Target Rifle Trigger Guard

This drawing shows the trigger guard as used on our target rifle. The short spur shown on the rear of the guard is there only to fill the gap in the upper part of the pistol grip (see Fig. 3-34). To open this action we attached a plate to serve as a thumb piece, as shown, to the front of the trigger guard housing; with the plate projecting about thumb width to the right of the receiver edge. Pushing down on it opens the action. On a later rifle we omitted the thumb plate and welded on a long finger piece to the underside of the trigger guard bow as shown.

Takedown Bow Plans


On the left shows the rear view of the breech block and the position of the release lever. The other two cross section views show the lever at rest and depressed to draw in the extractor plunger. The extractor used for this system is shown in Fig. 3-8. Also see Figs. 3-11, 3-27 and 3-37.


On the left shows the rear view of the breech block and the position of the release lever. The other two cross section views show the lever at rest and depressed to draw in the extractor plunger. The extractor used for this system is shown in Fig. 3-8. Also see Figs. 3-11, 3-27 and 3-37.

Target Rifle Trigger Guard



Fig. 3-37 REAR VIEW OF THE TAKEDOWN RECEIVER Rear view of the FM No. 2 VAULT LOCK takedown receiver showing the notches on the inside of the receiver walls and the notches in the rear of the trigger guard housing, and the hinge pin positioned in those notches and held in place by the bent peg (see arrow) fitted into the bottom of the tang plate. The notches in the trigger guard housing are also shown by dotted lines in Fig. 3-11.

Fig. 3-38 FRONT VIEW OF THE TAKEDOWN RECEIVER Front view of an FM No. 2 VAULT LOCK receiver modified into a takedown and quick action disassembly system. This shows the split receiver ring. The center arrow points to the groove on top of the extractor housing and the stud in the bottom of the receiver to hold the extractor assembly in position against the breech block. The two arrows at the bottom point to the two rails and grooves at each side of the extractor housing which holds the extractor housing assembly up and allows it to be slid rearward into the breech block recess for quick and easy removable after the trigger guard and breech block assemblies have been removed. Also see Fig. 3-36.

Side view of the No. 2 takedown action showing the placement of one of the two takedown or draw screws through the upper receiver ring (the second screw is on the opposite side and about 3/16" to the rear of the first screw) and the absence of the extractor housing retainer and the trigger guard housing hinge pins. This photo also shows the recess milled into and partly through the right receiver wall (a similar recess but wider is in the left wall) to reduce the weight of the action. The clear through areas of this recess should not extend any farther forward than the breech block support area as shown by A in Figs. 3-3 and 3-5. These recesses can best be closed by making panels from the same wood that the stock is made from and epoxied in place after the rifle is finished and blued. This was done with the rifles and actions shown in Figs. 3-D, 3-E and 3-J.

Vault Lock Rifle Actions

Here is shown the forearm fastening arrangement we used on our .223 FM No. 2 VAULT LOCK rifle shown in Fig. 3-A and on our .22 caliber target rifle (Fig. 3-K). As explained in the text, this arrangement is the same as used to fasten the buttstock to the action.

Instructions and Sequence of Operations for Making the FM No. 2 Vault Lock Action

The very best steel to use for the receiver is 4140, a chrome-moly steel widely used in the arms industry for making many firearms parts including receivers, breech bolts and barrels. Some steel firms list it in three grades; 4140 Heat Treated, 4140 Normalized and 4140 Annealed. For the purpose of making the FM VAULT LOCK receiver, the first choice is 4140 Heat Treated, with a hardness of RC 27-30. Although it is very tough, it can be readily machined and hand worked and it needs no further heat treating after the receiver is finished. The second best choice is 4140 Annealed, which is the cheapest and easist grade to obtain. As is, it would be suitable for a rifle in .22 Long Rifle caliber, but for ail other calibers 4140 Annealed needs to be heat treated to a hardness around 25-30 Rockwell C before machining. This heat treating should only be done in a controlled temperature heat treating furnace and our advice is to have this done by a heat treating firm. There are other chrome-moly steels which are also suitable for the receiver but 4140 Heat Treated is the first choice.

The breech block for the FM VAULT LOCK action can also be made from 4140 Heat Treated steel. However, softer steels can also be used such ¿s common steel shafting. For all centerfire calibers, when a softer steel than 4140 Heat Treated is used, the breech block should only be fitted with the Mann-Neidner type firing pin with a hardened bushing. In this case the breech block need not be hardened, although you might want to have its surface hardened by having it carbonized by a heat treating firm.

The trigger guard housing and the extractor housing can be made from cold rolled steel. The hammer, trigger and safety should be made of tool steel so they can be hardened. The same tool steel can be used to make the pivotal bar, extractor, extractor lever, trigger lever and hold-close plunger, but these parts do not need heat treating. All pins are best made of drill rod. The firing pin and breech block plunger can also be made of drill rod, and they should be heat treated.

