Concerning Flues 20's, there's another area of concern in addition to the barrels. On the very lightweight guns, some have suffered cracked frames where the water table meets the standing breech. Years back, we had a member (Greg Tag) who was keeping track of Flues failures. (The only ones I recall were 20ga guns.) In at least one case I recall, the owner apparently shot some of the "light" big box special target loads . . . which are OK in terms of shot charge (7/8 oz), but perhaps not pressure and/or velocity. I don't remember whether the gun in question still had its factory short chambers or whether they'd been lengthened. But if still short, then those factory 2 3/4" hulls would have resulted in additional pressure increase, perhaps additional recoil, etc. Anyhow, the frame was specifically identified as a possible weak point on those earlier and very light 20's (per the earlier post), and it would have been a very bad idea to shoot standard American factory ammo in those guns. 2 1/2" RST's or European factory loads to CIP pressure standards would be the way to go. But obvious from the weights listed that all Flues 20's are not equal in that respect.
