Lapping Scope Rings

[ricco1949]

IMO much of ring misalignment is due to base misalignment. I have yet to find a 700 where the picatinny rail mated perfectly. Either the rail releases at the front bridge when the front screws are loosened or rail releases at the rear bridge when the rear screws are loosened.......hence the need for bedding the rail. The one l bedded yesterday released .004-005 on the front bridge before bedding.

 

[Ledd Slinger]

The amount of recoil isn’t the deciding factor of whether to lap or not. It could be the deciding factor for whether to use rosin or not, but the deciding factor for lapping is if both front and rear rings are round and coaxial to each other. If not, lap or get a better set. If they are, don’t waste the time and energy ruining a good set of rings.

Why lap rings as opposed to bedding them? I’ve bedded rings before and I think it’s fairly easy and provides better results than lapping (but this is coming from a guy that has never lapped rings).
Is there an advantage to one technique as opposed to the other??

I lap to make room for bedding. Lapping also gives the ring surfaces a rougher surface for bedding adhesion. Bedding could be done without lapping but you can end up with "hot spots". By that I mean if you only had say 30-40% contact on the bare rings to begin with, then that's roughly what you will still have when the bedding shrinks because those contact areas on the scope tube will have a much thinner layer. So when the bedding shrinks over time, you might end up back at square one. If you lap the rings generously before bedding, then you have a good even layer of compound between the tube and rings at all points which, in theory, should maintain even contact on the tube when the compound shrinks. Therefor I would not bed without lapping.

I also recommend using JB Weld for bedding scope rings over MarineTex or Devcon. MarineTex has the least amount of shrinkage by far over time, but it also has a lower friction coefficient than the others (More slippery surface). JB weld maintains a better gripping surface after curing. If you have used both MarineTex and JB then you'll know wat I'm talking about. Devcon kind of sits in the middle. Not as good of grip as JB, but also shrinks quite a lot over time. I use MarineTex for receiver bedding because of how well it holds dimensional form over time and JB weld for scope bases and rings for it's greater gripping ability to avoid slippage and movement. If scope tubes had recoil lugs built into them, then I would surely use MarineTex for base and ring bedding.

 

[Ledd Slinger]

The amount of recoil isn’t the deciding factor of whether to lap or not. It could be the deciding factor for whether to use rosin or not, but the deciding factor for lapping is if both front and rear rings are round and coaxial to each other. If not, lap or get a better set. If they are, don’t waste the time and energy ruining a good set of rings.

I've marked scope tubes on 338 Lapuas and verified them slipping in rings with poor contact after 20-40 rounds. Lapping cured the problem for a greater gripping contact area. So if you don't think it helps in securing a scope under recoil, you might want to try it on bigger rifles.

But recoil is not the only reason. Another great benefit is proper alignment of the scope to the receiver and bore which results in less mechanical adjustments required to get zeroed on paper. I always ensure my scopes are at "optical zero" before mounting them. Wit proper lapping, I have never had to adjust windage more than 1 MOA to get zeroed horizontally on the target.

 

[ronemus]

But an alternative are the Burris Signature Zee Rings. That's what I use. The only downside I have found is that if you move the scope fore/aft you will have to re-zero.

+1 They're self aligning and allow offsets to minimize adjustments to zero, and I've never had a ring mark with them - win, win, win!

 

[Dave M.]

I lap to make room for bedding. Lapping also gives the ring surfaces a rougher surface for bedding adhesion. Bedding could be done without lapping but you can end up with "hot spots". By that I mean if you only had say 30-40% contact on the bare rings to begin with, then that's roughly what you will still have when the bedding shrinks because those contact areas on the scope tube will have a much thinner layer. So when the bedding shrinks over time, you might end up back at square one. If you lap the rings generously before bedding, then you have a good even layer of compound between the tube and rings at all points which, in theory, should maintain even contact on the tube when the compound shrinks. Therefor I would not bed without lapping.

I also recommend using JB Weld for bedding scope rings over MarineTex or Devcon. MarineTex has the least amount of shrinkage by far over time, but it also has a lower friction coefficient than the others (More slippery surface). JB weld maintains a better gripping surface after curing. If you have used both MarineTex and JB then you'll know wat I'm talking about. Devcon kind of sits in the middle. Not as good of grip as JB, but also shrinks quite a lot over time. I use MarineTex for receiver bedding because of how well it holds dimensional form over time and JB weld for scope bases and rings for it's greater gripping ability to avoid slippage and movement. If scope tubes had recoil lugs built into them, then I would surely use MarineTex for base and ring bedding.

Such an excellent well explained reasoning for lapping and bedding. I’ve bedded with JB Weld before and it’s critical to find the right release agent. Thanks Ledd for the great reply. I love when my viewpoint is different from someone else’s and then after reading their well laid out reasoning, they can convince to give this method a try. And that is exactly what I intend to do.

Dave

 

[Ledd Slinger]

Such an excellent well explained reasoning for lapping and bedding. I’ve bedded with JB Weld before and it’s critical to find the right release agent. Thanks Ledd for the great reply. I love when my viewpoint is different from someone else’s and then after reading their well laid out reasoning, they can convince to give this method a try. And that is exactly what I intend to do.

Dave

I use Kiwi neutral color shoe polish as release agent with every and any type of epoxy bedding compound. Can't beat it. Provides a very thin layer between the bedding and object to be released. So thin I just have to trust that the shiny surface on the metal means it's there.

 

[nmkid]

rifles that are wearing a muzzle brake which sends a shock wave into the next county when they unload a 90-120gr payload, it becomes a different story

Love it!!