Home Forums Hunting & Shooting Ask The Gunwriters What creates barrel heat: velocity or pressure?

yup so would be accelerated to the speed of light be dramatic, but back to guns, torque on the bullet and coupled with the engraving process isn't gettin anywhere enough press.

Wore a neat looking little .22 Long Rifle case brand for most of a Summer once. Between the right earpiece of my shooting glasses and temple.

From a 10/22. a hot day, and the rifle had been fired quite a bit. Got it flicked out of there in a second or so.

It felt very hot to me at the time.

I read this a long time ago, so in may not be 100 percent accurate, but talking about the heat from a cartridge case ejected from a semi-auto.

What I read was that the action opened while there was still some gas inside the barrel, and that escaping gas was what made the case so much hotter that a like case fired in a bolt action or other manually operated repeater.

This is easy enough to prove. Operating a bolt action as fast as you can, the fired case would only be warm. There would not be enough time for it to cool down that much, if the brass was heated by the powder gases. I don't think the heat from the brass would conduct into the rifle's barrel that fast, enough to make that much difference in the temperature of a cartridge fired in a semi-auto as opposed to operating a manually operated action as fast as you can.

I have never ejected a cartridge from a bolt action that was too hot to hold in my hand, although I have picked up brass off the ground that was fired in semi-autos that was still too hot to hold in my hand. The brass was ejected and lay on the ground considerably longer than it was left in the chamber of a manually operated rifle, yet it was still too hot to hold, indicating that it was very hot at the time of ejection.

Watched a left-handed pistol-shooter invent some wild and leapy new dance steps when a spent case from his .45 auto ricocheted off the divider at his right and into his open shirt front, right into his exposed chest hair (no skivvy shirt).

The same sort of thing plumb discombobulated a well known pistol champ when he saw an ejected case from his .45 fly into the cleavage of a busty female next to him on the firing line.

She was wearing a tank top and no bra, so he was already somewhat distracted.

Ken,

Being left-handed I've had several ACP cases go down my collar over the years. They were minor compared to a 7.62x51 from an M1A.

Its the cycle time. If you can cycle a bolt as fast as an auto for example, the caswes from the bolt would be as warm. Lets see that would be around 800 for an ar, around 600 for an Uzi etc. Its not possible to get to the bolt fast enough. This feature is used in select fire weapons as an advantage. The ejected brass acts as a "radiator" to pull heat off the weapon before it can be absorbed. Gas opertated weapons are designed with escape ports to remove this gas after the bolt assemblies have moved a specific distance so as not to have gas left in the barrel.