2" or 3" offset cantilever mount?

[el jefe]

Im looking at a vortex cantilever mount for my vortex pst 1-4. It will be mounted on a ddm4 v5, should i get the 2" offset or 3"?
What are the pros and cons of each? Id also like to use flip up sights at some point to so im leaning towards the 3".
All help is appreciated!

 

[hbean]

All depends on your cheek weld and eye relief of the scope you are using.

 

[kombayotch]

The 3" offset is preferable for position shooting, particularly the Canadian version of kneeling.

I like the Vortex 3" non-QD mounts as they are nice and streamlined and very light. The only 2" offset mount I have is a Spuhr mount, and I have to bridge the hanguard to get it far enough forward.

 

[kombayotch]

Let me elaborate on this a bit further. Sights like the Elcan typically have short eye relief (2 3/4") while regular scopes like your PST have 4" eye relief. In order to have the eye relief in the same location as it is when the Elcan is mounted flush with the back of the receiver, you need to have the ocular lens of your PST 1 1/4" forward of the back of the receiver. This requires the 3" offset mount. The 2" offset mount puts it flush with the back of the receiver.

This is what you want in order to be equivalent to having the Elcan mounted to the rear of the receiver:


The 3" also allows you to mount with the ocular flush with the back of the receiver if you so chose. It allows for greater flexibility than the 2" offset mount.

 

[el jefe]

Thanks Kombayotch! I was hoping 2" offset would work as i have one on hold that i intended to pick up on sat. Maybe ill just have them order me a 3" offset.

 

[kombayotch]

The 2" offset mount is fine for a precision setup that you will primarily shoot prone, but it puts you as far back as you would ever want to go for mainly position shooting with no flexibility to move the scope forward.