We’ve talked a bunch about barrel nut installation setups on AccuracyTech in the past. Specifically Rem/Age style barrel installations where a Savage style nut is used to install a barrel onto a Remington Action. Barrel Nut Installations are becoming more and more popular. Now you see high end, custom actions, like the Bighorn TL3 and Mausingfield being threaded for Savage style threads. This enables the user to install a barrel of their choice. The owner can set the headspace with gauges and lock everything down with the barrel nut. All of this can be done without having to ship the action off or pay the $700-$850 that a rebarrel typically costs.
Barrel Nut Installation
I broke it down in the opening. It’s essentially screwing the barrel into the action until the headspace is correct and using the nut to lock everything in place. When I went to install my new Criterion barrel pre-fit barrel on my new Bighorn action I took photos of the process. This way I can give the readers a visual guide and explanation of the steps involved. It is very simple with the right tools. It takes around 10-15 minutes for a barrel nut installation. You can swap calibers the same way. For example, I could remove my 6×47 Lapua barrel and install a 308 Winchester barrel. Since the bolt heads on the Bighorn TL3 are swappable, I can even go to a 223 Remington for practice. That’s been the plan all along!
Barrel Nut Installation Preparation
The first step in the barrel nut installation is inspecting your barrel. Give it a good look and make sure everything looks right before you spend the time installing it. Check the crown and muzzle threads for any damage or problems. Have a look at the chamber end too. Everything should be polished and shiny. If you see signs of rust or scratches there’s an issue. It should be free of tool marks in the chamber and on the crown area. A wonky crown can cause accuracy issues so make sure that looks good.
The goopy looking stuff on the threads by the chamber is anti-seize compound. You can find it in any auto parts store worth a damn. It helps keep things from rusting and galling inside the receiver after you put everything together. The last thing you need is to try and remove a barrel that’s shot out only to find that it’s basically cold welded itself in place. I try to put a healthy dose of it on there and smear it around the threads with a gloved finger. The barrel nut will help spread it around as it’s installed.
Barrel Nut Installation Assembly
Next up we’re going to start putting things together! I typically start by threading the barrel into the receiver until it bottoms out. Then I’ll unscrew it a couple turns and get to work with the headspace gauges. Once you get the barrel into the receiver it should be a snug fit. If there’s excessive wobble you may have an issue with the threads in the receiver or on the barrel. Properly cut threads should interface pretty tightly.
Once you’ve got the barrel on there and you’re in the ballpark it’s time for the headspace gauges. Headspace is something to be careful with. Excessive headspace allows for room between the shoulder and chamber wall, or between the case head and bolt. You don’t want extra space in either spot. Too little headspace will prevent the bolt from closing or could result in an excessively tight case after firing. You typically see two types of headspace gauges. A GO Gauge and a No GO Gauge. The bolt should close normally with a GO gauge in the chamber. If the bolt closes on a No GO gauge you have too much headspace.
Barrel Nut Headspace
I start with the GO Gauge. Place that in the chamber or work it under the extractor of the bolt and gently close the bolt. Then with the barrel nut loose, thread the barrel into the receiver until you feel it make contact with the GO Gauge. Hand tighten the barrel nut to keep things in place. Don’t bring any wrenches into play yet. We’ll get to that once we have everything set where we want it. Open and close the bolt on the gauge. It should work without being overly tight or difficult. It should feel just like chambering a regular loaded round.
Now that we know the bolt closes on the GO Gauge. It’s time to check it with the No GO Gauge. This gauge has a red stripe of paint on it. Remember that. Red means STOP. If the bolt closes on the No GO Gauge you have excessive headspace. You need to thread the barrel in a touch farther with the GO Gauge in place. Then try it again with the No GO Gauge. You should get what you see in the next photo. The bolt should stop before it cams over and locks in place. The bolt should NOT close properly on a No GO Gauge!
Barrel Nut Installation Lock-Down
Now it’s time to lock it all in place. Follow your manufacturers specs and recommendations here. Take all the gauges out of the chamber. The gauges are made from a denser steel than the barrel. If you leave a gauge in the barrel you can tighten things down and potentially mar your chamber with the gauge when you add a big wrench to the mix. Things move when you put all this together, trust me. Take the gauges out. Put the torque wrench on the nut or the action wrench and torque it to specification. My Bighorn action calls for 40-80 Ft-Lbs for the nut. I set the torque wrench to 50 Ft-Lbs and torqued it down.
Double check everything. Once the action and nut are torqued, check it all. Drop the Go Gauge in and make sure the bolt opens and closes freely. Then drop the No GO Gauge in and make sure the bolt still continues to fail to cam over and lock closed. If something moved you may have to loosen things up again and reset it. After you do this a few times you will have little trouble getting it right the first time. Until you’ve done it a few times make sure you double check everything. Better to get it wrong on the bench and redo it than have a problem with live ammo at the range!