Looking for advice for my 1899 Krag Carbine

[Mike4MSU]

I had previously posted some information and photos under the topic My first Krag. Everyone was very knowledgeable and helpful regarding my Krag. One member pointed out that the rear sight screw on my 1901 sight was not correct. I was fortunate enough to find an original screw which I received today. Im posting several photos showing the dilemma. The tapped hole and screw diameter of the existing (incorrect) screw is too small compared to the one I received (which appears to be the correct screw). Can someone verify I received the correct screw? If so, should I leave the existing screw in there as it must be an original configuration? Should I drill and tap for the larger diameter (correct) screw? Thoughts, comments or opinions?

ADDING THE BELOW INFO

I labeled the 3 screws

1 - This is the front screw that came with the Carbine. I believe it is period and correct. There are no problems with it and it sits correctly in the recessed hole of the sight.

2 - This is the rear sight screw that came with my Krag Carbine and 1901 sight. I dont know if its period and Ive been told its not correct for a 1901 rear sight screw. The threads are clearly thinner than the other two screws and there seems to be unusual wear on the threads. The head on the screw is too wide to sit down into the recessed pocket of the 1901 sight. It does appear to hold the sight on tight.

3 - This is (Im told) a period correct, not a reproduction, rear sight screw for a 1901 sight. The threads seem to be about the same size and pitch as the front screw which makes me believe it is correct. It will sit in the recessed pocket of the 1901 sight which also leads me to believe it is correct. The threads will not engage with the tapped hole.

Thank you,
Mike

[FredC]

Those stake marks around the holes look like someone peened them to take a smaller standard screw.
Original Krag screws have an unusual thread form by todays standards. The pitch and diameter are not standard either. Finding the correct tap would be hard today plus the peening and probably tapping with standard taps will leave you with less metal in the holes there should be. I think I would take some time and approach this cautiously.
My first thought would be to make a correct krag screw out of tool steel and heat treat it and try to "form" the threads with the hardened screw. Not sure if there is enough metal in there for that or if you can pick up the original threads at the entrance. If you do not pick up the threads correctly you will have double threads with none being strong.
Can you label or describe the screws in your photo? Purchased original, and existing screws.

[Mike4MSU]

Modified the original post to include description of screws. Let me know if additional photos or angles would help.

[PeterG]

Those babies are stripped.

If you can get dies for an M4 (diameter .159) scres with a 1.0 mm pitch, you can patch them up. But I have never see a set of dies for this old, French screw size.

Is your rifle original/collectible? If not, I suggest you re-tap the screw holes in the barrel and open up the holes in the site to match.

[Mike4MSU]

I plan on shooting it, but would like to keep it as original as possible. It appears to be a legit 1899 carbine with a period replacement stock. I believe it may have gone through an arsenal rework as an engineer carbine. The current screws hold the sight firm in place. Heres a link to my original post with lots of pics:

http://www.kragcollectorsassociation.org/cgi-bin/yabb2/YaBB.pl?num=1550857775

Mike

[Mike4MSU]

Butlersrangers posted the following photo of a front and rear screw for an 1898 Krag Carbine with a 1901 sight. The rear screw is clearly longer than the one I received. Its difficult to tell, but the diameter might also be slightly thinner than the front screw. Ive heard some 1899 Carbines shipped with an older sight. Maybe this sight was upgraded and it has an earlier tapped hole? Were some of the rear screws different diameters?

[blfrankjr]

#2 is not right. #1 is correct and #3 looks correct too.
No disrespect meant towards you but my advice is take it to a professional gunsmith or machinist who knows what they are doing. Little room for error here, barrel steel is soft and I believe that's an original $$$ barrel.

[Mike4MSU]

No offense taken. I wasnt going to tap the hole myself, I just wasnt sure if I should have it done. Besides the if it aint broke... adage, Im not sure if the correct screw was ever used in the rear location as the current screw size is so much smaller (thinner). Starting to wonder if I should leave it. Could it have always been that way?

BTW, it is definitely a period carbine barrel.

Thanks for the input
Mike

[FredC]

I have one inclination to keep using the screw that came with it. By chucking on the threads one could turn down the head so it fits in the pocket. It would look reasonably correct.
My reservation here is the OD portion of that screw shows wear. If it is just catching by the points of the thread it may strip if too much pressure is applied.

Redrilling a new set of holes just forward or behind the originals could be a solution if yours was not so potentially collectable. The hand guard would not fit the sight if this is done.

Building a forming screw/tap to displace the metal to something resembling the original threads is the other option I see. Working with this barrel, it could go wrong as mentioned in my first reply.

Whether the CMP could re-barrel it to carbine specs and not lose collectors value I will let others weigh in on this option.

On that first solution I could do it in 5 minutes with the screw and sight in hand. Others have reduced head size by chucking on the shank with a hand drill and filing. I would not recommend this as the chuck jaws may damage the outside of the threads and cause a marginal fit to strip. If you have a local machine shop that has the right size collet it would take them no longer that it would take me to do it.

[Mike4MSU]

Got lucky!

I took a closer look at the threads tonight and it seemed to me that the original threads were still there. The peening clearly deformed the hole and prevented the correct screw from even starting. Also, it appeared there was some "junk" in the threads intended to close/tighten the hole, it was of a brownish color. Either way, the correct screw is installed and sits just proud of the base, but Im afraid to try and take it any further.