Hi all today I went to a local gun shop (bad idea for me)and they had a used sidelock labeled Jonathon Browning .50 cal Mountain Rifle it shows a lot of use but not abuse, bore is clean and not rusted the nipple area shows no rust.It has a single trigger, adjustable rear sight and brass hardware, my questions are who manufactured these (my first thought was Lyman) and if anyone knows what the rate of twist is I didn't think to measure it,The asking price is 350.00 it shows wear the stock could be refinished but I kind of like the used look.any info or opinions would be helpfull thanks.