Chamber wall thickness

[trotterlg]

What would be the minimum chamber wall thickness for a .223?  Larry

[John Traveler]

The late, great P.O. Ackley once documented the progressive turning down and firing of military ammo in a Springfield M1903 .30-06 barrel.  He stopped when the chamber wall thickness was 0.080" and the barrel muzzle thickness was 0.020".  These were impractical dimensions for a sporting rifle barrel, of course, but demonstrated the strength of barrel steel.

In answer to your question, the barrel wall thickness of a Savage 24 combination rifle/shotgun chambered in .223 is probably the lower limit of practicality at about 0.250" chamber and 0.200" muzzle wall thickness.  Keep in mind that this is a two-barrel design and the shotgun barrel gives the rifle barrel additional rigidity.

[trotterlg]

I'm doing a barrel stubbing project with a Handi rifle.  The blank I have is .224 bore and .800 at the breach.  With threads it is about .725 to the bottom of the threads.  With a chamber of .375 that leaves a wall thickness of .175.  This is inside a 12 gauge stub, but I don't think you can count the 12 gauge barrel as it really doesn't totally support the chamber area directly.  I am really doing a .221 fireball, but the chamber presures are the same as a .223.  Think it will blow up?  Larry

[John Traveler]

I'd be very careful of using a .22 blank with those dimensions.  Are you CERTAIN that it is rated for centerfire cartridges and not rimfires?

I would think that the potential hazard here is not the possibility of it "blowing up" but rather the progressive development of increased headspace with each firing. and THAT can be disastrous.

Also, is your single shot break open action rated for the 50,000 psi of the .221 Fireball cartridge?  One of the more curious things I've seen was an old double barreled shotgun with chambers sleeved for .223 Remington.  After less than a dozen rounds, the breech face blew open with a casehead-sized hole.  A sure sign that the old gun was being stressed out!

[gunnut69]

If the HandiRifle is a more modern one it will indeed handle high pressures..if not? I too wonder at the dimensions of the barrel you are contemplating using.. Sounds awfully like a barrel dimension for a 22 LR blank. Have you considered the chore of moving the firing pin strike and bushing it for the much higher pressures it will encounter..

[Rangr44]

IIRC, Handi's that were originally issued as shotguns have cast iron receivers, not suitable for rifle cartridges or their attendant pressure(s).
 
Handi's, orignating as C.F. rifles have steel receivers, AFAIK - thus allowing the use of any barrel, smoothbore or rifled.