Explain difference in barrel heat....

A

Aqualife

New member
30 years ago or so I bought a Winchester 70 264 Win mag with dreams of hunting out west. I’d take it to the range with a box of 140 Remington core-lokt. The barrel would be extremely hot after firing 2 rounds, could never trust the 3rd shot. After waiting between shots I got it zeroed at 200 yds with in a 3” group.

This last year I finally got to take my trip out west for Antelope. I decided to shoot Nosler 100’s. The barrel doesn’t get nearly as hot. I can shoot 5 shot groups with out any issues.

Anyone have any idea why this is the case? More Pressure with the 140?
 
If I had to guess, probably the powder used. Some can be "hotter" than others

It could also be the outside temp. Colder temps mean the barrel cools faster.

.264 Mag has a MAX psi of 64,000 psi, so regardless of powder it should not have been over that, although it could have been less.
 
A lots of powder burning and small volume of barrel steel..

Have a M70 First Series post-64, in 7mmMag.
Throat is burned out, long seating the 160 gr bullet out by 0.125" just to hold a paper plate @ 100yds. Presently using 4064 powder to reload as a "7x57" Mauser round. MI whitetails don't seem slighted when shot.

Just eh magnum loads after five shoot the group when outside the black of a 50 yard pistol target, let the rifle sit with muzzle up and bolt open to get a "chimney effect" to cool down,

Bought replacement barrel that seems to have a better throat, will know shortly.
 
So bullet length sounds like as good of a reason as any. In addition the 100’s are moving faster so less time in the barrel, less transfer of heat.

Guess it all adds up.

Thanks everyone.
 
Lighter bullet is higher velocity and more FRICTION.

Slower heavy bullets means more heat rise pushing the heavy bullet.
 
Bullet length.
Click to expand...

Slower heavy bullets means more heat rise pushing the heavy bullet.
Click to expand...

This certainly seems logical, and I'm not disagreeing. I'm just asking, is this just a guess based on logic, or has anyone seen any documentation to back this up.
 
You must log in or register to reply here.
Back
Top