Home Forums Hunting & Shooting Express Rifles and Big Bores Only Extension Rings on a Big Bore

Hi All, I'm new here and have found this site to be very informative with many knowledgable posters. I've been reading Romo's thread on scoping a .375 with great interest since I'm trying to decide the same thing. I've got a question for you - most of the scopes that have been mentioned will require using extension mounts on my rifle (Ruger RSM). Never having used these mounts before are there any loading/extraction issues when using them? Should I just stick with the Leupold 1.5x - 5x VXIII? Thanks! CEJ...

I've had an LPS 1.75-6x42 on a RSM w/ an extended front ringmount. I don't recall ever having a problem w/ this mount blocking the loading port. I'll check, but I do believe I've had a 1.5-5X and a 1-4X on this same rifle w/out the extension ringmount. I use this rifle mostly w/ fixed sights but have several scopes setup w/ ringmounts so it would be easy for me to check.

Gary

GaryVA - Thank you for the information! I appreciate you taking the time to check on this for me. CEJ...

Extension rings are fine if you have to use them. I have an enfield 1917, still in 30-06 but it has a weaver extra high extension ring on the front to clear the scope bell. I plan on replacing the scope that is currently on this rifle, a simmons pro 50, with a much clearer burris fullfield. The burris has a longer tube and a smaller objective bell, so I can get away from the extension bases.

I don't think that you will have any problems with the extension ring blocking feeding or ejecting.

CEJ,

I pulled a few rifles and scope combos from my safe to better answer your question. I take it that you possess the RSM; but in case you do not, here it goes:

The current version of the Ruger RSM:
- to mount my obnoxiously big LPS 1.75-6X42mm I use the lowest LEU ringmount w/ the front extention(extends to the rear). The only portion of this front ringmount that extends rearward between the scope body and the ejection port is a small lug at the bottom of the ring itself that is machined flat and only adds .125" thickness below the scope tube for the front to rear width of the ring. For all practical purposes, there is no additional obstruction in using this extended mount vs. a standard ringmount. Ringmount spacing(outside to outside measurement) on the RSM is 5.140". Ringmout spacing w/ the front extension reduces this to 4.685". I can mount a LEU 2.5X, a LEU 1-4X, and a LEU 1.5-5X on the RSM using the lowest standard Ruger ringmounts, even w/ the Butler Creek scope covers installed.

To put all of this into perspective:

- The loading port window of a M70/416Rem Safari Mag is only 3.375" long.

- The loading port window of a CZ550/375HH Safari Mag is only 3.465" long w/ a cut the witdth of the extractor that is 3.650" long.

- The loading port window of the RSM is 3.6" long and has less obstruction w/ a mounted scope than the M70/416Rem Safari Mag has unscoped.

I hope this is of some help,
Gary

GaryVA - Thank you sir! That's just what I needed to know! CEJ..