How Hot is Your Barrel

[bobm]

We know the bore surface just ahead of the leade is subjected to 3300 F plus degrees of gas burn temperature for just a millisecond. Being well above the steel melt temp, a certain amount of steel molecules exit with the gas each shot. This extreme heat is absorbed rapidly by the barrel mass, like a heat sink, and goes outwards to the exterior of the barrel cooling along the way. No good way for the average gun tinkerer to get an accurate internal surface heat measurement at the instant of combustion.

My Hawkeye shows sad wear as expected on those high mileage barrels. Bronze brushing and patch pushing has very noticeable drag in the first three inches of bore. But they still shoot well for me. The end is approaching, though.

My rounds are not in the chamber long enough under match conditions to worry about increased pressures and velocities. I do not run maximum loads in 7mm-08, not needed to topple the steel animals.

Barrels are like car tires, expendable. If you drive a lot you will need new tires eventually. I have two pre-fitted replacement barrels in my house for the day these present ones give up.

 

[K22]

I go out of my way to avoid a shooting out of a hot barrel. I can because I'm not a match shooter. The only time I shoot from a hot barrel is for a followup shot during hunting. I don't have precise records but I can tell you that if I have to take a second shot it's at best a 50 - 50 proposition on making a hit. This is why I TRY to make the first shot count, i.e. one shot - one kill.

I do practice frequently (about twice a week) but let the barrel cool between shots during practice session. "Cool" being defined as cool to the touch. In my game I'm only interested in the cold barrel shot.

Each to his own but I cringe at the range when I see fellow shooters firing shot after shot in rapid succession until you can't touch the barrel without burning your fingers. I don't get it but I don't get a lot of stuff in this modern world.

 

[Park ranger]

In high power, we shoot 10 shots in less than 60 seconds. Just saying

 

[K22]

In high power, we shoot 10 shots in less than 60 seconds. Just saying

I will pray for your barrel.

 

[JimSC]

considering the throat is the main part of the barrel that gets heat damage and it is being heated to appx 700 F will 20, 30 or even 50 degrees difference on the exterior of the barrel make ?

Here is a 50 year old DOD paper on the subject

http://www.dtic.mil/dtic/tr/fulltext/u2/404467.pdf

 

[cw308]

K22
I guess some people just like to shoot fast just for the fun and noise of shooting , I see it all the time . I for one shoot for accuracy , first and last shot . I guess I'm lucky I don't need a few foul shots for my rifle to group . My first to the 30th shoot where I want it .

I'm a benchrest shooter only , 308 Cal. Rem 700 is my one an only for at least the last ten years now , it's a part of me now , as comfortable as pointing my finger.. Never rush a shot , barrel never gets too hot an never shoot more then 30 round at a range trip .

The thermal strip I put on my barrel gives me a safe temperature reading letting me know how hot the barrel is , my stop point is 113 degrees , works just fine for I shoot 10 shot groups of 3 usually 10 shots then a cease fire at the range for 15 minutes then another 10 . Range time is about two hours every Sunday weather permitting. Good talking , shoot straight .

Chris

 

[270WinDude]

I go out of my way to avoid a shooting out of a hot barrel. I can because I'm not a match shooter. The only time I shoot from a hot barrel is for a followup shot during hunting. I don't have precise records but I can tell you that if I have to take a second shot it's at best a 50 - 50 proposition on making a hit. This is why I TRY to make the first shot count, i.e. one shot - one kill.

I do practice frequently (about twice a week) but let the barrel cool between shots during practice session. "Cool" being defined as cool to the touch. In my game I'm only interested in the cold barrel shot.

Each to his own but I cringe at the range when I see fellow shooters firing shot after shot in rapid succession until you can't touch the barrel without burning your fingers. I don't get it but I don't get a lot of stuff in this modern world.

I'd be curious to see the implications on the group size of that barrel treatment. In the military we used our M4s and M16s like that. Those barrels got so hot you'd easily burn and blister if you touch it. All day sometimes they stayed like that. Still hit targets at 300 with those little 223s. Personally I feel better about chamberings like the 30BR over things like that 220redline or whatever on the other forum/thread here. I take what little measures I can to keep it from overheating. My biggest concern or question now is shots per day. If I'm heating it then cooling it I'm wondering if I should keep it at 30ish shots per day or take better advantage of range time and go for as long as concentration allows.

 

[cw308]

JimSC
I'm a Army Combat Veteran served in Vietnam May 1967- 68 your barrels would turn gray from firing , the M2 50 cal. would what we called a cook off just from the round feeding into the hot chamber , only way to stop it is snap the link or let it run. We were young didn't know if it was bad for the weapon and never gave it a thought

Now that I shoot Benchrest only and baby my rifle , I think back on those days . It takes me two hours now to shoot 30 rounds . The cost of powder , bullets and primers , the cases I have plenty from a friend that shoots but doesn't reload . Things change for the better . Life is Good , thanks for the article .

