[Chief RID]

I have wondered about this and so I'll ask. If I have load data for a 7 1/2" Redhawk and I shoot a 5 3/4" blackhawk does that mean I will see slightly lower pressures than the redhawk? If so does that mean that I have a little extra safety margin built in with my shorter barrel for that load?

 

[Jack Monteith]

Hi, Chief:
 Nope. The pressure peak will be the same, and it will be within the first inch of bullet travel and likely within the first quarter inch. The extra air the bullet has to push out of the longer barrel weights a lot less than the bullet. A longer barrel will give lower muzzle pressure, but muzzle pressure is much lower than peak pressure.

  Bore diamter and condition will make a difference, length won't.  Seems to me that we should spend a little more time on the basics of Internal Ballistics. Mr. Gates?

Bye
Jack

 

[James Gates]

Exactly right, Jack! The peak pressure will be the same. The exrta barrel length give the gas more room to expand in, and based on the burn rate of the powder, will cause an slight increase in velocity (all things being equal).
The longer barrel gives some people a better sight radius, however as eyes grow older the sights on the shorter barrels my be more clear and sharpe. There is some advantage that the long bareels have as for less barrel flip due to the lower muzzle pressure. Also there is a little less blast. On the flip side though the shorter barrels don't ride up as much when you sit down ( longer barrels better at crossdraw). Quite frankly, it is really up to what one likes. No animal will ever live to know the difference in barrel length...dead is dead!
Best Regards, James

(Edited by James Gates at 7:42 pm on Aug. 13, 2001)