Just to note: The 510C looks like a great rifle sight but it won't work with the CROM on a 1301T. You would have to pic rail mount it, add the Magpul SGA and the cheek riser, plus lose the ability to cowitness with the irons.
I have the 510C on an AR and it's a great sight, but wouldn't want to mount it on a shotgun for the reasons you mentioned. Even with the SGA stock and riser that's a fairly clunky sight and could see it getting in the way when reaching over the top of the shotgun and loading a single shell into the receiver.
The 508T is more durable and I like the more squared profile.
I run the 510c on a Ruger PCC which has shotgun ergos with the factory stock. The added height over bore allows a more upright shooting position and it similarly does not allow cowitness which I was concerned with at first, then realized that the QD on the 510c works pretty well. I have a bunch of holosun T1/T2 clones and could easily put one on that would cowitness with the irons but would rather have the large window and simple ability to QD the 510c.
Sounds like you have a solution that works for you. But I'll add that with the 1301T in particular, one additional problem with using the 510C in particular would be the picatinny rail itself. The weight of the 510C combined with the Pic rail only being attached with a few screws combined with 12g recoil is going to equal failure at some point. Yes, people have already had rail failure with smaller RDS, usually because the screws break... 12g recoil is brutal on equipment.
Ken
BBI: ...”you better not forget the safe word because shit's about to get weird”...
revchuck38: ...”mo' ammo is mo' betta' unless you're swimming or on fire.”
Gave the bottom of the operating range a try today. Let it sit outside for about 50 min while I walked the pup. Shake Awake worked. I was surprised the buttons were not stiff as I scrolled thru power setting and dot-circle modes. Cant say the same about buttons on a Sat phone or GPS. Shot 13 rds let it set while I picked up brass then another mag. Sight never fogged up until I came in, (didn't shoot inside) but no issue's sighting with both eyes open.
Pretty cool...
Almost painfull