While pressure is a consideration, the real limit to the Encore and its smaller Contender/G2 brother is the issue of bolt thrust.
The larger the case head the more bolt thrust there is against the frame and stretching will occur, flexing at best.
I believe T/C offered the 375 H&H in its rifle barrels and I know they offer 7mm Rem Mag and 300 Win Mags in them so they will handle any belted magnum round when loaded to industry standard pressures.
Still in my opinion, the Encore is best suited to the high pressure rounds on the '06 case and the wildcats on the same case.
The RUM and WSM cases are just to large in the case head and these cases will result in frame flexing, possibly stretching and very short case life.
I know this because several years ago I had Virgin Valley Custom Guns build me an Encore barrel in 7.21 Tomahawk. THis is Lazzeroni's fat short magnum with a case head even larger then the RUM and WSM.
Virgin Valley told me this was a great round for the Encore when I asked about using the large case head in the handgun. They said they build them all the time and it would be a great barrel.
While that was being built, I picked up a used Encore barrel in 7mm-08, the throat was severely pitted but only for about 1/2", the rest of the bore looked great.
At teh time I was not smithing so I took the barrel to a local smith and asked if he could rechamber it for the 7mm STW which would easily clean up the pitted section of barrel.
He told me that the 7mm RUM would be a much better round(real reason was he had that reamer in stock and did not want to get an STW reamer).
I asked if the Encore would handle the big RUM and he said that since it as a fatter body with more surface area around the case, it would produce less back thrust because the case would grip the chamber better, I knew this was B.S. from the start but decided to let him do the RUM any way.
Well, I got both barrels back within a week of each other and I tested the 7.21 Tomahawk first. This barrel was built using a Lilja blank so I expected great things from this barrel.
Accuracy wise I was not disappointed, the barrel printed 3/8" groups on average I was very happy until I started shooting the brass a second time. On that firing a bright line formed just above the case head, clearly signs of the beginnings of case head seperation.
I measured the case wall thickness at this point on the cases and found that in only two firings the case had gone from around 0.038" thick to 0.010" thick, unsafe for another firing.
I was a little unhappy as this brass runs abour $2.00 ea!
The 7mm RUM was the same exact way.
Even with much reduced loads, the cases were seperating on the third firings. Not as big a deal with the RUM as brass is much cheaper but still alot of money down the drain.
I still have those two handgun barrels but mainly keep then as a reminder of the limits of the Encore action.
Since then I have started my shop and am still into high performance handcannons which I hunt big game with. My action of choice now is the XP-100 which is vastly stronger then the Encore in every way and much more accurate as well.
If your going to get an Encore rifle or handgun, use the standard case head sizes, I would much recommend staying with the '06 family of rounds even over the belted magnum but you can use the belted magnums in the Encore.
Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.
I've got an Encore that I shoot as a 308 quite a bit , and some of my loads are pretty stout , enough to flatten primmers vry well , I still get 8-10 loads with Lapua brass. This is a custom barrel that fits very tight and my frame has a large tight pin also
I also have a 7mmRem mag in the encore its a factory barrel , I have run some loads in this barrel up to the primer flattening limit and got about 3 loads out of Rem brass that was FL sized each time.The barrel seems to have suffered no ill effects
But due to the barrel having to be so small in diameter at the case I woulden't recomend anything any wider than the standard belted mag. The WSM and RUM case will make the chamber wall pretty thin.
Rost , are you using the factory stocks on the Encore ? If so and your considering one of those monster cases you may want to invest in a new but stock and recoil pad. The stock on the Encore doesen't do anything good as far as recoil controle goes.