Which caliber Mountain Rifle is it?
Posted by Zonie, April 17, 2020 about a specific JB Centennial Edition that came with a wooden crate:
"If I can believe the "Third Edition Blue Book of Modern Black Powder Values ®" you seem to have a mixture of the Browning rifles they had made in 1978.
The book says:
JONATHAN BROWNING MOUNTAIN RIFLE. - .50 Cal. perc., 30 in octagon barrel, single set trigger, engraved lock plate, select walnut stock, cased with medallion and powder horn. 1000 mfg in 1978.
100% $750, 98% $595, 95% $400
MOUNTAIN RIFLE - .45 or .54 cal. perc., similar to Johathan Browning Mountain Rifle, withoug Centennial embellishments, not cased.
100% $595, 98% $525, 95% $475
This book was published in 2003 so multiply the prices listed by 1.421 to find the current price in March 2020. ($750 = $1065.42 in current value)
Of course, guns values depends on what the current market is for a particular gun and in your case, the presence of the case and powder horn that was sold as a part of the Centennial Mountain Rifle outfit will increase the value higher than the plain Mountain Rifle. "
See Post #5: --->>>
https://www.muzzleloadingforum.com/threads/browning-mountain-rifle.120756/#post-1653112
Your gun could be worth 1.421 X $595 = $845.
Whether you can actually sell the rifle for that much is a matter of speculation since parts are not readily available for it.
And the net realized at a live auction would depend on bidders interest and would also be reduced by the auction fees.