Rifle Actions

(Here's another old article of mine. Again, the information is out of date.)

Rifle Actions
I’m going to give you my impressions of some of the rifle actions that are available and suitable for building into a sniper rifle. I’m not going into extreme detail. These are just the features and attributes that stick in my mind. I haven’t worked with every action out there. For example, Weatherby actions are good, strong actions but I’ve never been called on to customize one and I’ve only had to repair a couple of them. If an action has only been out for the last five or ten years, I’m probably not familiar with it. If an action has been brought out in the last two years, I can about guarantee I’m not familiar with it. I won’t concern myself with actions that I consider unsuitable despite being very familiar with them (88 commission Mauser for example). I also won’t address the .50 BMG actions.
I don’t have examples of each of these actions on hand so, if I make a mistake or miss something, please give me a break, but feel free to correct me.
My personal choices for building a bolt-action sniper rifle would be the Winchester M70 Classic or the Ruger M77 MkII. For a specialty weapon I might select one of the custom actions. In a semi-auto I’d use one of the AR variants like the Stoner SR25.
Remington M700: The Remington 700 is probably the most used action for building precision tactical rifles in the U.S. The Marine Corps M40 series and the Army M24 are both built on the 700. It used to be common for benchrest shooters to have a 700 action fitted with an aluminum sleeve to stiffen the entire action. Right now, it would be less expensive and more effective to simply buy one of the full custom benchrest actions. The Remington 40X is the target version of the M700.
Pros-
Fast lock time- The faster the lock time the better as there’s less time to disturb your aim between when the trigger is pulled and when the round finally ignites. Also, a fast lock will usually induce less vibration into the action as it fires. Lock time is not actually critical in a field rifle and actions with a slower lock time are quite suitable.
Adjustable trigger- The Remington trigger is easily adjusted for both sear engagement and pull weight.
Round action- A round bottomed action is easier to bed than one with a flat bottom. The round action is also easier to work on when it’s chucked up in a lathe.
Spring plunger ejector- A spring plunger ejector assures that, no matter how slowly you open the action, the fired casing will be thrown clear of the action.
Aftermarket parts and service- Everybody makes parts for the 700. Everybody works on the 700. Finding a gunsmith familiar with the 700 is no problem. Top quality aftermarket parts are readily available.
Cons-
Adjustable trigger- A trigger that’s easily adjusted gets out of adjustment easily. The fully adjustable triggers are also more complicated and delicate than non-adjustable triggers. There’s also the temptation to play with an adjustable trigger. Much of my work consisted of repairing triggers and actions that had been “adjusted” by the customer.
Spring plunger ejector- A spring plunger ejector is easily jammed with dirt or corrosion. Sometimes it’s not desirable for a sniper that his fired brass be flung from the action as the flash can attract attention.
Small extractor- The small spring extractor on the Remington isn’t prone to failure but it is less durable and grabs a smaller portion of the case rim that some other extractors. If a case sticks sufficiently, a small extractor may tear through the rim more easily than a larger extractor. The Remington extractor can also be difficult to replace in the field. None of this is a real big deal but it’s something to consider. It’s common to modify the bolt on a 700 to accept a Sako style extractor.
Push feed- The extractor doesn’t engage the rim of the cartridge until the bolt is pushed all the way forward where the extractor snaps over the rim. If you were to fail to push the bolt all the way forward, and then try to feed a second round, it is possible to have a double feed and jam the rifle. Correct manipulation of the bolt will prevent this.
Round action- Although a round bottom action is easier to bed, it has a tendency to twist in the bedding; thus the obsession with how far to torque the action screws. (The Marines use a minimum of 65 inch [not foot]-pounds. The Chandlers suggest 85 inch-pounds.)
Separate recoil lug- The recoil lug on the 700 is not attached to the receiver. It’s held between the receiver and the barrel when the barrel is screwed in. This is a potential problem if the lug is loose or isn’t machined square on both faces. The Marines have gone so far as to weld the lugs to the receivers on their M40A3 rifles.
Mauser 98 (CZ, Mark X, etc.): The Mauser 98 action has been produced by a number of companies with minor variations. My personal favorite is the CZ or Brno action.
Pros-
Large extractor- The 98 series has a huge claw extractor that engages a significant portion of the cartridge rim giving plenty of extraction power.
Fixed ejector- A fixed ejector allows the sniper to eject a case with as much or as little force as desired. By slowly pushing the bolt back with the back of the firing hand thumb, the round will be tipped out into the firing hand fingers for easy collection. The same technique with a spring plunger ejector is just a bit trickier.
Integral recoil lug- The relationship between the lug and the receiver is consistent. There is no problem with the lug twisting in relation to the receiver under recoil.
Controlled feed- With a controlled round feed the rim of the cartridge slides under the extractor as the round comes up from the magazine. The cartridge is held by the bolt as soon as it clears the magazine and reduces the chance of a double feed due to incorrect bolt manipulation. I prefer a controlled feed but I don’t consider it an absolute necessity.
Cons-
Slow lock time- The lock time on a Mauser is relatively slow. I wouldn’t use a Mauser to build a benchrest gun or a high-end varmint rifle but it is still suitable for most long-range field shooting.
Fixed ejector- If you want your fired casing to be ejected with force, you must remember to work the bolt briskly. It’s possible to leave a fired case in the action if you work the bolt too slowly.
Winchester M70 Post-64: This is the action that Winchester designed to replace the M70 in production until 1964. It may actually be a slightly more accurate action than the pre-64 version. This is the current standard production for the Winchester M70.
