Yes, It is very necessary to lap your scope rings. Especially if they are not a matched pair. Small defects and imperfections are often hidden from view and can only be shown through a vigorous lapping process.
Choosing the correct size scope rings is one of the most important choices you can make to outfit your bolt action rifle. Often they come in three different height sizes Low, Middle, and High.
During the manufacturing process, these scope rings can have microscopic burs or can get slightly deformed during the forging process. For the average target or hunter shooter, this may not be a big deal. But for professional and competition shooters these defects can cause slight movement in your scope after each shot.
Scope rings are designed to clamp down tightly over your rifle scopes center tube. They are made to come in a variety of sizes to suit the tube diameter of various sized rifle scopes. The most common scope tube sizes are 1-inch and 30mm.
Tools needed to lap your scope rings.
- Screwdriver or Allan key for your scope rings
- Scope ring lapping kit bar, for 1-inch or 30mm. I love the Wheeler all in one lapping kit shown above.
- Lapping paste often around 220 grit.
- Tipton Gun Vice or another way to secure your weapon.
- Cleaning cloth.
How to use a scope lapping kit
Start by positioning your rifle scope onto the rifle and bolting down the holding rings. Make sure it is in the perfect position for your firing style and eye relief.
- Secure your rifle into a gun work vice and make your weapon safe.
- Remove the rifle scope and the top cover ring.
- Place some 220 grit grinding lapping compound into the bottom and top scope rings.
- Place the scope lapping tool onto the rings and screw down the two top scope rings gently.
- Slowly move the scope lapping tool back and forward along with a gentle twisting action.
- Slowly screw down the top scope rings to provide extra pressure on the scope lapping tool.
- After 15 minutes of gentle action, remove the two top scope rings and check for at least 3/4 contact between the lapping tool and the scope rings.
- Repeat the steps if you have less than 3/4 of the polished area.
Some people only lap the bottom two scope rings without the top covers on. I don’t like this procedure as you may not get a good clamp on the top scope rings.
Problems you can have without lapping your scope rings.
Without a properly aligned scope rings, you can have minuscule movement in your gun scope after each round. If you scope moves so will your projectile down the range.
I have also seen peoples rifle scopes be bent or crimped in the middle due to incorrect alignment of the scope. When this happens you can get permanent damage to your high power rifle scope.
Marking of the outer pant work is another problem with incorrect scope alignment. This will affect the resale value of your expensive gun scopes.
Your scopes are a precision piece of engineering. They are made up of many pieces of centered glass to provide maximum resolution and magnification. If these pieces of glass get moved around due to pressure being applied in the wrong position, then the whole image will be fussy and incorrect.
When I brought my Compound crossbow I found I had run out of scope adjustment at over 30m distance. The cheap scope rings had a bur that was throwing out the scope being parallel with the crossbow. Five minutes of lapping fixed the problem.
Always lap your scope rings even on crossbows you will get better accuracy. Sighting in a scope on a crossbow will be a breeze once everything is lined up straight.
Cheap Scope Rings vs Expensive
At the end of the day, everyone wants an accurate gun that can shoot sub 1 MOA groups at a long distance. (1″ per 100 yards.)
But most of us also want the best value for money accessories for our weapons. Now if you are a full on competition shooter then buy the best that money can buy.
On the other hand, if you just target shoot when the weather is nice or plinking out the back yard then some cheap eBay scope rings may be the answer.
I would stick to these 4 tips to get the best bang for your buck on quality scope rings.
- Always buy scope rings that have 4 screws to clamp down your quality optics.
- Align them up true
- Use a lapping kit to get a good snug fit.
- Don’t over tighten each holding screw. 15-18 inch pounds is plenty.
You can save yourself a few dollars by lapping and aligning up your cheap scope rings. I have used some expensive 1-inch Vortex Precision Matched Rings and got the same bullet grouping from a set of budget Tenako rings. I must say that the Tenakos were lapped first.
Stick with 4 screw scope rings and lap them yourself. As long as the tolerances are good you can’t go wrong.
To have an accurate weapon for hunting or target shooting, then it needs to be set up correctly. That means that it is necessary to lap your scope rings when they are new. Especially if they are cheap.
You can buy matching scope rings that don’t require lapping, but they will be expensive and will have been lapped at the manufacturer anyway. Save yourself some money and do it yourself.
Be sure to buy a quality scope. Stick with scopes with reputable brand names like Vortex, Leupold, Bushnell, Nikon, Athlon, and Vixen. I use a Vortex Crossfire II 3x9x40 on my Tikka T3x, it’s a great scope.
Once you have your scope rings lapped and mounted to your rifle you clamp it all down tight. A little bit of never seize on the screws will help them come out again in the future.
If you set it up right the first time you will have a lifetime of accurate shooting. If you want even more accuracy then check out our post on which bipod for sling stud mount. Happy Hunting.