mounting scope

[Superduty]

I have a Pendersol Rolling Block in 45/70 with a heavy oct barrel. My question is what spacing should I use for the scope blocks to give me lots of elevation for long range. The scope is a Unertl 1 1/4" and I have not drilled and taped the barrel yet. I am planning on using a long base on the rear so I wont be drilling over the chamber.

[bigted]

depending on the barrel length i believe that the distance between the ring center on a Unertl is 7.2 inch if memory serves. my Unertl does well with a 30 inch barrel and the mounts spaced on center at the 7.2 inch ... probably 7 and 1/4 inch would do fine and if more is needed then i would space them closer together for more impact adjustment per click or tick.

another thing that you should find is that on the further ranges it may behoove you to add a higher mount block on the rear to add range that you will run out of fairly soon ... then you will contend with the front hitting the barrel or getting so close that you will lose the full round sighting inside as you will begin to see the front of the barrel in the scope. really all depends on the barrel length tho.

[Doc Highwall]

The 7.2" spacing give you 1/4" clicks.

[Tatume]

My CPA Stevens 44-1/2 also uses 7.2" spacing for the Lyman Super Targetspot and Junior Targetspot.

[Doc Highwall]

The Unertl scope micrometers have 50 clicks per revolution or .0005" per click so you can calculate scope click graduations based on scope block spacing. 100 yards = 3600" divided by 7.2" equals a ratio of 1:500, so 500 times .0005" = .250"

[Kermit1945]

http://www.assra.com/cgi-bin/yabb/YaBB.pl?num=1371268800

[Superduty]

Thank you for your replies . I thought it was around 7 1/4 in. just wanted to make sure before I drill and tapped the barrel.