OK Guys,

When you're making scope bases for Leupold QRW rings on an FN Commercial Mauser do you want the scope to sit exactly level with the front ring for a caliber that generates 40 lb-ft of recoil for ranges of 300 yards and less?

Scope will be a Zeiss Conquest 1.8-5.5 or a Leupold 1.5-5x. I believe both have considerable vertical adjustment.

(Can obviously add some vertical offset in the milling process. If needed ... how much? Front higher than rear?)

Why would you want one ring higher than the other? If you are talking about putting the scope on at an angle to the bore why would you want to do that? I can not visualize your problem. I would think the recoil to be irrelavent.

The point is not that one ring is higher than the other ... the plane that the rings sit can be made not to be exactly parallel to the bore.

For example, if the distance between the center of the of the rings is 4.3" ... 6" at the target is approximately 0.007" off parallel with the center of the bore.

I do not know if commercial scope bases have a built-in offset for recoil. This is what I am asking.

I do understand that long range bases can be had with as much as a 20 MOA built-in offset ... I don't think I'm in that situation.

Am asking because I am almost ready to set up the mill to do a pair of mounts and the equipment will allow me to do such an offset.

If it is a bench shooter, and you want to get to 1000 yrds, then yes you can put some moa in the base.
If it is a hunter, I wouldn't. Just my opinion.

Mike

For distances out to 500 to 600 yards, no offset is needed and factory rings and bases do not ordinarily have any. Most high velocity cartridges will only require about 10 MOA of elevation adjustment at 600 yards and that is well within the capability of most rifle scopes.

For longer distances, say to 1000 yards, some offset is certainly nice since it allows you to sight in for those longer yardages while still keeping the reticle near the optical center of the scope. Using such a setup at shorter distances is a compromise, however, since you can't keep the reticle optically centered at all distances.

But with the higher quality scopes that have large diameter tubes and a lot of vertical adjustment you can go all the way to 1000 yards without any offset.

Ray

Thanks for the explanation, I wasn't thinking in terms of extra long range. Any extra long range shooting I have done was with a Unertl or SuperTargetspot and they have the proper mounts for it or you just changed the bases. I thought that was the concept behind the 30mm tube size for more adjustment. All my shots are well under 300yds so I never have that problem. At my age I can't see any further even with a scope and even if I could see it I couldn't judge the distance or the wind.

Based on bore sighting a lot of rifle in a perfect world I would want about 5 MOA for a near 3000 FPS cartridge and maybe 15" to 20" or more for a 2000 FPS round. A 45-70 might take 30 to 40 MOA.

However a barrel and receiver setup that is not on axis or a crooked barrel can make your plans not work out.

You can make your own observations and draw your own conclusions though. Just take a number of well sighted rifles and put them in a cleaning cradle or on a bench rest and view a target at about 100 yards through both the bore and the scope.
You will be able to see the difference between where the bore is pointing and where the scope is pointing.
You may find you have some rifles that are not very straight and do not point where you think they should. After about a dozen or so you will get a general idea of how much the bore points uphill (or the scope down hill) for a general velocity range.

A 3000 FPS rifle usually looks like it is pointing 3 to 5 inches up hill and a low velocity rifle like a 45-70 looks like it is pointing up hill 2 to 3 FEET. (edit these are at 100 yards)

Ireload

I'm confused. Are you saying that you want to build that much offset into the bases when the scope reticle is optically centered or when it is sighted in for a particular distance?? And what distance, specifically??

When a rifle is sighted in the scope will be pointing at a different spot than where the bore is pointing. That's a given. You have to compensate for the bullets trajectory. But why would you want to build in a particular offset into the rings except for the longer yardages??

Ray

Cheechako,
If I had free reign to do as I please (theoretically speaking) I would build bases that put the rifle on zero at the distance I planned to zero it with the adjustments optically centered. For me this is usually 200 yards. If I were building a long range target rifle then I would try to put it on zero at the range to be used.
The optics work best when centered and it gives you the most adjustment to work with when changing loads. I don't like having to crank the adjustments way off center. But making this type of plan work is not as simple as it may seem since barrels and receivers are not always straight.

Ireload

I have to agree with everything you said. That's exactly the way I try to make my rifles. Not always possible, of course. Rings with the floating inserts, such as Burris or Jewell, will help to get you pretty close.

Ray