Scope Lapping
- Thread starter thumbtack
- Start date
By my measure, it is important when you need to correct a problem. No, you don't need to do it for every scope/ring combination. However, you should still diagnose every mount to determine if it is required. I have a 1" bar and 30MM bar to help me do this. I first do a "wipe" test to determine the contact areas. The salection of rings is very important and the cheaper ones would be more likely to need lapping. I have learned that cheap rings are not worth your time.
I know a fellow that laps all his rings, all the time. So much so that he had a different set of problems with one mount.
Just a bit of clarity; We lap the rings for a good scope mount. ...
Be Safe !!!
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I generally at least float the lapping bar across the lower mount saddles.If I show 80% or so contact I call it good.There are enough variables in a 2 piece base setup I believe it at least needs to be checked.
The rings are capable of distorting the scope tube.The scope mfg tries to work to tight tolerances and we warp the tube.
If there is a machine shop around that has a Swiss Turning machine,the bar stock they feed it will typically be od ground .005 under nominal size.That means you get a .995 ground dia for 1 in.
Realize grit sizes are a screen mesh size.so in theory,something around a 320 to 240 grit would cause a .995 bar to lap 1 in.
No need to refinish,you cannot see the id.
The rings are capable of distorting the scope tube.The scope mfg tries to work to tight tolerances and we warp the tube.
If there is a machine shop around that has a Swiss Turning machine,the bar stock they feed it will typically be od ground .005 under nominal size.That means you get a .995 ground dia for 1 in.
Realize grit sizes are a screen mesh size.so in theory,something around a 320 to 240 grit would cause a .995 bar to lap 1 in.
No need to refinish,you cannot see the id.
Bailey Boat
Moderator
How many times have you seen "light ring marks" or how about "shows signs of mounting" when reading about a scope for sale???? A properly mounted scope will NOT show any signs of having been mounted and shot. Trued and lapped rings can't damage a scope tube, otherwise...... Well, roll the dice!!
depends on the rings really. Ive used some nice rings that never left scratches, and I've used other that are so far from round the edges cut into the scope finish like knives *cough Ruger, cough*
Lapping is still a good idea though, it will make the contact area uniform and distributes the pressure evenly, give you better "grip" and be less likely to damage a scope tube from being slightly out of alignment.
Ruger rings use some stubborn steel that is very slow to lap. I can't say for sure but my guess is they machined them and then heat treated them, which when the metal heated/cooled slightly warped the concentric areas. Even when lapped to about 60% there are still gaps you can see between the scope and tubes on all my Ruger rings.
My burris rings were softer lapped very quickly and nicely.
I had a pair of seekins precision that never required lapping.
Lapping is still a good idea though, it will make the contact area uniform and distributes the pressure evenly, give you better "grip" and be less likely to damage a scope tube from being slightly out of alignment.
Ruger rings use some stubborn steel that is very slow to lap. I can't say for sure but my guess is they machined them and then heat treated them, which when the metal heated/cooled slightly warped the concentric areas. Even when lapped to about 60% there are still gaps you can see between the scope and tubes on all my Ruger rings.
My burris rings were softer lapped very quickly and nicely.
I had a pair of seekins precision that never required lapping.
I think it's a good idea to use a couple of the ring centers to check alignment first. This ensures you start with the best possible alignment before you lap, so you remove the least metal.
Be wary of ring bases that don't mate well to the receiver. You don't want to spoil the gun finish by lapping those into place, but you can use JB Weld to bed them, or you can scrape the bases off the receiver if you know how to use hi spot blue and a triangle scraper.
Be wary of ring bases that don't mate well to the receiver. You don't want to spoil the gun finish by lapping those into place, but you can use JB Weld to bed them, or you can scrape the bases off the receiver if you know how to use hi spot blue and a triangle scraper.