hot heavy barrel?

[Axis II]

ive never owned a heavy barrel rifle until last summer and only shot enough rounds to sight it in.

I am now doing load work ups and shooting much more and noticed its getting hot after 10 shots. I though heavy barrels weren't supposed to get hot real quick?

savage axis 2 223rem.

thanks

 

[Reloadron]

It's about the frequency of the shots. Ten shots in what? Like Ten shots in ten min, a shot a min or ten shots in 5 min, two shots a min? Outside air temp? There are some variables. Also, define hot?

When I shoot .308 Winchester in a heavy barrel I average a shot a min and while the barrel warms up it does not get really hot and my point of impact doesn't drift to speak of. The same is true of my .223 Remington bolt gun.

Maybe for one of my science projects I should measure the barrel temperatures.

Ron

 

[Axis II]

Its not scorching hot like I have gotten the sport barrel and doesn't really change POi but it gets hot enough to where if I held it long enough it would be uncomfortable.

I generally shoot one and check it in the scope and see where it hit and grab another from my box and feed it and chamber and get my breathing and everything right and settle the hairs and fire so I would say about 1min between shots. temps are around 60-65 degrees.

I shoot 5 at one dot than shoot 5 at another dot I would say roughly 10shots in 6-10min.

 

[gotboostvr]

I would make sure and leave the bolt open to help air circulate while getting ready for the next shot.

 

[Reloadron]

Well as you can see a heavy barrel is not immune to barrel heating effect. As long as your groups do not begin to grow There is nothing to be concerned with. Both my rifles have heavy stainless barrels and while they get warm they are hardly hot and I generally shoot about like you, approximately 1 min between shots and sometimes less. I can get a rough idea of my group through my scope so I don't look through my spotting scope each shot. Tomorrow is looking good for the range. I have primer test on tap so don't know that I will try any temperature measuring. I want to get to that too as I am curious what the numbers actually are.

Ron

 

[Reloadron]

I would make sure and leave the bolt open to help air circulate while getting ready for the next shot.

Good point and I know I do just that.

Ron

 

[Axis II]

I would make sure and leave the bolt open to help air circulate while getting ready for the next shot.

I tend to do that also if I'm not in a hurry. (usually shoot after work) Ill be loading some up tonight and remember to slow it down and leave the bolt open tomorrow.

 

[Jackal]

It its not changing color, its not hot...

 

[Reloadron]

I tend to do that also if I'm not in a hurry. (usually shoot after work) Ill be loading some up tonight and remember to slow it down and leave the bolt open tomorrow.

We are finally looking at some decent weather. Have some .308 I want to shoot and maybe some .223 will go downrange.

Ron

 

[briansmithwins]

Heavy barrels don't heat up as fast as thinner ones but they stay hot longer too.

The only way around that is by increasing the surface area (which is why Lewis and Hotchkiss MGs had fins) or by using a water jacket. For most applications fins or water just ain't worth it.

BSW

 

[Reloadron]

Heavy barrels don't heat up as fast as thinner ones but they stay hot longer too.

The only way around that is by increasing the surface area (which is why Lewis and Hotchkiss MGs had fins) or by using a water jacket. For most applications fins or water just ain't worth it.

BSW

Makes a good point. More mass so takes longer to heat but also takes longer to cool back down.

Ron

 

[MrCleanOK]

Without going into a full on heat transfer lesson. . . the heat energy introduced to the barrel by firing 10 shots is nearly the same for a sporter or heavy contour barrel. Because the heavy barrel has more mass to heat up, it's final temperature will be less than the sporter contour, given the same heat input.

If, in imaginary heat transfer world, you are shooting both barrels until they reach the same "too hot to handle" temperature then letting them cool, because the sporter barrel has less mass, and a higher ratio of surface area to mass than the heavy barrel, it will cool off faster via radiation and convection.

While it would be interesting to model, I couldn't do it without dusting off my old heat transfer textbook and working for a few hours on the computer. So if you want real numbers you'll have to find an engineer that cares more than I do

 

[Damon555]

Most of my rifles are heavy or varmint contours. Ten shots in a few minutes will heat up just about any barrel even with small calibers like 223/204. Now if you're shooting a bigger caliber the barrel heating will be more pronounced. As mentioned above the heavier barrels take longer to heat up but as a trade off take longer to cool down.

Almost every one of my varmint/target rifles like to be shot while the barrel is on the warm side. If your rifle is bedded correctly your POI should stay the same. As a matter of fact my most consistent shooting rifle is a Criterion barreled Savage 223 AI that puts the cold barrel shots in the same spot as the hot barrel shots.....and my bedding is questionable because I did it myself and only bedded the recoil lug....but I must have done something right.

 

[Steve S.]

Last season, I surprised a recon platoon of deer; they took cover and opened up on me. I displaced when the heavy stuff started up and then when they tried to flank me, all hell broke loose. Actually, the deer don't shoot back so my barrel never gets more than slightly warm even at the bench - haven't felt a "hot" barrel since 1972. Good shooting!

 

[spitballer]

Operating temperature is very directly related to rate of fire, and it should be controlled like any other specification. Normally when I'm target shooting I simply fire at a rate of one round per minute and let it go at that, but just last week I got some solid advice from one of the range officers who said that I should be able to press the back of my hand against the barrel for at least four seconds, otherwise it's too hot.

 

[GooseGestapo]

It also depends on the caliber and cartridge being fired.

A heavy barrel .22Hornet will heat much slower than a sporter weight .22-250.