Begin by squaring off the receiver to the approximate dimensions as given in the drawings. Spot, drill and ream (or bore) the hole for the 1.00" breech block. The hole should be made at an angle of approximately 3° rearward from top to bottom (see Fig. 3-5). The amount of angle is not critical and it can be as much as 4° and still be satisfactory.

As discussed later on, the loading port can be made either to the right or to the left or it can be opened on both sides so you can load the rifle from either the right or left. If the latter is done the top shelf does not have the support of one of the receiver walls and is thereby weakened. In this case the top shelf can be made stronger by drilling and reaming the breech block hole from the bottom and not going all the way through, leaving the hole at the top closed and flat as shown in the insert of Fig. 3-5. This not only leaves the breech block hole closed above but strengthens this shelf by the 1/16" thick metal left on top. Making this blind hole is quite difficult but if you can manage it you might also consider making the receiver this way if only one receiver side is opened up for the loading port.

NOTE: The FM VAULT LOCK action was especially designed to utilize a cylindrical breech block, the reason being that it is much easier to fit such a breech block in a receiver than one with square corners and parallel sides. However, the design in no way limits this action to a cylindrical breech block and if you have the facilities to machine a 1.00" square hole with parallel sides through the receiver then you can substitute a square block in place of the round one. In doing this nothing else has to be changed except that the top shelf must be made longer. The use of a square breech block will make the action much stronger. Therefore, if you want the rifle chambered for a belted magnum or ultra-hot wildcat cartridge then we suggest making the action with a square breech block. Also, in this case we suggest making the firing pin to be inserted into the front of the breech block with a threaded and shouldered bushing similar to the Mann-Neidner design.

BARREL SHANK (see Fig. 3-6)

The next step is drilling or boring the hole for the barrel shank and threading it. We recommend a l"xl6 thread, although a l"xl4 is okay. Follow by threading and fitting the barrel in the receiver, but not completely at this point. Leave the shank a bit longer than is necessary and face it off square.

BREECH BLOCK (see Fig. 3-13)

Make a start on the breech block next, leaving it a little longer than final length, to be dressed to length later. Dress off the face at the same angle as you have made the breech block hole so that its face will evenly contact the breech face of the barrel. The face of the breech block need be just slightly wider than the diameter of the cartridge head the barrel is chambererd for, but in any case it need never be over 5/8" wide. Our drawings and specifications show the breech block face approximately .475" in width at the firing pin hole, which is ideal for most standard cartridges. Now, with the barrel threaded in the receiver and the breech block wedged in its hole against it, remove metal from the top of the breech block until it is flush with the top of the receiver. Do the same at the bottom of the breech block, although we still suggest leaving it project up to .10" which will be trimmed off afterwards.

The next step is to mill the slot in the bottom of the receiver for the trigger guard housing. With the barrel (or threaded stub) and the breech block wedged in, the breech block is adequately rigid to allow milling the slot through both the receiver and breech block in the same operation, thus assuring the slot in both parts will match. Make the initial slot only .750" deep. When this has been done, the barrel and breech block can be removed and the milling underneath completed; milling in front of the breech block hole to .875" depth for the extractor housing, and to the rear of the hole and support metal (A in Figs. 3-3 & 3-5) to a depth of 1.175".

Next the loading port is milled out, following that, mill the slot for the passage of the hammer and safety, and then recess the rear of the receiver for the stock abuttment. All this can be followed by removing the surplus metal from the top rear of the receiver. The beveling of the bottom sides of the receiver should not be done until after the hole for the trigger guard housing pivot pin has been drilled unless you decide to hide this pin, which is described at the end of the chapter, nor should the recessed panel milling be done until this hole has been made.

Make the trigger guard housing next. The finger piece spur can be made integral with it or it can be welded on afterwards. The housing is made long enough (see Fig. 3-10) so that the extractor housing can be cut off from the front of it.

Next remove metal from the top front part of the trigger guard housing, fitting the housing into the receiver until the bottom of the housing groove is level with the bottom edge of the receiver. With the housing held in place in this position, drill the hole through the receiver and housing for the pivot pin. After this is done the bottom edges of the receiver can be beveled and the panels milled out.


The next step is to fit the extractor housing into place. Square the rear end of it, position it in the receiver so that the squared end touches the breech block, clamp it in place and then drill the hole through the receiver and the housing for the pin. This pin can be as small as 1/8" in diameter. You might also consider eliminating this pin by the method described later in this chapter. After this the excess metal from the bottom and front of the extractor housing is removed, making these surfaces flush with the receiver metal.

