Joined
·
3,958 Posts
An issue that appears too often is the improper relationship between the rear sight base to the rear sight base platform. The platform is the flat area the base sits on.. Sight adjustments will not register properly if the platform is machined too low or if the sight base is machined to low.. That may not be clear, if one or the other described conditions exists, the base will float when the unit is assembled,, and the shooter cannot see it because the cover in the way.. That is not good and waste results..
How to check for a floating sight base..
Remove the rear sight, clean all lube off the bottom of the base and the entire platform area..
Install the base holding it in place with both knobs secured..
Lift up on the base and try to slide a thin piece of shim underneath the base... If it goes all the way to the front of the platform a better fit can be obtained by adding more shim stock until base is snug.
The sight cover is suppose to do this job, and is does on the M14/M1's, commercial parts are a different story, not always but too often
I use copper shim stock, and to check I use feeler gauges,,,. 004" usually does the job. If shims are needed try to profile them to the outline of the platform for a drop in fit..
If, and it occurs, the platform is to shallow presents a much larger issue, maybe another time.. Art..
How to check for a floating sight base..
Remove the rear sight, clean all lube off the bottom of the base and the entire platform area..
Install the base holding it in place with both knobs secured..
Lift up on the base and try to slide a thin piece of shim underneath the base... If it goes all the way to the front of the platform a better fit can be obtained by adding more shim stock until base is snug.
The sight cover is suppose to do this job, and is does on the M14/M1's, commercial parts are a different story, not always but too often
I use copper shim stock, and to check I use feeler gauges,,,. 004" usually does the job. If shims are needed try to profile them to the outline of the platform for a drop in fit..
If, and it occurs, the platform is to shallow presents a much larger issue, maybe another time.. Art..