Barrel a Remington 70o without a lathe? With a short chambered barrel, no lathe, no problem!
Pre-threaded short chambered barrels allow a gunsmith to replace the barrel of a rifle without the use of a lathe. A vise, action wrench, depth micrometer, reamer and headspace set allow for installation.
A short chambered barrel is one that has the threads cut to the factory specifications, a bolt nose recess (in the case of a Remington 700), and a chamber that is cut too shallow for final head space. This is the “short chamber” part of the barrel. The short chamber allows for variation in tolerances among different receivers. By reaming the chamber to the final depth, the short chambered barrel can be safely head spaced on the rifle.
While a short chambered barrel is typically harder to install than a Savage or Remage barrel nut style, they offer a much thicker shank and finished look. In my opinion, they are well worth the effort over a barrel nut system design. To learn more about the Remage barrel system, see Rebarrel a Remington 700 without a lathe: McGowen’s Remage barrel conversion. To learn more about the design differences between a Remington 700 and Savage 10/100, including how barrel shank thickness differences in both, see Remington 700 versus Savage 10/100: Comparative design notes.
Short chambered barrels are available for a number of rifles but most commonly encountered for the Remington 700. To see some available short chambered barrels from Shilen, click here and here, and from Satern, here. Satern and Shilen both make outstanding barrels, I would be happy with either. The best part is the price. In most cases, these pre-threaded barrels cost about the same as an unfinished blank (I assume this is due to economies of scale). That means for the money you would have spent having someone else machine the barrel, you could buy a few tools and do it yourself. How cool is that?
While some short chambered barrels are available from barrel makers, the short chambered barrel I’ll be installing in this post, had been threaded and chambered by me, for another rifle. When I measured it against the action shown here, the chamber was short. The process shown here works in this case as well as with a production barrel such as the Shilen or Shilen shown above.
In addition to using a short chambered barrel as a replacement on a factory rifle, using one on a new receiver allows the smith to build a custom rifle from the group up without using a lathe. How cool is that?
Selecting the new pre-threaded barrel is probably the most exciting part. Satern or Shilen? 308 Winchester or 6.5 Creedmoor? What profile to pick? Once you have your barrel ordered, you’ll be ready to begin.
In this post while I’ll be using a barrel that I have pre-threaded and short chambered, the techniques shown in this post would be similar to those used to install a typical pre-threaded short chambered barrel.
Prior to getting to work on this short chambered barrel, please take the time to carefully read the following disclaimer:
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.
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.
The tools and techniques needed for a project like this are specialized. For background on this post, I would suggest familiarizing yourself with the following:
- Chamber reamers– an overview of chamber reamers, pretty much everything you’d ever want to know about them.
- Blueprinting a Remington 700 action– how to blueprint an action using hand tools.
- Chambering a rifle barrel– the chambering process on an unturned blank using a lathe. While this is heavy in specialized tools, it also provides a good foundation for this discussion.
In addition to these posts, I’d suggest looking at some complete gun build posts which can be found on rifleshooter.com’s project gun page.
Installing a short chambered barrel requires some specialized tools. I ordered the following from Brownells:
- Manson chamber reamer in 308 Winchester
- Head space gauges
- Reamer handle
- Do-Drill cutting oil
- Depth micrometer
- Barrel vise
- Action wrench
If the action already has a barrel on it, the barrel needs to be removed with an action wrench and barrel vise. If you plan on blueprinting or truing the action, now would be the time to do it. The blueprinting process will change the rifle’s head space dimension.
The short chambered barrel I’ll be using for this post is chambered in 308 Winchester. I always like to take a look at the SAAMI drawings of a chamber before I start working. A link to the SAAMI specifications of 308 Win can be found here. Note ammunition sizes run smaller and chamber sizes run bigger. This allows the cartridges to chamber.
This is our action, it should look familiar as it has been used for quite a few different posts. I always begin by measuring the action WITH the recoil lug in place. Alternatively, the action could be measured without the lug in place, however, the actual thickness of the lug would need to be accounted for in the measurements.
WARNING: The lug shown here is a Holland’s oversized recoil lug, this lug is .250″ thick, thicker than the factory .186″ lug provided by Remington on factory guns. Most short chambered barrel will require the factory .186″ thick lug. While you may be able to headspace a pre-threaded 700 barrel on a receiver with a .250″ lug, you’d be creating a dangerous condition with a barrel tenon that is too short and too much of the cartridge case unsupported. On most pre-threaded 700 barrels, the manufacturer assumes an OEM thickness lug, make sure you check the measurements and verify this with the builder if you are in doubt.
