William M. Large was one of the founding members of the National Muzzle Loading Rifle Association. He also sold some of his rifling machinery to
Green River Rifle works in Roosevelt, Utah and helped them set it up. Some of his barrels had the stamp that is on your rifle. Others had JJJJ which represented initials of daughters. GRRW sold barrels choked at the muzzle and warned against shortening or altering the muzzle end - the result being the curse or be devilment of lost or poor accuracy. A 36 inch straight walled barrel I have is choked at the end of the slightly larger than 1" octagon that came from Bill with planer marks. It is tighter than .54 and a .526 round ball works best in it. I would refrain from funneling the muzzle for easier loading in the field. As others on the forum have stressed, you have piece of history valued by many. You could easily sell the barrel or rifle and get enough new barrels from contemporary makers that you could funnel the muzzle. Hopefully you don't need to reload quickly in the field or hunt and get a clean, humane kill with the first shot. You didn't mention what caliber the rifle was. Donald King was a rifle maker and gun club member in my home town (Wichita) and his rifles are also collectors items. He was also a crack shot like modern rifle maker Ron Long. J. Vincent and sons made distinct and handsome smaller caliber (.45 or less) rifles in Ohio, same state where Bill was set up and lived. You can find a lot of information on Bill on line. Bob Roller who made locks wrote a lot of reminisces of he and Bill. The old Green River Rifle Collectors Association newsletter had info of rifles built on Bill's machinery. Doc Gary White of GRRW knows a lot of that company's history and would be a good resource for Bill Large info. John "Dinglehofer" Baird , author of two books on Hawken rifles, published the Buckskin Report out of Montana and you can find in back issues articles mentioning Bill. I would definitely shoot it and see what kind of accuracy you can wring out of it. In 60's and 70's Bill Large Barrels were very popular and made good showings at Friendship (Indiana) NMRLA national competitions. Who built the Bill Large barreled rifle pictured on the piano?