Your question = Will barrel life actually suffer if the barrel is shot hot vs allowing cooling? Or, asked another way, if a rifle's barrel would have had a life of 5000 rounds when shot in very slow fire, would it have a life of <5000 if shot in 1/minute rate?

Do you mean if you shot one round per minute one after another for 5000 straight minutes? if so then i would say no.

 

So, my question(s) are:

How hot do you allow your barrel to get?

Is there really a problem if one allows a modern bolt-action barrel to get hot during longer strings of fire, not necessarily rapid-fire, but say 1/minute?

Does heat affect accuracy in the short or long term?

Will barrel life actually suffer if the barrel is shot hot vs allowing cooling? Or, asked another way, if a rifle's barrel would have had a life of 5000 rounds when shot in very slow fire, would it have a life of <5000 if shot in 1/minute rate?

?

I am noway an expert, but I had always been taught that you must let your barrel cool. For instance growing up, I would watch my Dad and my Uncles shoot 2 to 3 shots, then it would cool, they would either switch places or switch rifles as the others were cooling.

When I go to the range, I usually take 2 or 3 rifles, and with my magnum calibers I shoot 2 to 3 shots, then I let it cool.

Have had many of old timer tell me out at the range that what I am doing is the right thing, I don't know if it is or not, just the way I klearned it, was always told if the barrel gets to hot, it eventually mess things up.

 

Think about the heat inside. If the barrel is too hot to touch, what do you guess the chamber temp to be? At what temp does throat erosion accelerate and the rifling start to flake?

 

Julian Hatcher's Hatcher's Notebook and Book of the M1 Garand spell out a lot of barrel life tests, basically he found no discernable damage or accelerated wear in the barrel as long as you didn't shoot more than 15 rounds per minute.

Now, military M16s/M4 (and many other guns) have chrome lined bores that make full auto and long durations of shooting at high volume safe without damage.

 

Lumberjak is thinking like me here. It takes some amount of time for the heat generated inside the barrel to get radiated to the outside of the barrel.

I've experimented a few times with pushing a solvent soaked patch down the bore right after ejecting a round. Dry patch after that. I would expect that the bore stayed "cooler" than if I had not done so.

Two things I noticed:

#1 Firearms cleaned to near "zero" fouling with very little effort after such treatment.

#2 Accuracy was not near as good as when I let the bore foul as in normal strings of fire.

Thought was about how the muzzle-loader folks treat thier barrels at the time.

Cheezywan

 

Hatcher didn't say that it wouldn't erode, he didn't say that all calibers were equal either, he simply said that rapid fire (within reason) wasn't a major factor in barrel life.

Now, a 16" pencil thin barrel on a compact rifle would probably not be able to stand up like a Colt LMG barrel. Thats my opinion, not Hatcher's.

 

Hard to tell now but I'm guessing you agree with hatcher?
I would guess this quote would be incorrect then?

"The big enemy to barrel life is heat. A barrel looses most of its accuracy due to erosion of the throat area of the barrel. Although wear on the crown from cleaning can cause problems too. The throat erosion is accelerated by heat. Any fast varmint type cartridge can burn out a barrel in just a few hundred rounds if those rounds are shot one after another without letting the barrel cool between groups. A cartridge burning less powder will last longer or increasing the bore size for a given powder volume helps too. For example a .243 Winchester and a .308 Winchester both are based on the same case but the .308 will last longer because it has a larger bore."

 

Who are you quoting? I don't necessarily agree with that statement, especially given my above opinion that a 1 1/4" Lilja barrel will last much longer than a pencil thin barrel like on a Ruger Compact in the same caliber and fired side by side.

 

You seem to be saying that rapid fire does not affect barrel life by quoting Hatcher. I doubt you would put the quote up if didn't agree with it. The Garand is neither fully automatic or chrome lined...pretty much a standard rifle barrel and 15 rounds per minute is a round every 4 seconds. I say a round every 4 seconds is rapid fire.
Now your last statement seems contradictory. In comparing a large and small barrel, are you saying a barrel's ability to shed heat is a factor?
If rapid fire does not shorten the life of a Garand barrel, why would it affect a Ruger Compact...same stuff.

