How many rounds/period could warp a barrel?


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Ignition Override
June 4, 2008, 04:48 AM
How about with the Mini 14 or 30's thin barrels in a five or ten-minute period etc?

I got a tiny finger burn the other day after shooting just forty rounds in about 5-10 minutes, even trying to keep clear of the barrel.

But made sure that those floating grapefruits won't bother anybody else, ever again.

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General Geoff
June 4, 2008, 04:53 AM
rule of thumb is that if your stock bursts into flames and/or begins to melt, you're probably warping the barrel. ;)

TAB
June 4, 2008, 04:56 AM
Lets see on a min 14...

2 shots in 10 mins...

Gunsby_Blazen
June 4, 2008, 06:23 AM
OH ha-ha Tab
everyone bashes the mini, swear.....

Art Eatman
June 4, 2008, 08:03 AM
Back in the 1980s I messed around with high-cap mags in my Mini. Used "near misses" to run off a neighbor's herd of goats.

Several occasions. Goat are like cats: No conscience.

Rapid shooting, pretty much using up a 30-round mag or two.

Never affected the POI of a first shot from a cold barrel, later. Several coyotes found that out. :D

I don't know why folks expect a skinny barrel to be a benchrest tight-group gun. Doesn't matter if it's a Mini or one of Roy Weatherby's buggy whips. Three shots and it's time to do something else. The world is full of slow learners, I guess.

Art

Bwana John
June 4, 2008, 10:35 AM
Until you see a Mini-gun's barrels at night after a couple of good bursts youve got NO IDEA how hot those things can get.

Im talkin white hot, all of um. No warping, no sagging, ect. Probley not much rifleing either ;)

Ill see if I can find a picture of a guy lighting a cigerette off a hot FAL barrel.

benEzra
June 4, 2008, 11:09 AM
I would imagine that permanent warping would never occur; your primary damage mode will be erosion of the throat and rifling by 1000-degree, 50,000-psi gases, combustion-product solids, and hot copper sliding over hot unlubricated steel at 1500 or 2000 mph. The hotter the steel gets from repeated shots, the softer and more susceptible to wear it gets.

Firing a single magazine in twenty seconds or so won't noticeably damage a barrel if you let it cool after, particularly if the barrel is chrome lined. Firing multiple magazines in succession without chance to cool may, though.

I think the military M16 manual says that in the context of sustained fire for long periods, the rate should be limited to no more than 15 rounds per minute to avoid barrel damage, but it's been a long time since I've read that.

Personally, I have never heated the barrels of any of my guns (even my AK) to the point that they start smoking the oil off, AFAIK, and I don't plan to.

Walkalong
June 4, 2008, 11:19 AM
My Mini 14 has survived numerous 30 and 40 round mag emptying excersises with no change in 100 yard performance, but it was never a tack driver. I would not do that to a nice barrel capable of excellent accuracy. ;)

lions
June 4, 2008, 11:54 AM
My brother and I love shooting with my dad and his mini. So much so that anyone on the outside looking in probably thinks we are actually trying to melt the barrel. I don't have any rounds/minute numbers but way more than I would have guessed.

P.S. ignition override, thanks for taking care of those floating grapefruits, they're so annoying!

pgeleven
June 4, 2008, 12:10 PM
we cracked a M2 heavy barrel on a range. it had been dry for several days and range control would not allow us to fire linked ammo because the tracers could start a fire (we were on the big island of hawaii in the middle of a lava rock field, i suppose lava rock has a higher flash point than diesel...? whatever...) anyway a few days later they allowed us to fire provided we delinked all the tracers and shot only ball. our PL had us do that and we relinked the tracers into belts of 200-250. that night after the shoot some dew set in and the following morning we were given the green light to go hot with the tracers. with 4 vehicles doing a 'talking guns' exercise with straight tracers, it looks like a scene from star wars. well one of the guns decided to start cooking a fresh belt off. runaway gun. once the crew chief yelled that the gun was a runaway, our PL said to drop from the turret and let it eat the belt, it was a more sound decision to get the crew out instead if the gun blew instead of having them do an immediate action. we watched from the side as the barrel went from red to orange to white and the ammo finished feeding through the weapon. about 5 minutes after the feed tray was lifted there was a incredibly loud POP. we thought another round just got fired. apparently while cooling down the barrel decided to split right down the middle. the gun was a total loss because it expanded into the bolt extension group and was not able to be removed.

Tarvis
June 4, 2008, 12:36 PM
Thats a good story PG ;).

Im talkin white hot, all of um. No warping, no sagging, ect. Probley not much rifleing either
Remember that those barrels are made to do that, also they are connected by a metal ring close to the crown so they don't move too much.

hotlead
June 4, 2008, 01:23 PM
I have put many consecutive rounds through a M2. I have never heard of a barrel blowing up though? I have had a case blow up in the breech do to bad head space and timing. Glad I had the flak jack on!
I have had many Mil. gun barrels glowing red, or white during the day time.

rcmodel
June 4, 2008, 01:29 PM
I would imagine that permanent warping would never occur; your primary damage mode will be erosionYou are quite correct.

Semi-auto rifle barrels do not perminately "warp" from overheating.

But they will fry the rifling in front of the chamber pretty darn quick!

rcmodel

ctdonath
June 4, 2008, 01:37 PM
about 5 minutes after the feed tray was lifted there was a incredibly loud POP.
There's something funny about the juxtaposition of "incredibly loud POP" with "firing thousands of rounds of .50BMG from multiple guns", sorta like describing a nucear explosion as "it was a loud BANG".

pgeleven
June 4, 2008, 02:14 PM
I have put many consecutive rounds through a M2. I have never heard of a barrel blowing up though?

you must trust me, at this range we expended several thousand rounds per gun. as an armored unit, when we rolled out we brought PALLETS of ammo

There's something funny about the juxtaposition of "incredibly loud POP" with "firing thousands of rounds of .50BMG from multiple guns", sorta like describing a nucear explosion as "it was a loud BANG".


well, understandably we had ear protection in during the firing, and the barrel broke when we had cleared the guns and removed our plugs. but for me at least, any loud pop or crack at a range after 'cease fire' is called tends to amplify itself. if youve ever seen a M2 HB in person you can imagine the report of that much metal cracking in half.

Wes Janson
June 4, 2008, 02:18 PM
http://www.researcheratlarge.com/Ships/CV16/AAReport/index.html

Take a look at this picture:

http://www.researcheratlarge.com/Ships/CV16/AAReport/05022.jpg

Methinkith that barrel would probably qualify as unserviceable, perhaps. ;P

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