Questions about heavy barrels

K

Kimio

New member
This has had me curious for a while now, and I've recieved mixed replies. From my understanding, heavier barrels (Which I assume are thicker than traditional ones) allow for more rounds down range before the barrel over heats. This, if I'm not mistaken, helps prevent or reduce the effects of "heat distortion" negatively impacting the round as it makes its way out of the barrel.

Others have told me that its strictly meant to reduce over heating, and it doesn't necessarily improve accuracy. So which is it?

Historically, I recall many machine guns sport heavy barrels, to help sink heat more efficiently among other reasons that elude me at this time.

can someone please clarify?
 
The heavy barrel is stiffer.The heavy barrel distorts less through out the heating cycle. For example my Dad had a Weatherby 300 mag MkV with a pencil barrel and it would at 100 yards from a bench consistantly cloverleaf the first 3 shots then the group would start opening up rapidly after the 3rd shot [since the Weatherby was a hunting rifle it doesn't matter about the groups opening up] The heavier bar would hold tighter groups longer .
 
Heavier barrels tend to be thicker and more rigid. A flexy barrel with a lot of whip can suffer from inconsistent groups. AK's are known for heavy barrel whip, with pencil barrels and accuracy seems to be improved with stiffer barrels, Ruger also seemed to prove this with their newer MINI guns, they got updated with thicker barrels and accuracy is reported to be significantly better.
Heavier guns tend to be more accurate in general. More barrel material means that there's more material to absorb and lose heat.

So a heavy barrel has the potential to be more accurate, and it will defiantly take more rounds to overheat.
 
There's probably some sort of crazy formula for calculating this, but a barrel with a higher specific heat will take longer to heat up and cool down. But the barrel being thicker also gives it more surface area to cool. And if the barrel has some sort of flutes or a heat sync-type shroud, it would further increase the surface area and the amount of metal that is getting heat applied to it.
It is reasonable to assume a thicker barrel will take longer to heat up and also cool down since there is more thermal energy being absorbed by the barrel, which it then needs to get rid of.

But you should know that quick heating and cooling of metals is what causes major stress. Having a barrel with a higher specific heat, that heats up and cools down more slowly, will probably last longer, than a pencil barrel that is getting hot quickly and cooling off quickly.
 
I agree with the other posts on heavy barrels also shorter heavier barrels are more accurate, less barrel wip. When target shooting I try to shoot 1 round 1 minute apart, keep barrel close to the same heat & cool down between each round, I dry fire between shots. Works for me, Hope I helped Chris
 
Heavy barrels make for heavier guns. Heavier guns are easier to hold steady. Thin barrels have the potential to be just as accurate, they just require a more skilled shooter to make it happen.
 
If a heavier barrel will not overheat as quickly, a firing shots through a hot barrel (especially stout loads, near or over bore capacity) wears the barrel out sooner, do heavy barreled rifles generally have better barrel life?

Edit-as for machine guns, it is definitely a heat sink thing, although the thick Kevlar gloves they used to change barrels on the 'ma deuce' shows you how hot that thing gets.
 
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Thin barrels CAN be as accurate as thick barrels BUT most won't hold that accuracy for a long string of shots. Heavy barrels are steadier to hold and maintain a more constant level of accuracy/point of impact through a longer string.
There are too many factors involved to make patent always/never statements about barrel performance. Until the barrel is installed and tested, there's no given from one to the next. Even the slightest indiscernible variation in metal or machining can make a profound difference in the finished product.
 
Thin barrels can be close in accuracy to heavy barrels. Having said that, a heavy barrel is much more forgiving. A light barreled rifle has to be built correctly for it to shoot.
 
I've seen no difference in accuracy between whippy slender barrels compared to stiff thick ones over the years. If they're equal quality and fit correctly to the receiver, the accuracy difference is equal and excellent. They'll put many shots downrange with great accuracy with all shots fired 20 to 30 seconds apart. In high power rifle matches, 10 shots are fired in 60 or 70 seconds and will easily shoot sub MOA at 300 yards. Then do that all over again 5 minutes later. Rounds are fired every 5 to 6 seconds in such events.

Factory rifles rarely have their receiver faces squared up so the hard contact point causes barrels to whip in that axis as the heat up. Square up their receivers and good accuacy happens. Unless you've got a poor quality barrel to start with. Commercial rifles are notorious for this debacle; rarely are good custom match rifles.

Don't forget folks, a barrel vibrates and whips the same amount and frequency for every shot fired regardless of temperature; with one exception. Machine gun barrels get much hotter than rifle barrels unless you shoot a rifle at the same rate of fire as a machine gun. Many folks have won long range matches shooting 1 shot every 15 to 20 seconds for 22-shot strings and never made a sight change except to correct for wind; shooting standard weight 7.62 NATO service rifle barrels that are virtually the same weight and profile of sporter rifle barrels.

Ever notice that virtually all folks complaining about their rifle's barrel changing point of impact as they heat up are using factory sporter rifles?
 
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