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Gunsmithing Crown tool
- Thread starter plinkin
- Start date
Something like this with some lapping compound?
Gunsmith tool brass muzzle lap rifle pistol crowning gun barrel lapping crown | eBay
Here is a 45 degree brass muzzle lapping tool. It has a range from. 17 to. 50 cal. It can be used on a lathe or hand drill. Note:This is. Don't be fooled by the copy cats that steal my ideas! NOT a crowning tool.
www.ebay.com
I'm not sure if there is an issue or not.
I got this new barreled action and during load development it shot everything I threw at it .5-5/8 moa which is also the best I've ever shot, this is also my first custom. So when I went out to try to dial it in it was shooting 1inch, I tried going back and loading exactly what I had be for with the same results, I was even getting flyers.
I tried alot of different things over 200 rnds or so to get it shooting back like it was but it never came back. So I started thinking maybe I nicked the crown while cleaning it.
I got this new barreled action and during load development it shot everything I threw at it .5-5/8 moa which is also the best I've ever shot, this is also my first custom. So when I went out to try to dial it in it was shooting 1inch, I tried going back and loading exactly what I had be for with the same results, I was even getting flyers.
I tried alot of different things over 200 rnds or so to get it shooting back like it was but it never came back. So I started thinking maybe I nicked the crown while cleaning it.
The photo is a little out of focus, but I don't think you've nicked the crown - you'd be able to see that. Even if it was slightly nicked, my bet would be something else changed. Have you checked action screws, scope base, and rings?
I wonder if your barrel is needing a cleaning are you now seeing pressure signs on the brass of primers?
Regarding nicking the crown tgats what I was thinking I'm also fairly careful but didn't want to rule it out. Yes I checked all fasteners on the rifle with the wheeler fat wrench. 25 in lbs on the base (tl3), 18 for the badger rings, 65 for the action screws xlr envy also made sure the barrel was tight at 80 ft lbs.
Barrel Crowning Tool
11° crown cutting tool for rifle barrels. This tool is used to cut an 11 degree target crown in your muzzle. This relief cut is primarily to protect the actual crown which is the exact point where the bullet leaves the muzzle.
www.cncwarrior.com
You just buy a pilot for the corresponding caliber you’re looking to crown. I’veused this when I cut down AK barrels and it does a fine job.
Try a known factory load that shoots well and use that as a baseline. Might be something in your reloads.
I tried 168 fgmm at the same time as my reloads with either the same or worse results. The only thing I question regarding my reloads is seating bullets when I use stainless steel media cleaning. I always wonder if the super clean neck negates consistency and accuracy.
Also when I was breaking in the barrel per PVA instructions and while using the same poa, I went from 41.5-44 grains of powder to find my max load the rifle punched 1 ragged hole while shooting the cleaning rounds and the max load rounds.
I'm kicking my self trying to figure out what I did or am doing
Couple of things to check, and to keep in mind if you do recut crown. The 11 degree tool works very well on all calibers with the proper brass pilots. Mine has a T handle attachment and do all of them manually to avoid cutting too fast. Key, after cutting, is to use the appropriate brass lap and medium to fine compound to create a very fine radius at juncture of rifling and crown to eliminate any potential for having created a burr after cutting crown.
That said, I just got a Teslong borescope and found varying degrees of carbon buildup from QD suppressor brakes which was affecting accuracy in several rifles. The muzzle tool was also helpful cleaning up the existing 11d crown, reinstalled and GTG, once again. Noticed you had a threaded muzzle and could be a possible source of issue.
That said, I just got a Teslong borescope and found varying degrees of carbon buildup from QD suppressor brakes which was affecting accuracy in several rifles. The muzzle tool was also helpful cleaning up the existing 11d crown, reinstalled and GTG, once again. Noticed you had a threaded muzzle and could be a possible source of issue.
OK, if it's not shooting FGMM 168's reasonably well, something is off. How many break-in rounds did you fire (you said there was a variety and everything shot well)? Other than clean it, did you do anything else to the rifle?
As far as nicking the crown, take a close look at it under good light light. Do you see any nicks or burrs? Take a cotton swab and insert into the muzzle and pull it out while applying some pressure to the bore (do it as many times as it takes to check all sides of the bore). Does it catch or leave fibers as it leaves the muzzle? Eliminate the crown issue, it can take this thread down a rabbit's hole about whether or not a nick in the crown will make much of a difference in group size. If you want, buy and use the brass crown lapping tool - unless you use it with an hammer drill, you won't ruin the barrel.
Regarding case neck being too clean, factory ammo is clean when loaded. Unless the neck tension is too high, it shouldn't be a problem. If you want, use dry lube.
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To answer your original question, yes- there is a tool that can be used to put a chamfer on the muzzle exit...
Not sure if I'm on board with doing it by hand rather than in the lathe, but a 60 degree piloted counterbore can be used to clean up/ make a concentric "relief" where the rifling terminates at the crown.
I doubt the crown is the issue since it was shooting fine initially and burrs/imperfections don't spontaneously appear.
I suspect it might have more to do with copper fouling on a new barrel.
Not sure if I'm on board with doing it by hand rather than in the lathe, but a 60 degree piloted counterbore can be used to clean up/ make a concentric "relief" where the rifling terminates at the crown.
I doubt the crown is the issue since it was shooting fine initially and burrs/imperfections don't spontaneously appear.
I suspect it might have more to do with copper fouling on a new barrel.
Lathe ideally preferred, but requires barrel removal. Absent a lathe, have run about a dozen or so by hand-carefully. OP was asking about a drill operated process, which I would discourage without some further process control. With right tool and pilot, feel pretty confident in my manual execution. Have trued up a bunch of revolver forcing cones with similar tools from Brownells, with similar results.
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Ok the cotton swab test was negative
Last night I cleaned the rifle again with what I would say a thorough method, 2 wet patches of boretech eliminator let sit then brushed, 2 more wet patches the 2 dry. I went out and got a box of hornady match 168, fgmm 168 and had 20 or so of my 175 smk hand loads left that I loaded 42.9 of 4064 from a satterlee test I had done previously. So i went to 200yrd prone which I haven't done in a while, I usually shoot off a bench at hundred because I feel more stable and we dont have any prone at 100. Anyway I'm not sure what it was maybe me but its shooting pretty good now. The group right below the bullseye is my handloads 4 shots, the worst group is the hornady and the group above the bullseye is the fgmm 5 shots.
Last night I cleaned the rifle again with what I would say a thorough method, 2 wet patches of boretech eliminator let sit then brushed, 2 more wet patches the 2 dry. I went out and got a box of hornady match 168, fgmm 168 and had 20 or so of my 175 smk hand loads left that I loaded 42.9 of 4064 from a satterlee test I had done previously. So i went to 200yrd prone which I haven't done in a while, I usually shoot off a bench at hundred because I feel more stable and we dont have any prone at 100. Anyway I'm not sure what it was maybe me but its shooting pretty good now. The group right below the bullseye is my handloads 4 shots, the worst group is the hornady and the group above the bullseye is the fgmm 5 shots.
Attachments
The PVA (Rock Creek) barrel- cut or button rifled?
Sure sounds like it was a copper fouling issue; if so hopefully whatever's going on in there will get lapped out as you shoot it and not foul so quickly.
Sure sounds like it was a copper fouling issue; if so hopefully whatever's going on in there will get lapped out as you shoot it and not foul so quickly.
Your group on the left looks great but you have two groups . Just wondering if your having scope troubles or still fighting copper ? Anyone would be happy with that group at 200 but bringing the two together would be money !
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