With the extractor housing in place carefully remove metal from the front of the trigger guard housing so its fits into the receiver and can be pivoted without binding.

HOLD-CLOSE ASSEMBLY (see Figs. 3-25 & 3-26)

Now is the best time to make the hold-close assembly. Mill the slot and cut into the front of the trigger guard housing for the end of the hold-close plunger to fall into. The pin to hold it in place and to limit its forward movement is also the pin that will hold the trigger lever in place. Installed, the hold-close plunger should offer considerable resistance to the opening movement of the action.

PIVOTAL BAR (see Fig. 3-15)

The next step is to link the breech block with the trigger guard housing. Make the pivotal bar and drill the hole for it. Follow this by cutting the slot in the breech block skirt to accept this bar. Note that this slot is wider than the pivotal bar, this to allow some initial movement of the trigger guard housing before the breech block is pulled down (Fig. 3-14). The purpose of this is to pull the hammer off the firing pin allowing it to retract before the breech block starts moving down. At this point, with the breech block and trigger guard housing in place, you should be able to lower the breech block part way, with its lowering motion stopped when the top of the housing comes into contact with the rear corner of the slot in the breech block. The corner of this slot (see B in Fig. 3-17) then has to be beveled off enough so that the breech block can be lowered to a point where its top surface halts 1/16" above the bottom of the loading port. Later on, depending on the size of the cartridge the rifle is chambered for, more can be removed from this bevel to allow the breech block to open still farther. The final halting of the breech block will be determined by the extractor parts.

After fitting the trigger guard housing we suggest you next fit the barrel. Breech the barrel so when it is set up tightly into the receiver there is no more than .001" gap between the breech block and barrel. Chamber the barrel, doing this with the barrel removed and headspacing so that a new cartridge case chambers flush with the breech. The chambering and headspacing must be done right and for detailed information on this we suggest you read a gunsmithing book which contains this information

EXTRACTOR PARTS (see Figs. 3-7, 3-8, 3-28, 3-29 & 3-30)

Now make and install the extractor, extractor lever and the breech block plunger. Considerable precise fitting is required here. We suggest the following order: fit the blank extractor in the housing first but do not make its pivot hole for rimless cartridges oblong at his point. Leave the extractor hook (its upper tip end) longer than needed. Cut the slots in the receiver and barrel to accept the extractor. Shorten and shape the extractor hook as shown so that a cartridge case can be chambered with the extractor engaged with it. For rimless cases and a few certain rimmed cases, file the pivot hole oblong towards the extractor hook, making the hole oblong enough so that the extractor drops low enough to slip under the cartridge rim when chambered. Now drill the hole in the extractor stem and install the spring and plunger. Bevel the top front end of the extractor hook enough so that the extractor will snap under the rim of a chambered cartridge case. Follow this by removing enough metal from the top face of the breech block (C in Fig. 3-17) so that the extractor can tip back far enough to clear a rimless cartridge case being inserted or extracted from the chamber (see Fig. 3-8).

At this point fit the breech block plunger (Fig. 3-18) and the extractor lever. Notch the rear of the extractor lever and the lower end of the breech block plunger so that the downward travel of the breech block is now halted at a point where the top of the breech block comes within about 1/8" of being flush with the bottom of the loading port. Next cut a notch (D in Fig. 3-28) in the upper rear face of the extractor stem and on the upper end of the breech block plunger so that the breech block is stopped in its upward travel precisely when the breech block top is flush with the top of the receiver and just before the breech block contacts the barrel as shown in Fig. 3-7. The rim recess in the face of the hook must be slightly deeper than the rim of the cartridge (this applies only to rimless cases), this so that on closing the action the breech block will push the extractor ahead, allowing the hook and the entire extractor to rise and engage in the extractor groove in the case. There should be no binding of the extractor parts or in the breech block with the extractor.

An alternate method for the breech block plunger arrangement is shown in Fig. 3-8. The breech block plunger is a 3/16" round rod which should be a snug fit into its hole. The smaller hole to the rear of it provides a means to drive the plunger out. The faced off end of the plunger should project 1/8" from the breech block face. The extractor is made to nearly contact the face of the breech block and then a 3/16" wide groove is milled in its face for the plunger to slide in, with the groove milled to a height that stops the breech block at the precise place as explained in the previous paragraph. A similar groove is then milled into the face of the extractor lever as shown. The plunger can be made of brass welding rod and the use of this metal somewhat dampens the noise of the opening snap of the action. For a rifle in the .22 rimfire caliber the plunger must be fitted in a deeper hole, be a sliding fit and be backed by a spring. In addition, a hole must be provided in the extractor lever (as shown in Fig. 3-30) so that the plunger can be depressed with a tool to allow removal of the breech block, or use the method shown in Fig. 3-36.

