Empower Yourself: Build a Custom Rifle at Home

You can assemble and attain outstanding rifle performance without outsourcing efforts.

June 24, 2024 By Tom Beckstrand

Anyone looking for a new bolt-action rifle historically had two options: The first, and most common, was to buy a rifle from a rifle manufacturer. The second was to buy a rifle from a custom gun builder. The custom route was more expensive, but allowed the consumer to get exactly what he wanted.

There is now a third option that offers all the advantages of a custom rifle without the expense and delay of having a gunsmith build it. The rifleman can separately buy a receiver, pre-fit barrel, trigger, stock and bottom metal and put those components together at home without needing to do any fitting. The only tools necessary are a barrel vise and an action wrench. American rifle manufacturing has become so precise that a rifle assembled at home will headspace correctly and be safe to fire.

THE BIGGEST CHALLENGE

There are three dimensions that determine whether a rifle will headspace correctly. Headspace is defined as the distance from the bolt face to the chamber feature that limits cartridge penetration in the chamber. The feature that stops cartridge penetration usually impacts the case’s shoulder but can also impact the case’s belt, if it has one.

rifle action and barrel — Using "go" and "no-go" gauges ensure your rifle is within the appropriate tolerances for the desired chambering. (Photo courtesy of Mark Fingar)

The first feature that determines headspace is the distance on the bolt from the back of the bolt lugs to the bolt’s face. The second dimension is the distance from the receiver’s internal lug abutments to the receiver’s face. The final measurement that matters is the barrel’s shoulder (that impacts the receiver face) to the cartridge chamber depth. There can only be .003-inch cumulative variation in these three dimensions for a rifle to still headspace correctly. The receiver has historically been the limiting factor in this equation. Receivers are the largest component and it’s harder to control dimensions on large parts because even steel moves around when it’s cut. Receivers also comprise two-thirds of the critical headspace dimensions. However, when a receiver is done right, the rifleman can order a barrel in the mail, thread it on and go shoot with total confidence that everything headspaces correctly.

The Heart of the Rifle

The Zermatt Origin receiver used in the rifle seen here has a Remington 700 footprint and is the lowest-cost receiver capable of controlling dimensions to the required level. Two companies have been making bolt-actions capable of holding tolerances like this for some time: Zermatt (formally known as Bighorn) and Impact Precision. Both companies have their roots in the precision-rifle-competition world, which has a demanding clientele. There are quite a few features on the Origin that make it ideal for the frugal do-it-yourselfer. It’s a two-lug action with a 90-degree bolt lift and has controlled-round feed, a fixed ejector and offers toolless disassembly. Simply twisting the bolt shroud allows the firing pin assembly to be pulled rearward and out of the bolt body. This is useful in the event of a pierced primer because fixing it only takes a few seconds with Zermatt’s design.

The Origin also has bolt heads that are removeable from the bolt body. Swapping bolt heads allows the shooter to move from anything with a .223 Remington case head, to a PPC/Valkyrie/Grendel/ARC case head, to a .308 Winchester case head, to a magnum case head. The feed lips cut into the receiver’s underside mirror a Remington 700, so hinged floorplates and AICS-pattern magazines both work.

bolt and handle — The Origin bolt features removable bolt heads allowing the user to adapt the action for a variety of cartridges. (Photo courtesy of Mark Fingar)

Where the Origin separates itself from other custom actions is the safety factor. The things people will do at their loading bench never cease to amaze me. One (sadly) common practice is to disregard loading manuals because “those are written by lawyers!” No, they are not. Loading manuals are developed with instrumentation that measures pressure and listed maximum loads should be considered a hard stop in anyone’s load development. Exceeding those loads guarantees chamber pressure will exceed 65,000-ish pounds per square inch (psi). Throw in a rainy day or an obstructed bore and pressures spike quickly. There is no reason to exceed maximum loads listed in manuals.

Zermatt understands that occasionally the unthinkable happens, so they’ve done extensive high-pressure testing on the Origin. The first indicator that some engineering went into making this receiver safe are the two ports near the receiver face. If a cartridge ruptures, these ports vent the gas away from the shooter. If the gas is of such high pressure that it forces its way down the bolt body, there is a port in the bolt body that faces down into the magazine well when the bolt’s closed. Gas will move out that port and down into the magazine well, away from the shooter. If the high-pressure event is so extreme that it forces the bolt rearward, the bolt handle is designed as a lug that will collide with the receiver body, stopping any movement rearward.

