Several methods have been posted on how to stabilize an eyepiece that moves too easily once screwed out to focus for "older" eyes. Some state that the eyepiece moving cannot move the crosshairs in relation to the target but I have put my AR into a service vice clamped to a table and any touch on the eyepiece moves the crosshair in relation to the target with a Bushnell AR223 scope. I wanted to eliminate that movement. Use of o-rings has been suggested by several posters (thanks to those persons) and I used that method for a time. It works pretty well but it isn't rigid. But I found a way to rigidly lock the eyepieces on my scopes that do not have a locking ring.
Go to theoringstore and search "nylon wear rings". These are apparently designed to go on a piston, much like the Yong Heng/AV/Tuxing etc. rings but they are much larger. They are made apparently of a "nylon 66" type material-rigid but flexible enough to be put onto the scope eyepiece. These are listed in various diameters, cross section thickness, and width. I ordered 1.5 inch diameter size by 1/8 inch cross section in both 3/8 inch wide and 1/2 inch wide. My eyes are pretty bad and the 1/2 inch size is still way too wide. 3/8 size required quite a bit of sanding to fit. I should have ordered 1.75 diameter size because the measurement is for the outer diameter but it worked for my scope because the rings can be placed in boiling water and softened temporarily to allow fitting.
Focus your eyepiece and then turn out about a quarter turn, maybe a bit over that. Using sandpaper, sand the side of the ring until it just fits into the opening between the flange of the eyepiece and the rear body of the scope tube/housing. Then you can tighten the eyepiece ring down and it will snug up onto the nylon ring which can be stretched over the end of the eyepiece and will spring down snugly onto the eyepiece tube. You can tighten the eyepiece down as much as desired but I couldn't get more than about a quarter turn once the ring was in place. This effectively "locks" the eyepiece so that it cannot move once tightened. It cannot shift if bumped but can be easily loosened by hand. It took about a half hour to sand the ring down to fit since you need to keep checking width until it will just fit into the space. And every person will have a different amount of eyepiece opening to fit it to.
Anyone who thinks this is something they could use should remember that the measurement is for the outer diameter of the rings. Measure the eyepiece tube where it screws into the body of the housing and choose a ring size that can fit. My tube measured 1.5" and that is what I ordered-1.5" x 1/8" cross section x 3/8" witdth. 1.75 in 1/8 cross section would probably have been perfect as that would have a 1.5 inch center diameter but as noted these can be placed in boiling water and softened to fit to place after sanding. They will stretch enough to go over the tube and then try to return to original size making them snug. The 1.5" size I bought really is a snug fit and doesn't move on the tube at all once snapped on.
Hope this might be helpful to those needing it and thanks to those who suggested the o-rings as they did function.
Go to theoringstore and search "nylon wear rings". These are apparently designed to go on a piston, much like the Yong Heng/AV/Tuxing etc. rings but they are much larger. They are made apparently of a "nylon 66" type material-rigid but flexible enough to be put onto the scope eyepiece. These are listed in various diameters, cross section thickness, and width. I ordered 1.5 inch diameter size by 1/8 inch cross section in both 3/8 inch wide and 1/2 inch wide. My eyes are pretty bad and the 1/2 inch size is still way too wide. 3/8 size required quite a bit of sanding to fit. I should have ordered 1.75 diameter size because the measurement is for the outer diameter but it worked for my scope because the rings can be placed in boiling water and softened temporarily to allow fitting.
Focus your eyepiece and then turn out about a quarter turn, maybe a bit over that. Using sandpaper, sand the side of the ring until it just fits into the opening between the flange of the eyepiece and the rear body of the scope tube/housing. Then you can tighten the eyepiece ring down and it will snug up onto the nylon ring which can be stretched over the end of the eyepiece and will spring down snugly onto the eyepiece tube. You can tighten the eyepiece down as much as desired but I couldn't get more than about a quarter turn once the ring was in place. This effectively "locks" the eyepiece so that it cannot move once tightened. It cannot shift if bumped but can be easily loosened by hand. It took about a half hour to sand the ring down to fit since you need to keep checking width until it will just fit into the space. And every person will have a different amount of eyepiece opening to fit it to.
Anyone who thinks this is something they could use should remember that the measurement is for the outer diameter of the rings. Measure the eyepiece tube where it screws into the body of the housing and choose a ring size that can fit. My tube measured 1.5" and that is what I ordered-1.5" x 1/8" cross section x 3/8" witdth. 1.75 in 1/8 cross section would probably have been perfect as that would have a 1.5 inch center diameter but as noted these can be placed in boiling water and softened to fit to place after sanding. They will stretch enough to go over the tube and then try to return to original size making them snug. The 1.5" size I bought really is a snug fit and doesn't move on the tube at all once snapped on.
Hope this might be helpful to those needing it and thanks to those who suggested the o-rings as they did function.