Chris

 

[JimSC]

JimSC
I'm a Army Combat Veteran served in Vietnam May 1967- 68 your barrels would turn gray from firing , the M2 50 cal. would what we called a cook off just from the round feeding into the hot chamber , only way to stop it is snap the link or let it run. We were young didn't know if it was bad for the weapon and never gave it a thought

Now that I shoot Benchrest only and baby my rifle , I think back on those days . It takes me two hours now to shoot 30 rounds . The cost of powder , bullets and primers , the cases I have plenty from a friend that shoots but doesn't reload . Things change for the better . Life is Good , thanks for the article .

Chris

CW, that 700 is from 1 round. I think the actual gas temp is around 2700 and up depending on the powder. You can find videos of full auto AR's turning the barrel red, the key phrase is full auto. I just don't see 150 being that much worse than one at 115. Of course I am no gunsmith and that is just a guess. In a match I run a 20 round group in about 10 - 15 min depending on wind shifts. I tend to take more time when doing load developing, closer to 20 rounds per hour even on windless mornings. I have considered dropping 50 bucks on a chamber cooler, they do work.

 

[cw308]

JimSC
Jim the article I read was in accurate shooter technical information , a competition shooter uses the thermal strips on his barrel , made perfect sense to me , better then feeling the barrel . I guess it comes down to heat , some barrels start shooting good with alittle heat .

For me I don't panic if it raises to fast , let's me know to slow down between shots , to a point . Don't want it to spoil the fun of shooting . Better to concentrate on shooting then worrying about barrel heat . I will eyeball the thermal strip after every group of ten .

My barrel is 1" thick a M24 Im sure the inside is much hotter them the outside , just don't want to burn it out from heat if I can help it , rather wear it out from shooting . Can talk gun stuff all day so ilI let you go for now .Good talking to you . Still looking for that 10 shot one ragged hole group at 200 . Maybe Sunday , sure , wishfull thinking . Be Well.

Chris

 

[bobm]

Fr. Frog's Rules of Internal Ballistics

1) There ain't no magic powders!
2) There are no magic cartridge cases!
3) Details! It's in the details.
4) Inconsequential increments are meaningless.
5) Most gun writers are pathological liars.

Flame temperature is very close to the same for all smokeless powders and runs about 3300 degrees F. Ball type powders tend to be from 3200 to 3300 degrees F and extruded powders tend to run 3300 to 3400 degrees F but there is wide variation.



http://www.frfrogspad.com/intballi.htm

 

[bobm]

Whoa...about #2. I thought the Creed was magic.

 

[JimSC]

The DoD study listed earlier showed anywhere from 2400 to 3580 F and the temp rose in correlation with the velocity so I would bet FR Frog is pretty much dead on.

found this while digging around also

heat distribution of one round in a browning machine rifle.

heat to cartridge case ................................................ 131.0 b.t.u.

to kinetic energy of bullet ............................................ 885.3 b.t.u.

to kinetic energy of gases ............................................ 569.1 b.t.u.

heat to barrel .......................................................... 679.9 b.t.u.

total 2,864.0 b.t.u.

heat generated by friction ........................................... 212.0 b.t.u.

http://wintersoldier2008.typepad.co...-gained-over-a-long-career-in-the-united.html

 

[djporter]

The heat strips seem like a good idea, just where on the barrel would be the best place to locate them?

 

[cw308]

djporter
Think of where the bullet is sitting in the chamber , place the strip where the tip of the bullet is ,place the strip on the side of the barrel , so you can easily be seen .

 

[Ccrider]

Gave the strips a spin. 10 shipped were about 20 bucks. They shipped the same day I ordered and I got them the following day.

Placed one at the start of the barrel. They turn from black to a color as the barrel heats up. Much more consistent then going by how the barrel feels to touch.

The temp here yesterday afternoon was mid 80s. After ten shots I was 113. Less than 10 minutes and the barrel had cooled back down to the 90s.

I like them. No more guessing. Saves time.

 

[cw308]

I'm glad you gave it a shot , it's the same strip I'm using , worked the same for me ,I shoot in 3 10 shot groups . At the end of my 10 shots the temperature is 113 just like yours . The strip is a much better system then the touch method . You'll be giving them away after others see the strip on your barrel . Mine is on for 3 years now and going strong , until the next time , shoot straight and keep one eye on the label .

Chris

 

[Ccrider]

Thanks for sharing Chris.

 

[cw308]

My Pleasure . Stay Safe out there.

Chris

 

[bigfish28]

if I remember correctly at 120 F when you touch you will feel instant pain. Lower temps may be uncomfortable but you can touch it for at least a few seconds.