The statement you don't agree with is from Lilja.

 

Consider the pressure/temprature combination every time the cartridge is fired. Sorta like sticking a cutting torch into the chamber. There's going to be incremental washing away of metal with each blast. If the metal is already hot, the easier to remove more metal. The use of a borescope (mine is the Hawkeye brand) will tell you interesting things about bore wear and throat erosion. Since acquiring one, my loads have defenitely been reduced a notch or two.

 

Consider the pressure/temprature combination every time the cartridge is fired. Sorta like sticking a cutting torch into the chamber. There's going to be incremental washing away of metal with each blast. If the metal is already hot, the easier to remove more metal. The use of a borescope (mine is the Hawkeye brand) will tell you interesting things about bore wear and throat erosion. Since acquiring one, my loads have defenitely been reduced a notch or two.

Kdub,
You've hit the crotch of the matter [as Archie Bunker said]. The thing is, does good barrel steel actually heat enough at a 1/minute ( 60/hr ) rate of fire to accelerate the rate of barrel wear? I don't want to shoot rapid fire [10/minute] for a whole hour , but I do want to fire off a box of 50 and not take all weekend...

And, I'd like to focus on "std rifle calibers", not big magnums nor overbore varminters like 220 Swift.

Good discussion so far!

I'm surprised Uncle Nick hasn't weighed in...

.

 

Well, it looks like Lilja has found different results than Hatcher. Now, Lilja is more concerned with ultimate bench rest accuracy and Hatcher was more concerned with battle accuracy, which I believe applies to the broader spectrum of shooters.

I did some more digging and found that Olympic Arms also has that similar statement about barrel life, they agreed with Hatcher.

 

I had no idea that the broader spectrum of shooters was only concerned with battle accuracy. Understandable for my area, we don't have many battles here. Most seem to be concerned with the best accuracy they can get.
Does this apply to the Ruger Compact as well?
All in all, you shoot as fast as you like, I'm going to let mine cool.

Kdub...stayed awake in metallurgy class didn't you

 

I fire 5 shot groups with my magnums, time the shots exactly 60 seconds apart.


I had a some bolt sticking rounds in the .300, that got that baby hot FAST. Retumbo is a real cooker if you let it be.

 

I figure I'll use this older thread to ask my question. Is there any discernible difference in barrel temps using different powders to get similar velocities? I understand that simple physics says the energy generated in the barrel is going to going to be divided up into heat, recoil, and the energy imparted on the bullet. Yes, there are other components but I'm not trying to get into the weeds here. My wife is shooting a Sako Vixen 223 and loves the trigger and the performance of the gun, but it does have a fairly light barrel. Typically we have stayed at 100 yd so I load 55 gr rounds in the wimpier range of H335 to limit barrel heat and allow her to shoot with less delay between shots. Now she's starting to shoot longer range. I can step up the velocity, but then then she gets slowed down to allow the barrel to cool. I'm just wondering whether there is a powder that would allow a little higher velocity without a major increase in barrel heat.

Or, would it make more sense to switch to a slower, more stable, heavier bullet and try to get the accuracy that way? Then again, maybe the smart move would be to use this as a reason to go shopping for a really good target rifle with a heavier barrel. And better optics of course. Maybe even a a larger caliber with a good muzzle brake. Maybe I shouldn't even be asking about powders in the first place.

I could spend months experimenting, but with so much experience and knowledge at my fingertips.....

 

1). Is there any discernible difference in barrel temps using different powders to get similar velocities? I understand that simple physics says the energy generated in the barrel is going to going to be divided up into heat, recoil, and the energy imparted on the bullet.
2) Yes, there are other components but I'm not trying to get into the weeds here.
.....

1) yes, but to answer this, #2 has to go bye-bye

For brevity, let's pretend there is only single base and double base powders. Double base will typically have more total energy potential (more nitro to burn) and this will impart more velocity and accordingly more heat. Depending upon the coating package, you will have higher burning temps, or lower. The 748 family as an example has a relatively low burning temp compared to some of its contemporaries. UncleNick at one point had a chart with some burning temps floating around the board, or at least a chart with joules of energy.
Also tied to the coatings, are the side effects. Such as "Hodgdon's" extreme powders. One of the drawbacks to them is the Hard Carbon fooling they produce, which are like diamonds. Very abrasive.

