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So may be over thinking but gonna ask.


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So as a machinist I deal with various tolerances on parts from +-.0002 to +-.005

Now when having to hold tight dimensions temperature makes a big difference because metal expands and contracts with temperature change. That being said

Do you sight in your gun in similar Temps to hunting conditions like hunting last year in 20 and below did u see if scopes still on? Do you keep guns in garage or similar temp rooms during season to stop from expanding and contracting? Again just wondering as I'd assume all rings and barrels are metal and will change...I just don't know how much

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The thought of expansion and contraction is not something that has ever even crossed my mind. I site my gun in when it is probably still 55-60 degrees. Maybe warmer or cooler depending on the year. I have not ever had to readjust my scope after the initial site in but always take a few shots every year to make sure I am still on my mark. You would have to speak to someone that takes much longer shots in much more extreme conditions than me to see how expansion and contraction really effect a shot. My guess would be if you site in at 70 degrees and make a 600+ yard shot at 10 degrees there has to me some effect. How much I have no idea...My guess is the effect would be so minimal at ranges shooting in the woods that you wouldn't have to give it a second thought.

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Im a Tool & Die Maker myself, and i have not shot in extreme cold temperatures. But i dont believe there to be much of a difference. A good quality scope shouldnt have a problem, they are built and designed for toughness anyways. but i would be more worried about the charge even firing in extreme temps(w/ muzzleloaders).. especially from moisture in barrels when they sweat going from room temperature to below freezing constantly and not getting fired..

 

Or trigger mechanisms/actions freezing up on any gun when parts have to move to activate for a shot.. maybe but, our living environments around here do not get as cold or hot as temperatures needed to expand or shrink steels..

 

i would like to experiment the extreme cold temps and Muzzle loader shooting.  

 

I personally keep my "loaded ML" in the vehicle or garage depending when im hunting next.. so its not not getting sudden change in temperature.. 

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You would have to know the thermal properties of the barrel as well as the round ,if you are using a sabot ,that would make a difference as well. I changed some guide pins in a die last week that had to be frozen in liquid nitrogen before installing,I'm guessing once it heated back up it was probably at least a .003 interference.

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You would have to know the thermal properties of the barrel as well as the round ,if you are using a sabot ,that would make a difference as well. I changed some guide pins in a die last week that had to be frozen in liquid nitrogen before installing,I'm guessing once it heated back up it was probably at least a .003 interference.

See I was thinking more of the Rings and maybe even scope body's more than barrel distortion. Being that rings and scope body's are so thin I'd think that extreme temperatures changes could move them...how much I'm not sure but would think in a rifle looking down a 3 or 400 yard shot a few thou movement at the gun would be huge out aways....again just wondering if it happens

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The average shooter would never be able to 'shoot the difference' IMO, with respect to the firearm itself.

All other things being equal, a 70*F temp change on the mechanical end of the gun/scope combo is minor.

 

But, all things are never equal. Powder density in the case, relative humidity in the air, quality of the scope and mounting hardware, and the effects of the cold on that nut right behind the trigger come into play as well.

 

High-volume shooting, like on a prairie dog hunt, can heat up a barrel to the point where it will grill a steak. The only problem I've ever had was when a round was left cooking in the chamber of a hot barrel. They can shoot pretty darn funny at that point, and there's no telling what they'll do. That would be about a 400*F change in temp.

 

I hit a fox in January a few years ago, and without changing anything except my clothing hit a woodchuck in July with the same rig and load. Both shots were right around 200 yards and the difference in temperature was about 80*F. The hit on the woodchuck might have been an inch high.

 

 

 

Edited by philoshop
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After 50 years of machining , heat treating and destructive and non destructive  testing.

As said above Don't worry about it. Unless you are shooting your MZ loader at 0 degrees or below, then don't walk with your muzzle down, when you go to fire it you might hear poof instead of bang. 50 caliber sabots Do Shrink enough to slide out of the bbl.

Note: we fooled around with a lot of conversions years ago, one thing was making double barrel rifles out of 410 side buy side shot guns. We would use barrel liners machined .001 larger then the bore , put the liners in a chest freezer and the bbl. in an oven at 500 degrees.Then slide the liners in the barrels.Then chamber them. We made .35 Rem., 44 mag., 30 -30 and never had any come loose.

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Barrels are designed (supposed to be) to expand and contract uniformly. The barrels that have less effect are fluted and bull barrels. Flutes are supposed to allow faster cooling with more surface area compared to solid barrel and bull barrel is supposed too hold shape and tolerances better. 

 

With all that said, I target my rifles in with cold or cool barrels in the fall. I did it during the summer once buteven tho it was warmer I never had the gun shoot differently.

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After 50 years of machining , heat treating and destructive and non destructive  testing.

As said above Don't worry about it. Unless you are shooting your MZ loader at 0 degrees or below, then don't walk with your muzzle down, when you go to fire it you might hear poof instead of bang. 50 caliber sabots Do Shrink enough to slide out of the bbl.

 

 

Never gave that any consideration as to the sabot shrinking . Interesting . I was thinking of hanging the ML upside down in the garage with a balloon taped to the end of the muzzzle just to try it out . That would make for a neat test . 

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After 50 years of machining , heat treating and destructive and non destructive testing.

As said above Don't worry about it. Unless you are shooting your MZ loader at 0 degrees or below, then don't walk with your muzzle down, when you go to fire it you might hear poof instead of bang. 50 caliber sabots Do Shrink enough to slide out of the bbl.

Note: we fooled around with a lot of conversions years ago, one thing was making double barrel rifles out of 410 side buy side shot guns. We would use barrel liners machined .001 larger then the bore , put the liners in a chest freezer and the bbl. in an oven at 500 degrees.Then slide the liners in the barrels.Then chamber them. We made .35 Rem., 44 mag., 30 -30 and never had any come loose.

That's awsome....how did you machine the rifled barrel liners? Or can u buy liners then just turn outside Dia to desired fit? That is very cool would love to do a 12 g 270 ou

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We bought the liners for the calibers that we wanted, I have no idea if the still sell them ,the way less and less thing are made now days. I will have to check in the Brownells catalog. I wish we would have taken pictures of the rifled shot guns , some of them we mounted scopes on also.

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Very cool

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One of my Buddy's is best gunsmith I've ever met can do some amazing things. And me a buddy and his dad all built a 1919 semi auto belt fed browning was a cool build as well as the many ar and ak builds but now can't do any of that

Edited by stoneam2006
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From my experience in the dessert where an 60-70 degree change in 8hrs is common the temps affect the powder more than the barrel or the scope mounts. as far as the muzzeloaders go if mine is loaded its stored outside it never goes in and out of the heated house or camp. I have never had a sabot slide in a cold barrel but I had it happen with powerbelts twice.

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I would love to do a bunch of gunsmith work since i have any machine needed to work with, but if the company found out i had a weapon on their "grounds", i think id have to look for a new place of employment.. 

 

Ive heard quite a bit of not so good comment on these powerbelts the last year or two.. ive never seen a sabot slide out, but ive only shot shockwaves out of my ML's.. I did miss a doe on a 0 degree evening a few years back.. could have been me for all i know but i never would have questioned the sabot... interesting

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I doubt it would make a difference at 100 yards. If your barrel is free floated, then you can pretty much not care about a thing. I tend to check my rifle a week before deer season because its the most similar weather and I have never seen much of a change at all. If you use quality ammo and scopes, you shouldn't notice a difference at any normal range in NY. Maybe at 400 plus yards you might start to see something.

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