Yes - bullets are lighter and faster in "Express" rifles, thus the rifling is slower.

In the bufflao hunting days, probably close to an equal split between grooved lubed and paper patched (commercial bullets mostly).

Perhaps the grooved lubricated were more prominent due to the prolific use of the surplus .50/70 rifles, both Sharps and Rem. RB's. Later on when made available, the Govt. did sell some .45/70's but the .50/70's were most prominent on the plains, in carbine rifle length.

This one used a groove lubricated bullet of 450gr. with 70gr. powder, as loaded in the military ctgs and supplied at the forts on the frontier. Many back then, called the .50/70 the 'big .50' - as compared to the smaller .45, .44 and .40's of the day.

Thus, these are the grounds for the continuing argument about what ctg. Billy Dixon actually used at Adobe Wall Indian battle - was it the original "The Big .50", aka .50/70, or the brand new barely released that year (maybe not even made it to Arizona yet), .50 2.5", known also as the .50/90 and also called "The Big .50" - however, it not known (by me) when it was 'coined' as such.

What is known, is that most .50/90 Sharps had 36" rate of twist, while the .50/70 Government rifles, both RB and Sharps had 42" twists. Both were deemed inaccurate (compared to more specialized .40 and .45 cal Sharps rifles) past about 300yards due to their slow twists.

To find the actual twist, a rod is used. Enter the rod at the chamber with a tight patch on a jag, stopping just a bit into the rifling. Make a mark on the rod, TDC at the chamber mouth, even with the breech-end of the barrel.

Make a mark on the rod at 6 o'clock on the rod (bottom of the rod), or put a piece of masking tape on the rod with a mark, same location. Push the patch into the bore and when your mark comes around, up to 12 o'clock (straight up, put another mark on the rod at the breech mouth, even with the end of the barrel.

Withdraw the rod and measure between the marks X 2 = rifling twist rate. This is the best method for shorter barrels if the rod will not rotate a complete 360 degrees within it he length of the barrel.