A day with a riflesmith: Supertuning the savage action.
We live in an age of specialists. If we desire the best solution to a problem, an expert with the appropriate skill set is consulted. The medical field is a good example. When, my beloved dog went blind, I took her to our local vet (who is very good) and he verified her condition and referred me to a canine ophthalmologist. Although my vet is highly skilled, he realizes that other vets with advanced training in specific types of surgery are the best option for some patients. End result: she got her sight back.
Gunsmithing is like that. I focus mainly on semi-auto pistol and rifle work. If a customer comes to me with a bolt-action rifle I can help him to a certain extent, but if he really wants to squeeze the last bit of accuracy out of his pet thunderstick, I send him to a master riflesmith for action work and barrel fitting. My bolt gun guy is Lawrence (Larry) P. Racine. Larry agreed to walk me through the process of blueprinting a rifle action for this article.
I've thought for many years that the best gunsmiths are usually machinists. The gunsmithing trade can be broken down into two major categories: armorers and gunsmiths. An armorer repairs firearms by replacing parts. A gunsmith has the skills necessary to fabricate and fit parts.
A gunsmith can thread and chamber a barrel, make a firing pin, mill a scope base from a block of steel, sweat on a front sight and inlet a stock. People with these skills seem to be increasingly rare. Visiting the shop of a true craftsman is a great pleasure for me.
On a warm spring day, I drove through the old mill towns of New Hampshire to Larry's modest shop south of Keene. At 74, Larry is an active gent who spent his youth as a tool and die maker working for the Capital Screw Company in Keene from 1958 until they closed in 1982.
He began participating in NRA Highpower Rifle competitions in 1967 with the service rifle and after shooting a Garand for two years, he moved on to bolt-action match rifles. He quickly received a Master classification and turned his focus to long-range shooting, winning a spot on the 1992 and 1999 Palma teams. In short, Larry not only knows how to build a rifle, he knows how to shoot one.
The Savage 110 series rifles were introduced in 1958 and have been in continuous production since then. The original rifles were designed by Nicholas Brewer and had counterbored barrels so the bolt head was actually surrounded by the barrel shank when the bolt was closed.
The early bolts also differed from current production and the extractor was a band type that wrapped around the outside of the bolt head. The current bolt and barrel configuration was designed by Robert Greenleaf and introduced in 1966.
Changes included a sliding plate type extractor, elimination of the barrel counterbore and a different trigger.
In 2003, the introduction of the user-adjustable AccuTrigger rocked the rifle world and other manufacturers scrambled to introduce safe, light triggers of their own. At this same time, Savage magazines began transitioning from a conventional staggerfeed configuration where rounds fed alternately from the left and right to center-feed with the top round centered in the feed lips.
The rifle action we used as a demo for this article was a Savage Model 11 in 7mm-08 I happened to have in the shop for a new barrel installation. Although I couldn't get an exact date of manufacture from the Savage website it is an Accu-Trigger action with a stagger-feed type magazine so I'm guessing it was produced between 2003 and 2005. Larry and I are both big fans of Savage centerfire rifles and I'll point out some of the reasons why.
The first thing we did after removing the barrel and bolt was to insert a mandrel through the action for lathe work. Larry has made numerous mandrels for various actions, but in this case we used a commercial tool marketed by Brownell's intended for the Winchester Model 70.
Now, you're going to scratch your head and think "wait a minute, the model 70 is 1"-16 thread and the Savage is 1 1/16"-20"? Correct, but the Savage receiver will just fit over the Winchester threads and a 1/4"-28 bolt through the rear action screw hole secures it to the mandrel.
The receiver tang is stopped against the lathe chuck jaw. Ideally, we should be pressing Brownell's to produce a dedicated Savage mandrel. Are you out there, Pete B.?
Another consideration is the fit of the mandrel in the bolt tunnel. A mandrel you purchase or fabricate yourself should be a close fit. The Savage receiver was bored .701" or .010" over the diameter of the bolt body.
With the action secured to the mandrel, we turned on the lathe and observed the receiver face while it was rotating. What we were looking for were off-center threads. Savage receivers are cut from bar stock and heat treated after machining, so a little warping of the finished part is expected.
I'm sure the factory has determined the most efficient heat treatment technique while still maintaining acceptable tolerances and rates of production, but some receivers do exhibit thread run-out that may not be acceptable for a target rifle when the original barrel is being re-installed.
I once had a Winchester Model 70 rifle with off-center threads that were bad enough to cause the bolt to bind slightly when closing it on a cartridge.
Correcting the threads requires them to be re-cut larger. If you try to reinstall the factory barrel after action blueprinting, the threads will be too loose. But if a new barrel is threaded and fitted to the receiver you can simply cut the threads a bit oversized. The threads on this Savage action were fine, so we proceeded to trueing the receiver face.
Ideally, the receiver face must be square to the action centerline and perfectly flat, so the recoil lug bears evenly on it. We made a very light first cut for photos so you can see the runout of our sample receiver.
Obviously, if this face is not corrected, the recoil lug will only contact one side of the receiver ring and tightening the barrel nut may cause uneven pressure on the barrel shank. Any side stress on the barrel or receiver hurts accuracy. We only had to remove four or five thousandths to clean up this particular receiver, Some are better and some are worse.
Now, I know what some of you are thinking ... cutting the receiver face reduces headspace. Well, yes and no. If we were working on a Remington 700 or any other rifle with a fixed barrel shoulder, you would be correct.
