Guys,

I have three rifles built on commercial Mauser actions. Two are FNs and one is a Parker-Hale. All are fitted with Weaver two piece bases. The rear base in all cases is steel. I am using Leupold QRW rings.

I'd dearly love to run the same spacing on all three rifles as it would allow me to move scopes around from time to time. The spacing on the FNs is identical. Could be handy if I have a scope down or need a spare for a trip.

The spacing on the FNs is identical. The spacing of the Parker-Hale is narrower by 0.040" or so.

Now the question: Is it not true that in this kind of mount, the stress is taken by the back surface of the slot in the mount? If that is true (and I am not being a purist), can I mill the slot in the rear mount of the Parker-Hale back to fit the spacing of the other two mounts and still have a strong scope mount?

Would not be particularly pretty, but it could work ... right?

Thanks!

Your idea of altering the width of the slot should work OK, you are only opening it up .0400".

I have to think* though that the stress is borne by the front of the slot not the rear. When the gun is fired it moves backwards. The scope and rings tend to remain stationary (our friend inertia at work) hence the scope rings would contact the front of the base cross slot first.

*If I'm all wrong about this someone will chime in. It has been a few years since high school physics class

Gun Cat is right about the front of the slot being the load bearing point during firing. The inertia of the scope/mount has it tend to stay stationary when the rifle recoils, so the front of the slot holds the scope mount in place.

Don

Not having the bases in front of me would it be possible to turn the rear base around and mill a NEW slot the proper distance? If slot is in the center of hole spacing it is of course a moot point.

Ye Gods ... what a dumbass mistake on my part! Of course you guys are absolutely correct. I really was asleep when I ask the question. Gonna have to set an 11 pm late limit on posts.

I need to TIG up the slot and recut it if I want the scope mount spacings to match on the three rifles.

Thanks Guys ... and my apologies for a late night stupid!

quote:

Originally posted by mstarling:
I need to TIG up the slot and recut it if I want the scope mount spacings to match on the three rifles.

What about widening the slot in the front base?

Extend the slot forward so the scope ring will still ride against the front of the slot. The resulting slot clearance (at the back of the front bases's slot) should not be obvious to the eye or allow too much play in the ring fit.

I had to draw a picture.
It just goes to show, we are not as smart as we think we are

Either will work:
1) Mill out the front edges of the two FNs in the rear mounts.
2) Mill out the front edge or the front mount of the PH.


The nasty stress I calculate is on the rear screws, pulling them up.

I'll admit I drew a picture too...before posting my latest idea

Brownell's has Weaver base material that is un-slotted. Just get a chunk of that and mill a new slot in the Parker Hale base to match the others.