After 1500 rounds my Omega Z5 has started to foul.I use Harvester greens, regular not crush ribs, with Hornady .44 cal 240 and 300 gr XTP's with a max charge of 90gr 2f T7.Its a very recent development and I think there is alittle erosion factor involved .However I dont ever recall hearing of a muzzleloading barrel suffering from erosion.Pitting from neglect or breech burn from improperly lubed round balls yes.I cant believe it would even be possible.My problem was very recent in appearance and starts roughly where the sabot seats on the powder charge and continues up bore for about 4 inches.The barrel has some VERY minor tool marks , but has never fouled before.I'm currently looking at a number of possible causes as its a bugger to remove with Hoppes and a bore brush , but the bright side is it has no effect on accuracy.She's a very consistent 3/4 - 1 3/8 inch grouper at 100 yards. I wont lap her as the sabots are a very nice fit and it would just be my luck that accuracy would be lost. The other day I shot her at 200 yards and using wind flags, I fired when things were calm and fired 1 group that measured , center to center , 11/16 inch for 3 and the next 3 were an inch even! I packed up and went home after that ! The 11/16's load was the 240 gr .44 XTP in green Harvesters over 80 gr 2f T7 lit by CCI 400's in Variflames. The 1 inch was a 300 gr .44 XTP in green Harvesters over 90 gr 2f T7 lit by CCI400's in Variflames. She mounts a Leupold VX1 2x7 in Leupold low QR rings and base. While it can be an issue and certainly is annoying at times, dont make more of it than necessary.it will drive you nuts and greatly diminish your enjoyment of a finerifle.BTW the worst plastic fouling I ever saw was found in sabot shooting shotguns.REALLY NASTY!