When I was selling and installing scopes, I came across a wide variety of set-ups, from two-piece bases to rails machined into the receiver. After installing probably 50 scopes, I learned not to assume that anything is aligned and installed properly, unless I did it my self. More often than not, I lapped the rings as a final step. Even with rails and tactical rings, the lapping process always reveals some imperfection in the final alignment. Why? Because either the rail is not straight as installed, or the rings are not fully machined and therefore have poor mating surfaces (most DIYer’s can’t tell the difference between extruded and machined rings). The base-to-receiver interface is definitely a weak point.
If the rail is machined into the receiver and the rail is properly deburred, or a good gunsmith installed the base properly (i.e., epoxy bedded, with no torque on the base screws during epoxy set), then the alignment of fully machined tactical rings should be good enough. Notice that I just described a high end set-up.
I found that most DIY rail installations produced crooked rails, especially on Remington 700 receivers. That’s because most of the YouTube videos are incorrect. Rail installation on fully tubular receivers (e.g. Savage) is usually straight, but I always lap anyway because the rail could be torqued either during manufacture or installation for a variety of reasons.
FYI, you don’t need fancy tools to confirm good ring alignment. A steel ruler and a flashlight usually suffice. Because I have the fancy tools and lapping bars, naturally I use them when in doubt, which is 95% of the time.
Other lessons learned:
1. Never use Chinese rings, except for Burris products. Aside from the poor QC, most Chinese machine screws suck.
2. Always use a good torque wrench, set to the recommended torque value for each screw.
3. Always use Blue Loctite on base and ring screws (not rail cross bolts, of course).
4. Always check the receiver bolt torque as a courtesy. Many problems with large groups are due to loose action screws.
5. Always do an optical boresight alignment after installing the scope. >95% of the time that gets the shots on paper at 100 yds.
6. Lapping the rings essentially turns a marginal set-up into a perfectly aligned set-up. The cost savings is not only in the parts, but also in labor if the alternative is having the rifle manufacturer or gunsmith do the rail installation. If you’re only doing one installation, then I recommend having a good gunsmith do it. If you plan on doing it more than once, then the cost of the lapping bars is probably warranted.
If the rail is machined into the receiver and the rail is properly deburred, or a good gunsmith installed the base properly (i.e., epoxy bedded, with no torque on the base screws during epoxy set), then the alignment of fully machined tactical rings should be good enough. Notice that I just described a high end set-up.
I found that most DIY rail installations produced crooked rails, especially on Remington 700 receivers. That’s because most of the YouTube videos are incorrect. Rail installation on fully tubular receivers (e.g. Savage) is usually straight, but I always lap anyway because the rail could be torqued either during manufacture or installation for a variety of reasons.
FYI, you don’t need fancy tools to confirm good ring alignment. A steel ruler and a flashlight usually suffice. Because I have the fancy tools and lapping bars, naturally I use them when in doubt, which is 95% of the time.
Other lessons learned:
1. Never use Chinese rings, except for Burris products. Aside from the poor QC, most Chinese machine screws suck.
2. Always use a good torque wrench, set to the recommended torque value for each screw.
3. Always use Blue Loctite on base and ring screws (not rail cross bolts, of course).
4. Always check the receiver bolt torque as a courtesy. Many problems with large groups are due to loose action screws.
5. Always do an optical boresight alignment after installing the scope. >95% of the time that gets the shots on paper at 100 yds.
6. Lapping the rings essentially turns a marginal set-up into a perfectly aligned set-up. The cost savings is not only in the parts, but also in labor if the alternative is having the rifle manufacturer or gunsmith do the rail installation. If you’re only doing one installation, then I recommend having a good gunsmith do it. If you plan on doing it more than once, then the cost of the lapping bars is probably warranted.
Last edited:
