|
Joined: Jan 2019
Posts: 2,653
Campfire Regular
|
OP
Campfire Regular
Joined: Jan 2019
Posts: 2,653 |
Was looking down the barrel of a friends rifle with my bore scope trying to figure out some accuracy woes. After cleaning out the gobs and gobs of copper I found an inconsistent start to the rifling in the throat. The rifling started shallow like but each land started at a different depth or distance from the leede. They didn't vary much maybe a 1/4 of an inch or so. Is this common? My rifles all start with sharp rifling and all at the same location in the throat.
GOD Bless America
|
|
|
|
Joined: May 2005
Posts: 9,611
Campfire Outfitter
|
Campfire Outfitter
Joined: May 2005
Posts: 9,611 |
In an earlier post John mentioned that was not uncommon in some rifles. You might want to pm him or just re post in the gun writer section. powdr
|
|
|
|
Joined: Feb 2001
Posts: 50,673 Likes: 2
Campfire Kahuna
|
Campfire Kahuna
Joined: Feb 2001
Posts: 50,673 Likes: 2 |
I had a 358Norma rebarrel job done by a known smith... chamber cast shows the chamber so eccentric to the bore that there is no leade on one side at all...
Mark Begich, Joaquin Jackson, and Heller resistance... Three huge reasons to worry about the NRA.
|
|
|
|
Joined: Jun 2004
Posts: 7,205 Likes: 7
Campfire Tracker
|
Campfire Tracker
Joined: Jun 2004
Posts: 7,205 Likes: 7 |
This is, sadly, not all that uncommon. If a barrel blank is perfectly straight and is set up perfectly, a perfectly concentric chamber should result. If the barrel is not straight and/or the set-up less than perfect, eccentricity can result. A close fitting pilot will minimise error but if the set-up is eccentric or misaligned in any way, perfection is pretty unlikely. GD
|
|
|
|
Joined: Dec 2007
Posts: 1,524
Campfire Regular
|
Campfire Regular
Joined: Dec 2007
Posts: 1,524 |
I've got a Rem Mod 7 in 7-08 that is like that. Reamer either went in crooked or the pilot forced it to one side and the star of each land is at a different spot. Either way it is a moot point. With 139gr Hornady bullets it is a solid sub MOA for five shot rifle. I was prepared to rechamber or rebarrel but after shooting it, there is no need. My 12 yr old son used it to drop his first deer this past fall at 125yds.
Last edited by gzig5; 02/22/19.
|
|
|
|
Joined: Feb 2012
Posts: 1,531
Campfire Regular
|
Campfire Regular
Joined: Feb 2012
Posts: 1,531 |
I've got a .280 Remington in a 98 action with an ER Shaw barrel. It shoots < MOA for at least 3 shots sometimes for all 5 if I do my part and I had a guy look at the barrel with his scope just for kicks because he had a scope. I didn't think he would find a problem because of the way it shot, but he surprised me when he told me this same thing. But he said that wasn't anything to worry about if it shot good and it does.
Last edited by Filaman; 02/26/19.
What goes up must come down, what goes around comes around, there's no free lunch. Trump's comin' back, get over it!
|
|
|
|
Joined: Jul 2015
Posts: 14,788 Likes: 5
Campfire Outfitter
|
Campfire Outfitter
Joined: Jul 2015
Posts: 14,788 Likes: 5 |
About the only thing you can do with a barrel like that this side of a rechamber or a rebarrel is run some lapping bullets through it.
Politics is War by Other Means
|
|
|
|
Joined: Mar 2016
Posts: 282
Campfire Member
|
Campfire Member
Joined: Mar 2016
Posts: 282 |
About the only thing you can do with a barrel like that this side of a rechamber or a rebarrel is run some lapping bullets through it.
How would lapping bullets change anything?
|
|
|
|
Joined: Dec 2012
Posts: 2,014 Likes: 2
Campfire Regular
|
Campfire Regular
Joined: Dec 2012
Posts: 2,014 Likes: 2 |
If it's a crooked chamber there is nothing that's gonna fix it unless you have enough shank to cut off and start over or new barrel.
Last edited by sherm_61; 02/28/19.
|
|
|
|
Joined: Jul 2015
Posts: 14,788 Likes: 5
Campfire Outfitter
|
Campfire Outfitter
Joined: Jul 2015
Posts: 14,788 Likes: 5 |
About the only thing you can do with a barrel like that this side of a rechamber or a rebarrel is run some lapping bullets through it. How would lapping bullets change anything? The OP said that their barrel "...rifling started shallow like but each land started at a different depth or distance from the leede." Sometimes you can even-up the lands up with lapping bullets. They cut less as they move down the bore. As I said, it may not work. But it's cheaper than the alternatives. I would start with it. Valve grinding compound is cheap. If it doesn't work your out <$20 with homemade lapping bullets.
