Given the choice, I would probably opt for the Santa Fe Hawken. The .53 caliber bore is not a problem. Production made moulds are readily available in .520” and .526”, as well as cast balls in both sizes and swaged balls by Hornady in .520”. The Santa Fe Hawken is not a perfect replica of the original St. Louis rifles, but it is pretty close. That may not matter to a lot of people, which is fine, but it matters to me.
The Browning JBMR is a nice, solidly built modern muzzleloader with traditional styling. Browning designed their own hardware (the buttplate is massive), breeching system (internal and external), and lock. The Browning rifles are said to be extremely accurate shooters. I don’t care for the ram’s horn on the snail but I understand a lot of people like it. Some original rifles had single set triggers, like the JBMR, and I don’t have a strong opinion on that one way or the other. I don’t know if the JBMR trigger has to be set to fire or if it can be fired unset. There can be some advantages in having a single trigger instead of two in a hunting situation, especially if it can be fired unset.
The JBMR’s Achilles’ heel, and the real deal-breaker for me, is that they are notorious for breaking mainsprings, and replacements are virtually nonexistent. A forum member once sent me photos of the inside of a JBMR lock in un-cocked and full-cock positions. The distance that the lower leaf of the mainspring has to swing is quite impressive. I think it is likely that the Browning lock design just stresses the mainspring too much. I contacted L&R locks a while back and asked if they had considered adding a JBMR replacement lock to their RPL line, with better-engineered internals. I received a very cordial and courteous response, but they indicated they had all they could do just keeping up, as it is. There were no plans for a JBMR replacement lock in the future, and it was unlikely that there ever would be.
I will say that the JBMR has a lot of appeal. It is a nice looking rifle, for all of my criticisms.
Best regards,
Notchy Bob