Pros-
Good extractor- The extractor isn’t as big as a Mauser but is larger and stronger than the Remington.
Integral recoil lug
Flat bottom receiver- The flat bottom receiver is a little more difficult to bed than a round bottom, but it doesn’t twist in the stock when fired. The bedding will hold up a bit better and action screw torque becomes less critical.
Spring plunger ejector
Simple trigger- The M70 trigger is adjustable for pull weight by turning two locking nuts. Adjusting the engagement surfaces must be done with a stone. The trigger is simple, durable, and easy to maintain. The M70 trigger is very unlikely to get out of adjustment.
Availability of aftermarket parts and service is nearly as good as the Remington.
Cons-
Push feed
Spring plunger ejector
Slow lock time
Thin receiver ring-The receiver ring where the barrel enters is a bit thin on the M70. If you want to put a really long, very heavy barrel on a Winchester, you may see more flex in the action than you would with a Remington. This is not a big concern, especially with the medium-heavy barrel contours typical to a sniper rifle.
Winchester Pre-64/Classic (Dakota 76): Winchester offers a model 70 action they call their Classic. The Classic is similar to the old pre-64 action and closer to a Mauser 98 action. The Dakota 76 is also similar to the pre-64 M70.
Pros-
Large extractor- The Classic uses an extractor similar to the Mauser.
Fixed ejector
Simple trigger
Controlled feed
Cons-
Thin receiver ring
Slow lock time
Fixed ejector
Ruger M77 MkII: This is the action currently used in the Ruger M77. The older M77 was a little different. I don’t care for the three position safety on the new model, but overall I feel the design is superior to the old M77.
Pros-
Large extractor
Fixed ejector
Great floorplate latch- I think the floorplate latch on the M77 MkII is simply the best in the business. It absolutely won’t open under recoil and it is well protected against bumps.
Mechanically simple- The M77 MkII action has very few moving parts; fewer parts, fewer problems. Maintenance is easy on the M77.
Strong- Ruger has always overbuilt their actions. The M77 is plenty strong.
Integral bases for scope rings- The receiver on the Ruger is machined for special rings. This means the rings are pretty much recoil proof but it also limits your options versus a Weaver or Picatinny type rail.
Non-adjustable trigger- The MkII trigger is simple and easy to maintain. It has no provisions for adjustment so the surfaces must be stoned and the spring clipped or replaced to change the pull. However, once a MkII trigger is tightened and adjusted, it won’t get out of adjustment.
Integral recoil lug
Diagonal bedding- The forward action screw on a M77 is set at a diagonal and pulls the action down and back into the stock. This is a particularly effective method to mate the receiver with the bedding and produces excellent accuracy potential.
Flat bottom receiver
Controlled round feed- Early MkIIs used the push feed. Current models are controlled round.
Cons-
Sloppy tolerances- Newer Rugers may require considerable truing and tightening.
Integral scope bases- Specialty optics may need to be mounted further forward or rearward than the Ruger rings allow. Also, shimming Ruger rings for extra elevation is difficult enough to warrant machining up a custom set or using Burris rings.
Lack of aftermarket parts
Sako
Pros-
Machined to insane tolerances- You don’t have to true a Sako action.
Three locking lugs- Makes for a short bolt lift.
Good extractor
Fixed ejector
Fast lock time
Cons-
Integral bases for scope rings
Lack of aftermarket parts
Custom actions (Hall, Stolle, Geske, Gilkes, BAT, Time Precision, Nesika Bay, etc.) : There are a number of custom bolt-action makers out there. If you want to build the ultimate 1,000 yard rifle, especially for odd-ball custom cartridges, you’ll go ahead and spring for one of the custom actions.
Pros-
Ultimate in precision and stiffness-Mass production actions just aren’t in the same league with these.
Cons-
Price- These actions will run several thousand dollars for the action alone.
Many of these actions are not available as repeaters.
Non-standard parts- You had better hope the manufacturer doesn’t die or go out of business. If a part breaks, your local gun store is not likely to have a replacement on hand.
Limited availability of aftermarket parts and service.
Semi-autos-
Heckler und Koch: The H&K roller locked action has no gas system allowing the barrel to be free-floated. The PSG1 is very accurate but very expensive and heavy.
U.S. M14/M21/M25: The M14 series is difficult to accurize. Building a sub-MOA M14 is as much luck as skill. The M14 is a chore to bed. The bedding breaks down quickly. The M25 has a recoil lug welded to the rear of the receiver and holds its bedding better than the M14 or M21 but it’s still not great. The gas system causes all sorts of vibration when the rifle is fired adversely affecting accuracy. I love the M14 but its heyday as a sniper’s weapon has passed.
AR15/AR10/SR25: The Eugene Stoner designed AR series of rifles are so easy to accurize it’s scary. There’s no conventional bedding to break down. The gas system has no piston or operating rod to induce vibrations. The barrel can be very nearly free floated. The very light gas tube isn’t attached to the receiver so disturbs the barrel vibrations minimally. Building a MOA AR is a piece of cake. AR receivers are greatly less expensive than custom bolt actions but competitive benchrest guns can be built on them.
BAR: The U.S. Special Forces have built some .300 Winchester Magnum sniper rifles using the civilian BAR. The BAR was more accurate than most of the other civilian semi-autos but used conventional gas system. I had a couple of customers trade their BARs in on bolt guns due to vertical stringing that I suspect was due to the gas system. I haven’t tried to build an accurate BAR myself, and I don’t know how successful the Army’s rifles were. The only real advantage to the BAR is that it will handle cartridges longer than the 7.62 NATO.