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I found a MN and the guy said it does not shoot accurately. He said something about thinking it was due to the crown but it can be several things as to why a gun is not accurate. Anywhoo it got me thinking. Let's say it is the crown of the barrel. is counterboring a practice still done on a regular basis and how complicted of a job is it to have done? What normaly would ityou cost to havethe a MN practice counterbored? I know very little about this so any info is appreciated.
 

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If it's the crown, then all it needs is a re-crown. If it hasn't been counter bored already, and it's the lack of sufficient lands to the crown, then a counter bore is an option. I am sure it is still done. I would ask a gun smith first I guess. It is essentially a re-crown when completed.

It's much easier for those "it's just a $100 gun" folks to hack off the barrel.
 

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If I could suggest... Try different flavors of ammo before having the iron touched. I have a few mosins nagants with good and some with worn crowns. Others have been counter bored. They all shoot in different ways and are each finiky to the ammo they are fed.
 

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Right up til u find out it's a model 1907 and u told him to cut the barrel
 

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Like you said in the original post, It could be other things besides the crown or current condition of the barrel.
 

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juby,

There's a whole range of options/severity when it comes to muzzle treatment. IMO it's wise to figure out where you're at, and only do the minimum necessary to restore shooting condition. Because lots of things can affect group size, I judge the crown's health based on inspection, and not necessariliy accuracy by itself.

As is:
Ideally, the crown should be uniform in width all the way around, and have a sharp edge where it meets the bore. It's typical for milsurps (and many used commerical guns) to have some small dings. In the collector spirit, any mod detracts from the history and decreases the collector value. This is the collector forum, so I have to give the standard disclaimer.

Touch Up:
The homebrew clean up is to go find a brass wood screw with a head slightly bigger than the bore. Chuck it in a hand drill, put a little lapping or polishing compound on it. Spin the head of the screw in the crown a little, and stop once there is a concentric even shiny band all the way around. Do as little as possible and hit it with a little cold blue afterwards. I typically do this to every used gun I get - it makes them shoot better, is mostly invisible, and I don't have any guns I consider too valuable to shoot or touch up.

Recrown:
If a ding won't polish out, the next step is to make some chips with a special crowning machining tool. Often the damage has been caused by cleaning from the muzzle end, and jamming a steel rod against the crown. Recrowning is an honest machining step, and may get some boos from the collectors. At a minimum it is respectful to recrown with a profile that matches the original.

Counter Bore:
On some Mosins I've looked at, there is an oval "divot" on the crown, usually on the 11:00 or 1:00 position. The bore at the muzzle looks like the number "8". I believe its from cleaning from the muzzle side, and scrubbing the same area over and over with a steel cleaning rod. The damage is much too severe to polish or machine out, and extends as far as a 1/2" into the bore. I've shot a couple like this, and they don't print for crap, even when then bedding is OK and the trigger guard screws are tight.

Counterboring is about the only option at this point other than barrel replacement. If you can get down into fresh rifling, counter boring is a viable salvage procedure to restore accuracy. I have a Rashid with a counter bored barrel, and it shoots just fine. I wouldn't try it without a professional machininst. You don't see counter boring that much anymore - IMO it's because of widespread use of both chrome lined barrels and pull through cleaning kits. On milsurps, you don't see it because it's really easy to just buy a Mosin with a nice barrel instead. If Bubba's making a scoped sporter, he'd probably just hack off the barrel behind the front sight, and square it off with a file.

My brother in law was in Iraq with the Air Force, and said they didn't put anything down the barrels except bullets. They would clean the bolts and guts religiously, but had to turn in the rifles as a unit to the armorer when the barrels had to be cleaned. There is something to the old addage that you can do more damage cleaning a gun than shooting it, and clearly someone at the DOD did the accounting math.
 

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crowning pics

#1 crown on 1953 Russian SKS, pretty good for as-is milsurp rifle. Could be improved, but must weigh alteration of collectable.

#2 nice symmetrical soot pattern after the ole brass screw polishing trick on VEPR AK, and resulting 2 MOA group

#3 very slight touch up on Mosin with the brass screw, just enough for a concentric shiny band

#4 Wide shiny band after remachining the crown, prior to rebluing. Mosin with previously very dinged muzzle

#5 Mosin muzzle with cleaning rod "divot" at 7:00 position (sorry poor photo). Possible candidate for counter boring
 

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If you want to shoot it and the rifleing is gone at the muzzle, then counterboring is the best option. Lots of these old rifles have crappy bores with little or no rifleing. If it is strictly a collectors piece then leave as is. I have counterbored several Mosins to very good effect. If you have to pay someone, then it probably isn't worth the cash
 

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How to Counterbore a Rifle

I've never had a problem counterboring, even with my little chinese tabletop drill press. Just use a 3/8" top quality 45 deg. (standard) bit at the proper speed, set the barreled action up clamped vertical and parallel to the drill and so the bit will swing out right over the bore center. Make sure the drill is fairly tight, minimal wobble. Use plenty of cutting fluid or motor oil to keep it cool, make short cuts under enough pressure to cut the bore continuously. if you're too cautious and let it rub instead of cutting it'll just get hot. Pull the bit out and inspect for good rifling around the cut. When you hit decent rifling you're done. Knock any chips off with a piece of brass or plastic.
I've never had a problem centering either because the 45 deg. drill bit really wants to go right down the center of the bore or maybe because I'm so anal retentive I get it perfectly centered and straight. I've always gotten back within a 3 in. group at 100 yds, benchrest, sandbags.

BTW if you "just cut an inch off the barrel", congradulations, Bubba. You've killed the rifle's collectibility. Counterboring doesn't since the military, especially with Mosins, did it regularly as a way of getting the accuracy back without interfering with the bayonet mounting. In fact the most accurate milsurp I ever owned was a Finn capture 91 with a counterbore. One hole at 50 yards, using the copperwashed milsurp ammo.
 

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Here is a better pic of the rifle in the #5. This pic was AFTER we tried cleaning up the crown. This rifle clearly needs something more drastic, fitting in Porholio's "Counterbore" category. You can see that the rifling does not extend to the crown. This rifle currently shoots 2" groups at 50 yds.

Auto part Metal Rim Wheel
 
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