From what I understand an "O" ring is inserted behind the breech block plate to improve the gas sealing when fired. "O" ring is made of......I'm not sure but the Shilo Sharps forum fer the paper cartridge Sharps has Hombres there that will be glad to advise and help. Nice Pards there.
Someone mentioned that the floating chamber sleeves,as they are called are adjusting devises. Not so. They are made to let the gas push them rearward as the breech block plate is pushed forward to seal the gases.
From what I understand the newer Pedersoli Paper cartridge Sharps don't haqve the chamber sleeve that moves anymore but have a hardened stainless steel breech block face and the fairly new "O" ring behind the breech block face improvement.
I don't believe IAB ever had the "O" ring or the moving chamber sleeve. Just the moving breech block face.
One word of caution with the Paper Cartridge Sharps rifles and carbines. Powder brushed from the top of the breech block after loading and closing the breech can build between the barrel and the wood forearm. Enough powder under there and the gas escape upon firing can ignite any powder in the forearm and.....splinter it a good one and injure the shooter. Always check to see that no powder gets between the barrel and the forearm of these Paper Cartridge Sharps Rifles.
I sealed mine with some of that sticky wax used for those toilet installation seals. Handy stuff. Hardware stores and building supply stoes sell the sealing nrings of sticky wax.
I had a "45" Caliber Pedersoli Sharps Sporting rifle with the long barrel. That rifle and my good eyes ,when I was a good bit younger, were hell on ground hogs(wood chucks) that dug big holes in the farm fields. That 45 caliber bullet shot like a cartridge Sharps and was good at long range. It was a 45 cal. bullet weighing 290 some grains. It had good enough sectional density to stabilize the bullet "way out there". One of the most accurate rifles I ever owned. The seventy grains of powder FFg I used was a good load.
Strange.....I just haphazzardly with no fancy loading proceedures droped the bullet in the chamber...gave it a little push with a short dowell till I heard and felt the "snick" of the first driving band engage the rifling and droped in the powder...closed the breech block....blew the excess powder from the top of the block....capped the nipple and fired.
That danged rifle was sowell balanced and so easy to shoot with the set trigger I could regularly wack those vermine out at the 375-450+ yards with great regularity. It was one of the best experiences I ever had with a non-cartridge firing gun. Shot as good as a custom muzzleloader with the fast twist barre land the false muzzle or a cartridge Sharps. The paper cutter Sharps shot that well with no special fancy cartridge building like then predecessor cartridge Sharps. You know...how people sometimes search for a good load cartridge in a Sharps forever. Not with the Paper cutter 45 I had. Drop the bullet,fill the chamber with powder,cap and fire. Just too simple and easy. Great gun that Pedersoli.
I still have the mould for the bullet that came with the gun and a new never used spare mould. The .451 bullet at 290 gr. is a good one fer a 45 that takes that size bullet. The moulds just sit in my drawer with all my older moulds building dust. The rifle has been gone a long while. Blew too much gas and got gas cutting and....no one back then, no one, could instruct me on how to fix it or fix it fer me. One reason I turned into a "Kitchen Table Gunsmith. Had to learn to do things myself. Unknowing to me the breech block face on my gun was defective and didn't move or come off. It was really pressed on there. Never knew then that the breech block face was supposed to ove. It functioned well enough with just the chamber sleeve moving for quite awhile. Traded it in on the new fangled cartridge Sharps I have now. Now I have a regiem of loading cartridges with extra care and precision and use every trick I can come up with to keep the cartridge gun shooting as good as the old paper cutter did with no fancy fanfair or do-ins at all.