Who shoots pellets anymore? Those of us that shoot inlines these days use Blackhorn209. Shoot the entire can without ever having to clean/swab the bore.
As for excessive force to load an inline, You should try my Hawken with a .575" patched ball in order to get an idea what excessive force is!
Some modern day traditional barrels still use soft steel. Modern inline barrels normally are cut from the same barrel stock that company uses for their modern centerfire barrels. CVA for example does this. I've put a handful of thousands of rounds through a couple of those guns a couple years ago, barrels still look like new.
As for hard reloading on an inline, the same can be said for a traditional rifle. A modern inline gets whats called a Crud ring when using powders like T7, its the HOT primer that causes this hard crusty build up, not plastic from a sabot like some try to pawn it off as. Using a "cooler" primer like a 410 shotgun uses, normally sold as Winchester 777 or CCI Inline MZL primers, this crud ring is greatly reduced to the point where the shooter, depending on his load set up, can reload up to 5 -6 shots before swabbing the bore free of fouling is needed.
Now getting to the traditional guns, my personal rifles develop a reverse crud ring, this one is the first 4" of the muzzle rather than at the breech end of my inlines. #11 cap for some reason just gives me pure heck at the muzzle with all powders I shoot.
Best thing I ever did to my 58 Hawken was use Dynatek Bore Coat in the bore. The clean up with goex is simply amazing, 2-3 swabbing patches on the range and its CLEAN. The powder residue on the patch once dry is a light gray color, not nasty black. Powder fouling inside the bore was greatly reduced which allows me to shoot my regular hunting patches lube with TOW mink oil and not have to look for a hammer to get the ball down the tube.