Savage rifle barrels, however, have no shoulder, and headspace is adjustable with the barrel nut. So unlike a Remington, if headspace is slightly altered by modifying the receiver face, bolt face or lapping the locking lugs, we won't need a chambering reamer to bring it back to spec.
The barrel nut is one of the unique features of the Savage rifle that endears it to gunsmiths and tinkerers, but it was originally incorporated into the design to ease production, not for our convenience.
Like the receiver face, the bolt face should be flat and square to the center line. If you examine some Savage bolt heads closely, you will note the area around the firing pin hole is lower than the periphery. This irregularity is due to the polishing method the factory employed to de-burr new bolts. They are tumbled in media much like reloaders tumble brass cases.
The bolt is disassembled into its component parts so we can work on the bolt head. Unlike a Remington, Savage bolt heads are interchangeable and easily separated from the bolt body. The extractor and ejector are removed and the bolt head is simply clamped in the lathe chuck to true the bolt face. We removed only a couple thousandths from our sample bolt to clean it up.
The next modification will be adding a chamfer to the leading edges of the bolt head that engage the angled ramps at of the locking surfaces in the receiver. Looking through the front of the receiver, these ramps are at 2 o'clock and 8 o'clock. The chamfers allow the bolt to operate smoothly without a sudden hitch as the bolt starts to close.
Another feature unique to the Savage 110 series rifles is the adjustable firing pin. While the bolt assembly is in pieces, we adjust or at least check firing pin protrusion. Grab the bolt head and push the firing pin assembly into it. Protrusion can be measured with the end of a set of dial calipers using them like a depth gauge:
Larry's formula for firing pin protrusion is the firing pin radius plus .010"--.015". In this case the firing pin diameter is .057" so the radius is .028" and protrusion is set at .038" to .043". The factory setting is usually .050" or more.
A little more firing pin movement results in increased impact energy transferred to the primer. To adjust protrusion, compress the spring and turn the firing pin stop nut clockwise to increase and counterclockwise to decrease.
At the other end of the firing pin assembly is the cocking piece. Adjustment of this nut regulates the amount of compression of the mainspring and firing pin travel. When the rifle is fired, the forward movement of the firing pin is halted when the firing pin stop nut hits the inside rear surface of the bolt head.
The cocking piece pin must never bottom out in the bolt body notch when the firing pin is at rest in the fired position. A little clearance between the pin and the bolt body (around .010") is necessary, but no more than that. Adjustment is similar to the firing pin adjustment: compress the spring and lock washer, turn the cocking piece as necessary.
A tip from Larry when reassembling the bolt: moving the friction washer from behind the baffle to the position between the baffle and bolt head will prevent the baffle from wiping the grease off the bolt lugs.
Lapping the Lugs
The modular design of the Savage bolt assembly allows the bolt head a certain amount of movement, resulting in the lugs bearing evenly against the receiver locking surfaces even if the receiver isn't square. Some people say that lapping Savage lugs isn't necessary. I would say we lap lugs not only for 100% contact but also smooth bolt operation.
Lap the lugs with an assembled bolt and the barrel removed from the action and the trigger assembly installed. Apply lapping compound to the rear of the locking lugs, insert the bolt into the receiver and work it back and forth. The spring tension between the cocking piece pin and the sear results in enough rearward pressure to the bolt lugs to lap the contact surfaces.
Once you are satisfied with the lug contact disassemble the bolt and clean off all traces of lapping compound. The receiver will also have to be cleaned well and a touch of grease applied to the locking surfaces.
Savage recoil lugs are stamped out of sheet steel and are unlikely to be flat. Once again, we want 100% contact between the recoil lug ring and the receiver face. There are two options available: modify the existing lug 'by surface grinding it or purchase a custom aftermarket lug.
Since Larry has a surface grinder in his shop, we simply ground the original part flat, but most people won't have access to this type of machine and very nice ground lugs are available from Brownell's for less than $40.
One side of the lug has a small protrusion that aligns it to the receiver when the rifle is assembled. We avoided this spot, leaving a dark stripe on the lug where it wasn't ground. Some Savage target rifles are currently offered with a nice flat machined lug to replace the standard issue stamped part.
When the barrel nut is tightened, it compresses the recoil lug against the receiver face, and we want 100% con tact between all surfaces so the back of the nut is cleaned up. We used the threaded chamber end of a barrel that had been cut. off as a mandrel with the nut against the lathe chuck jaws. This nut was pretty flat and Larry said they usually aren't a problem.
Although technically not part of truing the action, I include the trigger as part of the overall blueprinting package. The Accu-Trigger is not bad in its original form, but a lighter, crisper trigger pull is possible with a little work on the engagement surfaces.
When I drop off an action at Larry's place I usually ask for the "2-pound trigger." Hey, if it's too light you can always add weight with the adjustment screw.
How much does blueprinting an action affect accuracy? Depends on the rifle. I would say that if you have a rifle that seems to be pretty accurate out of the box, then action work will only improve it. On the other hand, if your rifle simply won't shoot into a bucket, the problem is most likely a barrel and/or bedding issue and action tuning alone won't solve the problem.
For instance, I purchased a Savage Model 11a few years ago in .243 Win that would print 1-inch groups at 100 yards pretty consistently out of the box. The rifle was accurate but I was pretty sure it could shoot better.
Larry blueprinted it, along with trigger work, and groups dropped below 1 inch with the same load. Aside from the action work, it's a stock factory rifle. You will have to decide for yourself if a little more accuracy and consistency is worth the money. Larry can be reached at 603-357-0055 or larry@LPRGUNSMITH.com.