Question about 300 PRC magazines

Dog Doc

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Minuteman
Sep 15, 2010
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Olathe, KS
Easing into ELR with a 1-mile build. I have a Defiance action/Bartlein barrel, and it will be going into a KRG Bravo chassis with a lot of weight added. I am trying to choose a magazine and can't seem to find much info. Is it best to just pick one and go? Or do I need to check with the builder on chamber dimensions to determine if it should run a binder plate or not? Sorry if this has been asked before.