Lapping Scope Rings

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Lapping Scope Rings

Post by brett1868 » 12 Jun 2017, 11:37 pm

After waiting almost 8 months I finally picked up my Weatherby Mk.V Accumark 6.5-300WbyMag. Being a quality rifle that's capable of some long range work I invested the time into bedding the base and lapping the rings over the long weekend. Thought I'd take a few pictures with the view that it might be helpful to others.

Prior to lapping I test fitted the rings to the base and using the lapping bar torqued the rings to the base (70 in/lbs). Removed the bar and moved onto the lapping process.

I then used "Painters" masking tape to keep the paste out of the action. Better to use too much tape then too little cause you don't want the paste getting into anything. Just a couple dabs of paste on the rings before going to work with the bar using a forward back, left right action whilst applying light pressure.
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Once the bottoms were around 80%, I removed the bar, cleaned up the paste,

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I put a few drops of oil on the bottom rings and a few dabs of paste on the top caps. I screw them down with just enough pressure that I can move the lapping bar.
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At this point I mark the rings for position / orientation. As the bar becomes loose due to materiel being removed I nip the screws up a fraction working in a figure 8 pattern to ensure even pressure whilst also keeping the gap either side as even as possible. Some of the paste will make its way into the bottom half which is desirable as it'll finish them off.
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All done with 95% coverage and still enough gap either side to torque down to 35 in/lbs.
The critical thing to be aware of is not to remove too much materiel or there won't be enough bite in the rings to secure the scope under recoil.
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All done and ready for the scope to be mounted....tomorrow night.
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Re: Lapping Scope Rings

Post by pomemax » 13 Jun 2017, 12:07 am

The most over looked part of scope fitting whenever I fit a scope I gladwrap the action I don,t like using tape
I worked for 3M in the tape section for 16 years I know whats in it , even painters Tape ok if its off same day .
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Re: Lapping Scope Rings

Post by MalleeFarmer » 13 Jun 2017, 6:18 am

Looks Good Brett! Though I have only lapped one set of rings and I didn't take as much material off as you perhaps I didn't take enough off... :oops: oh well. Looks like you've done a neat job though!! :thumbsup:
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Re: Lapping Scope Rings

Post by Mitch » 13 Jun 2017, 7:00 am

Do you have a pressure trace system by the looks?
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Re: Lapping Scope Rings

Post by brett1868 » 13 Jun 2017, 8:11 am

Mitch wrote:Do you have a pressure trace system by the looks?


Yep, was wondering if anyone would ask about the sensor glued to the chamber. Since there's little to f..all load data available so I've punched all the numbers into Quickload and will do the hard yards developing a winner.
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Re: Lapping Scope Rings

Post by brett1868 » 13 Jun 2017, 8:19 am

pomemax wrote:The most over looked part of scope fitting whenever I fit a scope I gladwrap the action I don,t like using tape
I worked for 3M in the tape section for 16 years I know whats in it , even painters Tape ok if its off same day .


Didn't think to use glad wrap, but that's a good idea I'll keep in mind for next time. Usually I cut the finger tips off a latex glove and pull them over the bases with a little tape to the bases. The process took maybe 30 minutes start to finish so no chance of the tape doing any damage and I wiped everything down with isopropyl alcohol once done and then an oily cloth.
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Re: Lapping Scope Rings

Post by brett1868 » 13 Jun 2017, 8:31 am

MalleeFarmer wrote:Looks Good Brett! Though I have only lapped one set of rings and I didn't take as much material off as you perhaps I didn't take enough off... :oops: oh well. Looks like you've done a neat job though!! :thumbsup:


I aim to get >%90 coverage which on this occasion was very quick, something I've noticed with the Night Force rings. I've done probably a dozen or more sets of rings including Barrett, Leupold, Nightforce, EraTac, DTA and Sphur with various amounts of effort required to achieve the >%90. Price isn't always a good indicator of quality cause I've found the Nightforce to be the most consistent with the ease of lapping. The worst set was a 1 piece base from DTA which I ended up scrapping due to it being warped and incapable of being lapped, imagine the tension on a scope tube using a warped base. Sako Optilok have to be my all time favourites for alignment even though they suck the big one with how the rings are secured to the bases...

I've got 2 more scopes to mount in the near future so I'll endeavour to shoot a video showing the process start to finish.
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Re: Lapping Scope Rings

Post by brett1868 » 13 Jun 2017, 11:23 am

bentaz wrote:
brett1868 wrote:
Mitch wrote:Do you have a pressure trace system by the looks?


Yep, was wondering if anyone would ask about the sensor glued to the chamber. Since there's little to f..all load data available so I've punched all the numbers into Quickload and will do the hard yards developing a winner.

Can you tell us a bit more about the pressure sensor? Where you get them how it works, cost?
Cheers


https://www.shootingsoftware.com/pressure.htm

I'm heading deep into the precision end of reloading and needed to invest in the tools to capture data for analysis as relying on groups won't cut it anymore due to variables (Climate & Me) corrupting results. I've added a LabRadar Chronograph, RSI Pressure Trace II, Quickload 3.9 and Shooters Lab which when coupled to the laptop along with the TruPulse 360R LRF / Kestrel 6400 provide pretty much the complete picture of the shot.
I purchased the pressure trace unit directly from RSI in the U.S along with an additional 5 pack of micro strain gauge kits at a cost of $1550 inc the $220 wallet raping by Aus Customs.
Setup involves measuring the chamber and gluing the sensor approximately midway between the case head and neck with a special type of cyanoacrylate. I then had to measure the case wall thickness at that point, I used a Neco case gauge although a you can also cut the case in half and measure with a micrometre. The setup measurements have to be dead accurate or there'll be errors in the data which you don't want when it comes to chamber pressure. I'm attempting to get the first shots down range this week with the full setup so I can analysis the data during the week.
Time is my enemy at the moment, I owe JS some documentation, I'm flat out with my usual job, There's a backlog of brass that needs loading and I'm bush this weekend testing 50BMG loads with a new design of projectile. Next week is also looking nasty then I'm US bound on the 24th.
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Re: Lapping Scope Rings

Post by Mitch » 14 Jun 2017, 5:09 am

brett1868 wrote:
Mitch wrote:Do you have a pressure trace system by the looks?


Yep, was wondering if anyone would ask about the sensor glued to the chamber. Since there's little to f..all load data available so I've punched all the numbers into Quickload and will do the hard yards developing a winner.


Haha sorry for spoiling most of the fun knowing what it was.

I only know what it is as i did a lot of research into them not long ago. Very nearly bought one. Only problem is i fear i may use it, then put it in the cupboard never to be seen again
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Re: Lapping Scope Rings

Post by brett1868 » 14 Jun 2017, 8:32 am

Mitch, it's a pity the sensor gets destroyed if removed cause at almost $50 each it's an expensive exercise gathering data on multiple rifles. The package comes with 1 sensor but since I was up for postage and customs I bought a 6 pack of extras. Initially I'll only use it on the 6.6-300 and the big 50 as I have zero load data on the 6.5 and I'm curious to see how fast I can safely push the half inch 750Gr AMAX.
Possibly I might make the unit available to others for a fee later in the year if this sounds helpful for those who want the data without the large $$
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Re: Lapping Scope Rings

Post by SendIt » 04 Jul 2017, 2:16 pm

Interesting Brett, you're the first I've seen to do it with the top half of the ring screwed on for pressure.

Usually it's done top then bottom if everything I read.

Makes sense to do your way though. Nice one.
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