i can unscrew the barrel but the roll outs don't really bother me, because its my 1st pump i got use to holding the trigger and sliding the pump forward to shoot. probs not the best tactics but it works a treat (i have videos in the pump section, look for my user name) as i said above i want to try to increase the accuracy, but im not sure it its worth the hassle or not.With your armson the main problem that a freak bore would help with is roll outs, I assume the barrel unscrews? - If it does put two strips of insulation tape about 1/2 inch long in the breach end if you're having roll out problems.
I do mate just depends on the barrel you want machining reallyI think that @Monkeyboi did bore one of his barrels in the past for a freak insert. He may be worth a shout.