Building a custom 7mm Rem Mag Hunting Rifle-PART 1

As the bolt action rifle continues to evolve, so do the expectations of what a “normal” rifle might look like. Forty years ago, “hunting rifle” meant a walnut stock with a deep blue finish. Twenty years ago, it may have meant a stainless steel barreled action with some sort of all weather synthetic stock. Nowadays, it likely means the rifle is a lightweight precision rifle with a chassis. In this post let’s look at how I built this modern hunting rifle.

Before we get to work, let’s take a look at the following disclaimer.

The contents of are produced for informational purposes only and should be performed by competent gunsmiths only. 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.

Any modifications made to a firearm should be made by a licensed gunsmith. Failure to do so may void warranties and result in an unsafe firearm and may cause injury or death.

Modifications to a firearm may result in personal injury or death, cause the firearm to not function properly, or malfunction, and cause the firearm to become unsafe.

This is a custom build, and like most, it starts with an action. To obtain an action, you can either buy a new one or, as is the case here, take one off of an existing rifle. The gun is a factory left-handed Remington 700 SPS. The owner was quite fond of the rifle and had been hunting with it for some time. Since it was sentimental, he wanted to use it as a base for his future build.

The plan is straight forward. I’ll use the action and bolt from the original rifle, fit a new stainless steel match grade barrel into it, install a blended brake, install a match trigger, then place it all in an MDT chassis. The precision shooting and hunting worlds will collide and excellence should result!

I ordered the following parts from Brownells for this build:

My donor rifle, a bone stock Remington 700 SPS with a left-handed action. From a machining perspective the fact that it is left-handed doesn’t really matter. From a gunsmithing/parts perspective it does. The action, bolt, trigger mechanism and some small parts are different. For instance, the small bolt stop spring is unique to the left handed gun, if you drop it, you may not find one in stock for some time.

Once I strip the barreled action from the stock, I need to remove the barrel. I do this on a barrel vise with an action wrench. My vise is a Farrell I ordered it from Brownells. I hold it in my shop press that has a pneumatic cylinder to speed up the process of clamping down on it. I like using a Brownells action wrench that wraps completely around the action. The barrel is then coated in rosin and clamped down. With a pipe on the action I can break the action lose.

After the barrel is removed, I assess the actions I am working on prior to deciding on whether or not I plan on blueprinting (or truing them). If the action looks good, I pass on the extra work and use it as is. If it looks a little wonky (that’s a technical term), I’ll work on it. The level of work I do on it and how I perform those operations are also action dependent. As a rule I try not to perform work unless it is absolutely necessary. This action was wonky. You can see the rough tool marks on the front of the receiver rings. Based on past experience with Remington actions, I pegged this one as a candidate for truing or blueprinting.

For this rifle, I decided to use my Manson Receiver Accurizing System. The system consists of a tap, die, and pair of tapered bushings.

The first step in the process is to use the receiver tap to re-cut the minor diameter of the receiver threads and square the two receiver lugs. To do this, I simply coat the tap with oil and gently turn it into the action. It is guided by the two bushings that had been inserted into the action.

Next, I run the tap into the action. Unlike a standard tap, I don’t take a small turn and back it off to break the chip. In this case, I lube the tap and just turn it until it bottoms out.

To square up the receiver ring, I use this ring facing tool. It has a bronze bushing that turns around the back of the tap.

This is one of may favorite tools. It rapidly produces a clean true surface on the front of this action. Notice the difference from the previous picture.

I checked the bolt lugs to make sure that they mated up against the receiver lugs. To do this, I simply coated the surfaces with a marker, put the bolt in place and rotated the hand up and down. If the marker was missing on one lug and present on the other, I’d have to cut the rear bolt faces. In this case, both lugs of the bolt lined up right so I could continue working without cutting them. I decided I wanted to work on the bolt face. To true this, I used this bolt face burr and tooling block shown above.

The bolt face tooling block screws into the front of the action. The burr is then placed into the bolt (under the extractor lip) and sent up through the action and tooling block. A hand held cordless drill is then run to machine the front of the bolt face.

The solid carbide burr makes short work on the bolt face.

This action is now ready for a barrel, and that is where I’ll pick up the next post!