Early Guards w/ Rings

[Jersey Devil]

Can anyone explain to me the differences between the two types of early trigger guards with the concentric rings?

I have a no-pad housing and some other early parts that I'd like to build up the housing with, but I want to use the correct early guard and I'm told there's an earlier and later version.

Any help is greatly appreciated, thanks in advance!!

[Orlando]

I dont think I have a picture but there are rings around the hole in the back of milled trigger guard on the early version. Later milled version has hole but no rings

[Moorem1s]

Orlando,I believe there were two sizes with the concentric rings. I think this is what Jersey might be referring to. I do not know the exact size difference between each, but i don't think it was by much. Pyle's book on the gas trap mentions it,and may show photos(going off memory-at work so I cannot reference it).

[CCyooper]

According to Pyle, p. 156, first variant 0.296" and the second 0.3' diameter hole. He indicates the grasping ring/groove range ended around 15K.. Canfield indicates the hole was 0.375 and states grasping grooves were used until the 40K range. I know not much help... however, if you look at the data sheets most rifles after 15k have TG's without concentric rings... just an observation.

[Jersey Devil]

Thanks for the info, guys!!!
Much appreciated.....now it's time to start measuring!!