So I just got a new to me (unfired) 30 yr. Old Model 70 Featherweight 270. Installed Leupold (Weaver Style) bases and Rings. Sighting in at 30 yards, found I shoot 4" low, and am end of travel on my Leupold VXIII 3 1/2 X 10 Scope...no more vertical adjustment. SUGGESTIONS. Deer Dr.
Winchester Mod 70 Featherweight 270
- Thread starter Deerdr
- Start date
Either you have the wrong bases or you need to shim the rear base. A quick check is to lay a straight edge across the bases; they should be level or very close to it.
Thanks Dogleg...according to #s I have right bases. They appear level with a straight edge...To raise POI I would shim rear base?And how much would I shim for 4" increase in height at 30 yds? On some rifles I have reversed front and back bases, but the front ring on 70s is higher than back. Thanks for your help.
The math is simple enough. Ring spacing X distance to move impact/distance to target. All the distances are in inches including the range.
Assuming that your ring spacing is 5 inches; you're looking at 5 X 4/1080 = .0185" shim.
That would get you onto the scope, but barely. You don't want "barely" . In a perfect world scopes would be run in the center of their adjustments, but in the real world it doesn't have to be that precise. Guys run 20 MOA and more rails that move the reticle 20 MOA from center on purpose.
Since you would require even more shimming than the example of 18 thou, lapping the rings afterwards is in order to avoid kinking and stressing and marking your scope tube. A better solution might be a set of Burris insert rings with offset inserts.
How close is the scope to center on the windage adjustment? If its cranked far to one side or the other it can severely limit the amount of vertical adjustment available.
Assuming that your ring spacing is 5 inches; you're looking at 5 X 4/1080 = .0185" shim.
That would get you onto the scope, but barely. You don't want "barely" . In a perfect world scopes would be run in the center of their adjustments, but in the real world it doesn't have to be that precise. Guys run 20 MOA and more rails that move the reticle 20 MOA from center on purpose.
Since you would require even more shimming than the example of 18 thou, lapping the rings afterwards is in order to avoid kinking and stressing and marking your scope tube. A better solution might be a set of Burris insert rings with offset inserts.
How close is the scope to center on the windage adjustment? If its cranked far to one side or the other it can severely limit the amount of vertical adjustment available.
... pretty sure I am confused here.. but if your front "ring" is higher ... it sounds like you have mismatched rings. Both rings should be same height ... to accommodate the dimensions of the action - the "bases" may be different heights and when they are each must be installed in the correct front/rear locations .. the net effect is then a scope parallel to the bore (supposedly)
I am also certain you are correct .. but stranger things have happened - anyway if the rings are correct sure wont be the first time that bases are not dimensionally correct for a receiver .. or a receiver is not similarly correct. I like the Burris solution best. But sometimes just mounting the scope to the front base leaving the rear base free from the receiver (but attached to the rear ring) can show a little gap between rear base and receiver... a piece of thin plastic from a margarine container (or devcon) might takeup this gap if it exists and eliminate the problem. Would suggest DeerDr boresights on a horizontal bar at 25-30 meters (a broom handle would work) and see when his scope reticle corresponds to the bore sight .. saves some trips to the range and and will get pretty close..
I agree. I've see receivers that were misdrilled, receiver rings that over machined and were lower than normal, and most recently a M70 rear base that wasn't even close to the same height as the one I replaced it with. It was a Weaver, and clearly marked with the same number. Then there's the bases in the wrong packages.
I can usually sort this type of thing out in a few minutes when everything is in my hand. You probably can too.
Perhaps trying all new bases and rings will solve the issue. As implied perhaps something in the rings and bases is out of whack. Starts the process of elimination. I had a similar issue with one of my Win 9422's and Weaver rings. Tried a new set and all worked well.
Anyway this project was one of those ones that wouldn't come together....Went from New Leupold "Weaver Style" bases and Rings, to old style Weaver bases, new style Leupold "weaver style" rings.POI was way low, no more adjustment on VXIII.....Ok I'll try Leupold STD bases and Rings....Still WAY to low at 30 yds....Reading an old gun book, this guy says on the Featherweight 70s Dual Dovetail is the Way to go...I love Win 70s and I've got some NEW Old Stock 1" Dual Dovetails. Install em....off to my range with some 130 gr Ballistic Tips over H4831 .......BINGO....The OL girl loves the Dual Dovetails...The Rifle was for my Favourite Cousin from Timmins, and I'm so happy it finally came together...Thanks for all the input and ideas "NUTTERS". She loved the Ballistic Tips and H4831 too....but you all know that....
BigUglyMan
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Usually works the other way...drop $150 on Talley LW or something comparable and then they don't work but $25 on Weaver rings and bases and you're off to the races. Nice to see that you bucked the odds on that one!
