doublegunshop.com - home Forums General Discussion Classic & Custom Single Barreled Sporting Rifles @ doublegunshop.com Drilling Krag receiver

Want to mount a Lyman 48 on a US Krag, gunsmith says receiver is just too hard to drill. Now I have seen innumerable Krags with 48s on them so there must have been a solution to this problem, hopefully without putting a torch to the receiver and softening the whole thing. Vaguely recollect reading about putting a drop of solder on the spot you want to drill and leaving the tip of the iron in it for a while. Any suggestions would be helpful.

Try the exact spot where it's to be drilled and see if it is indeed case hardened there. I've had a couple of Krags and '03s that were able to be drilled and tapped with nothing more than regular HS drills and taps. The negligable surface hardening in the area was easily punched through with the drill and it's soft underneath as it's supposed to be.

If it is a deep hard case, the exact spots can be marked and a very small cone point grinder stone (Dremel type) that can be drill press mounted can be used to first grind thru the case. Make the spot just slightly larger than the needed hole and tapped thread to be cut so you're working in the soft metal only.

The old method of drawing off the hardness with either a very small torch tip like an '0' or the soldering gun trick works, but can either leave a ring of discolored metal in the first instance if it gets away from you and can be very slow in the second instance in my experience.

Another way, if you have them, is to just break through the case with a slightly larger diameter carbide drill.

The usual method is to use a carbide bit to break through the skin, then a standard bit to drill the main hole, and finally the carbide bit again to break through the other side's skin. I use a 3-flute carbide bit sold by Brownell's and it works well.

Many times the hole will then need to be annealed to allow tapping the threads and this can be somewhat tricky. If heated too much, to a red heat, with the heat source removed abruptly, the steel of the hole will then be quenched and re-hardened by the cooling action of the surrounding unheated steel. The solution is to heat the inside of the hole so that the bright steel turns blue or purple, no hotter, and then remove the heat source slowly. The steel in and around the hole will then be soft enough to tap the threads.

An alternative spot annealing method prior to drilling the hole was detailed by Maynard Buehler in the first edition of Brownell's Gunsmith Kinks. He suggested heating a separate cube of steel to a red heat and then placing it in contact with the receiver at the hole's location, and allowing it to cool slowly. This would theoretically anneal the spot of the hole without changing anything else or discoloring the steel. I've never tried this method but apparently it works.

Sounds as though you may need a different smith...
Regards, Joe

Mounting a Lyman 48 on a Krag can be tricky so I called my friend John Wills because I know that he has mounted a couple. First the case is thin and the inside soft. I found this out with the Krag pieces I have as well. The problem with a 48 on the Krag is there are two holes and they are not in line so when you mount the receiver in the mill one hole will be on a slope. John uses a 3/6" carbide end mill and plunges down until he has a flat spot for his center drill. The other hole he uses a carbide center drill then a carbide drill, then tap normally.

I have a US Krag on which a micrometer peep sight (IIRC, a Marble's) is mounted by removing the entire magazine cutoff assembly. The mounting bracket part of the sight has a screw that fits into the hole in the receiver where the cutoff resided.

Thanks all. Waterman, the several Redfield sights also go onto a Krag without D&T. But only the Lymans have QD staffs that let you remove the bolt easily.

You can remove the bolt on this on.

http://www.gunbroker.com/Auction/ViewItem.asp?Item=126297641

Wouldn't the sight staff as on the redfield in the krag auction interfere with the case ejecting?. Most that I've seen mount further back on either side of the rear receiver ring. Frank

I saw a Krag at an auction yesterday that two holes D&T'd in the middle of the extractor, fore and aft about 3/4" apart. Was there a sight that fit on the extractor at one time?

Clyde Baker's book talks about them, I don't recall the maker.
Here is a link to a now expired auction with one such sight

http://www.gunbroker.com/Auction/ViewItem.asp?Item=126040814