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Originally Posted by Llama_Bob
Originally Posted by Mule Deer
Thanks.

My experience is that the temperature of the rifle does affect velocity. I have tested ammo both ways, by heating.cooling the ammo only, and by firing in outdoor conditions from below zero to 100F, with the ammo often heated a little more by "greenhousing" it in a clear plastic bag. Sometimes frozen ammo works about like it does in actual cold, but more often it doesn't.


This would require quite a bit of explanation before I'd buy it. The working theory is that powder burns differently depending on its start temperature. Possibly the primer explodes differently too. If changing the temp of the rifle chamber or barrel mattered, an entirely new physical theory of what's happening would be required and not much is coming to mind. Maybe the bore contracting in the cold?!? I did a little math on that, and I believe going from the hottest to the coldest possible "cold bore" barrel temp only changes the bore diameter a couple ten thousandths, so that's hard to believe.

I'm not saying it's not interesting, but absent a physical theory of what's going on I suspect error/testing difficulties.



Maybe poster denton will chime in on this topic. He has studied the effect of barrel temperature.

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.264 is a great bullet and long live the 264 Win.Mag. ! i own some of the other 6.5 too`s but i kinda think the future might have another answer yet too ? not sure but i am going to check it out 25 Creedmoor with the 7 1/2 twist barrel real soon ,131 gr, Black Jack bullets in 25 caliber ? i know my 257 Weatherby Mags preform well on deer and antelope out to 600 yards for many years, as i would bet a 264 Win.Mag. has for many hunters too for many years.


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Originally Posted by Siskiyous6
In the April Handloader, Terry Weiland's article "In Defense of Belts" loses track of the title's stated subject, and decries 6.5 MM's in general, and the new 26 Nosler in particular, despite not having any experience with it, and says the .264 Winchester Magnum is obsolete.

Of course there is no definition of obsolete that would satisfy many at the fire, but I hold that the .264 Winchester Magnum is still one of the finest long range options out there for Western Game.

Some of the finest hunters I know carry nothing else in the field for Moose, Deer, Bear, Elk, Goats, Sheep, and Antelope. And any of the various 264's would kill the same range of game.

Would anyone here refuse to hunt because they were going to have to use a .264?

If you have one of these pieces of junk laying around and want to offload it fast PM me.

I suggest to never read anything by him again. He is obviously just trying to stir the pot so somebody will mention his name. Beauty is in the eye of the beholder, and so is obsolete.

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Bob,

Have heard two theories, both from various industry professionals, one about bore dimensions in real cold. The other is that the instant a warm bolt-face touches the very thin cup of a primer, it changes the way the primer ignites slightly, since the priming compound contacts the cup.

I tend to believe "field" results, shot with everything at the same temperature as they would be when actually hunting, over simulated lab results--which is why I started testing handloads in actual environmental conditions in the early 1990's. One thing that tends to confirm the field results is that POI of the loads that don't chronograph the same can vary. Not always, but that often depends on the rifle, not the velocity. Many rifles do not change POI at 100 yards even when muzzle velocity varies 100-150 fps, but others do. As is demonstrated when working up handloads with various powder charges.


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Terry is a good writer, I enjoy his stuff.

Being controversial is no stranger to that business. After all, here we are talking about him, using his name.

Col. Charlie Askins was a master at that. It worked, he got people talking, sold copy. And lived fairly large in San Antonio.

Terry is selling copy and books, laughing all the way to the bank.

DF

Last edited by Dirtfarmer; 04/17/19.
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Originally Posted by Llama_Bob
Originally Posted by Mule Deer
Thanks.

My experience is that the temperature of the rifle does affect velocity. I have tested ammo both ways, by heating.cooling the ammo only, and by firing in outdoor conditions from below zero to 100F, with the ammo often heated a little more by "greenhousing" it in a clear plastic bag. Sometimes frozen ammo works about like it does in actual cold, but more often it doesn't.


This would require quite a bit of explanation before I'd buy it. The working theory is that powder burns differently depending on its start temperature. Possibly the primer explodes differently too. If changing the temp of the rifle chamber or barrel mattered, an entirely new physical theory of what's happening would be required and not much is coming to mind. Maybe the bore contracting in the cold?!? I did a little math on that, and I believe going from the hottest to the coldest possible "cold bore" barrel temp only changes the bore diameter a couple ten thousandths, so that's hard to believe.

