Scope Leveling datum plane

[Sundodger]

Thank you sab1,

1) I like your use of an alignment pin to set the bases to the action. I was really struggling with this, there was much more slop that I liked which made me frustrated the base manufacture didn’t do a tight hole/tight slot dimensional tolerance scheme. What diameter is your alignment pin(s)? Do you use them on each of the base screws or only one on back and one on the front? My only concern is the manufacturing tolerance between the datum axis’s of the front mount screw holes and the datum axis of the rear mount screw holes.

What I did was use a touch of rubber cement between the base and rifle action, drop on my rings/bases, start the base screws in both the front and rear mounts, threaded them to snug, backed them out a bit, shook the mounts, then laid my lapping bar across the rings. Then some more shaking and pressure I got them to where it felt like the front and rear rings should be concentric, slowly and carefully removed the lapping bar but trying to make sure the rings/bases do not move. Then torqued them down and went on to lapping them.

NOTE: I am using Talley one piece ring/base mounts.

2) This is the gun “vice” I have, I am not sure if it will work how your procedure requires. There is no provision to lock it down. I might play with it and see what I can do though

http://www.cabelas.com/product/MTM-S...&WTz_l=Unknown

3) What distance do you typically use?

4 and 5) That does make sense, thank you. Mine might struggle with it being a smaller dia bore and a stock with a comb that’s raised about ½”. When the gun is still locked down and the scope reticle is lined up with the weighted line do you move the elevation adjustment through its range of motion to make sure it the vertical reticle line stays lined up with your weighted line? It seems that would verify that plane made between the bore axis and scope axis is vertical.

[sab1]

Thank you sab1,

1) I like your use of an alignment pin to set the bases to the action. I was really struggling with this, there was much more slop that I liked which made me frustrated the base manufacture didn’t do a tight hole/tight slot dimensional tolerance scheme. What diameter is your alignment pin(s)? Do you use them on each of the base screws or only one on back and one on the front? My only concern is the manufacturing tolerance between the datum axis’s of the front mount screw holes and the datum axis of the rear mount screw holes.

The alignment pins line up the rings to each other, not the rings or bases to the action. See the photo on this page:

Scope Alignment Pins

I have not found a way to ensure that the scope axis and the bore axis are coplanar, but those pins will at least ensure that your scope isn't twisted.

2) This is the gun “vice” I have, I am not sure if it will work how your procedure requires. There is no provision to lock it down. I might play with it and see what I can do though

http://www.cabelas.com/product/MTM-S...&WTz_l=Unknown

I use this one:

HySkore Sighting System and Cleaning Vise

3) What distance do you typically use?

I've had success with as little as 30' (in the house) to as much as 50 yds (outdoors). I don't think it matters, much, as long as the distance gives you a good "sight picture" down the bore.

4 and 5) That does make sense, thank you. Mine might struggle with it being a smaller dia bore and a stock with a comb that’s raised about ½”.

The smaller diameter bores aren't really an issue. You just have to experiment with your VRL's sight picture down the bore.

When the gun is still locked down and the scope reticle is lined up with the weighted line do you move the elevation adjustment through its range of motion to make sure it the vertical reticle line stays lined up with your weighted line? It seems that would verify that plane made between the bore axis and scope axis is vertical.

No, I don't. All that would do is verify that the scope's elevation adjustment tracks on the same plane as the retical's vertical post. It wouldn't verify that the bore axis and scope axis are vertical to each other.

Regards,
Scott