If the CST TF1 action could be summed up in one word, it would be innovative. If one takes the time to really think about the history of the bolt action design, you won’t find a great deal of difference from models available today versus models Paul Mauser introduced over a century ago. What sets our action apart?
Problem: Concentricity
Bench rest shooters get a lot of credit, and rightfully so, for advancements in rifle accuracy. Any one of the shooters at the top of there game will tell you how important a geometrically correct action is to obtain consistent accuracy. More specifically, the bolt must be in line and true to the center of the barrel’s bore with surfaces of the locking lugs seating square and equal. Tight tolerances of the bolt body diameter to the receiver body inside diameter while lapping lug seats square is typically how accuracy minded shooters have tried to achieve this goal in the past. However, a one-to-one fit of the bolt to the receiver would be a recipe for a seized up gun and wouldn’t last anyways once wear sets in. Some clearance must be available to function the rifle without binding, making absolute concentricity impossible.
Problem: Bolt Harmonic Vibrations
Several rifle accuracy theorists suggest perfect timing of vibrations at the exact moment the bullet exits the muzzle will deliver top accuracy for any given rifle. This is what is occurring when shooters “tune” their rifle by using different components and powder charges during handloading. Adjustable muzzle tuners are another example of this phenomenon. Some rifles require a lot of time and effort, not to mention new barrels, to defeat accuracy-robbing vibrations. What causes these vibrations? A lot goes on inside a barrel during firing, but what about mechanical movement from the action itself? A simple example of this would be to release the firing pin forward on today’s actions and feel for any bolt movement. You will detect quite a bit of play allowed once pressure from the firing pin spring has been released. Imagine all that stored up energy on the bolt allowed free just at the moment of firing and it is easy to see how mechanical “banging around” can occur inside the receiver every time the trigger is squeezed.
Solution: CONE-LOKtm BOLT
We address both of these problems with a better bolt design. If you can imagine holding a funnel and dropping a ball inside too large to slip through the spout, you can visualize how the CST Cone-Lok bolt design works. The ball finds perfect center of the spout every time. The conical surfaces of the locking lugs seated into the mating conical surfaces of the receiver will allow the bolt to self-center every time the bolt is closed. But this is only part of the solution. Tapered locking lugs can be found on other actions as well. What makes the Cone-Lok design better is the same geometric interaction occurring at the rear of the bolt as well as the front. A spring pressurized floating bolt handle with a conical face mates into its own conical seat at the rear of the receiver body. The two opposing conical seats forces both the front and the rear of the bolt under pressure to align concentric to center of bore, regardless of bolt fit or wear. But this is the kicker; under pressure from a disk-spring housed in the bolt shroud, the bolt stays locked up concentric totally static throughout sear release and firing pin movement, preventing any accuracy robbing vibrations.
Problem: Angled-Sear Engagement Induced Bolt Lift
Sear override trigger systems are commonly seen on a lot of bolt-action rifles today, particularly American made models. Their simplicity has made them a popular choice with a huge assortment of aftermarket versions available. Unwittingly however, they create a defect when attempting to lock the bolt up concentric and with the lugs equally seated. The angled face of the sear interacts much like a ramp to the cocking piece face. Under pressure from the firing pin spring, the cocking piece will ride up the angled sear face causing the rear of the bolt to rise and the top locking lugs at the front of the bolt to move slightly forward, off their respected seats. All this creates misalignment of the bolt to center of bore, unequal lug seat pressure, and more mechanical movement of the bolt when the energy stored up by the firing pin spring is released. The importance in preventing these conditions has already been explained above. Again, bolt clearance is necessary for proper function, thus preventing rear bolt lift in its entirety impossible. Although triggers with square or vertical sear engagements may prevent the ramping effect of an angled surface, with all that spring pressure at the bottom of the bolt, unequal pressure of the locking lugs in their respected lug seats will certainly occur.
