Type 38 not hitting the side of a barn =/

I realized someone counterbored it and they probably didn't know what they were doing. They removed the rifling about 1.5" from the muzzle but no real edge for where the rifling begins. I'm no gunsmith but I'm thinking there should be a very pronounced edge to where the rifling should start right? Has anyone done their own counter bore? I've read posts where guys have successfully done themselves. I can't make it shoot any worse so I'll give it a shot myself. Probably 11/16th titanium bit with cutting oil then work it slowly by hand to remove burs and see. Worst case then goto the gunsmith.

I better google for that. Midway probably has it.

Depending on what tooling you have available could change how you do it.

Flat crowning is a option and the easiest.

Lathe would be ideal, but could be a pain considering depending on how it was drilled before as it might not be centered. A drill press might work better if they drilled it off center as at least you could pick up the hole easier. I am not sure I would buy a special drill myself, I likely would just cut what is required with a standard high speed drill with a 140 degree point on it (hard metal angle), taking time to grind it carefully. Then I would grind up or have a flat drill finish it off once I felt I cleaned up the damaged area. As to drill size, a 6.5 Arisaka (roughly .264" bore) should be able to be cleaned up nicely with a 9/32" (.281") drill if its nicely centered (large enough that it shall erase all the rifling well not taking too much meat out of the barrel). If the damage is more extensive than that, you can always choose a larger drill to compensate, but 11/16" seems excessive to me.

Note I have never counterbored a barrel, just basing this off the machining I have done and continue to do for a living.

I was wondering how much bigger to go so when I was watching youtube videos of milsurps that were already counterbored and shooting fine the only one that mentioned the size of the counterbore was .05" over groove. The lands of the rifle should be around .260 so a hole .310" might be what is needed? Again I'm no gunsmith, just going by what I saw. I wonder if the farther down the barrel one has to get to the lands also means a larger hole is needed to avoid any kind of contact from the side of the barrel or air compression throwing it off. Ideally I'd just take it to someone here in the LA area so I emailed one place that came up on a google search but all seem to not do this kind of gunsmithing.

I counterbored a Swedish Mauser once with a convenient drill bit and a hand drill. Worked fine. The existing bore kept it centered. I had nothing to lose, the rifle was in very bad shape and I essentially brought it back from the dead. The thread is on here somewhere. A gunsmith would charge me $100 if I remember right.

That's exactly what I was thinking. I've read others have done it and worked fine. I did it with my Spanish Mauser and I didn't get it to shoot better but it was my first attempt. What size bit did you use?

Since I'm not allowed to have tools, I would take it to my gunsmith. He may even notice why it actually is not shooting properly since you are not positive it is a bad counterbore.

Thanks yes still waiting for a gunsmith to respond but now I am positive it is the muzzle. Whether it's a bad counterbore I can't tell but since I've probed down the muzzle there doesn't appear to be a rim to where the lands start. It's almost like the last inch and a half is smooth into the lands which 100% would be bad. If someone tried to counterbore and just barely remove the lands but leave the goove is hard to say but when using a feeler there doesn't appear to be any edge. Maybe it was worn out due to over aggressive use of steel cleaning rod?

What maker and serial number range is your rifle ? What ammo were you using ?

Rifle is in garage so I'll check in a bit but its made around 1918 judging by another rifle with a slightly higher serial that stated it was made in 1918. Hopefully that one was correct. I was shooting 140g boat tails which are probably not ideal but it wasn't a little off, it was 12" in either direction and the rifling is gone in the last 1.5" of barrel so I'm sure the barrel is the issue. I made some 160g rounds so I'll try those next weekend but I'll still take it to a gunsmith to be counterbored. I think there was just one maker back then. Koishikawa Arsenal (Tokyo)

That bullet is not going to do well in that rifle .

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Originally Posted by bob q

That bullet is not going to do well in that rifle .

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I agree. I've still got to take it to my counter bored since there is no rifling in the last 1.5". Either it was decades of a steel cleaning rod or someone did a bad job counterboring.