"Fudge" Factor 4 Barrell length?

[NeveraVictimAgain]

When trying to compare the power of different calibers-as listed in the NRA Firearms Fact Book- I'm often frustrated that the listings are for differenct barrell lengths. For example, it's hard to compare .22LR and .25ACP when all the listings for .22 are with a 6" barrell and the only listing for .25 is with a 2".

Does anyone know-or can postulate- a rule of thumb? Something like "velocity will double for every 50% increase in barrell length for cartridges of the same caliber" or whatever it might actually be?

THANKS!

Dave

[fecmech]

I'm not sure if there is anything cut and dried in that respect. I can tell you that normal high velocity .22's run 940-980fps out of my 3.5" P-22 auto and about the same out of a 4" S&W revolver. CCI Stingers run in the mid 1200fps range out of the same 2 guns. I think the main reason for the .25's in the micro guns is feed reliability and firing reliability. If you shoot a lot of .22's you will experience a fair number of misfires even in quality guns. Centerfire cartridges are way more reliable. My $.02

[Shear_stress]

North American Arms has some very good ballistics data for various barrel lengths (see link below) on their website. Granted, these data apply only to their specific guns, but it can be very useful for getting a sense of muzzle velocity relative to barrel length.

http://www.naaminis.com/naaveloc.html

[MICHAEL T]

NAA info fun to read as 25 auto kicks a lot of the 22 LR in behind. :neener:
What gets me is people carry one of these for SD and turn up their nose at a 25 auto. I like the NAA 22 mag but would never carry one for SD to slow on 2 nd shot and to much recoil. I'll empty a 25 while your trying to recock the NAA and get back on target.