You might want to see if you can find a pic of the rings mounted first....I bought a set and do not like the way they look....now I can't move them out and ponied up the money to buy the quality set...TPS with 20 MOA base.
I would recomend against the burris with the inserts, but I know that others will disagree here.
Burris is the only one I know of with the plastic inserts. Jewel has a set with aluminum inserts. Not trying to hi-jack the thread but, a friend and I've been working on a set of rings and base combo for several years. The pic here is still a prototype, the finish on them will be a clean bead blast or possibly anodized to your choice of color.
I'm getting closer to start manufacturing these, if I can get enough interest again. Rear base tapers up and front base tapers down. Aluminum inserts for either 30mm or 1" tubes. Allows you to loosen the ring caps, loosen the clamp on the ring and slide either the rear up or the front down or a little of both to get your 100 yard zero as close to bottom as possible, then tighten with no lapping and perfect scope alignment. I have a 100 yard zero on my .338-.378 (3100 fps) with a 8.5-25 lupy and have enough internal clicks to go out to around 2100 yards.
SAKO OPTILOCK have plastic rings - and there is a set of P1913 bases to couple them to a P1913 rail. BUT iirc they are not available with adjustable rings so the base needs to be sloped if you want 20MOA.
THEY also do a 30MOA sloped 1 piece base with 30mm plastic rings for the TRG - 'kin expensive IIRC.
I have them on 2 diffrent rifles, and only have good to say about them, no ring marks, no lapping bars, and not a lot of money. Mine are on a .223 and 22-250. I have read that some have had problems with them moving on heavy recoiling rifles.
I've got a set of the Burris Signature rings in a dual dovetail mounts on my 338 RUM. The scope hasn't budged a bit. I also used the offset rings so I didn't need a tapered base. I would recomment them to anyone. I love them. They are going on every one of my rifles.