locales. The only real cold weather hunting I've done is a winter cow elk hunt in the '05 to '06 season at an elevation of 9,500+ feet. In the morning, getting out of the truck, the temps were usually between -12F and -6F and probably got as warm as the high teens or perhaps low 20's. But nearer to where I live it's not common to get below zero but temps in the teens and low twenties are typical in the coldest months. The stars would have to align just right for it to be one of those cold weather clear (and not storming/blizzard) where I can also get to the range and validate POI and chronograph results. I like the idea of it all, but most of my hunting conditions are 40-65 degrees without all the extremes. I sometimes wonder if I worry too much about something that largely doesn't affect me...
“There are three things all wise men fear: the sea in storm, a night with no moon, and the anger of a gentle man.”
― Patrick Rothfuss, The Wise Man's Fear
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Campfire Ranger
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Campfire Ranger
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John, not to get off topic, but have you ever tested any of the black powder substitutes such as Pyrodex or T7 for velocity change/POI change with temp drops ?
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Campfire Kahuna
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Campfire Kahuna
Joined: Jul 2001
Posts: 60,156 Likes: 13 |
No, not really, because when I shoot black powder guns (whether my T/C Hawken or cartridge rifles) I use black powder. Odd, I know, but there it is....
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.”
John Steinbeck
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Joined: Jan 2006
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Campfire Ranger
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Campfire Ranger
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I understand as I don't consider my Knight in-line a primitive weapon either. Thanks anyway.
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Campfire Ranger
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Campfire Ranger
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DakotaDeer & Brad,
The only way to know for sure is to do the work. As MD hinted at, powder is just one variable to the equation among at least 10 others that I can think of, which makes for a lot of miserable combinations to test. Once in a while you get lucky and find some that shoot well in a variety of conditions but usually this is not the case. I have a whole shelf full of loaded ammo marked for different temps, climates, and conditions for specific rifles. Then I have a bunch of GP ammo that I use for everything else. I always seem to have something on hand that fits the bill but only rarely do you find a load that does several different conditions well. Consequently, my rifles are divided into three temperature extremes -10 to +30, +30 to +60, and +60 to +105 all of which represents the spectrum of temperatures where I live. This is not to say that I have a lot of rifles, but rather that through experimentation, I have found a lot of loads for them that work under certain conditions.
Flower Child Which load should I take when I expect the temperatures to be anywhere from 10 to 50 all in one day's hunt, or from 0 to 60 in few days' hunt?
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Campfire Member
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FWIW - To get 185 TTSX's under 2.82 OAL in my Kimber Montana I had to trim the case to 1.995" - a little short by most books. If you are not shooting a Kimber, you might have that problem. Working with the 185 TTSX's I have not had good luck with X-terminator, High SD's, poor accuracy, low velocity. Just worked up some TAC, got the velocity - but not enough data on accuracy. 8208 is some fantastic stuff, should easily cut your SD's in half, pretty easy to get top velocity in the .338 Fed, accuracy in my gun is good (not great). No change in velocity from 40-85 deg (no cold weather data yet).
Just saw Alliant released its 2000MR, supposedly the same stuff as in the factory .338 Fed ammo. Published velocities are the best for the .338 Fed yet (in a quick glance). Anyone tried it?
"Do you want it "Right", or "Right now"? - always a good question.
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Campfire Ranger
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Campfire Ranger
Joined: Aug 2003
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It's not fun gutting out deer when it's -20F, made that mistake once, never again.....(grin)
I've learned that one way to discover how cold your hands truly are is to "burn" them by poking them in the steaming guts to warm them up. Yow. (But warm guts are one's friend when working on game in the cold. I never carelessly cast them about until the gloveless cold chores are complete. )
Sometimes, the air you 'let in'matters less than the air you 'let out'.
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