Same time I got this 10 gauge I also picked up a Parker circa 1891 12 gauge G grade . This one has worked very nicely with the Lyman 525 grain sabot slug loaded with the Claybuster knockoff of the WIN AA12 wad . And of course pushed with SR7625 and lit with a WIN 209 . I found these slugs did pretty well in the gun at 25 yards I have yet to try further . Three slugs from the right barrel at 25 yards were in about 2" and about 2" to the right . Three shots from the left barrel were two inches to the left and about a 2" group . I am thinking they "should" cross at about 35 yards . Incidently I tried the slugs as they dropped from the mold and they did okay , but later someone suggested I fill the hollow bases with hot glue and they shot a shade better .
This gun had a severe break a number of years ago and someone put forth a good deal of effort to repair .
The stock seriel numbers to the gun and has a skeleton buttplate !
That was kinda a selling point for me .
Here's the Lyman slug I'm using , reminds me of a air rifle pellet on roids !
The right and left groups fired from the gun at 25 yards .