Magazine and bottom metal — Depending on the bottom metal you choose, you can have flush-fit or AICS-pattern magazines. (Photo courtesy of Mark Fingar)

Zermatt so thoroughly tested the Origin that they even welded a plug in the barrel and then loaded a cartridge that created chamber pressure right around the 125,000-psi mark. All three ports vented gas, the bolt handle stopped the bolt from coming rearward, and the receiver split forward of the gas ports to the receiver face. The action did not explode, and it routed the blast away from the shooter. All of this is included in the lowest priced action capable of taking pre-fit barrels.

Build-Ready Barrels

The action is an important place to start, but the next most critical component of a DIY rifle is the barrel. Any receiver can be sent to a gunsmith to have a barrel fitted to it. However, many gunsmiths already have the prints for the Origin and other actions capable of taking pre-fit barrels and can cut one for you at any time and then just drop it in the mail. This eliminates the need of sending a receiver to the gunsmith with the wait time associated. Many of the larger gunsmith shops keep barrel blanks in stock and can cut and spin whatever is needed. I reached out to Gray Sloan at Swift Creek Rifles for the barrel on this rifle. I told him I had an Origin action and wanted a hunting barrel chambered in 6mm Creedmoor. Turnaround time from placing the order until the barrel arrived on my porch was nine days.

I’ve known Gray for several years and wanted to pick his brain on pre-fit barrels and his experience with various custom actions. When I asked about his experience with the Origin, Gray said: “Each one we’ve measured is dead-nuts on. There are no variations from one action to another. The only action we’ve seen match it is the Impact." Gray also explained the gap between a “go” and a “no-go” gauge is .001-inch to .004-inch. If you cut to the short end of “go” at .001 inch, it’s not uncommon to have a slight crush on factory ammunition when closing the bolt. Swift Creek Rifles cut my barrel to .002-inch headspace and it fit and functioned beautifully. I was in a hurry when the barrel showed up at the house, so I grabbed it and headed to the range. I ran a dry patch through it, screwed it on hand-tight, bolted the barreled action into the stock and started shooting. The results were exceptional accuracy for three-round groups at 100 yards. (See attached table for details.)

accuracy test results — (Accuracy test table provided by Tom Beckstrand)

Once I got home, I did the right thing and tightened the barrel to about 80 ft-lbs. There are only a few tools needed to build a rifle at home, but a good barrel vice is one of them. I have the Bravo Vice from Short Action Customs (SAC) and it carries my top recommendation. SAC uses inserts to fit different barrel contours, so one wrap of drywall tape to protect the finish and into the insert is all it takes to immobilize any barrel. Next, I used SAC’s modular action wrench to tighten the Origin onto the barrel. That done, the only other tools are a hammer and punch to drive in the two pins holding the Trigger Tech trigger. I put a two-stage Diamond trigger in the test rifle because that’s what I had, but a regular old Trigger Tech Primary would be ideal for a rifle like this one. That trigger sells for $165.

The final two pieces I used for the most economical DIY rifle are the Grayboe Eagle stock and Hawkins Precision Hunter bottom metal and magazine. The Grayboe Eagle is made from fiberglass epoxy matrix, so it is rigid and relatively light. There are lighter stocks out there, but the Eagle has aluminum pillars to support the action, quick-detach sling-swivel cups in all the right places, adjustable comb height and adjustable length of pull. It can be made to fit the shooter and that’s invaluable when trying to spot impacts on your own shots, a practice that is essential for any hunter.

adjustable comb on stock — Grayboe's Eagle stock is a great option for precision-minded hunters. It features an adjustable comb for a customizable fit. (Photo courtesy of Mark Fingar)

The Hawkins Precision Hunter bottom metal lets the Hawkins hunter magazine mount flush enough that it doesn’t get in the way and still holds four rounds of 6mm Creedmoor. This bottom metal has a cantilevered magazine release tucked inside the trigger that will not release under recoil. The magazine release is also adjustable.

A rifle like this is more expensive than what’s found in the gun store but considerably less than a custom rifle. The Origin action sells for $900, a stainless steel pre-fit barrel without Cerakote or a threaded muzzle runs about $650, the Grayboe Eagle is $570, the trigger is $165, bottom metal is $200 and the Hunter magazine sells for $120. AICS-pattern magazines are available for about $50, so having one that is flush-fit costs a premium. All in all, this rifle costs $2,605 to build at home and that’s about as cheap as it gets. One way to knock the price down a bit is to buy a KRG Bravo stock that’s about $200 cheaper, but also about 10 ounces heavier than the Eagle. Both are good selections.

This isn’t the cheapest way to get into a rifle, but it’s a fair price for the type of rifle that can do things that factory-built guns can’t. I could re-barrel this one to a .223 Remington or 6.5 PRC in about five minutes and it would cost $775 for the bolt head, barrel and magazine to do the conversion. Choosing to do a DIY rifle is a great way to get exactly what you want while spending the least amount of money possible.