Re-barreling the M1903A3 Rifle in .308 Winchester

A step-by-step guide for replacing the barrel of a deactivated war trophy rifle.

Story and photos by Frank Jardim

Over the years I’ve seen many otherwise fine rifles with poor barrels sell cheap because barrels are usually the most expensive part on the gun and the gunsmith’s labor to install it was never going to be less than a C-note for the most simple replacement job.

Vintage 20th century bolt-action military rifles are among the easiest and most economical to re-barrel. It’s not particularly hard, as long as you have a replacement barrel and the right tools. Though you can change a barrel with a bench vise and a pipe wrench, to do the job like a pro requires a pro’s tools.

Your savings in gunsmith labor will pay off the investment in the first two or three jobs. My first job was a .308 Winchester conversion of a reclaimed DEWAT (deactivated war trophy) M1903A3 Springfield drill rifle I bought from the CMP (Civilian Marksmanship Program) many years ago. THE 1903A3 IS one of the easiest guns to re-barrel. A lot of this has to do with the availability of excellent quality replacement barrels from Criterion Barrels (criterionbarrels.com). The CMP uses Criterion barrels in their restoration shop and after installing thousands of them, has never had one fail to index properly. Criterion actually makes barrels for all the American service rifles, from the Krag to the AR-15, and a couple British guns too. Their barrels are match grade quality at a bargain price, thanks to a highly refined manufacturing process.


The 1903A3 barrel costs $219.99 and is a direct replacement for the original, lacking only the U.S. Army Ordnance roll stamp. The threads are properly timed and the mark stamped on the side; the extractor slot and front sight key are cut, and the barrel is parkerized. All you need to do is screw it on and set the headspace. Since the barrel has to index in a specific spot to keep the front sight properly oriented, the barrels are all short chambered by .010 inches so they can be finish headspaced to suit your rifle.


Criterion was a pioneer in the development of match grade button rifling. They do all their barrel machining operations in-house, including finishing their own rifling buttons. Before the bore of the barrel blank is rifled, it is lapped to remove tool marks until mirror smooth. When the rifling button is drawn through, by a custom-built CNC machine, the resulting lands and grooves are consistently uniform. Their ordnance-grade 4150 chrome moly barrel steel is stress relieved before and after the rifling process to maintain dimensional integrity during machining.
The specialty tools required for this project were an action wrench, chamber reamer and headspace gauges. You’ll also need some quality sulfur-based cutting oil like Brownells Universal Do-Drill. The vise and wrench need to be bought or made, but the reamers and gauges can be rented from several companies for a fraction of what it would cost to buy them if you don’t see yourself doing another gun in the same caliber again.


Customarily, the barrel is held still in a vise while a specialized action wrench is used to torque the receiver on or off. The action wrench jaws are designed to disperse force around the ring of the receiver so it won’t be crushed or bent. The Brownells tools I use are excellent quality and so rugged, they seem indestructible. The Brownells barrel vise bolts to the workbench and uses split shim inserts of various diameters to grip the barrel between the base and top plate secured with four massive socket head bolts. Aluminum bushing inserts protect the barrel from marring.
Cost for the vise and a #8 (1.175-inch) bushing for the 1903A3 Springfield was $149.99. Additional bushings in other sizes cost $29.99. Brownells’ action wrench is comprised of a universal handle that fits about 20 custom upper jaws that bolt on to match the receiver. The wrench with the Springfield upper jaw was $124.99. Additional jaws for different guns cost $40 to $70.

MY PROJECT RIFLE was a re-activated DEWAT drill rifle originally sold by the CMP. They were DEWATTED for parade use by breaking off the tip of the firing pin and gas welding: the firing pin hole on the bolt face closed, the barrel to the receiver, the magazine cut-off down so the bolt can’t be removed, and finally a hardened pin in the chamber. Some were very lightly welded and their receivers were restored to function by cutting the barrel and cut-off away through the weldment and leaving the receiver itself intact. Contours were restored with careful filing and a Dremel tool before reparkerization. Some surface defects from the original weld, and the heat that made it, will remain visible in the finished receiver and are easily detected on an assembled gun in the exposed cut-off area.


