Marble Arms Rifle Sights
The Leader in Iron Gun Sights.
***The sight combination that Evil Roy and Griner Gunworks have used for years on the Uberti 1873 .357’s are the 37W 3/32 Gold Bead Front Sight and the .66 Long Flat Top Rear Sight. Uberti 1873 .45’s are the .41W 3/32 Gold Front Bead Sight and .66 Long Flat Rear Sight.
1. Measure the diameter of the barrel at the point of the rear sight is going to be installed and at the point of the front sight going to be installed (example: 1.0″ rear sight and .750″ front sight).
2. Divide the diameters by 2 (example: 1.0” / 2 = .500” and .750″ / 2 = .375″).
3. Check the rear sight height adjustment chart. You want to be about 1/3 up from bottom adjustment. using a sporting rear #67 adjusts from .300″ to .510″. Total adjustments is .210″. Divide .210″ / 3 = .070″. Add the .070″ to the lowest adjustment height (which is .300″) and you come up with .370″. This is 1/3 up from bottom adjustment.
4. Add the 1/3 adjustment to the center line distance (example: .370″ + .500″ = .870″).
5. Subtract the front sight center line figure from the rear sight height (example: .370″ + .500″ = .870″).
6. You need a combination of front ramp and front sight with the height of .495”. Ramps are measured from the base to the bottom of the dovetails. Front sights are measured from the bottom of the dovetail to the top of the bead.
7. Or you could go with a front sight height of .588″. .495″ (height need from top of barrel to top of sight) + .093″ (which is the depth of the dovetail cut in barrel).
How to Use Table Above-Suppose a rifle, having a sighting radius of 24” between front sight and receiver sight, shoots 6” high at 100 yards, even with the rear sight adjusted as low as possible. Remove front sight and measure overall height, preferable with a micrometer. This might be .410”, such as a Marble No. 41MR. Reference to columns for 24” and 6” on table above will show a necessary correction of .040”. This would mean a new, higher front sight (with an overall height of .410” plus .040” for a correction height of .450”) such as a Marble No. 45MR, should be installed.
Sighting in should be done with a bench rest or prone with a sand bag or other rest for the rifle. Do not put rifle barrel or forearm directly on solid surface, but put the back of your hand or wrist on the rest and hold forearm of the rifle securely in your hand with approximately the same tightness of grip you would use when shooting at running game. If the firearm or barrel is rested directly on the sand bag or rest, the rifle will shoot higher than when held firmly while shooting at game as more “muzzle flip” will occur.