Winchester 70, 30-06 Retro Build

My buddy Kevin had an interesting idea for a project.  He wanted to rebuild his Model 70 Winchester into a rifle that looked similar to the Model 70 that the USMC was using during the  the Vietnam war.  These heavy barreled rifles were equipped with a pre-64 Winchester action, a wood stock and Unertl scope (I’d suggest checking out Sniper’s Hide Forums for discussion on the original configuration of this rifle).

While he didn’t have the correct pre-64 action for this project, he did have a push feed long action, wood stock, Unertl scope and bases.  So while this isn’t a correct build, it is built in the spirit of the original rifle.  Sometimes I think that we get hung up on the details and spend a great deal of money chasing parts; while that’s fun, it doesn’t have to be mandatory.  For this project, the only part we had to order was the new heavy barrel from Douglas.

Among Winchester shooters, many are fans of the pre-64 style controlled-round feed actions and prefer it to the push-feed post-64 models.  Having worked extensively with the push-feed Model 70 I don’t see why they aren’t more popular.  Those that I’ve fired have been reliable and shot well.

Beyond building on a Winchester action, this post is also interesting since we are building a precision heavy barreled rifle in 30-06, in a wood stock with an Unertl scope that mounts directly to the barrel.  That’s not something I often do.

The Winchester action shown here has been featured in a few other posts on this site, including Howa 1500 v Winchester 70 action comparsionBarreling a Winchester Model 70 with a Remington 700 sporter barrelRebarreling a Winchester Model 70 and Gunsmithing basics: Tapping a blind hole.

I ordered the following supplies from Brownells:

Before we start working, let’s take time to review the site’s 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.

I always start by measuring the action I am working with.  I use a depth micrometer to measure the distance from the front of the receiver to the bolt face (headspace) and bolt nose (I subtract .010″ from this number for my tenon length).

Dimensions in hand, it’s time to start the barrel work.  I headed over to my Precision Matthews PM-1440GT lathe.  
The PM-1440GT is the lathe I upgraded too from the G4003G lathe that I used for years on this site.  While the PM-1440GT costs more than the G4003G, I believe that the enhanced performance is well worth it.

I hold my barrels a number of different ways.  Sometimes I use a four-jaw chuck, sometimes I use a spider, and sometimes, as shown above, I use a 3-jaw set-tru chuck.  A set-tru chuck opens and closes like a typical 3-jaw scroll chuck, however, you can adjust the rear of the chuck to make it concentric with the lathe.  In the case of a barrel, this is a great feature.

Much like my mounting methods, I dial in the bore on my barrels a number of ways.  Lately, I’ve been taking readings directly off of the bore with a long reach indicator (above).  

With the barrel dialed in, I make a facing cut on the end of the barrel and cut the tenon to the correct diameter and length.  When I face a barrel, I feed from the bore out; this prevents a burr from forming in the bore.  This action has 1″-16 threads, so I cut the initial diameter to .998″, .002 less than 1.000″.

I get the tool post set up for threading.  I’ve been using carbide inserts, they last longer and take heat a little better than high-speed steel inserts.  However, if you are running slower spindle speeds or want a better finish, high-speed steel is the ticket.

With the threads cut, I test fit the action to make sure it fits well and everything lines up well.

A look at the completed threads on the Winchester barrel.

This is my preferred chamber set up lately.  I’m using a Manson floating holder and a Manson piloted reamer.  I run a relatively slow spindle speed and keep the reamer coated in Viper’s Venom cutting oil.  I like to keep consistent pressure on the reamer while the spindle is turning.  This prevents a chip from getting caught under a tooth and rolling in the chamber.  A deep mark on a chamber can be a big problem; depending on the case taper, you may not be able to polish it out.

As I creep up on the final depth I like to check my progress with a depth micrometer and a “go” headspace gauge.  On this action, the headspace measurement is from the front of the receiver ring to the bolt face.  When the headspace gauge is in place, measuring from the rear of the gauge to the shoulder of the barrel tenon will give a measurement larger than this value (unless you went too far) that indicates how much further you have to go.

Depending on the cartridge and who makes your headspace gauges, the difference between a go and a no-go gauge for most cartridges is around .006″.  If you ream to the exact go depth, when you torque on the barrel your bolt will most likely not close on the go gauge.  This is because you normally end up with .002″-.003″ worth of crush when you tighten the action.  To address this you can either make your chamber .002″ deeper than the go gauge, or you can use an extension handle and finish head-spacing your barrel by hand once the action is installed.  Back in the day some smiths would machine until no-go fit, tighten the barrel and check it.  They’d end up with the finish job closing on go and not on no-go because of the crush.  That may be OK for hunting rifles, but for precision rifles we want to keep the tolerances much tighter.

I always check the tube before I pull it off of the lathe to make sure that the action closes on go and stays open on no-go.

Now it is time to finish the muzzle.  I went ahead and flipped the barrel around so I could dial in the muzzle.

We weren’t quite sure what crown to use, so we went for one of my perennial favorites, the .420 dished target crown.  I cut it in one pass with a form tool in the floating tool holder.

Now it’s time to buff the barrel.  This a barrel spinner on my belt grinder.  I like to use a very fine belt and take my time.  I find that it provides superior results over starting with a course grit and then changing to finer grits.

Here the action is tightened down in place.  You can use your Brownells’ M700 action wrench for this too.  The top of the receiver ring on a Winchester 70 is 1.35″, same as a Remington 700, and the bottom is flat.  Simply use the top jaw of your 700 wrench against the flat on the Brownells’ handle and you are all set.

Finally, I fixture everything up to drill the holes for the Unertl scope.  I covered this process in another post, so I won’t cover it here.  See Gunsmithing basics: Tapping a blind hole for more information.

After everything was put back together Kevin headed to the range with his new rifle!

Looks great!  But does it shoot?

It sure does!  This is a generic hand load he developed with the 168 SMK.

This project was a lot of fun.  In the gunsmithing and precision rifle world we tend to get stuck on projects with expensive parts.  Working on a well used rifle and a collection of surplus parts with a new barrel was great fun!  Now I just have to get to the range with him so I can shoot it!

To learn more about Precision Matthews lathes, click here.