Keep in mind the Sideslinger is open on the end depending on what you prefer. I have a mk ii target 6 7/8” I tried in it also. It does still work fine with iron sights but the barrel sticks out 1/2” below the holster. If I was not using it suppressed I would look at a leather holster made to the...
https://www.tandemkross.com/scoped_sideslinger_leather_holster
I was looking for a leather holster for my 22/45 lite that would work with my fast fire lll and suppressor when it gets approved and this was all I could find.
I just put new rings on mine last year. The bases are off set so you have to use different height rings. Low/medium, medium/ high, or high/x-high. I went with ss ruger rings in low and medium for a 40mm. Heavy but they match the gun nice.