Browning B78 Scope Mounting Issues

[Allen Kitts]

I have a rifle that I am trying to mount a scope on for my neighbor. It is a Browning B78 in 7mm Mag. It has Leupold two piece steel bases on it and Leupold rings. The scope he wants mounted on it is a Leupold VX6 HD 3-18. I put the scope on it last night, got it all leveled up and took it outside to bore sight it on a target I have set up at 100 yards. I cannot get enough travel out of the scope to get the crosshairs on at 100 yards. Maxed out I am still about three to four inches low. I ahve not fired it yet but thought one of you may have seen this before or maybe have some idea of what I am talking about and have some advice. I thought it was the scope so I took another one that I had still in the box mounted it up and leveled it, same results. Thanks in advance for any comments or suggestions.

 

[Critter Picker]

Are they the dovetail style or picatinny style?

 

[Allen Kitts]

dovetail

 

[Rosebud]

Is one base higher than the other?

 

[Allen Kitts]

It appears the rear base may be a tad higher than the front

 

[Rosebud]

Swap them out. Reverse them. Had 1885 Winchester in .405 that was the same.

 

[Allen Kitts]

The rear base is already a little higher than the front. the front mount is incredibly thick, If I put it on the rear it would be way out of whack. I will take some pics tonight and post them so you can see what I have.

 

[kiwikid]

Some years ago I read that what you are finding is common on the B78 rifles. One solution is to use a low ring on the rear base and a medium ring on the front base.

 

[Rosebud]

Never messed with a B78. But your right about the height of the bases. I think KiwiKids idea makes sense.

 

[Critter Picker]

I would agree with fosebud. Try to swap them out. Am I thinking wrong. Wouldn't a high rear base make it shoot high?

By the way I'm jealous of that 78 , always loved them.

 

[8x68s]

I'm assuming the barrel is a heavy round rather than octagon?? And is the front base bottom rounded or angle machined for an octagon barrel?KiwiKid has the solution I have used for a custom, heavier octagon barrel. Could also have the front base machined thinner. I have a spare rear base to give if the measurements are different than what you have. See pic. You would need a higher rear base than what you have (or a lower front base).
Freebie if you can use it...
Greg

 

[Allen Kitts]

Thanks guys for the reply's and the info. I put some shims in the ring and it raised the scope up enough to get it on target looking through the bore. Hope to get out to shoot it in the next week or so I will pass on my findings.