Counter bore or leave it alone?

[Rapidrob]

I have a very nice Greek M1907 6.5 M/S rifle with the "classic" cleaning rod damage at the muzzle. Because of this,it does not shoot well. The muzzle looks like a clover leaf.
Should I have the barrel counter bored or just leave it alone?

[missionary5155]

Greetings
If it was mine and I enjoyed shooting it, it would get counter-bored.
I did my H&R Garand that could hit a piece of typing paper at 50 yards Got out a 3/8 drill bit and carefully got it all lined up. Cut in 1/2 inch. Next day it was shooting 4" at 100 yards with the same load.
I still have that barrel set aside for the next owner if he so deicides to put it back on.
Mike in Peru

[gnoahhh]

I would counterbore it, but I would do it in a lathe and go in an inch or two to be sure to clean up the cleaning rod damage.

[Outpost75]

A good way to counterbore is to use a rotating pilot chamber reamer having a pilot which "fits" and run the reamer into the muzzle only enough that the case shoulder on the reamer cleans up the damaged crown. The neck and throat of the reamer will cut a concentric counterbore to remove any interior cleaning rod damage.

The chamber reamer doesn't have to be the exact same caliber as the barrel. I have used a .270 Winchester reamer to clean up worn .25 and 6.5 barrels, just swapping the pilot, and it works well. A .30-'06 reamer works to clean up anything from a 7mm up through a .303.

[Rapidrob]

Thank you for the ideas.

[EDG]

Have you slugged the bore so you can measure the groove diameter?
Bullets that fit better might shoot better. Also the long heavy RN Hornadys may work better than short bullets.
I wonder why the muzzle is damaged since those rifles are easy to clean from the breech.

Success of counter boring may depend on how deep the muzzle damage extends into the bore.

I have a very nice Greek M1907 6.5 M/S rifle with the "classic" cleaning rod damage at the muzzle. Because of this,it does not shoot well. The muzzle looks like a clover leaf.
Should I have the barrel counter bored or just leave it alone?

[lefty o]

my first question is, does it shoot acceptably? if it does, dont mess with it. if it doesnt, then you have to decide if the collector value outweighs the value as a shooter.

[indian joe]

I would counterbore it, but I would do it in a lathe and go in an inch or two to be sure to clean up the cleaning rod damage.

I counterbored an Italian sharps as you suggest - done to remove a rust pit that caused leading - stopped the leading problem but gun was not accurate - cut it off and recrown it and recut the front sight dovetail and it shoots good.

Suck it and see I guess ..................

[buckshotshoey]

A simple re crown might be enough to do the trick. And I dont see a re crown hurting the value any.

If you have to go more aggressive, maybe a recessed target crown will get it. I would think this way...if it's a shooter, do it. If it's a safe queen, leave it alone.

[hazmat]

Greetings
If it was mine and I enjoyed shooting it, it would get counter-bored.
I did my H&R Garand that could hit a piece of typing paper at 50 yards Got out a 3/8 drill bit and carefully got it all lined up. Cut in 1/2 inch. Next day it was shooting 4" at 100 yards with the same load.
I still have that barrel set aside for the next owner if he so deicides to put it back on.
Mike in Peru

I have done the same thing with Mosins and even a SKS! If the Finnish Armory did it as wartime expedient to make crappy rifles shoot better, why can't you!??!

[303Guy]

What diameter is the counterbore normally done?

[LAGS]

The Counterbore diameter does not matter.
The bottom edge of the counterbore is essentially a Rebated Crown.
That becomes the end of your barrel.
The counterbored section is just a pipe that the bullet passes thru.
I always do a Casting of the end of the barrel at the crown, to see what shape the rifling and crown are in, before I decide to Re-crown, or counterbore.
Then I decide if I can just re-crown the barrel, do a Slight barrel trim, ( 1/4" ) then re-crown it.
Or if a deeper Counterbore is in order to keep the barrel looking original.
But even if the barrel is worn from Cleaning Rod Wear, look at the angle that the cleaning rod can reach on an angle, and determine how deep you really need to Counterbore.
A Casting can show the wear that is present.

[Outpost75]

As a practical case-in-point, I have Marlin 1894C in .357 Magnum which got shot back in 1985 with its muzzle packed with snow when I shot at and killed a deer. Doing so bulged the muzzle noticeably, so you could feel it on the outside diameter with your fingers! I ran a .357 Magnum reamer into the muzzle until the rim seat just carely "kissed" the original crown, leaving a .380" diameter counterbore to a depth equaliing the length of a .357 case. Afterwards the Microgroove barrel shot better than it ever did and was much easier to clean! I still have the gun and it is a deeer camp favorite.

[LAGS]

@ Outpost 75
That is a great Fix.
And has given me a great idea.
I have a .22 rifle that I was given, that the barrel has muzzle wear from cleaning from the wrong end.
I just happen to have two .22 LR chamber Reamers.
I think I will do a counterbore on the rifle like you did, and see if it can improve accuracy.
The rest of the barrel is in great shape because the previous owner was obsessed with cleaning it.
But he just wore out the muzzle doing it from the wrong end.