Pic rail for my Marauder

You have several choices, there are both 1 piece and 2 piece. The problem lies with the Marauder magazine, you have to successfully straddle it. The one piece ones will mess you up. The BKL has two different varieties in 1 piece, one takes a full 4 inch of rail and the other takes 2 inches. UTG has a 4 inch rail that takes a 3 inch bite on the dovetail. These are WEAVER and not picatinney with mil specs. Your best bet is the 2 piece units. UTG has one, Hawke offers one as well. I've used the BKL 2 piece dove tail to weaver. You should be able to straddle the mag and mount your scope. They are 1' long and add about a half inch in height over the dovetail rail. The UTG are lower, much less expensive, as are the Hawke mounts, out of all listed I never tried the UTG and Hawke 2 piece. 
 
What you want is a UTG part # MNT-DT2PW01 Dovetail to Picatinny Rail Adapter (2 per pack). Pop these into your picatinny mounts to make them fit any dovetail rail.

https://www.pyramydair.com/s/a/UTG_11mm_3_8_Dovetail_to_Weaver_Adapter_2pcs/4148

Don't forget to use the Airgun Nation code for 10%off as well.

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