1 piece or 2 piece bases for mounting scopes

Whisky Tahoe · May 17, 2019

Today I went to mount a nice optic on one of my rifles and realized I needed different bases.
I had already replaced the Leupold Dove Tail style in favor of Picatinny aka wide weaver style bases. I had selected 2 piece bases because I liked how clean they look. Unfortunately my new scope has a shorter tube than my bases & rings will support. I should have went with a 1 piece base.

I'm not sure why I didn't learn this wisdom earlier, probably because older long range scopes tend to have longer tubes. The Nightforce Benchrest scope I was mounting has a shorter tube than the Burris Black Diamond that I was replacing and was not quite fitting in my extra wide signature rings on my Savage Long Action by about 1mm. The combination of shorter tube, near fixed ring options with 2 piece bases, and longer action conspired to be too far apart for my new scope.

Here's the key learning I walked away with.
1 piece rails have much more flexibility for mounting position and ring placement than 2 piece bases. I should have reviewed the scope dimension specification and worked this out ahead of time.

I already knew that Picatinny and Weaver style are more flexible than dovetail style as far as ring placement but before today I felt that you could go with either 1 or 2 piece bases. Lesson learned and even with 2 day shipping I'm not shooting this weekend.

I have been converting to wide rings (3 screws x2 per cap) especially the signature XTR series which provide better holding capability along with increased MOA flexibility/range and the benefit of no ring marks due to no metal to metal contact. My Savage 300Win Mag was the first Long Action rifle I converted. The short action rifles had enough flexibility to get by with two piece bases.

Here are a few notable differences for choosing 1 or 2 pieces based on my experience including today:
1) 1 piece picatinny bases have more slots which increases mounting option flexibility
2) 1 piece picatinny bases with increased MOA elevation are readily available, typically 20 MOA
3) 2 piece picatinny bases may have alignment issues if the holes are not true
4) 2 piece picatinny bases don't cover the port like 1 piece bases do.

What experiences do you want to share here?

No_Regerts · May 17, 2019

As a hunter who doesn't like to lug around a lot if extra weight, I use two piece bases that I choose depending on the action and LOP. For instance, I use Leupold Dual Dovetail with non-reversible front mount on an M700 long action. They are strong and look nice. On a pre-64 M70, I use Talley steel bases and rings because they are a smidge higher than Leupold lows and a smidge lower than mediums. Its as low as I can mount a scope and clear the bolt handle. On Tikkas, I use Talley lightweights with the rings toward the muzzle. Tikkas seem to have short LOP and I have to get the scope away from my face.

YMMV. I've even had to go as far as restocking to a longer LOP to make a rifle/scope fit me well.

bsa1917hunter · May 17, 2019

No_Regerts said:
As a hunter who doesn't like to lug around a lot if extra weight, I use two piece bases that I choose depending on the action and LOP. For instance, I use Leupold Dual Dovetail with non-reversible front mount on an M700 long action. They are strong and look nice. On a pre-64 M70, I use Talley steel bases and rings because they are a smidge higher than Leupold lows and a smidge lower than mediums. Its as low as I can mount a scope and clear the bolt handle. On Tikkas, I use Talley lightweights with the rings toward the muzzle. Tikkas seem to have short LOP and I have to get the scope away from my face.

YMMV. I've even had to go as far as restocking to a longer LOP to make a rifle/scope fit me well.

I usually agree with everything you post. However, most of my rifles wear leupold dual dovetails. Pre 64's with their 3-9×40 rifle scopes sit nice and pretty with low rings. My tikka superlite also wears DD's. My really old rifles (sporter m1917's) wear weaver style bases and burris zee rings. These 2 piece base and rings are simple, strong and fairly light. They are also damn good looking/aesthetically pleasing. If that makes a difference. I dont like big bulky, excessively/unnecessarily heavy base/ring set-ups. Sometimes the weaver base is better because it offers more flexibility for mounting short tube scopes. Especially the bases that have 2 cross cuts in them. I use this style religiously on my savage rifles. I also like talley lightweights, as you suggested, for some applications.

No_Regerts · May 17, 2019

bsa1917hunter said:
I usually agree with everything you post. However, most of my rifles wear leupold dual dovetails. Pre 64's with their 3-9×40 rifle scopes sit nice and pretty with low rings. My tikka superlite also wears DD's. My really old rifles (sporter m1917's) wear weaver style bases and burris zee rings. These 2 piece base and rings are simple, strong and fairly light. They are also damn good looking/aesthetically pleasing. If that makes a difference. I dont like big bulky, excessively/unnecessarily heavy base/ring set-ups. Sometimes the weaver base is better because it offers more flexibility for mounting short tube scopes. Especially the bases that have 2 cross cuts in them. I use this style religiously on my savage rifles. I also like talley lightweights, as you suggested, for some applications.

You don't have problems with your bolt handle contacting the scope when you use DD lows? I have some current M70s that have no problem, but the bolt handle is shaped a little different.

Whisky Tahoe · May 17, 2019

No_Regerts said:
As a hunter who doesn't like to lug around a lot if extra weight, I use two piece bases that I choose depending on the action and LOP. For instance, I use Leupold Dual Dovetail with non-reversible front mount on an M700 long action. They are strong and look nice. On a pre-64 M70, I use Talley steel bases and rings because they are a smidge higher than Leupold lows and a smidge lower than mediums. Its as low as I can mount a scope and clear the bolt handle. On Tikkas, I use Talley lightweights with the rings toward the muzzle. Tikkas seem to have short LOP and I have to get the scope away from my face.

YMMV. I've even had to go as far as restocking to a longer LOP to make a rifle/scope fit me well.

I did fail to mention weight, thanks for bringing it up. It is a big factor. This rifle is a range only with a heavy stock and no weight limit. If i had to deal with weight, the bases and rings can be made in either steel or aluminum which give more options. Like you mention finish is an important factor. Gloss finish on a classic hunting rifle is hypnotic. I kept leupold gloss rings on my Sako for that very reason.