Pressure vs heat

[bigd 7378]

As a rule what would be harder on throats and lands. Running pressures at max say 64-65k or running hotter powder say N570 vs N165. I know N570 is harder on throats than N165. I guess my question would be would N570 at 60k be harder or easier on throats vs N165 at 65k?

 

[Tiny Tim]

Great question. I have no idea, but I want to say flame temp is more destructive than pressure. I'm sure there is some give and take there. Perhaps ql users may be able to shed some light on the subject.

 

[Dean2]

Pressure in and of itself does not wear the barrel, temperature and flame do. Overbore cartridges tend to operate at higher pressure but the real issue is burning that much powder and forcing the flame down a hole that is too small to be optimal. A 7 RUM and a 7 Rem mag run nearly the same pressure 65,000 vs 61,000 PSI but the RUM wears the barrel a whole lot faster, 800 round barrel life vs 2000, because it burns 95 grains rather then 65 grains of powder. If you up the pressure on the 7 Rem mag to 65,000 psi by adding a few grains of powder you will be over SAMMI spec but you will get very close to RUM velocity and still have far longer barrel life.

If you push pressure too far however, catastrophic failure will definitely shorten barrel life before the flame gets it.

 

[blksno]

Pressure in and of itself does not wear the barrel, temperature and flame do. Overbore cartridges tend to operate at higher pressure but the real issue is burning that much powder and forcing the flame down a hole that is too small to be optimal.

If you push pressure too far however, catastrophic failure will definitely shorten barrel life before the flame gets it.

I litterally was in the process of typing almost this exact statement.

Pressure, isn't hard on barrels at all, it's what CAUSES the pressure that is hard on barrels. If you simply plug both ends and increase pressure up, it doesn't harm the barrel at all. It's the combination of heat from the powder, and the heat from the friction that degrades barrels. The hotter you get the steel, the more susceptible it becomes to wear from friction. Heat and friction in conjunction are very bad over time.

 

[bigd 7378]

If N570 is used, would there be a difference in flame temp between 60k and 65k? In other words does 10 grains of said powder burn as hot as 80 grains? Or does pressure have something to do with heat also

 

[bigd 7378]

Then why is N570 so hard on barrels when there are other powders that burn as hot