While my drill rifle was a great candidate for reactivation because of the light welds, not all of them are. Some welders were sloppy. I’ve seen reclaimed receivers that were reparkerized and showed big halos around the weld area where a lot of heat was put into them with the torch. I’d question the heat treatment and safety of those.
For the record, the CMP doesn’t advocate the reactivation of DEWAT rifles for the simple reason they can’t certify them as safe. They will also disqualify competitive shooters using them at the CMP matches if they discover it during their safety inspections. They’ve found rifles put together on receivers so heavily, and needlessly, ground on the bottom of the ring that barrel threads showed through the .030-inch gap! They’ve also had plenty come into their shop for work, some from customers who had no idea their rifles were built on reactivated receivers.
Their policy is to inform the customer, and if the customer still wants the work done and signs a waiver holding them harmless, the CMP will do the work but won’t certify the gun as safe. As such, they replace the firing pin with a deactivated one and return the finished rifle in a non-firing condition along with original, undamaged firing pin. What the customer does from there is on them.


BEGIN THE BARREL swap by applying some penetrating oil to the receiver ring/barrel junction inside and out over the course of a few days. I’ve been a fan of Kroil brand and I’m still using the gallon can I bought 10 years ago. While the oil is doing its thing, set up your barrel vise. Find something solid and heavy to mount it on with two ½-inch bolts. The left side of the bench is preferred because the weight of the bench helps to stabilize it when you are trying to torque off a stubborn barrel. Always clean the oil off the barrel and receiver with solvent before clamping. You don’t want them spinning in your tools.


Once clean, install the bottom barrel bushing, barrel, then the top bushing and cap. Start all four bolts in their holes and adjust the position of the barrel before you tighten them so the receiver wrench handle is where it’s easiest for you to work with. Since the 1903A3 barrel has a short shoulder, only the front two bolts on the cap do the hard gripping.
The two rear bolts just serve to keep the cap level and the force evenly applied. Get those front bolts as tight as you can with an Allen key alone and then give it an extra short push with the leverage of a 10-inch pipe extension on the tail of the Allen key Before mounting the receiver wrench, make a protective shim for the receiver ring to protect it from getting marred. I cut a strip from an aluminum soda can, wrapped it around the ring and taped it in place. The receiver wrench has a cut-out on the head for the recoil lug. The top jaw is relieved for the extractor hump. Screw the top jaw down evenly until it’s tight enough that it doesn’t slide or wiggle on the receiver ring. Don’t “go caveman” and overtighten or you can crush the ring.
With the wrench securely on the receiver, put your weight on the handle, turning counter-clockwise, until the receiver turns free of the barrel. If you need more leverage, slip a section of 1½-inch steel pipe over the wrench handle. Once you get it off, clean up the threads of the receiver ring with a wire brush and solvent to get any rust and dried grease out.
Mount the new barrel in the barrel vise, leaving enough exposed to see the witness mark on the left side of the barrel. I orient the mark facing up so I can see it easily and it puts the wrench handle pointing downward and to the left so I can lift it, rather than pull it. Grease the barrel threads, hand-tighten the receiver on, and wrap and tape the aluminum can shim back on before re-attaching the action wrench.
Have good light on the work so you can see where the witness marks are on the barrel and receiver. They will be easier to see if you fill them with white crayon. Before tightening, mine were about 3/8 of an inch apart. The barrel shoulder has about .003 inches to .004 inches of lateral crush against the receiver once tightened. That’s what holds it on.
Get a firm grip and lift the wrench handle to snug up the receiver while watching the witness marks. You may have to tighten and loosen the receiver a few times to set the threads before you can get the lines on the barrel and receiver to meet up and it’s been known to take up to 60 pounds of torque. Those witness lines can play tricks on your eyes.
Proceed slowly so you don’t overshoot the mark. There’s enough elasticity in the steel to recover from a few degrees of overtightening, but too much and you’ll deform the shoulder so much you’ll never get the barrel to snug up without pressing the shoulder back down. Lacking heavy rollers, you could carefully peen the shoulder back down with a hammer.
Be aware of the witness lines to get the barrel and receiver close enough to the ideal position that the rifle can be zeroed with sight adjustment. It might be perfect, or it might be slightly off when you meet those witness lines up. You may want to place a machinist rule or similar perfectly straight narrow object in one of the front sight key flats and see if it is parallel to the top of the rear sight base when you sight down the barrel. If it’s not, now is the time to make fine adjustments.

