WHOA! What's wrong with this 1917 (keyholing)

[bladeswitcher]

Just bought what appears to be a really nice 1917 off of Gunbroker. Everything looks great, including the bore. Went to shoot it today and couldn't hit the target at all. Finally set up my stand at 25 yards and still wasn't doing any good. After a few shots I realized that I was keyholing bullets all over the target board. One shot was a perfect profile of the bullet! This was with M2 ammo, btw.

Got it home and took a closer look at. I still think the bore looks good, but I think the crown needs work. It appears to have a few nicks and maybe even a slightly rough edge to the crown. Is this enough to explain the scattergunning and keyholing?

WHat's my next step? Try different ammo? Have a local gunsmith try to recrown it? Send it to a military rifle expert (any recommendations)?


What makes this more aggravating is that I just sold a different 1917 in much worse condition because I wasn't comfortable with the fact that the bore looked like crap and it was counterbored. That gun shot 2 inch groups at 100 yards! Stupid me!

Information

Warning: This is a relatively older thread This discussion is older than 360 days. Some information contained in it may no longer be current.

[jjroth]

lightly coat a spare bullet with "prussian blue" (@auto store).
gently insert into the muzzle abs wthdraw to see what mark are onr ther bullet. should show equal marks from thr rifling.

Also try lubing a lead rifle bullet and drive it through the bore to check the resistance should be equal or you may feel loose spot.

[tmark]

I'd be curious as to what the muzzle wear reading is using a bonified muzzle wear gauge. If you have a .30 cal bullet, drop it into the muzzle pointed end first to see how much of the bullet it swallows. If it swallows it past the cannelure, you have your answer. Excessive muzzle wear. A crowning job may help accuracy.

[kragluver]

In addition to the above suggestions, also slug just the throat using a lubed, pure lead slug. It should measure no more than .310 at the rifling. Keyholing can also be the result of a badly worn throat causing the bullet to "tip" slightly as it takes the rifling. I had a Lee Enfield with that problem. I tried everything, but finally ended up having to replace the barrel.

[bladeswitcher]

Thanks for all the suggestions guys. I need to come up with a lead bullet to try running down the bore. I'm really leaning toward the crown at the moment. I've ordered some muzzle laps and a couple of grades of grit. We'll see if that addresses the situation.

Here's a 180g CoreLokt at the muzzle:




Here's the muzzle itself. When I look with a loupe, I can see a burr:

[joem]

IMHO it looks like you might need to have it recrowned and head space checked.

[Johnny Peppers]

Use a double-ought (00) buckshot to slug the bore with. Oil the bore and seat the buckshot into the muzzle. You can then take a cleaning rod and with steady pressure run the buckshot through the bore. This will let you feel any tight or loose places in the bore, and will give you the bore size.

[bladeswitcher]

IMHO it looks like you might need to have it recrowned and head space checked.

Other than general principle, what makes you suggest checking head space?

[RED]

I seriously doubt that muzzle is causing that big a problem. If the bore looks good it probably isn't causing that huge a problem either. Even a shot out rifle will not be that bad at 25 yards. I wish I could tell you what IS causing trouble but it would be a pure WAG. You might try to contact the seller and he might shed some light on the issue. What kind of ammo are you using?

I had a Mauser that had been rebarreled to 25.06. For what ever reason it would keyhole certain bullet weights but not others and it was a 1 MOA shooter with my reloads. It was a strange gun in that it would chamber new brass or neck sized brass fired in it. I tried full length resized, once fired brass (fired in a different rifle) and it would not chamber. I never did figure it out.

Maybe Jim K. will weigh in on this one.

[hagar in SC]

Is it severely copper fouled? The copper can cover the grooves while acting as a kind of lubricant making the bullet skid over the rifling. I woulld clean it really really well, it may take a couple of days with Sweets, Kroil and JB bore paste.