Shortened barrel….bad groups now

[bluedog69]

"He" shortened it- or paid a smith to do it? I've used a piloted cutter for crowning, but that's after the barrel's been dialed in on the lathe. Who shortened, threaded and crowned the muzzle on this initially?

Him and another guy that owns a lathe. The guy with the lathe has chambered and barreled about 40 some barrels for himself and others.
The guy that this thread is about has cut, threaded, crowned about a dozen of his own barrels. This is the first one that has opened up with him. He is going to try load development to see what happens.

 

[bluedog69]

With the exception of our SBRs (9") and Coyote ARs (20") we have 24"-26" barrels on our Hunting rifles and they wear Cans. Almost no shift in POI with or without the Can.
Don't see the need to cut the barrel down to fit a can.
If it is too long to carry get a Chassis with a split stock.

I would agree. I couldn't cut a barrel down myself. As of now I don't own a can. Just brakes.

 

[338 dude]

I would agree. I couldn't cut a barrel down myself. As of now I don't own a can. Just brakes.

The load just needs to be reworked. You have changed harmonics and barrel time and cannot expect the round to perform the same. rework the load and you should be able to expect the same results that were achieved before I would think.

 

[Coyote Shadow Tracker]

The load just needs to be reworked. You have changed harmonics and barrel time and cannot expect the round to perform the same. rework the load and you should be able to expect the same results that were achieved before I would think.

I have seen a person cut his barrel a few inches with a hacksaw in a hacksaw miter box and after he cut the barrel he had a "Crown Cutter" from Brownells that he put on a drill and Crowned the end of the Barrel. to my disbelief the rifle shot very good!!!! This guy was a Hammer, Screwdriver, Vice Grip and Duct Tape kind of guy. Worked out FINE!!!

 

[Kimber7man]

Looks like he is shooting factory Hornady ammo - did he by chance change lot numbers?

 

[bluedog69]

Looks like he is shooting factory Hornady ammo - did he by chance change lot numbers?

I doubt it. He has many many rifles. I am kind of figuring that he bought this one to get into the 6.5 PRC realm. It shot great with factory and then he decided to shorten it for a can and coyote hunting in the dark. I figured he had worked up a load for this one like his others but he hasn't made it that far.

 

[bluedog69]

Does it take a box of shells to "break in" a crown job? Clean up the machining?

 

[tobnpr]

One other thought- might be completely unrelated to the barrel work, make sure he checks the "setup", esp if the groups opened up "shotgun" style.
Obviously the action, scope mount, and perhaps even the barrel was pulled to thread the muzzle. Back to basics- action screw torque, check scope mount, rings, etc...

Does it take a box of shells to "break in" a crown job? Clean up the machining?

No "break-in" here. Should be very minimal machining artifacts when the crown is correctly cut, esp with an 11 degree cutter if it was used properly. Take a cotton shop swap or Q-tip and rub it around against the inside of the crown, shouldn't grab any of the cotton.
I usually break the edge of the crown/rifling very lightly by "kissing" it with a 60 degree cutter.

 

[bluedog69]

One other thought- might be completely unrelated to the barrel work, make sure he checks the "setup", esp if the groups opened up "shotgun" style.
Obviously the action, scope mount, and perhaps even the barrel was pulled to thread the muzzle. Back to basics- action screw torque, check scope mount, rings, etc...


No "break-in" here. Should be very minimal machining artifacts when the crown is correctly cut, esp with an 11 degree cutter if it was used properly. Take a cotton shop swap or Q-tip and rub it around against the inside of the crown, shouldn't grab any of the cotton.
I usually break the edge of the crown/rifling very lightly by "kissing" it with a 60 degree cutter.

I will definitely pass all of this info on. I would imagine he torqued everything. I know he cut it off, and then when it wouldn't shoot he bought a special 11 degree cutter and put it back in the lathe again. Disassembled twice in other words.

 

[cjl2010]

Would using pin gauges on the muzzle to check any flaring of the muzzle be worthwhile?

 

[bluedog69]

To update this a bit. I talked to my buddy this morning and he said he loaded up some loads and fired a group of hand loads. Seven shots in 1.4" @ 100 yds. Not spectacular but the factories were about 4" groups after he shortened it up. He just picked a middle of the road load from a manual and loaded up 7. So he was pretty happy that he has a good chance of finding and improving on his guess load.