A roller on the frizzen really needs a ramped spring to work well.
The frizzen rubbing on the spring causes wear and gauling as well even with modern greases and oils.
By the 1825 the American Fur Company seemed to be specifying roller locks. Though not waterproof.
They seemed to have always specified "best" or "very best" locks for all orders.
Got this from a quick look in "Firearms of the American West 1803-1865".
Dan
I don't necesarily agree that a ramp is needed on the spring in conjunction with a roller. Working properly the roller simply reduces friction if used with a standard spring configuration. The ramp may help with pressure to keep the frizzen open / closed and allow for quick over center movement, but standard spring / frizzen designs work effectively as well.
Yes, a rollerless frizzen can cause wear and gauling, but if a rollered frizzen stops working properly, the narrow bearing surface of the roller will allow for much more rapid wear.
The ramp is not necessary but it sure helps a lot and will help control frizzen rebound.
The gauling is not a matter of can they all do.
But if the rollers are properly hardened there is no problem. BUT if not they WILL flat spot. So the roller needs to be one of the hardest parts on the lock. Temper it to a spring temper and its too soft. It must be well casehardened if made of mild steel. So if the lock has soft parts they need to be hardened and/or repaired and hardened properly.
Folks need to remember that a lot of locks sold to American gunstockers in the 18th and 19th century were made as cheaply as possible and were apparently marginally hardened
if at all. The makers then apparently installed them as they were received.
THEN we have the fact that a significant portion of reproduction locks were designed by people who did not understand anything more that that they can make money selling locks.
Locks cast from originals with the moulds made by people who did not understand the way the lock actually worked means that the relation between the mainspring, link and the tumbler are generally subtly different due to the cast parts being slightly different in dimension. Link or "plain" mainspring no matter it effects both. The subtle changes can make a lot of difference in how the lock functions.
So painting all "frictionless" locks with the same brush shows a lack of understanding I think.
It simply is not possible to make a tumbler/mainspring that RUB against each other as FRICTIONLESS as the link.
The older style will make an excellent lock and in service, sparking etc, may be indistinguishable from a lock with a link tumbler and roller frizzen.
BUT.
They NEVER are as SMOOTH all things being equal. I have BOTH, I have used both for DECADES and there is NO lube, oil, high tech grease etc that will make a rollerless frizzen contact point, for example, move as smooth as one with a roller. One part or the other always wears, usually the spring which must be SOFT enough to wear or it BREAKS.
They actually require MORE lubing and maintenance than the roller locks I own to prevent dragging and excess wear to the spring.
Dan