A former co-worker "shot out" a new Savage M12 Varminter in .22-250 in a single morning with 40gr Ballistic Tips running ~4,100fps over Varget powder. About 300rds in less than an hour on a prarie dog town.
He now takes a heavy barreled AR15 in .223 with 53 gr Vmax, and has a cup of coffee between magazines...

I only shoot three shot groups with my Savage M110 in .300RUM. I wait 5 min between groups, and clean every 20rds. After ~400rds, it still shoots under MOA with loads it likes. I have 140 cases. 50 were match prepped when new. I expect to "shoot out" the barrel without ever using those cases!
But at the rate I shoot it, not likely in my lifetime I have left.

 

[Orcon]

Yeah transport phenomena can be a real you-know-what. I found similar issues with my first bull barrel 308. I really assumed that the extra mass would let me shoot more shots per group and more groups in less time but that just isn't the case. I can get 5 rounds down tube in relatively short order before I have to stop to cool, I could probably do more but once that sucker gets hot it stays hot.

Nowadays I shoot a group, walk to my target and snap a photo with my phone and walk back. At 300 yards and up that is usually sufficient time to cool and a little exercise never hurts. I usually bring my 22 MkII along to practice fundamentals at 100 yards so I have something to do if I do overheat. I also don't shoot near as fast anymore and found that focusing on good technique and a comfortable shooting position did more for groups sizes than reloading or costly stocks and optics ever did. Just food for thought.

 

[amlevin]

If you can hold the barrel for any length of time, chances are it's not too hot to shoot. Remember that the hot water from a household tap can be uncomfortable and it's only around 120-130 degrees. The "annealing temp of 416R steel is around 1600 degrees (F) or more.

If your barrel isn't hot enough to "sizzle" when hit by water droplets, and as others have said, your groups haven't opened up, just keep shooting


FWIW, if you plan on shooting enough to make your barrel really hot, consider mounting it in an all metal chassis that free-floats the barrel from the recoil lug forward, and has plenty of cooling slots/holes in the forend. Some of the "heat creep" can come from uneven cooling on the barrel where the portion in the stock is unable to radiate heat the same as the top of the barrel.

 

[Orcon]

If you can hold the barrel for any length of time, chances are it's not too hot to shoot. Remember that the hot water from a household tap can be uncomfortable and it's only around 120-130 degrees. The "annealing temp of 416R steel is around 1600 degrees (F) or more.

If your barrel isn't hot enough to "sizzle" when hit by water droplets, and as others have said, your groups haven't opened up, just keep shooting


FWIW, if you plan on shooting enough to make your barrel really hot, consider mounting it in an all metal chassis that free-floats the barrel from the recoil lug forward, and has plenty of cooling slots/holes in the forend. Some of the "heat creep" can come from uneven cooling on the barrel where the portion in the stock is unable to radiate heat the same as the top of the barrel.

Assuming a generic Thermal expansion coefficient of 12 and a 24 inch barrel shifting from 50 to 100 degrees that would be 0.0156 inches of expansion. Right?

Is that enough to throw a turd in your accuracy punch-bowl?

 

[MrCleanOK]

Thermal expansion is absolutely enough to throw a turd in your accuracy punch bowl. Because the barrel doesn't heat and cool uniformly, thermal expansion imposes stresses on the barrel.

As a pretty extreme example of this, modern battle tank barrels have insulated shrouds installed over them. The primary purpose of the shroud is to insulate the barrel from the sun, which would warm the top of the barrel, causing it to expand (elongate) relative to the bottom of the barrel, which shifts the point of impact down. Additionally, we "re-zero" (not the actual term) the gun for changes in weather/sun conditions and after firing (about every 3-4 rounds, in practice). Tank crews that forget to "re-zero" during gunnery start missing targets after the first few engagements, and this effect is actually built into our gunnery simulators.


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[Orcon]

I cannot disagree. Most factory barrels are made from spooled stock and then straightened during manufacturing. Steel has memory and unless proprely stress relieved will bend and warp (albeit minutely) do to the unseen atomic arrangements in the steel.

What does armored calve call the rezero?

 

[MrCleanOK]

MRS (muzzle reference system) update. There is a crosshair reticle mounted at the end of the gun (the thing that looks kind of like an ACOG), and the gunner references that reticle to dial the correction into the ballistic computer.


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[briansmithwins]

A former co-worker "shot out" a new Savage M12 Varminter in .22-250 in a single morning with 40gr Ballistic Tips running ~4,100fps over Varget powder. About 300rds in less than an hour on a prarie dog town.

I can actually believe that. Small bores and high velocities are what burns out the throat. Hotter powders don't help either.

Letting the barrel cool between shots will increase barrel longevity, as will hardchrome or nitride coatings. But there isn't all that much you're going to do about the incandescent plasma eating out the throat of the barrel.

Barrels are a consumable item, just like bullets, cartridge cases and powder. Only most people don't shoot enough to actually consume too many barrels in one lifetime, excepting outliers like to example above.

BSW

 

[Snyper]

The only way around that is by increasing the surface area (which is why Lewis and Hotchkiss MGs had fins) or by using a water jacket. For most applications fins or water just ain't worth it.

I've often used a wet towel soaked in ice water when shooting on those 95* July and August afternoons. Wring out enough so it's not dripping then lay it on the barrel.

 

[briansmithwins]

I've often used a wet towel soaked in ice water when shooting on those 95* July and August afternoons. Wring out enough so it's not dripping then lay it on the barrel.

I'd be more concerned about warping the barrel (temporarily) by having it hot on the side you can't get to and the cold towel on the other.

BSW