Solution: Zero-Lift Cocking Piece
The solution to this design flaw was directed straight to the source. The Zero-Lift Cocking Piece utilizes a T-nut shape with precision machined flanges extending from both sides riding in a T-slot machined in the tang area of the receiver. Clearance from the top face of these flanges and the bottom face of the T-slot is held within .001”. This tight tolerance interaction during closing the bolt into firing position prevents any rear bolt lift caused by an angled sear engagement, yet allows complete free fall of the firing pin assembly during firing. This cocking piece design coupled with the Cone-Lok system eliminates any bolt misalignment issues even with the use of popular sear-override style triggers readily available today.
ZERO-LIFT COCKING PIECE
Problem: Firing Pin Alignment or Breakage
It has been proven that a smaller firing pin tip can yield better ignition while minimizing spring pressure. Reducing spring pressure in the firing pin assembly allows easier bolt lift and closing and creates less mechanical energy to be held in check, (vibrations). Perfect tolerances of the common single-piece firing pin inside the bolt body can be difficult and costly to machine. Even then, the problem with angled-sear induced bolt lift explained above could flex or bind firing pins during bolt lock-up and cause the smaller diameter tips to break.
Solution: Magnetic Floating Firing Pin Tip
A floating firing pin tip means just that; the tip is not connected to the rest of the firing pin assembly and can easily travel forward totally independent of whatever is going on behind it. Simply put, it is never put in a bind. This allows the use of a .062” diameter tip with a nice free fall to the primer. And for those who like to be prepared for anything, the tip can be easily replaced with a new one simply dropped in. Why magnetic you ask? Remember those metal-to-metal harmonic vibrations? Not only does a small rare-earth magnet embedded in the rear face of the firing pin tip prevent loss and allows easy removal and reinsertion, it also maintains contact to the firing pin assembly behind it, preventing metal-to-metal impact before primer ignition.
Problem: Action Screw Support
Most of us will agree to the benefits of a floating barrel. But have you ever thought how two quarter-inch screws with about .175” thread engagement each are totally inadequate in supporting all the weight of floating barrel, especially the much preferred bull barrels? This is a direct carry over from Mauser’s original design, which was never meant to support all the barrel’s weight. Not only that, but placing those two little screws at dead 6 o’clock allows a great deal of leverage applied from up top, especially with a round receiver body design. There is good reason top bench rest competitors permanently glue barreled actions to stocks.
Solution: Angle-Blocktm Bedding System
Glue-in bedding certainly works but with obvious disadvantages. The Angle-Block Bedding System was derived more from the barrel block concept utilizing multiple cap screws provided as fasteners. We believe rigidity provided by multiple fasteners can be applied directly to the receiver and will be equally effective.
Two design features are important: first, use torx head cap screws. Remington style flat-heads when torqued only flare out the aluminum seats they rest in, possibly causing splitting. Furthermore, the torx head allows more torque without stripping out the heads. Secondly, and vital, engage the bottom of the receiver off of 6 o’clock to disallow twisting from forces occurring up top. When faced with unsightly elliptical holes in the bottom of the stock to accommodate this second feature, we arrived at our angle-entry design bedding blocks.
Two sets of threads machined in each of three pads located at the bottom of the receiver are angled to a common intersection point at the bottom of the stock. Each entry point at the bottom of the stock allows two action screws to be inserted one at a time into an aluminum-bedding block permanently bedded inside the stock, just like aluminum pillars. Once each screw is tightened to an equal torque setting, you have a total of six action screws arranged in a V-block-like formation. The entry ports in the stock are small enough for the rear set of action screws to be totally invisible with the trigger guard in place. It is noteworthy that recently more bolt-action rifles are being introduced on the market with extra action screws. We believe the Angle-Block Bedding System to be far superior to any other configuration available and is applicable for any shooting discipline where top performance is desired.
Problem: Off-Center Recoil Surfaces
This theory itself is innovative. In short, we are theorizing that today’s bolt-actions during firing create recoil energy that is transferred to a surface well below center of bore, the origin of this energy. With all the mass above the center of bore subject to free movement during recoil, and the surface to absorb this recoil energy well below center of bore, an upward torque of the barreled action is occurring, actually trying to tear the barreled action from the stock. An example of this would be to shoot a conventional bolt action with the barreled action resting in the stock without any action screws. (Please don’t try this, especially your favorite high-power deer rifle!) The recoil lug placed below center creates the correct geometry for the barreled action to twist upwards in the stock. This twisting force is transferred directly to the action screw heads and threads in the bottom of the receiver, and in the case of poor glue-in bedding jobs, would be responsible for the breaking free of barreled actions from stocks. In fact, despite the relatively light recoil of the 6PPC, most bench rest actions feature a beefed up tang area with a square end providing the means to collect any “twisting” recoil energy.
