Crowning a worn muzzle

My M1 Carbine Marlin barrel is a bit worn especially at the muzzle. Knowing full well that the Carbine Is not a model of accuracy, is it worth the effort to re-crown the muzzle? Will a freshly cut muzzle be detrimental to the overall value of the firearm. I am going to re-crown my M1 Garand, but accuracy is what I want with that rifle. I had inadvertently purchase a Pacific Tool and Gauge pre-64 crown cutter that is incorrect for the Garand, (the correct profile 64 cutter for the Garand is inbound) but it appears that the tooling on the pre-64 PT&G cutter is very similar to the semi-circular crown of the Carbine. Any thoughts? Leave it alone or re-crown?

Without knowing a lot more about your carbine, it is almost impossible to give you a good answer. Is it a well worn rebuild or a valuable collector carbine. That can make a big difference!

There's also muzzle wear as well as crown disfigurement to consider. Both were cleaned from the front with rods mostly so they are worn beyond the outer crown.

My first question is "How does it shoot now?" There is no ready correlation between worn barrel and no accuracy . Reading WB (can't remember which one, maybe 3?) there is information about Inland approaching ordnance about using reject barrels that apparently look bad but shoot to acceptable. It was approved and these barrels were used.

I would do some bench rest shooting with good ammunition and see how it does at 100 yds with an SR-1 target center. If it holds the 9 ring that is about 6-7" and is good accuracy for the Carbine. If it holds the 8 ring that is about 9-10" and would probably be just about average for a used carbine. Forget 25 and 50 yds, they mean absolutely nothing. 100 tells the tale. Where a match very accurate Garand with excellent handloads will shoot 5 shots inside a US quarter, the carbine can't. Hold the ten ring and you've got a good one.
The next question is will it improve the accuracy to do the barrel work?

I am inclined to leave well enough alone. The rifle appears to be pretty darn correct for National Postal Meter. I don’t shoot it too often. Plinking with my hand loads usually connects with milk bottle sized targets in the 50 yard range. I was actually more concerned about lessening the overall value of the Carbine if the resulting white metal at the crown would be viewed as a detrimental act. I know it can be cold blued, but I am not sure if that is the right way to go.

My Garand really needs the touch up, so since it is a shooter, has a new Dupage stock and hand grips, and it is not a collector’s piece, I’m good to go there...

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Originally Posted by jimb16

Without knowing a lot more about your carbine, it is almost impossible to give you a good answer. Is it a well worn rebuild or a valuable collector carbine. That can make a big difference!

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I would say the latter after all the help I received here on this site after this novice purchased it from a private seller on Gun broker. It had been a safe queen for several decades prior to my obtaining the piece.

---------- Post added at 09:04 AM ---------- Previous post was at 08:55 AM ----------

I just need to figure out how to treat resulting white metal at the crown after I clean it up. Birchwood Casey Cold blue, the Birchwood Casey matte black touch-up stick, Ceracoat? I know the rifle barrel has a very dark (almost black) Parkerized finish. I simply don’t want to do the wrong thing as my new stock finishing, waxing and installation turned out beautifully. The crown repair is the last thing I need to accomplish before I start to visit the range....

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Originally Posted by ewall

I just need to figure out how to treat resulting white metal at the crown

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If you just touch the inside edge of the crown you don't have to worry, shooting it will color it, or discolor as the case may be. Finish won't remain because of bore brushes anyway. The front edge of the crown needn't be touched.

I've used a tapered reamer to clean up a nicked edge on a muzzle. Reaming just enough to remove the nick/ding will leave the crown mostly untouched and usually resolves the issue. With a very light touch and a few rounds through the barrel, the muzzle cleanup isn't even noticeable. BTW I ran a test of 24 carbines years ago where each had a different amount of MW ranging from 0 to 5. It wasn't until I got up to a bit over 4 that I found any significant reduction in accuracy. Carbines with an MW of 4 shot just about as well as those with a MW of .1. And that was with a wide variety of barrel makes as well as MWs. Complete recrowning normally isn't needed, just a cleanup of the front edge of the rifling.

If it has been a safe queen for several decades, I would tend to believe it has some collector value. That time in the safe means no one has had the opportunity to screw it up for all of those years. I would leave it as is and enjoy it in its current "unaltered" form.

IS the front edge of the Crown dinged up ? If so how badly ?
I'm having a hard time following your description.

As stated above it really takes shooting @ 100 yards to measure the effect of outer crown damage.

Pictures would help.
I've seen complete Counter Bores that made no or very little impact.

I have a S'G' shooter with a BA Blue Sky barrel that swallows a M2 round to the brass.
The following are the results from our very first outing together.

https://www.milsurps.com/images/impo...kvdwbybd-1.jpg

Using this board as an example of my sight picture and my first hold:

https://www.milsurps.com/images/impo...ipnaozp0-1.jpg

Results with that hold at 25 yrd at a 8" plate with 2" bullseye:

https://www.milsurps.com/images/impo...e509zha9-1.jpg

50 yrds @ a 8" plate but now a 3" bullseye. On the last target #3 (left one) I lowered my hold:

https://www.milsurps.com/images/impo...l8ojeos3-1.jpg

For my last hold position for target 3- far left one, I had the Black diamond just setting on top of the sight blade. The ole golf ball on the tee position. A few weeks later after swapping recoil plates, getting a better barrel hang and a little lower hold, along with a windage click or two I was able to tighten it up by maybe 30%. Getting 8-9 of 15 in the 3" bull from 50 yards. Never tried 100 yrds, but I'm happy with it for a $400 purchase sight unseen. More below about that day:

https://www.milsurps.com/showthread.php?t=61219

Good Luck ewall :wave: