Regarding weight of the finished trade rifles, they were not light rifles - here is some pertinent info:
1) brass mounted Lancasters:
In October of 1825 William B. Astor wrote Henry, "on the subject of Rifles. We continue to import a part of those annually required for our trade; but we usually get 100 or 200 manufactured in the United States, and it will depend much on both price and quality whether we do not in future procure the whole quantity in this country. The barrels of our Rifles are, from 3 ft 8 Inches, to 3 ft 10, and the calibre is in part of them 32 [to the pound] while others carry a ball of 40 to the pound - the Locks are of the best strong roller kind; but not water, proof - The stocks are generally of our native Maple, or Sugar-tree, but we may wish part of them of Black Walnut. The mounting including the PatchBox, is of Brass and well ornamented; and each Gun must have Wipers to screw-on to the thimblerods, and a good Ball mould. The whole weight of the Rifle complete, is from 9 to 10 lbs. . . ."
2) Kit Carson's early brass mounted B. D Gill trade rifle (which is in the Museum of the Fur Trade collection) weighs a whopping 12 pounds
Steel mounted Henrys (these orders even require a minimum weight of 10 lbs):
1) Sept 1831 Henry received an order for "10 rifles, sing. trig. bar[rels] 3 ft. 4 inches. Cal. 32 [to the pound]. 5 inch locks, best quality, maple stock, chequered, steel mt. with covers, weight of the gun when completed not less than 10# [lbs)nor more than 11."
3) another order to Henry, given in September of 1833, also called for steel mountings: "20 Rifles, Single trickers, Steel mounted same as last year, Balls 28 per lb and [browned] barrels 3 f 2 in long, The whole rifle not to weigh less than 10 lb. nor more than 11 lb."
The weight differential of the early (1825) Henry's to the later (post 1830) models, is most likely due to the weight of the barrel - early production guns more often used swamped barrels, while the later production guns may have used straight or tapered barrels. more often, which by the latter period were more common and more cost effective. BTW - the measurements given above for the two Henrys are from guns both dated 1834 and later - that's the year the scroll guard first appeared and the Lancaster is dated by the Museum as 1836.
as to swamped barrels on post 1820 western fur trade rifles, both trade and Hawken- most of the trade rifles by Henry, Deringer, et al in Jim Gordon's Museum are swamped albeit many are not as much as what most of the modern production guns barrels are. Also there are several still extant Hawken rifles with swamped barrels from the 1830-40 period, including half-stocks and the full-stock in the School of the Ozarks which was built in the early 1850's.
Based on measurements from several 1820-1830's era trade rifles I've seen, plus about a half-dozen of the Hawkens with swamped barrels there are two current commercial regular run barrels that fit close if not exact to many of these measurements, and IMO would work unless building an exacting replica of a particular original - then it would be custom time - standard twist rate on most barrels of the 1820-1840 era trade rifles is also 1:48" if that is a concern.
1) In 50 caliber only is the Rice Southern Classic
2) In 50, 54, or 58 - the 42" Golden Age/York profile which is made by several builders including Rice, Colerain, et al - this barrel could also be judiciously draw filed at the muzzle to lessen the swamp slightly, but that would entail a custom or hand done inlet of the barrel. Without any change though the difference between the swamp and the muzzle flare is only .063", just over 1/16" which is well within the parameters of many of the swamped barrels on 1820-1830 era trade rifles.
