I think max chamber pressure will have no actual bearing on the stock, only the "Recoil Factor". In order to fully determine this both wt of wads & powder charge would need to be known. Assuming they are similar between the two loads & the 1oz is a constant then we have 1200 fps vs 1165 fps. This amounts to a whopping 3% increase for the RGL over the Federal. If you shoot about 4 rounds of skeet or similar in a short afternoon the accumulated effect might be noticable by the end of the day. If you were shooting the slower loads & some joker slipped one of the heavy ones into your gun unknowingly, I highly suspect it would remain just that "UnKnown".
I advise no one on such matters, But, If it were me, I'd shoot'em.
