One nice adapter - B-Square Air Gun Adapters & Risers - 3/8" to "Weaver" Adapter (2-piece base), Blue 17025

Good low profile adapter. Solid build. Does not accept picatinny scope rings. Crossbar passage is slotted for a "Weaver" style scope ring that have a narrow cross bar channel. Could be modified easily. They adequate scope clearance for my 6x24x54AOE Opticsking (cheapo fun scope), and my Nikon 3x9x40BDC doesn't look too bad either on the B-Squares. Rifle comes up in a nice position. I like my scopes to fit as close to the barrel as possible. The 40mm objective lens of the Nikon is about .5" above the barrel on my vintage Winchester 275 WMR that has arched 3/8 dovetail receiver grooves. I just purchased Burris XTR Signature scope rings that won't fit this B-Square adapter because they are picatinny compatible only. Burris advertises the XTR's (signature's) as picatinny or Weaver compatible.........not, however Burris "Z" Signature rings will and do fit The B-Square adaptors. The "Signature" rings are awesome. I will be keeping the B-Squares because I do like them, and will find a use for them on another build. For this build, I'm going with a Weaver TO-10 48202 from PlanetOptics as well. Lowest adaptor base available for me. Fit is a very tight (I don't think it will fit tight) slide on adapter with set screws (stop screws) that I will be replacing with nylon tipped set screws. Any way I look at it, I'll have to modify an adaptor to make myself happy. The Weaver is less than 11 bucks. I will be extremely pleased if the Weaver adaptor turns out no less than perfect for me. By the way, my XTR rings are 1.25 high and the "Z's" are medium height. Both ring sets are Burris. Wish me luck as I do you.