Don't struggle trying to make worn-out parts work! I have two (2) stripped, NOS M2 .50 BMG barrel extensions; one still NIW, and the other unwrapped. Both are flat out new, but the unwrapped one has some very slight finish wear on some high spots - maybe 3-5% wear. $200 each, shipped. One (1) NIW M2 .50 BMG rear sight, current style. $150, shipped.
Payment by USPS money order only. Any other payment instrument will be returned uncashed and items relisted. FYI, my mailing address is a PO Box because the USPS doesn't deliver to the house out here in the desert.