Original Krag front sight studs were dovetailed and brazed.

  (You need to Login   (You need to Login

New bolt is likely to fit OK if made for 1898 or 1899 model. See   (You need to Login .

Headspace specs are largely the same as .303 British -
.064" "GO",
.067" "NO GO" (useful for fitting new barrels only),
.070" commercial "FIELD",
.074" UK military "FIELD REJECT".

A common amateur mistake is getting upset if used parts accept the .067" "NO GO" or .070" "FIELD". Given the general high quality of modern brass cases, .074" seems a reasonable and practical upper limit unless a new barrel is being fitted.

See   (You need to Login for an explanation, written for L-E .303's but applicable to Krag .30/40.