ONCE YOU HAVE the new barrel mounted, it’s time for the precision work of setting the chamber head space by hand-reaming the chamber to get it perfect for your receiver/bolt/barrel combination. I put a new bolt in this rifle but shot it enough with .30-06 to wear it into the receiver. If you are using a brand new bolt in your newly re-activated receiver, the time to lap the lugs to the receiver is now. You probably wouldn’t gain much head space as the bolt wears in if you didn’t. I wouldn’t expect .0005 inches as the high spots wear down, but I’ve been told by people who shoot better than I ever will that it helps accuracy if you lap the bolt lugs in.
There are two ways to finish ream a chamber. You can use a pull-through reamer or a standard reamer. The easiest (and only way for semi-autos) is with a pull-through reamer, which is turned from the pilot at the tip by a slender rod that extends through the barrel and out the muzzle. You improvise a handle at the end of the rod at the muzzle to turn it. A donut-like bearing slips over the back of the reamer, which is engaged by the bolt face. You put forward cutting pressure on the reamer by pushing the bolt into the battery.
The reamer itself is dimensioned to the exact size of the go gauge. Thus, when the bolt closes, you’ve cut the headspace perfectly to the minimum dimension…at least in theory. To be on the safe side, I wouldn’t ream it all in one pass. Stop with the bolt about 1/16 inch from lock up, clean everything up and check the headspace with the go gauge. There’s only .005 inches of difference between the go and no-go. There’s no downside to a pull-through reamer.
DEAD FOOT ARMS


So why doesn’t everyone do it this way, you ask? The tool costs more. Brownells.com sells the Clymer pull-through reamer, rod and bearing for $190, compared to $105 for a standard reamer. A quick online check of mail order three-day rental prices showed around $65 for a pull-through setup and $29 for a standard reamer. By the way, go and no-go headspace gauge sets cost $58 to buy from Brownells.com but only from $7 to $9 to rent. All these prices exclude shipping costs. You can find rental pull-through reamers in the U.S. martial calibers, but I’ve yet to find a firm renting a caliber outside of those. For this reason I chose the standard reamer, available in all calibers, to demonstrate a technique that will work on any bolt action. Regardless of the reamer you use, you need sulfur-based cutting oil to lubricate the tool and chamber. You’ll also need a means to clean the chips of metal off the reamer and out of the chamber at numerous intervals so you can take accurate headspace measurements. I suggest shop air pressure and a blow gun, but spray WD-40, a toothbrush, cleaning patches and a cleaning rod will get the job done. A small magnet you can reach into the receiver ring with is also very helpful to retrieve your headspace gauge. A standard chamber reamer is pushed and turned from the chamber end of the barrel and requires careful use to prevent cutting an oval chamber by tilting it off center with the bore axis while turning. The use of some sort of bushing to stabilize sideways movement of the driving extension is preferred, but skilled hands have finished chambers perfectly without bushings.

