One thing agreed upon by all who have ever used the .75-caliber Brunswick rifles is that they all shot terribly with patched-round balls. With my own Nepalese rifle, I had trouble getting hits on a man-size target at 40 yards. Any half-way good smoothbore gun would have given a better result and been faster to load.
However, the best guns from private makers in England (most British production was from them), Belgium (they sold to anyone including Russia) and Nepal (they apparently produced their own, perhaps using British lock parts) will shoot with reasonable accuracy using properly fitted patched-belted balls.
Jeff Tanner, in England, makes custom round-ball molds. If the rifle’s owner will send him a lead slug cast from his barrel, Tanner will make a mold to fit the individual’s gun for a little over $50. Tanner can be contacted at email@example.com for prices and information.
Properly fitted belted balls are important as there is considerable variation in the style and shape of the rifling used by as many as a dozen different English and other makers. One size of ball would not fit all guns, which gave no end of trouble with the guns when they were in British service.
Russian and Confederate (U.S.) ordinance officers designed different projectiles for these rifles decades after the rifles were first introduced. The Confederates used a special hollow-based .75-caliber Minie-style bullet, while the Russians employed an elongated projectile (Picket-type as called in the U.S.) with “wings or studs” to fit the barrel’s two grooves.
Most of the 850 rifles purchased by the Confederacy were sent to the Trans-Mississippi Region – far from the Richmond Arsenal. Once their supply of special bullets ran out, these guns would have been practically worthless. Even if bored smooth, these oversized barrels would not have shot .75-caliber round balls as well as the flintlock Brown Bess muskets used against them during their war of independence from Mexico.
The video below illustrates this problem and discusses the Tanner mold. A longer video on YouTube describes casting the bullets. It is located at: http://www.youtube.com/watch?v=uAIvwVncsdc&layer_token=e88b98c8325a7838.