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Thread: Scope Lapping???

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    Moderator stid2677's Avatar
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    Default Scope Lapping???

    Been doing some reading on scope mounting. Was wondering how important is it to true the scope and mounts to the action. How do you do it? Has anyone lapped their rings and saw improvements. Seems that it would be a critical part of the shooting equation to me, thoughts....

    Steve

  2. #2

    Default Always

    Years ago when I started shooting bench rest my mentor was an accomplished shooter and felt it to be imperative for accuracy.
    Since those days scope companies have come out with self-aligning rings and gadgets to do the same thing. I still lap mine the old fashioned way and use the same alignment bars.
    Lapping may not be considered nessacary by everyone BUt it has NO negative effects on proper scope function, so it doesn't hurt anything.
    It might help reduce damage to a high end scope or its finish though and that alone is worth the effort.
    Scope lapping kits are available from Brownells and are resonable, I tend to use an automotive valve laping compound at first followed by the compound in the Brownell kit.The valve lapping compound can has 2 grits which reduce lapping time, I then clean those off and ue the fine grit in the kit.
    You'll notice right away all rings aren't machined round, and they aren't machined smooth either.You'll see small bright rings appear where high spots were cut by reamers.
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    Member shphtr's Avatar
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    Default lap rings and bases

    I always lap bases to the action they are going to be used on - exceptions would be Ruger, Sako, and similar. I also usually lap the rings except for those that have some sort of self aligning feature, e.g. Millet, S&K, Gentry etc. Be care full not to over lap - usually about 50% to 75% is recommended. Proper lapping will usually ensure decreased torque on the scope tube and enable the rings to better grip the scope tube and hence decrease the chance of slippage.
    It is generally recommended that one ensure that the rings are aligned with each other prior to starting your lapping.

  4. #4

    Default Lapping

    I lap rings on every rifle, even my .22's. I doubt if you would ever find a truly accurate rifle without the rings having been lapped. Nothing to be afraid of. Just buy the right size lapping bar(1", or 30mm) and dig in(pun intended). You can use the bar to align the rings,also.

    You only lap the bottom ring, not the cap. As been already stated, only lap about 75%. You will easily be able to tell by occasionaly wiping off the compound and seeing the color change on the ring being lapped. Really only takes about 15 min. per set of rings. I get my kits from Sinclair International, and they come with instructions. Good luck!

    Al

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    Member Daveintheburbs's Avatar
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    Default

    Ok guys, I have the kit, but the instructions are somewhat sketchy, by 75% do you mean the original color is ground of 75% of the lower ring?

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    Member KRS's Avatar
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    Yes, the shiny new metal should be exposed on appprox 75% of each bottom ring... you don't need to keep lapping until it's all shiny.

    KRS

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    Member Big Al's Avatar
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    Default

    Or just buy Kelbly's rings that are matched hone and be done with it. The funny part of these replies is that there has not been a mentioned even once. Nobody seems to realize that scope bodies OD are not true dimension, they all vary. Seldom will you find a scope tube that is a true 1.000".

    Why is there no mention of zeroing the scope also and getting the scope as true to center with out using the internal adjustments, this gives you all the ability to return to center, you have to start at zero, to be able to return to zero.
    "The tree of liberty must be refreshed from time to time with the blood of patriots and tryants." (Thomas Jefferson

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    I doubt if you would ever find a truly accurate rifle without the rings having been lapped.
    I have Swede M41B with unlapped rings made in 1941, shoots 5 shots into .364 (or.354, I cant remmebr as the target is in my office) at 100....I have a Blaser LRS2 with unlapped rings that has put 10 shots into the same as above at 100....I've seen guns with lapped rings shoot like crap too (although it wasnt the rings causing the problem)

    There are no absolutes with guns, most of the time..

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    Member RMiller's Avatar
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    I have never lapped rings before allthough I do center my reticle and adjust the rings as close as I can get them before sighting.

    I thought this one looks easy enough more even me to use so I may lapp the next time I mount a scope. I wont bother with my current setups cause I wont mess with what aint broke.

    http://www.shooters-supply.com/web_specials.html

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  10. #10
    Member Big Al's Avatar
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    Russ is good people. I've had good results buying from him.
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    I also have to raise my hand and say that I have not lapped rings. I've known about it, read about it, but have not done it. I once had my gunsmith change out bases and rings as an after thought when I picked up my rifle after having it reamed for a different cartridge. I was there as he did it, and he didn't lap the rings either. That said, this is an interesting discussion, and you guys have me thinking. In fact, this is also interesting timing because just the other day I was mounting a scope at the range, and the guy at the bench next to me was offering friendly advice, saying that I should have lapped the rings before mounting.

    I think I've been lucky so far. However, I'm going to give lapping a try. One thing for sure, lapping can't hurt. Besides, I get to buy another gizzmo, and it gives me something else to monkey with during the winter.

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    Default Well

    This might be a solution. I was a foot off at fifty yards and the scope dial is cranked way over to adjust. Having the dial turned to an extreme is supposed to be bad so I just ordered a ring lapper from Haydon.
    I'll let you know how it works. I will have a 30mm tool for loan in Anchorage if you supply your own paste.

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    Quote Originally Posted by Doc View Post
    I also have to raise my hand and say that I have not lapped rings. I've known about it, read about it, but have not done it. I once had my gunsmith change out bases and rings as an after thought when I picked up my rifle after having it reamed for a different cartridge. I was there as he did it, and he didn't lap the rings either. That said, this is an interesting discussion, and you guys have me thinking. In fact, this is also interesting timing because just the other day I was mounting a scope at the range, and the guy at the bench next to me was offering friendly advice, saying that I should have lapped the rings before mounting.

