I do not believe Criterion makes a Krag front-sight base.

I saved pictures of some repro-sight examples, I have seen over the years.
I believe both of these photos show an S&S Firearms replica base attached to a barrel.

I am not certain of the origin of the first barrel. It appears 'dove-tailed' and maybe poorly brazed or soldered.

The second photo is a Criterion barrel. Criterion seems to leave a 'flat' to locate the front-sight in relation to the rear-sight holes.
I'm not certain if the base is dovetailed, as well as, brazed or silver soldered.
The owner had to send it back for a re-do, since the base fell off, the first time.

It seems to me, more could be done with the S&S base/flange to blend it in with the barrel contour?

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