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Blasphemy to drill/tap the receiver on a M12 for scope bases?

994 Views 34 Replies 12 Participants Last post by  gcrank1
I really like my H&R M12. I bought it without any sights. It came with the EGW scope base that bolts to the rear scope block mounting holes on the barrel and hangs out over the receiver.
I can feel the whole scope/mount vibrate a little when fired, and can see movement if I push down on the rear of the scope. However that is not really the main issue.
My main issue is the scope base does not extend back far enough to get a good eye relief.
I have the scope rings back as much as I can, and the scope as far back in the rings as I can, and it is still not comfortable. I have to move my head forward to get a proper picture through the scope, to the point it is not natural.
It is not LOP issue, as that fits me perfectly. The original stock that came on it when I bought it had been cut down to a shorter LOP and it was too short and uncomfortable. And I still had the eye relief issue with it.
While some do not like the stock, I find it actually very comfortable.

With the current scope mount not extending over the rear receiver ring, I got thinking, how much would it be frowned upon to have the receiver drilled/tapped for a scope base (either one or two piece) on top of the receiver?

It is a shame they do not still make the Ken Viani mount, and no one has started reproducing it. Finding one is very hard and cost almost what I paid for the gun if you do find one.

Or, does anyone know of any other scope bases/mounts for the M12 that can put the scope over the receiver?
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I’ve been thinking about getting the EGW mount for my old m12 as well but find the three options confusing with no real guidance found in my searches. My barrel is ~0.875” at the muzzle. Does that make the 0 MOA the correct choice?

I haven’t shot it in many years but got it out tonight to examine. I’ve got the Olympic & Palma irons and sighted it for 50yds way back when. Tonight in a standing position I can’t even get up my head low enough on that thick stock to properly use the sights. Not that I could hold it up very long anyway :rolleyes:
 

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I hope I'm not telling you something you already know. The "zero moa" refers to external elevation for your scope and has nothing to do with barrel diameter. One moa equals just a tiny bit over 1" at 100 yds., so your poi (point of impact) would be ~10" higher at 100 yds. than with the 0 moa base, all other things equal.
No worries! The question is the EGW mount comes in three flavors: 0 MOA, 20 MOA, -20 MOA. The only guidance EGW gives is the -20 is needed if you have a barrel that tapers to 0.75" at the muzzle, so you end up with a net 0 due to the barrel taper. I assume that means 0 MOA is the correct one for the heavier barrel like I have. I just cannot find confirmation of that anywhere.
 

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I'd be very curious to know why EGW says that. MOA means minute of angle, of course, and there's no relationship between moa and barrel taper. Does the EGW base mount on the barrel? If so, then maybe they're referring to the shape of the base at the mounting surface matching the taper of the barrel to avoid leaving a gap. Perhaps the 0 moa base is shaped differently at the bottom than the 20 and -20 bases. But if it goes on the receiver then it shouldn't matter. Maybe you should ask EGW.
Yes, the EGW mount uses the rear scope mount on the barrel and then cantilevers back over the action.
 

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I did it and never looked back. Two piece steel picatinny bases. Be sure to specify picatinny bases as Weaver rings will fit pic, pic will not fit Weaver. Burris XTR Signature rings will give you the option of +/- 0, 5, 10, 15, 20, 25, 30 or 40 MOA. I used +30 to get standard velocity 22LR out to 300 yards. This way I can dial elevation from 25 to 300+ yards well within the adjustment range of my scope. I couldn't be happier with the set-up.
Nice set up! How did you mount the bipod to the rail?
 

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Took mine to the range recently which reminded me that massively oversize stock keeps me from being able to get a proper sight picture with the irons. I will probably be selling mine. The only way I could use it is to scope it. I got it the first year the CMP offered them.
 
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