Solution: Center-To-Bore Recoil Surfaces
Admittedly without a stock that fully encompasses the action allowing 360 degrees of surface to absorb recoil energy, fully eliminating the leverage of free standing mass above the center of bore is not completely possible. However, we believe recoil surfaces that elevate right to the show line of the stock, or center of bore, are a definite improvement. The CST TF1 has two basic designs to create center-to-bore recoil surfaces; both are integral and machined into the receiver body, far superior to separately attached components. The Model SCP has an optional full 180-degree recoil lug, with surfaces, or “wings”, visible right at the show line of the stock. If the show line is not wide enough or if the integrity of the outer shell of a fiberglass stock needs to be maintained, the Model SCP standard recoil lug features grooves along its sides that stop right at the show line. This design is not visible once in the stock but provides two side surfaces much like splines to absorb recoil energy center-to-bore. The Model SBR designed for bench rest competition is similar, but with the under-lug eliminated and side tabs left in place, either extending visibly wider at the stock show line, or flush with side grooves.
Other Standard Features:
Capitalizing on what works and avoiding what doesn’t, the following are standard features of the CST TF1:
*3 lug design with a 60-degree bolt throw with a dual-cam cocking mechanism for easy bolt lift. The geometric advantages of a three-lug design cannot be overstated. Another positive byproduct is plenty of additional scope clearance.
*Actions are completly machined out of solid 17-4 stainless steel bar stock, while the bolts are machined from 4340 alloy steel. The locking lugs of the bolt and the face of the floating bolt handle are hard chrome plated (70 plus rc) .0002" deep for additional wear resistance and excellent lubricity. Core hardness of the action body and bolt is 40 to 42 rc for superior toughness.
*SCP and SBR models feature full-length integral picattiny, Anschutz dovetail, or Kelbly style scope base with optional long-range tapers available. Integral scope bases are costly to machine, but they are the best, particularly with long-range taper applications.
*Firing mechanism is easily field stripped from the bolt by hand, with no special tools needed. A simple clockwise twist (right hand models) allows complete removal of the firing pin assembly from the bolt body. The shroud can then be lifted up from the firing pin assembly, the floating firing pin tip easily removed, and the floating bolt handle slides free of the bolt body, all completely by hand.
*All models are supplied with trigger hangers fully adjustable for setting correct firing pin travel and detachable through the trigger guard slot. Different brand triggers can be installed and the correct firing pin travel set. The trigger guard is independently attached to the stock allowing trigger removal and adjustment without disrupting torque settings of the rear action screws.
*Floating ejector button will not influence a chambered cartridge and allows manually controlled ejection force.
*Traditional easy to use mauser style bolt release features a spring loaded claw that stops rearward travel of the bolt while not coming in contact with the bolt lugs, eliminating damage to critical lug surfaces during hard retraction.
*SBRR models feature a round action body design for glue-in bedding applications.
Summary:
When you consider all the different variables that apply to accurate rifle shooting, be it quality barrels, scopes, proper bedding, shooting technique, ammunition, it would be foolish to claim our action will always shoot better groups and scores than everybody else’s. Our goal is to eliminate variables involved with the action design itself, creating the most forgiving action possible, hopefully allowing you the shooter to see peak performance with less tune time, and hold that level of performance longer.
In short, the CST TF1 represents an uncompromising pursuit and passion for rifle accuracy. We believe the CST TF1 action to be the most advanced design to date with groundbreaking innovations specifically engineered to eliminate as many mechanical variables as possible, providing the most accurate shooting platform obtainable. So, if you desire a competitive edge or just simply the very best, we believe the CST TF1 action will provide you with the ultimate tool for the job, and definitive piece of mind that comes with it.
