misslead; I may have a plastic stock for a MK V. I'll dig out my take-offs tomorrow and let you know. Meantime, if you find one at a good price, jump on it. Around $50. $75 if it's new. I have several Wby Mk V take-offs, not positive about a plastic one.
misslead; I do have a plastic stock for a MK V with a #2 barrel channel. It is the right stock for a .257 Wby with factory barrel, unless you have a featherweight. It looks new.
Also have a wood Mk V take-off #2 barrel channel that has age cracks in the varnish. It will have to be refinished, but the wood is beautiful; at least AA, maybe AAA.