Ive used quite a few of the Federal Pheasants Forever 1 1/4 Oz 12 gauge in either 5s (later season) or 6s, (earlier, or, sometimes, just in the more open choke). It is/was a good load, but, I think the Beretta Silver Snipe I fed them to was at the very top of the service pressure it should be used with.

The R10 Darne was not.

Best,
Ted