The proper tool to measure the action is a depth micrometer, shown above. The distance from the front of the lug to the bolt face is the head space distance. The distance from the front of the recoil lug to front of the bolt lugs, minus .010″ should be the length of the barrel tenon. The difference in the distances from the front of the bolt lugs to the end of the bolt nose would be the depth of the counter bore on the end of the barrel. On a pre-threaded short chambered barrel, the primary measurement of concern is the head space dimension. These measurements are discussed in detail in Chambering a rifle barrel.
This is what a head space gauge set looks like for a rimless center-fire rifle cartridge. This is a set for 308 Winchester. Most gauges are purchased in a two gauge set, “go” and “no go“. These dimensions will vary from head space gauge manufacturer to manufacturer. Typically, “go” will be the minimum SAAMI tolerance. For instance, in the case of 308 Winchester, 1.630″. For rimless center-fire rifle cartridges, the “no go” is normally .006″ above minimum (1.636″ in this example), however, I have encountered gauges .004″ above minimum (1.634″). Because of these variances among manufactures, most gauge manufacturers DO NOT recommend using “go” and “no go” gauges from different manufacturers. A more detailed discussion on head space and head space gauge can be found here.
The set of gauges shown above is a specialty set, made by Forster manufacturing. The gauges are in .001″ increments from minimum to maximum SAAMI specifications to allow precise head spacing of rifles.
This is the short chambered barrel I’ll be using for this post, a Shilen #7 Select Match barrel with a 1:10″ twist that I’ve used on a few different projects. Checking the dimensions from the action shows this barrel will safely work on the action. (Editor’s note: that isn’t rust on the end of the barrel tenon)
To check the headspace dimension, I place a “go” gauge in the chamber and measure the distance from the rear of the headspace gauge to the shoulder of the barrel tenon. This is the headspace dimension of the barrel. In this case, the headspace dimension is longer than the one that is required because the chamber is short and the headspace gauge protrudes further from then end of the barrel than it should.
Depending on the depth of cut, you could either start reaming the chamber with the barrel off the action, which would require a lot of measuring, or thread the barrel onto the action and cut it with a reamer in a t-handle. I think most guys who work with short chambered barrels do it with the barrel on the action, so that is the way we will do it here.
To install the barrel onto the action, the barrel is threaded in place and torqued with an action wrench while the barrel is held in a barrel vise. Normally the barrel threads are coated with a layer of anti seize to prevent the parts from galling and getting stuck together. Sorry about the stock photo above, I didn’t take a picture of our project action being torqued into place.
Barrel vises come in a few different types. The one shown above is a Farrell, its an aluminum vise that two screws to capture the barrel. It is great for removing custom (not factory) barrels and installing new barrels. A bushing barrel vise, like the one Brownells sells, takes a little longer to set up but is a better option if you plan on removing factory barrels. In most cases, my Barrell vise isn’t even close to holding the barrel with enough pressure to allow removal of factory installed tubes.
Action wrenches comes in a few types as well. For heavy duty applications, such as removing a factory barrel, a wrap around action wrench is ideal. For installation and removal of custom barrels, a port (above) or rear entry wrench is easier to use. Use of these wrenches for removal of a stuck barrel can result in bending or warping the receiver and ruining it. For this reason I own both. For a one time project, buy or borrow the one that will meet your application.
I place the barreled action in the vise, insert the “go” gauge and attempt to close the handle on it. The handle shouldn’t close. You NEVER TRY TO FORCE A BOLT HAND down on a head space gauge. The gauge and bolt are removed for the reaming process.
Chamber reamers are expensive and extremely fragile. Care must be taken when handling a reamer to prevent a chip of damage that may ruin in. A reamer can NEVER BE TURNED BACKWARDS. Doing so will damage or break it.
Reamers must be methodically cleaned. You can either use compressed air or a small brush. I use both. After it is cleaned it is lightly coated with Do-Drill cutting oil (Viper’s Venom works well too). The reamer is CAREFULLY inserted into the chamber and gentle pressure is applied as it is turned. The secret here is to go slow and take your time. I would suggest starting with one or two turns at a time as you slowly cut the barrel deeper.
After each pass the chamber should be cleaned and the “go” gauge inserted. It is critical the gauge isn’t placed on a chip inside the chamber, doing so can damage the barrel. Now try to close the bolt. In this case, after a few passes of reaming and cleaning the bolt handle is starting to lower into the closed position. A sign the chamber is almost cut to depth.
After a few more passes the bolt closes on “go”.
I insert the “nogo” gauge. In this case 1.632″ (.002″ over minimum specification- most applications would call for a standard nogo gauge) and try to close the handle. It doesn’t. That means this rifle will close on a 1.631″ gauge but not a 1.632″, so it is head spaced at 1.631″ or .001″ over minimum. Great!
At this point the barreled action should be thoroughly cleaned to remove chips and oil (the chambering process can be quite messy).
That is it! The barrel is installed, head spaced and ready for final assembly. Here is what the finished rifle looks like…
Boom! How’s that for a hand reamer???
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