There have also been arguments as to the shape of the powder, and naturally the total amount. So as an example, which do you think is more abrasive:
Burning round grains being blown down the bore, Or, burning tumbling square ended sticks. Certainly could be a difference in search of an argument, but a difference none the less.

 

"Erosion" of barrel steel is oxidation of the steel and abrasive action of hot gasses and carbon. Steel begins to oxidize at about 500F as a very faint 'straw' color and progresses though surface colors to the beginning of incandescence.

If a finger laid on the barrel gets burned, move the finger and let the barrel cool.
Those with hand guards can go by smell and smoke.

 

I've had a Varmit weight and a lightweight rifle chambered in .308. The heavy barrel would resist heating as fast as the lightweight one. When the lightweight one gets hot, the size of my groups increase significantly, and I imagine barrel life is shorter when firing hot for long periods. Still, when in the confines of match shooting, you have to stay within the rules. During my years of silhouette shooting (five shots in 15 minutes, a 15 minute break while targets are being reset then another 5 shot string in 15 minutes, this repeat 4 times for a total of 40 shots in 2 hours?) I've seen guys fanning their barrels during breaks, trying to lay ice packs near them and a few other things. (Some were ruled illegal, some may have done some good, some were just plain weird) One has to find out what works for him or her in a match situation.

 

if anyone is worried about barrel heat and wear and tear on the throat and rifling, do as I do.

I drape wet rags over the barrel from the action all the way to the muzzle. As the wet rags warm up, I rotate them around and add more water to them. It ends up working just like a water jacket does on a water cooled machine gun.

I've shot over 20 rounds thru my 30-06 in as little as 30 minutes while the air temps were above 90 degrees, and the barrel never gets more than luke warm.

unless it is specifically prohibited, it would be an easy way to keep your M1 cool.

 

Interesting thread. I have been concerned about barrel temp too. I target shoot and Prairie Dog shoot and barrel temp gets hotter target shooting, the P Dogs don't come back fast after one shot, it may take 15 or 20 minutes.

I am using a Savage 12-112 Varminter rifle loaded to about 3200 fps and after a 5 string shot for group at the range the barrel will only rise about 10 deg from ambient. By the time I have shot 3 or four 5 shot groups with about 15-20 seconds between shots and about 4-5 minutes between groups the barrel will be 25 deg above ambient temp. The ambient temp in the mornings when I shoot is about 65 to 70 deg. Out in Utah where I shoot P Dogs the ambient temp may be 90 to 110 deg. and with the gun sitting in the sun it may be at 110 deg.

I notice no one is willing to give a max temp of the barrel to stop shooting. What is the accepted temp or does anyone even know? I load and shoot for best accuracy. I'm not interested in rapid fire.

 

Oh, but now you have to discuss uneven cooling of the barrel! The “wet side/top” cools faster... won’t the barrel bend in the cooler direction? What about the stock area... not able to cool as well as the naked barrel area.

I don’t think this is really much to worry about unless running full auto, or nearly so with semi-autos.🤡

 

Don't recall ever hearing of someone strapping a thermometer or using a heat laser gun to measure the actual temp of a hot rifle barrel. If you can't hold onto it - it's too hot.

 

I must’ve not posted when I did those things, kdub. Sorry about that.
I don’t have data enough to make a definitive statement about when to stop shooting based on external or internal temp, to assure no degradation in barrel life. I bought a few of the adhesive thermometers so I could play around checking external temps against internal chamber temps (with my IR thermometer).

One could certainly run tests to determine the trade-off between erosion rates, or dispersion increase, vs bbl temp, and then use that to come up with some rules of thumb that would tell a shooter what external temp to stop shooting at. I’m just not going to put the money necessary into the experiments.

 

An article on the subject.

Monitor Barrel Heat with Handy Temp Strips « Daily Bulletin

 

It was that type of thing I bought from McMaster-Carr. In the linked article, they mention Nomad47. He _may_ have been where I got the idea from many years ago, on the WSSM board.