I've acquired an old Nickel scope with claw mounts soldered on to it. The seller also found some bases that he said would work with them but I now discover the claws are fractionally too wide to fit in the slots.

I reckon that with a bit of judicious filing or stoning I can narrow the claws and then get them to fit - but should I even try? Is this a common situation or are the bases just plainly the wrong ones?

Too big claws is better than too narrow claws. But, as you know, once you file anything off it's gone for good! Be careful!

Me? I'd try the BASES first against the rifle I am thinking of fitting the 'scope to first. And if I can get them fitted OK then I'd look at seeing what can be done with the claws.

It may just save you a lot of "if only...." as it isn't just the width of the claws but also their relative height when those bases are actually mounted on a gun.

They are all hand fitted and many old ones are hand made one offs; smoke and file, carefully. Practice about 3 years at filing and fitting something unimportant first. That is why they cost $1500 to have a set fitted by a real gunsmith. Prepare yourself to say F it and put on some Leupold rings. To answer your question, yes, it is common and yes, they are the wrong bases because as I said, most of them were hand made and hand fitted at birth.

Thanks guys,
the mount bases cost $120, which is not cheap, though they do have some engraving. They had apparently been used on a double, deeply between the barrels. I would love to put the Nickel 1-4 on my Heym 88 .450/.400 but fear that, even if done by a first-class gunsmith, the mounting might detract from its value. So, if my nerve holds, I may file the underside of the bases flat and put them on a (home-made?) attachment to fit an old Greek MS I've sporterised.

Yes, I could destroy value and get nowhere - but I've done worse on the stock market

Also, Duane, the inside gap between the front claws is about .300" and it's about .275" between the rear ones. At least the base holes appear within a few thou of these measurements and are narrower on the rear base, as are the claws.

The inside gap between the front claw slots in the base is about .310" and it's about .240" between the rear ones.

The toes of the front claws (c. .630" across both) do fit into the slots but the heels are about four thou wider.

The outside width of the two rear claws together is .572" but the outside of the base slots appears to be only about .560", so this could be where most of the work would be required. I don't think the two bases are a pair because the chequering on the rear one is much rougher than the front one. The likely slop between the rear claws is a bummer, too. I'd rather it were at the front because the rear claws have lateral adjustments but no allowance for swivelling seems to be built into the front ones.

As an afterthought: would there be any merit in trying to open out the slots in the bases rather than narrow the claws? I bought the scope for collecting reasons mostly, so, while it's no big deal, maybe it would be better to risk the bases than mess with the claws too much.