Fixing a Custom 260 Remington Bolt Action Rifle

November 26, 2014 Bill Marr Gunsmithing 0

My buddy (the lefty) has had nothing but heartache with his custom 260 Remington rifle.  This was the first custom precision rifle that he commissioned 10 years ago.  He used quality components; a Nesika Model K action, Shilen barrel, McMillan stock, and a HS detachable magazine system (pretty much the only option back then).  The gunsmith who originally built the rifle did an excellent job.

At the time, the 260 Remington was becoming popular as a target shooting cartridge (Lapua 260 brass wasn’t available yet and guys were making it from 243 brass). Trying to squeeze the most accuracy out of the rifle, he selected a chamber with a .288″ neck.   This required brass to be neck-turned.  He found neck-turning cases to be quite a chore, so much so, that once he started he made it through about 10 cases and gave up.  The rifle did shoot, but the turning was too much of a hassle.

The rifle spent a few years in the safe when he spoke to a different smith about opening up the neck so he wouldn’t need to turn brass anymore.  The rest of the story is a bit sketchy.  The smith claimed he had a neck reamer the appropriate size, but ended up running a standard chamber reamer to open it.  When my friend got his rifle back it was no longer a shooter.

A lengthy inspection of the rifle found that the headspace was increased to .014″ over minimum.

I slugged the barrel (pushed a soft lead slug through the barrel to check for defects) and found the last 1.25″ on the muzzle end was pretty loose.  When originally built, my friend requested the muzzle end not be cut.  Tooling used by the barrel makers enters and exits the ends of the barrel which can result in loose ends. Because of this, most barrel makers (including Shilen) suggest removing the last inch of the barrel prior to installation.

Examination of the tenon found that it was undersized .020″ beneath the recoil lug.

To fix the rifle, we decided to cut both ends off of the barrel and then cut a new chamber and crown.  Hopefully, this would solve the accuracy problems.

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Brownells provided the following tools for this project:

Unfortunately, I didn’t take any pictures of the assembled rifle.  Prior to doing any metal work I measured the action and determined my barrel tenon and headspace dimensions.

The rifle was built on a Nesika Model K action.
The Nesika Model K action.
Originally the rifle was chambered in 260 Remington with a .288" neck by an excellent smith. The rifle shot well but the neck turning drove my buddy nuts. A less skilled smith attempted to "fix" this. End result, excessive headspace and rifle that doesn't shoot well.
Originally chambered in 260 Remington with a .288″ neck by an excellent smith. The rifle shot well but the neck turning drove my buddy nuts. A less skilled smith attempted to “fix” this. End result, excessive headspace and a rifle that doesn’t shoot well.
The tenon is cut off the end of the barrel. I dial in the barrel with a .0005" indicator followed by a .001" indicator.
The tenon is cut off the end of the barrel. I dial in the barrel with a .0005″ indicator followed by a .001″ indicator.
I begin by cutting the tenon to the lug diameter.
I cut the tenon to the recoil lug diameter.
The recoil lug has a larger inside diameter (1.080") than the required threads (1.062"x18).
The recoil lug has a larger inside diameter (1.080″) than the required threads (1.062″x18).
I cut the threaded part of the tenon to major diameter of the threads (1.062").
I cut the threaded part of the tenon to major diameter of the threads (1.062″).
The tenon is coated in Dykem. The area between the lug and threads is relieved and the end of the tenon is chamfered.
The tenon is coated in Dykem. The area between the lug and threads is relieved and the end of the tenon is chamfered.
I use a 60-degree high-speed steel insert tool to cut the threads at 18 teeth-per-inch.
I use a 60-degree high-speed steel insert tool to cut the threads at 18 teeth-per-inch.
A quick test fit on the action ensures everything fits.
A quick test fit to make sure the threads were cut properly.
Another test fit to ensure the action and lug properly fit.
Another test fit to ensure the action and lug properly fit.
I cut the chamber with a SAMMI spec reamer secured in a floating reamer holder. A pressurized coolant system pushes Do-Drill cutting oil through the barrel clearing the chips from the reamer.
I cut the chamber with a SAMMI spec reamer secured in a floating reamer holder. A pressurized coolant system pushes Do-Drill cutting oil through the barrel clearing the chips from the reamer.
I leave a cheap magnetic tray (I think I paid $1 for it at Harbor Freight) in my oil return pan. t does a good job of removing the shavings from the oil prior to it be filtered by the system.
I leave a cheap magnetic tray (I think I paid $1 for it at Harbor Freight) in my oil return pan. It does a good job of removing the shavings from the oil prior to it being filtered by the system.
I verify the headspace is correct. The action should close on the "go" gauge and not on the "no go".
I verify the headspace is correct. The action should close on the “go” gauge and not on the “no go”.
When I slugged the barrel the end was loose. This will be removed.
When I slugged the barrel the end was loose. The loose section will be removed.
The muzzle end of the barrel is dialed in and and squared.
The muzzle end of the barrel is dialed in and and squared.
A .420" target dish tool is used to cut the crown. I have run these at 70, 200, 220 and 360 RPM with oil. I actually find the best results are achieved at 360 RPM.
A .420″ target dish tool is used to cut the crown. I have run these at 70, 200, 220 and 360 RPM with a generous amount of cutting oil. I find best results are achieved at 360 RPM.
The form tool does a nice job on the crown. A piece of abrasive cloth is used to remove the sharp outside edge.
The form tool does a nice job on the crown. A piece of abrasive cloth is used to remove the sharp outside edge.

With a new chamber and crown this rifle is ready to be assembled and head to the range.  Let’s hope it shoots!

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