External Remington 700 bolt stop- no step cut installation- method 2

July 18, 2013 Bill Marr Gunsmithing, Uncategorized 0

The bolt stop is now test fitted to ensure proper function and placement.

External Remington 700 bolt stop- no step cut installation

In our first post on installing an external bolt stop for an M700, we made a step cut into the receiver (similar to a Blackheart International action) above the bolt stop, which was then through drilled for a pin to secure the bolt stop. Take the time to read the first post, for more information on how and why we installed an external bolt stop on our M700.  Here, we decided to go for a different look, by removing the step cut, spotting the hole with an end mill so we could drill for the bolt stop pin.

In addition to eliminating the step cut, we tightened up the front end of the bolt stop mortise, shortening it .033″. In order to spot the bolt stop pin hole, a 1/16″ carbide end mill is used.  We ordered a double ended end mill with a short length of cut in order to maintain rigidity.

For comparison purposes, this is what the final installation of the “no step cut” method shown here looks like:

The bolt stop is now test fitted to ensure proper function and placement.
“No step cut” bolt stop installation

Compared to the method shown in the first article here:

External bolt stop on M700
Note step cut above the bolt stop.  While this looks cool on a tactical rifle, we feel it might be a little much for a hunting rig.

Remington 700 external bolt stop 1

You can see the front edge of the mortise is tighter.  The bolt stop lever still functioned fine.  Assuming dirt and mud doesn’t get packed in it, the tighter dimension show here, should function fine.

During our review of our installations, we discussed the possibility of removing the top hole entirely and decided against it.  The first idea was to blind pin the bolt stop from underneath.  Problem is blind pins are a bad idea; if they sheer off, you are stuck and have a heck of a time removing them.  A couple of engineering and machine books we have around here, always advise against them.  The alternative would be to thread a screw from the bottom, with a tenon turned down on the end, inserted into a blind hole as a pivot point.  This had the obvious disadvantage of being inserted into a blind hole and would add a large opening on the bottom of the action.  Additionally, the 1/16″ pin size is awfully thin. Increasing the pivot pin diameter would help; however, with the bolt stop we use, the hole is very close to the edge.  A different stop would need to be designed or made.

The stop used here is a “Lawton/Nosler” style bolt stop from Pacific Tool and Gauge.

The action is held in a specialized sine bar/ lug drilling fixture from Holland’s Gunsmithing.  This fixture allows the action to be milled at the 9 o’clock position and the step to be milled and pin drilled from the top.  Alternatively, the action could have a flat, 0 cant, rail or scope base attached to the top of the action to index it in the vise.  This would also allow the step cut to be made in the bottom of the action, which may be preferred.

We ordered the following supplies from Brownells (part #):

An ample amount of time was spent planning the installation. Planning is necessary to ensure that the bolt stop has ample room on each end to function (we used .007″ on the front, .060″ on the back), doesn’t impede functioning by stopping the bolt too early, pivots in the correct location, and has appropriate support on the front and rear.  Some of the measurements we used will be shared, however, if you plan on installing one, you should develop your own calculations and proceed with caution.  Keep in mind, if the bolt stops is too short it may not extract a loaded cartridge or feed from the magazine.

Do not use a roll pin for the bolt stop.  It is too weak and will shear.  We used a 1/16″x1/2″ piece of hardened drill rod.

The contents of Rifleshooter.com are produced for informational purposes only and should be performed by competent gunsmiths only. Rifleshooter.com and its authors,do not assume any responsibility, directly or indirectly for the safety of the readers attempting to follow any instructions or perform any of the tasks shown, or the use or misuse of any information contained herein, on this website.

 

The action is attached to a Holland sine bar and secured in the milling machines vise. The centerline of the receiver is determined and the location of the bolt release mortise determined.
The action is attached to a Holland sine bar and secured in the milling machines vise. The center line of the receiver is determined and the location of the bolt release mortise determined.

 

A 3/16 solid carbide center cutting endmill is used to begin the bolt release mortise. The endmill is inserted into the work at .193" and stopped at .999" from the rear vertical edge. The depth of the mortise is .155". A through cut is then made from .729" to .900".
A 3/16 solid carbide center cutting end mill is used to begin the bolt release mortise. The end mill is inserted into the work at .193″ and stopped at .999″ from the rear vertical edge. The depth of the mortise is .155″. A through cut is then made from .729″ to .900″.

 

With the mortise complete, the bolt stop is test fitted into the receiver. It's a good idea to check before the set up is taken down incase the cut needs to be enlarged.
With the mortise complete, the bolt stop is test fitted into the receiver. It’s a good idea to check before the set up is taken down in case the cut needs to be enlarged.

 

The sine bar is repositioned to orient the receiver upright. A 1/16 solid carbide end mill is used to spot a hole for the 1/16" roll pin that will be used to secure the bolt stop. The hole is spotted .456" from the left, rear, vertical surface of the receiver and .095" in from the side of the receiver.
The sine bar is repositioned to orient the receiver upright. A 1/16 solid carbide end mill is used to spot a hole for the 1/16″ roll pin that will be used to secure the bolt stop. The hole is spotted .456″ from the left, rear, vertical surface of the receiver and .095″ in from the side of the receiver.

 

Locating a 1/16" drill over the spot left by the end mill, a hole is drilled completely through the receiver.
Locating a 1/16″ drill over the spot left by the end mill, a hole is drilled completely through the receiver.
The rear of the bolt stop needs to be contoured with a file to allow the the bolt to be inserted without depressing it. The contoured stop (left) is shown next to an unmodifed stop as supplied (right).
The rear of the bolt stop needs to be contoured with a file to allow the the bolt to be inserted without depressing it. The contoured stop (left) is shown next to an unmodified stop as supplied (right).

 

 

The bolt stop is now test fitted to ensure proper function and placement.
The bolt stop is now test fitted to ensure proper function and placement.

 

 

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