Politics is War by Other Means
|
|
|
|
Joined: Jun 2004
Posts: 886
Campfire Regular
|
Campfire Regular
Joined: Jun 2004
Posts: 886 |
I see this all the time with factory chambered rifles and by smiths who dial both ends at the same time. The names on that list includes some very reputable smiths and even barrels installed by the makers of the barrels. Holding the barrel at the shank with a collet in a CNC lathe or a 4 jaw even if the end is brought into perfect center it doesn't account for the internal curve in the bore that every barrel has. Done this way some rifling will start right at the neck while on the other side they can start as far as .500" out. This starts the bullet slightly canted into the bore. No amount of lapping or grit covered bullets will help it in any way. Oddly some guns can be quit accurate done this way but since it is not ideal why not avoid it. Ideally you want the rifling to start at the same distance from the neck all the way around. That is only able to be done by only dialing in at the throat and 2" farther in on the end you are working on. It is commonly referred to as the Gordy Gritters method. We dial in this way for chambering, crowning and muzzle threads and gives us consistent accuracy on every barrel job.
"Hired Gun" Quickest and fastest all motor sand car on the planet. 3.008 at 104.8 300' of sand.
NRA Patron Life Member, Gunsmith, Instructor, Chief RSO
|
|
|
|
Joined: Feb 2001
Posts: 50,673 Likes: 2
Campfire Kahuna
|
Campfire Kahuna
Joined: Feb 2001
Posts: 50,673 Likes: 2 |
I see this all the time with factory chambered rifles and by smiths who dial both ends at the same time. The names on that list includes some very reputable smiths and even barrels installed by the makers of the barrels. Holding the barrel at the shank with a collet in a CNC lathe or a 4 jaw even if the end is brought into perfect center it doesn't account for the internal curve in the bore that every barrel has. Done this way some rifling will start right at the neck while on the other side they can start as far as .500" out. This starts the bullet slightly canted into the bore. No amount of lapping or grit covered bullets will help it in any way. Oddly some guns can be quit accurate done this way but since it is not ideal why not avoid it. Ideally you want the rifling to start at the same distance from the neck all the way around. That is only able to be done by only dialing in at the throat and 2" farther in on the end you are working on. It is commonly referred to as the Gordy Gritters method. We dial in this way for chambering, crowning and muzzle threads and gives us consistent accuracy on every barrel job. Sorry, but you need to recheck your numbers. If that is what you meant to say you are full of it...
Mark Begich, Joaquin Jackson, and Heller resistance... Three huge reasons to worry about the NRA.
|
|
|
|
Joined: Jul 2015
Posts: 14,788 Likes: 5
Campfire Outfitter
|
Campfire Outfitter
Joined: Jul 2015
Posts: 14,788 Likes: 5 |
Done this way some rifling will start right at the neck while on the other side they can start as far as .500" out. This starts the bullet slightly canted into the bore. No amount of lapping or grit covered bullets will help it in any way. I was under the impression that the OP meant that it was more like an alternating pattern than a lateral phenomenon. Perhaps he could explain further.
Politics is War by Other Means
|
|
|
|
Joined: Oct 2014
Posts: 4,755
Campfire Tracker
|
Campfire Tracker
Joined: Oct 2014
Posts: 4,755 |
I see this all the time with factory chambered rifles and by smiths who dial both ends at the same time. The names on that list includes some very reputable smiths and even barrels installed by the makers of the barrels. Holding the barrel at the shank with a collet in a CNC lathe or a 4 jaw even if the end is brought into perfect center it doesn't account for the internal curve in the bore that every barrel has. Done this way some rifling will start right at the neck while on the other side they can start as far as .500" out. This starts the bullet slightly canted into the bore. No amount of lapping or grit covered bullets will help it in any way. Oddly some guns can be quit accurate done this way but since it is not ideal why not avoid it. Ideally you want the rifling to start at the same distance from the neck all the way around. That is only able to be done by only dialing in at the throat and 2" farther in on the end you are working on. It is commonly referred to as the Gordy Gritters method. We dial in this way for chambering, crowning and muzzle threads and gives us consistent accuracy on every barrel job. Sorry, but you need to recheck your numbers. If that is what you meant to say you are full of it... I don't see anything wrong with the numbers he posted. More likely you misunderstood what he said.
|
|
|
|
562 members (222ND, 160user, 1Longbow, 10Glocks, 12344mag, 222Sako, 75 invisible),
2,246
guests, and
1,187
robots. |
Key:
Admin,
Global Mod,
Mod
|
|
Forums81
Topics1,194,568
Posts18,531,853
Members74,041
|
Most Online11,491 Jul 7th, 2023
|
|
|
|