I'm not saying it's not interesting, but absent a physical theory of what's going on I suspect error/testing difficulties.


Our smokeless powder are progressive powders, which means they burn faster and hotter at higher pressures, which promotes even higher pressure.

Yet there is only a finite amount of energy in a powder charge. A certain part of which goes to heat barrel steel. More energy is consumed by cold steel than by warm steel. And the loss of energy to cold steel slows the progressive nature of the powder burn.

That is the theory of the mechanism by which a cold barrel reduces chamber pressure and muzzle velocity. Denton has shared with us on a couple of occasions data derived from actual shooting which supports such theory.

Personally, I have seen approximately 250 fps difference between the first shot from a cold bore and the third shot as the barrel heats in a 26 inch Model 70 Classic sporter in 264 using 140 gr partitions in combination with RL 25 (early production). The fast loads were accompanied by blown primers and case heads expanded so much they would not fit into the shellholder on the reloading press.

I recorded, the same data on two different days with this load. Shot #1 safe and sane at near 3100 fps, second hitting 3200 fps, and third exceeding 3300 fps.


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Originally Posted by Idaho_Shooter

...
Personally, I have seen approximately 250 fps difference between the first shot from a cold bore and the third shot as the barrel heats in a 26 inch Model 70 Classic sporter in 264 using 140 gr partitions in combination with RL 25 (early production). The fast loads were accompanied by blown primers and case heads expanded so much they would not fit into the shellholder on the reloading press.

I recorded, the same data on two different days with this load. Shot #1 safe and sane at near 3100 fps, second hitting 3200 fps, and third exceeding 3300 fps.




Never heard or seen anything like that. Even shooting high intensity cartridges in pencil-thin barrels in warm weather. But I guess one never stops learning.

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Originally Posted by chamois
[quote=Idaho_Shooter]
Never heard or seen anything like that.


Yeah, me neither. The big reason I do my own ballistics work is that so much of what's out there is simply wrong, or more to the point observations are assigned to the wrong causes.

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Originally Posted by Llama_Bob
Originally Posted by chamois
[quote=Idaho_Shooter]
Never heard or seen anything like that.


Yeah, me neither. The big reason I do my own ballistics work is that so much of what's out there is simply wrong, or more to the point observations are assigned to the wrong causes.


It was kind of a worst case scenario. There were many reports of early production RL 25 being really spikey. And the 140 partition has a very long bearing surface with a rigid copper mantle in the middle.


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Rl-25 and RL-26 both seem to be less than ideal in that respect.

I'm still going to say that in order to change the powder burn, you have to heat or cool the powder or possibly primer not the barrel/action. There is some conduction from the barrel/action to the case, but for that to happen the round sit in the chamber for a while.

Similarly, barrel heading is done with waste heat after the burn. What happens to that heat has no impact on velocity.

Last edited by Llama_Bob; 04/18/19.
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I found a Hawkeye, I resisted my compulsive tendency because it had a 24 inch barrel.

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I have a friend that has been using an old BDL .264 Mag since the late 70's. He rarely shoots more than a box a year, maybe less. He never hunts where he doesn't have to shoot over 300yds, mostly its under 100. Back in the mid-80s, I worked him up an accurate load with the Speer 140 going (by the book's data, no chrono) right at 3000fps ( .270 territory) he killed deer/hogs with them. I moved off and afterward another friend loaded the Nosler 140 Partition for him ( same speed) . Now he just uses factory ammo. His barrel is 24", of course, and if a 26" made a difference in his conditions, I don't think any of us could tell it, ha. I'm thinking its only beyond 500 yds or so it would come into its own. Most deer leases in East, Texas don't have those kinds of terrain. You might "see that far" down a pipeline ROW, etc, but its either brushy or otherwise unsafe to fling one down there. Even here in Utah, sure, some places you can strain a rifle barrel, but no real need to. For instance, even the prairie has dips/gullies, etc that can be used to stalk closer. Being a tall man, I never had trouble with a 26" barrel and 22" feels like a carbine to me, ha. 24" is a good compromise for me. My current Mod 700 .270 is a 22", but I wish it were 24", like my .338. I've even had 26" barreled rifles with a 2 1/2 long brake on them! Now that seems long to me.

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Quote
I found a Hawkeye, I resisted my compulsive tendency because it had a 24 inch barrel.


Send that info my way.


Last edited by SU35; 04/19/19.
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