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IIRC, SAMMI 22 RF is 24K, same for magnums.

The 17HMR was a lil higher...

CW
 

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my wsm has shown no presure problems
 

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I chambered a 17 HMR barrel in 17 Remington and 60,000psi or whatever it is worked just fine on an SB2 frame. Larry
 

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I clarified Larry's reply since he didn't mention the frame, the SS1 Sportster frame is cast iron and only works with rimfire barrels. Several members here and RFC have rechambered .17hmr Sportsters to 17WSM. Many members here have rechambered .22 cal Sportster barrels to centerfire chambering, but they need to be used on a centerfire frame, SB2 for anything high pressure.

Tim
 

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There are two things to consider regarding pressure. One in that the barrel itself contains radial pressure regardless of what frame it is mounted on. Longitudinal pressure (breech thrust) is dependent on pressure times chamber area. The .22 WMR has a base diameter producing an area of .039408 sq. inch. SAAMI max is 24,000 psi. 24,000 x .039408 = 945.5 pounds. In a hinged action such as the H&R most of the load is absorbed by the hinge pin. Only a small amount by the locking bolt whose main function is to keep the action closed whether the gun is being fired or not. One need only look at some of the small unlocked caliber auto loading blowback pistols to see how little force is actually involved. Many of the old 'cast iron' shotgun frames sufficed for early rifle calibers including the 30-30.

The main reason rimfire cartridges were long limited to lower pressures is due to case design. A rim thin enough and soft enough to be easily and reliably crushed by the firing pin was, given the limits of metallurgy at the time, also weak enough to be ruptured. As cases became larger rimfire priming required excessively large priming charges to fill the circumferential rims and it was difficult to assure that it was evenly distributed. Rimfire was replaced by centerfire because the latter was, in more powerful cartridges, more efficient, economical and versatile. The only advantage of rimfire was foe small extremely cheap ammunition. Once we get beyond that might as well use a small centerfire case such as the Hornet.
 

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trotterlg said:
I chambered a 17 HMR barrel in 17 Remington and 60,000psi or whatever it is worked just fine on an SB2 frame. Larry
I did not think of it before, But I also have a 17 Hornet and a 17 Fireball in H&R's that both where once 17 HMR barrels... BOTH are mounted on SB2 frames.

CW
 
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