I have never owned a No.1, held a few. Having said that I have read they can be hard to scope because of the eye relief problem. I found this out while researching a scope I had that seemed very long and had the turret far forward. It's an old Burris (early 1990's) Fullfield 1.75x5. It has no objective bell and the turret is 1/3 back from front. It's a rather long scope so it works well with No.1's and break open guns. The 1.75x5 range is good for a 45-70 also.
I once thought of buying a No.1 just for this scope but it ended up fitting very well on an Austin Halleck ML I have.
