ATI Scope Mount

[scoombes]

Hello:
I have a 1943 ROF No4 Mk1 at home that was previously bubba'ed. Because I like the history of these rifles and the action, I thought it would be great to use as a hunting rifle. I purchased a synthetic stock and scope mount for it and put the scope on. The mount as it turns out is incredibly crooked. I didn't notice it at first but after I tried to get it boresighted, I discovered this problem. I have read many posts about the ATI mount and the pros and cons of it but I did not notice a problem documented about the alignment. Has anyone else experienced this? I purchased adjustable scope rings after this realisation but they just bring the scope to a straight angle.

Information

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[Brian Dick]

Like most aftermarket No.4 scope bases, it clamps to the charger bridge which was obviously never intended to be a reference point for aligning a telescope over the center line of the bore. Get yourself a set of Millett windage adjustable rings and they can be a big help. They're made of steel and can be had in both 1" and 30mm sizes. If you're really serious about scoping your No.4, throw away the ATI base and buy a Fulton base. Yes, they are expensive but they are solid as a rock, have a Picatinny rail and pair beautifully with the steel Millett rings. I've bought, sold and traded ALL of the aftermarket mounts over the years and most are absolute crap to be honest. The Fulton bases are simply the best and most durable available.

[Brian B]

Brian,

Would you choose the low, medium or high Millett rings with the Fulton Base?

I am using it on a No 4 Mk 2 action with a heavy 7.62 mauser style barrel and no handguard. I will probably use the 40 mm or 50mm scope.

Thanks,

Brian

[Brian Dick]

Low rings usually work as the mounts sit high anyhow. Do you want a set? I have them in stock. If so, let me know quickly as your order will be processed today. Thanks.

[Brian B]

Brian,

Thanks for the quick reply. I have a set of low rings, but thought I might need some higher. I will see if the low rings work when I get the mount on the rifle.

Thanks,

Brian

[gravityfan]

I've tried just about all the no-gunsmithing mounts available.

Cad Technik mounts fit to the safety spring screw and the extractor screw. They provide longer versions of each. Trouble is that the screws and the holes in the mount are necessarily a few thou different in size. You can't get the mount not to move a little and give nasty vertical stringing. The mount also seems to exhibit a degree of plastic flexing.

The ATI and B-Square are similar to each other in operation. Both mount to the rear sight axis pin mounts, and both with screws that easily strip when you over-tighten them in an attempt to keep the mount from moving. I drilled through the mount (NOT the sight pin mounting holes - heresy!) and used a stainless steel allen bolt with washers and a ny-lok nut. They also mount to the bridge with headless grub screws that press on the metal of the receiver. They also don't hold zero and are subject to vertical stringing.

The only non-gunsmith mount I have used to any degree of success is the S&K. That also mounts to the rear sight axis pin holes, and I drilled through and used a SS bolt as usual. The forward attachment, however, is much better. It mounts to the bridge by winding in a wedge shaped piece that forces the mount into a rigid hold on the receiver. Just about the same principle as the new Savage Accustock in effect. These work well. I think this is because the wedge forces the rear fixing to be unable to slop about in the "loose" holes.

I had not heard about the Fulton, but looking at photos I think it mounts in a similar way to the S&K - with a wedge. Pricier, but with a far superior rail. I will have to try one out. Anyway, if Brian Dick says they are good, then they are good.

In short, don't use ATI, B-Square or Cad Technik. Try S&K or Fultons.

Hope that is of use.

Cheers.

[madcratebuilder]

I have a S&K mount on a No4 rifle, no movement at all. Used with Burris Signature Zee rings you can collimate the scope to the barrel.

First thing I do to any aluminum scope mount is to heli-coil any threaded hole. That well eliminate striping threads unless your gorilla handed.

[Brian Dick]

There is also a good quality aluminum No.4 scope base made in England by Armalon, (Armalon - Homepage). I prefer it to the S&K, however the S&K No.4 base is OK as are the Burris Zee rings, (I've been using them for many years). Steer clear of the SMLE base made by S&K. I've got horror stories about those. My preference will always be the steel bases and rings over aluminum. Just my 2 cents worth.

[gravityfan]

First thing I do to any aluminum scope mount is to heli-coil any threaded hole. That well eliminate striping threads unless your gorilla handed.

Neat idea, great pointer. Do you use some heli-coil kit of some specific size, or what? I'm familiar with the heli-coil process, but not experienced with them. Only ever used them on BSAs and Triumphs. Slight size difference!

Any recommendations for sourcing the needed bits?

Cheers

[madcratebuilder]

Neat idea, great pointer. Do you use some heli-coil kit of some specific size, or what? I'm familiar with the heli-coil process, but not experienced with them. Only ever used them on BSAs and Triumphs. Slight size difference!

Any recommendations for sourcing the needed bits?

Cheers

You can or at least used to be able to get the heli-coil kits in machine thread sizes. 10-32, 8-40, 6-48. I bought mine many years ago and they were on the spendy side. I would imagine they are still spendy.

I used to do a lot of fabrication with aluminum for remote controlled models and used those sizes all the time.