SemiAuto Barrel Overheating? - Tilted Forum Project Discussion Community

Suave · 05-23-2005, 11:38 PM

I'm told that the average rifle barrel will heat up quite quickly under sustained semi-automatic firing, and accuracy suffers after as few as 5-10 shots. Is this true? And if so, how do chrome-lined barrels and such stand up?

Lebell · 05-24-2005, 05:25 AM

yes, it is true.

Heat causes the barrel to deform, hence affecting accuracy.

Chrome lining is used to reduce wear on the barrel, not to dissappate heat.

But I personally don't know if the two are ever an issue, since the sustained fire and accurate fire are usually not done at the same time.

hrdwareguy · 05-24-2005, 07:00 AM

When the barrel starts to glow, it's time to let it cool off for awhile.

iamnormal · 05-24-2005, 04:37 PM

All barrels will heat up from only one shot.

Suave · 05-24-2005, 09:41 PM

It's not permanent though, is it?

cuervo · 05-25-2005, 03:27 AM

Here is the semi-auto rate of fire information for the M14-type rifle:
(from FM 23-8)
1 min --- 40 rounds per minute
2 min --- 40 rpm
5 min --- 30 rpm
10 min --- 20 rpm
15 min --- 20 rpm
20 min --- 20 rpm
30 min or more --- 15 rpm

So, in 10 minutes, I could shoot 200 rounds without damaging the rifle. At the end of that 10 minutes, the barrel could easily give you a nasty burn. The accuracy would suffer, but it would still be within specifications. If you were shooting for match purposes, the accuracy would be off more than acceptable. Unless you really, really, heated up a barrel, or did something to it while it was really hot, you won't damage the barrel and it will retun to its "cold" position, or close to it.

There are several ways to reduce heating and/or maintain accuracy. You could flute the barrel, giving you more surface area to disipate heat. You could free-float the barrel, so that nothing is touching it as you shoot. You could cryo-treat the barrel, which removes internal stresses in the metal, so the barrel won't deflect as much when it heats. The effectiveness and cost effectiveness of all of these could be argued.

ziadel · 05-25-2005, 09:21 AM

yeah, I typically stop when I can't hold a good site picture because of the 'mirage' from all the heat distorting my sight picture

and I thought barrels were chrome lined so as to prevent corrosion and slow down fouling of the bore?

BigBen · 05-25-2005, 09:53 AM

Automatic weapons are employed with this concept in mind:

As the rounds are fired, the barrel heats up and starts to warp. This creates a "Cone of Fire" that is used to create a "Beaten Zone". Not a problem.

iamnormal · 05-25-2005, 03:13 PM

When most stuff is heated it expands and when it is cooled it contract. It should change about the same way each time from cold to hot. Then you can figure out about were you are going to hit.
I would think the thing to do is shoot around 5 times then zero in the scope. Let the gun cool off then shoot once to see where it hits. Each shot after should be off less as the barrel heats up.

Suave · 05-25-2005, 08:59 PM

Quote:

Originally Posted by ziadel

and I thought barrels were chrome lined so as to prevent corrosion and slow down fouling of the bore?

Yeah, I'm an idiot. :P

05-23-2005, 11:38 PM	#1 (permalink)
Suave Twitterpated Location: My own little world (also Canada)	SemiAuto Barrel Overheating? I'm told that the average rifle barrel will heat up quite quickly under sustained semi-automatic firing, and accuracy suffers after as few as 5-10 shots. Is this true? And if so, how do chrome-lined barrels and such stand up? __________________ "Few people are capable of expressing with equanimity opinions which differ from the prejudices of their social environment. Most people are even incapable of forming such opinions." - Albert Einstein "Wise men talk because they have something to say; fools, because they have to say something." - Plato

05-24-2005, 05:25 AM	#2 (permalink)
Lebell Cracking the Whip Location: Sexymama's arms...	yes, it is true. Heat causes the barrel to deform, hence affecting accuracy. Chrome lining is used to reduce wear on the barrel, not to dissappate heat. But I personally don't know if the two are ever an issue, since the sustained fire and accurate fire are usually not done at the same time. __________________ "Of all tyrannies, a tyranny exercised for the good of its victims may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated; but those who torment us for our own good will torment us without end, for they do so with the approval of their own conscience." – C. S. Lewis The ONLY sponsors we have are YOU! Please Donate!

05-24-2005, 07:00 AM	#3 (permalink)
hrdwareguy "Officer, I was in fear for my life" Location: Oklahoma City	When the barrel starts to glow, it's time to let it cool off for awhile. __________________ Gun Control is hitting what you aim at Aim for the TFP, Donate Today

05-24-2005, 09:41 PM	#5 (permalink)
Suave Twitterpated Location: My own little world (also Canada)	It's not permanent though, is it? __________________ "Few people are capable of expressing with equanimity opinions which differ from the prejudices of their social environment. Most people are even incapable of forming such opinions." - Albert Einstein "Wise men talk because they have something to say; fools, because they have to say something." - Plato

05-25-2005, 03:27 AM	#6 (permalink)
cuervo Tilted Location: NC	Here is the semi-auto rate of fire information for the M14-type rifle: (from FM 23-8) 1 min --- 40 rounds per minute 2 min --- 40 rpm 5 min --- 30 rpm 10 min --- 20 rpm 15 min --- 20 rpm 20 min --- 20 rpm 30 min or more --- 15 rpm So, in 10 minutes, I could shoot 200 rounds without damaging the rifle. At the end of that 10 minutes, the barrel could easily give you a nasty burn. The accuracy would suffer, but it would still be within specifications. If you were shooting for match purposes, the accuracy would be off more than acceptable. Unless you really, really, heated up a barrel, or did something to it while it was really hot, you won't damage the barrel and it will retun to its "cold" position, or close to it. There are several ways to reduce heating and/or maintain accuracy. You could flute the barrel, giving you more surface area to disipate heat. You could free-float the barrel, so that nothing is touching it as you shoot. You could cryo-treat the barrel, which removes internal stresses in the metal, so the barrel won't deflect as much when it heats. The effectiveness and cost effectiveness of all of these could be argued. Last edited by cuervo; 05-25-2005 at 03:30 AM..

05-24-2005, 04:37 PM	#4 (permalink)
iamnormal Addict Location: In the id	All barrels will heat up from only one shot.

05-25-2005, 09:21 AM	#7 (permalink)
ziadel Myrmidon Location: In the twilight and mist.	yeah, I typically stop when I can't hold a good site picture because of the 'mirage' from all the heat distorting my sight picture and I thought barrels were chrome lined so as to prevent corrosion and slow down fouling of the bore? __________________ Ron Paul '08 Vote for Freedom Go ahead and google Dr. Ron Paul. You'll like what you read.

05-25-2005, 09:53 AM	#8 (permalink)
BigBen Comedian Location: Use the search button	Automatic weapons are employed with this concept in mind: As the rounds are fired, the barrel heats up and starts to warp. This creates a "Cone of Fire" that is used to create a "Beaten Zone". Not a problem. __________________ 3.141592654 Hey, if you are impressed with my memorizing pi to 10 digits, you should see the size of my penis.

05-25-2005, 03:13 PM	#9 (permalink)
iamnormal Addict Location: In the id	When most stuff is heated it expands and when it is cooled it contract. It should change about the same way each time from cold to hot. Then you can figure out about were you are going to hit. I would think the thing to do is shoot around 5 times then zero in the scope. Let the gun cool off then shoot once to see where it hits. Each shot after should be off less as the barrel heats up.