"o" rings for fireforming brass

[porthos]

when using a O ring in front of the rim (303 british) to get a better formed brass and eliminate head seperation; is there a best size O ring to use?? and by using this process would the shoulder be moved forward and require resizing??

[skeettx]

Use the one that will allow the bolt to be closed with a SMALL bit of effort.
For sizing, if used in the same gun, body resizing may not be required
You will just have to try.
Each gun is an entity unto its own
Mike

p.s. what kind of 303 gun and what is the bolt number?

p.s.s. what kind of load will you be using in the gun?

[porthos]

i have 2 enfield's a savage mk 4 #1* and a mk 4 #2 fazkelry (sp? ) the savage was like new with a very poor bbl. it had tool marks horizontal to the rifleing. replaced it with a BSA bbl (new, this was appx. 1990) it was short chambered and i rented a reamer to finish it . this one has a tight chamber. i didn't shoot it much after re-barreling. (went back to trapshooting ) didn't shoot a rifle between 1992 and 2013. the FAZ. i bought unfired around 2015. it has a looser chamber. the load that i shoot in the savage is 21.0 rl-7 lwith Lee 90371 sized to 313 w/ LBT lube i have since taken pound cast of all of my rifles anda will go to .314. i tinkered with some jacketed bullets in the savage. 45.0 of 4350 ; my poor notes say that "shoots under 2 in. at 100 yds" 10 shot group. i also shot a 10 shot group of 1.5 in at 100 with the lead load stated above. my eyes won't let me do that anymore. i put a scope (3 power weaver) on the savage. not quite strong enough for me, but i will not put a large scope on a military rifle. the Faz. bhas not seen lead bullets yet. the previous owner installed a parker - hale sight on it. then decided to not shoot it but to preserve it. i shot some S&B jacketed an it hovers around 2-3 inches. the parker hale sight helps. i have bought and cast around 600 NOE 314-210 RN . not sized or shot any yet. i have too much stuff to play with!

[samari46]

Try Harbor Freight for "O" rings first. just go get the rings as there is always something You just can't live without. Tool room for tool junkies. Ask me how I know. Frank

[GhostHawk]

Actually Harbor Freight sells a whole kit of O rings for a quite reasonable price.

I recently bought it as I was tired of rubber bands on my various tv remotes breaking.

The rubber bands keep them from falling on the floor daily where they are hard to find. I find the O rings work just as well. Look neater, and it was easy to find a size that was snug but not too tight.