    I think I've been lucky so far. However, I'm going to give lapping a try. One thing for sure, lapping can't hurt. Besides, I get to buy another gizzmo, and it gives me something else to monkey with during the winter.

    I am in the same boat as you Doc never tried it but been meaning to.

    Has anyone here actually did a before and after comparison to see if the accuracy of there rifle improved after scope lapping?
    Tennessee

  14. #14

    Default Lap Talley one piece light weights?

    How timely.
    I just cracked the box on my new VX-III 2.5-8...came with the cozy.
    I was wondering if the Talley one-piece light weights need or should be lapped. I think that because they are one piece they actually need it more to ensure proper alignment and a good grip on the scope. Any one out there lapped their Tally one piece light weights?

  15. #15
    Member shphtr's Avatar
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    Default Lap rings

    Not all rings need to be lapped - see my comment above. If you have the type of ring that it is appropriate to lap, once you start to lap your rings it will become obvious in short if lapping was needed or not. Do not over lap since the rings still will need a good crush fit to secure your scope properly.

  16. #16

    Default Lap 'Em

    Wildalaska, by truly accurate, I mean 5 shots under 1/4" (.250). Most reputable gunsmiths include ring lapping in their accurizing packages.

    green sourdough, I have lapped 4 sets of lightweight Talleys. They start out black on the inside, and as you lap, you will see the paint coming off and can see how much material you are taking off. Try to keep even pressure on both the front and rear of the lapping bar.

    Also, giving a slight twisting motion both pushing forward, and pulling back is reccomended and seems to help. You will see, as has already been mentioned, some rings need alot, some very little.

    Good luck, and have fun...It's easy.

    Al

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    Default

    There hasn't much discussion on here about alignment. I use alignment bars before I lap. Last week a friend brought his new swift over to get it lapped. He said he already had the rings lined up, he used the scope as a reference. Using the alignment bars his eyes bugged out a little seeing how far off they actually were. Now this mis-alignment could be lapped out but it would require a lot more metal removal and a risk of removing too much making the rings out of round. Also, the lapping bar takes just as much abuse as the rings if they are steel and therefore it has a limited lifespan. Better to get things nicely aligned before you start unnecessarily removing metal.

    My preference in order for alignment bars are:
    1: Kokopelli
    2. Hart
    3. Wheeler

    There are others but these are the ones I have used. I don't think the maker makes as much difference as does the design. The Kokopelli is definitely the most accurate and also the easiest to use. It will clearly show you what is going on. The down side is you need a set for 1" and another for 30mm.

    The Hart works OK for 2 reasons. One set does both 1" and 30mm. And the inner bars can be moved forward and back with the rings tightened. This is critically important for designs that are point to point. You need this movement to judge parallelism. The Kokopelli does not require movement, you see the alignment immediately.

    The Wheeler which I am guessing is the most popular because they are available from all the big stores, doesn't do much of anything. It is point to point with no movement and you need both sizes. If you think about it, adjusting the points together tells you absolutely nothing about how parallel the rings are, it just means that at some given point you made their paths cross. Now if you can slide them back and forth like the Hart then you may find for example: the points are perfectly together in the center, but if you move them towards the barrel the front point drifts off to the side, and when you move them all the way to the rear that front point now moves across to the other side. This is probably hard to follow with words, but it means the rear ring may be true but the front is definitely not parallel to it, but their paths just happen to intersect. This was precisely what was happening with the swift. In Wheeler defense you can move them forward and back with retightening after each movement, but what a time consuming effort.

    Alignment bars may also indicate that shims need to be used on the mounts if one is higher than the other.

    For lapping bars I prefer one with spiral cuts. The spiral grooves will collect the larger particulates and cut away at the rings from within the grooves. With a smooth bar the particulates are trapped between the bar and rings and equally cut both. Some smooth bars are made with a softer metal so the particulates embed in the bar metal rather than chew away at the bar. But IMO I think the grooves are a better idea. I think both of mine are Hart.

    The final things I do are take a little sand paper to remove any sharp corners from where the rings were lapped. As you lap down you are creating a sharp edge on the ring which may scratch the scope if you rotate or move it around trying to find your eye relief. Just a little wisk with the sandpaper will round it. Clean it all good with alcohol and touch it up with Super Blue.

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    Have any of you guys run a before and after test to see if the lapping or alignment helped accuracy?
    Tennessee

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    Member AKDoug's Avatar
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    I have never lapped rings and I have a couple amazingly accurate out of the box rifles. The rest of my rifles fall well within my expectations and they haven't been lapped either. Right now I have mostly Ruger rifles and maybe I'm just lucky..or the Rugers are less problematic.

    I am not going to discredit something like lapping that makes total sense, but I don't know if the average guy and the average hunting rifle needs the treatment. Some of us are like Al and factory barrels are not good enough...some of us are like Cub and don't clean our rifles much.. I fall nearer the Cub club

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    Wildalaska, by truly accurate, I mean 5 shots under 1/4" (.250).
    Gee I'm only .146 off with a rifle made in 1910 and a scope made in 1941 ...unlapped of course

    Most reputable gunsmiths include ring lapping in their accurizing packages.
    You sure about that?

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