BY GOOD LUCK, I found an old 6-inch long 3/8-inch ratchet extension rod with a .694-inch head diameter. My Springfield bolt body measured .695 inches, so the extension was a near perfect fit. All bolt actions have a little play between the bolt body and the receiver to allow for a sliding fit. To take up that slack, I wrapped a single lay of shiny Scotch tape around the ratchet extension head to bring the diameter out to .698 inches and take up the play.


The extension rod head is supported on three points of contact in the bolt way and needs to be held against them by hand during reaming. To support the rear of the extension rod steady and on center with the bore, I made a bushing on my lathe that fit in the rear receiver from a 7/16-inch nut and then chucked up the bushing and burnished the threads to fit the rod body with the rod itself. The bushing is held in the right place on the extension rod with a tight rubber O-ring.
Keep in mind that the maximum amount of metal you are removing from the chamber of a short-chambered Criterion M1903A3 barrel amounts to no more than .010 inches. That’s not quite the thickness of three sheets of printer paper. Cut with great care because if you overdo it, you can’t undo it. The barrel might be salvaged by cutting back the shoulder and re-profiling the breech and extractor cut, but that’s a lot of work and requires a lathe and mill. The main disadvantage of using a standard reamer by hand is that you don’t know how far you have cut until you check the headspace. In fact, this method is often referred to as the “Guess and Check Method.”
Establish your starting point by checking the clean, uncut, short chamber with the headspace go gauge and a clean, dry, stripped bolt, noting the position of the bolt handle. You might want to take a picture of it with your cell phone, looking at it from the rear as if you were shooting. Where on the clock face is the bolt handle when closed on the gauge? How much it moves clockwise after your first cut will give you an idea of how much metal you are taking off with each turn. Obviously, you need to keep the pressure consistent too. When checking headspace with the barreled action held vertically, the headspace gauge can be easily retrieved with a magnet. When I hand-finish ream a chamber, I clamp the barrel vertically between wood blocks in a bench vice because it’s easier for me to see what I’m doing and flush away the chips after cuts.
The oil and chips run down the barrel onto a piece of cardboard on the floor underneath, not back into the chamber area. Before inserting the reamer, it and the chamber are doused wet in cutting oil. The driving extension rod is then connected, followed by the rear bushing. Adjust the rubber O-ring so the rear support bushing is visible in the receiver’s cut-off slot.
A reamer doesn’t need much forward pressure to cut and it is only turned clockwise. You are either cutting or standing still. Never go backwards or you will dull the tool. Proceed carefully. Make your first turn/cut with gentle pressure and withdraw while turning. Remove the whole driving tool from the receiver so you can put it out of harm’s way on a clean piece of cardboard on the bench while you inspect. Look at the reamer and the chamber. There should be small metal shavings (chips) from the cut on the reamer’s shoulder and in the chamber shoulder. Blow or brush the chips off the reamer with a toothbrush and flush clean with WD-40; set it aside again.
Next, clean the chamber and inside of the receiver ring of all chips and dry it. The oil film can add .001 inches to your measurements, so it has to go before inserting the go headspace gauge and your dry stripped bolt again. See how far the bolt closes now. The new position of the bolt handle will give you a feel for how far you have cut and how far you still have to go. Then douse the chamber and reamer with cutting oil again, reinsert it along with the driver and bushing, and make another cut. Repeat the oiling, cutting, cleaning, checking process until the bolt just closes on the go gauge. At that point, you have set your rifle up with minimum headspace and you are done.

The process is more tedious than complicated, the most challenging aspect being devising the extension and bushing needed to drive the reamer in-line with the bore for a perfectly concentric chamber. If this seems like too much trouble, there happens to be another very economical option in the specific case of the M1903A3 Springfield. The CMP offers the best deal in town to people qualified under their program as part of their commitment to support competitive shooters. Their shop will sell you a brand new Criterion barrel, installed and headspaced on your functional and serviceable receiver for a total of $275 plus $29.99 shipping. Visit their website at thecmp.org for the details on that.