For all rimless cases and cartridges with thin rims such as the .225 and .444 Marlin, the extractor must be made as described above. The same extractor will also work very well with most common rimmed cartridges. However, for thick-rimmed cartridges such as the .22 Hornet and .30-30, the extractor need not have the oblong pivot hole or be spring loaded, and in this case the front of the hook need not be beveled off (see Fig. 3-29). In fitting this extractor hook it is best finished and recessed at the same time as the chamber with the chambering reamer. Also, the beveled surface C (Fig. 3-17) on the top front face of the breech block must be cut back only far enough to allow enough backward extractor movement so that its hook does not disengage from the cartridge rim. For .22 rimfire, the extractor should have a half-moon hook (Fig. 3-29).

The making of the ignition parts comes next. First make the opening in the trigger guard housing for the trigger and spot the hole location for the hammer pin. Then make the hammer to approximate shape as in Fig. 3-21, and finish smooth the surfaces in front and below its nose. Use paper or an epoxy glue to hold the hammer in place in the trigger guard housing, and while holding the housing in place in the receiver, position the rough hammer against the receiver just as it should be in the fired position as shown in Fig. 3-7. Now carefully remove the housing without disturbing the hammer and drill the hole through the housing walls and hammer for the hammer pin. Remove the hammer and drill the hole in it that will become the mainspring plunger notch. Then remove the surplus metal in front of this notch. After this the mainspring plunger and sleeve can be made and fitted, as well as the pin through the housing to hold the sleeve. After the hammer has been fitted, recess the rear of the breech block for the hammer nose to fall into, making this recess about .100" deep and shorten the hammer nose sufficiently so that it does not touch bottom when fully down.

Make and fit the safety next. Do not drill in the holes for the safety pivot stop pin until the safety has been notched to the hammer.

With the action parts you have already made placed in the action, open the action as far as it will go and spot the approximate location where the safety notch has to be made on the hammer for the safety to engage over it (Figs. 3-8 & 3-9) and machine this notch. The angle of the notch on the safety and hammer must be such that on disengaging the safety from the hammer, the hammer is drawn back slightly. The notch on the hammer and on the safety can best be milled in by using a standard sight slot cutter and this will give you the correct angle for both notches. When the notch has been made so that the safety just engages it when the action is opened, you are then ready to spot and drill the hole through the trigger guard housing and safety for the safety pivot stop pin, enlarging the hole in the safety afterwards to allow pivotal movement. Make the safety spring with one coil about as shown in Fig. 3-20. We used .034" spring wire to give the safety sufficient tension so that it requires considerable thumb pressure to disengage the safety. This is very important as under no circumstances should the safety be dislodged regardless of how smartly the action is closed.

Now make the trigger. Make its sear tip slightly longer and higher than needed, center it in its hole so that it can be pivoted and drill the hole for its pin. Using pins about one inch long, mount the hammer, safety and trigger on the outside of the trigger guard housing so that you can see what has to be done. Your next job is to make the sear notch in the bot-

torn of the hammer. Make it deeper than needed so that a flat surface can be obtained. It must be at the approximate angle as shown in the drawing and its bottom edge should be sharp. After this shorten the sear tip of the trigger so that the trigger engages into the hammer sear slightly before the hammer becomes engaged with the safety. Before going any further, make and fit the trigger lever and drill and tap the holes for the three trigger adjustment screws. When all of this has been done, assemble all the parts into the action and you are ready to make the final adjustments and synchronize all the parts together.

To synchronize all the parts it will likely be necessary to do a little hand filing here and there and perhaps you may even have to make a part or two over if too much filing has been done. First, the breech block must open low enough to clear the extractor hook and the extractor hook tip back far enough at the same time to clear the bottom line of the chamber for rimless cartridges. If either does not, perhaps you will have to lower the notch on the extractor lever and/or remove more metal from the upper slanted surface of the breech block. Next, there must be enough width of the pivot bar notch to allow the trigger guard housing to swing down enough in its initial opening movement before the breech block is pulled down to retract the hammer. Next, on fully opening the action, the trigger must first drop behind the hammer sear notch, then the safety must engage with the hammer, and on closing the action and disengaging the safety, the hammer should move a very slight amount before being stopped by the trigger. The sear notch on the hammer should be at such an angle that with the trigger engaged with it to its full depth, on pulling the trigger the hammer is moved very slightly back. This motion should be barely perceptible to be ideal, and not perceptible at all after the trigger is adjusted for minimum sear engagement. This will mean that even with a very light tension trigger spring and shallow sear engagement, that the trigger will positively want to stay engaged with the hammer until it is deliberately pulled back by the shooter. If the trigger has a tendency to slip out of the hammer sear notch of its own accord, and you will be able to detect this easily by slowly pulling the trigger back with the hammer cocked, then you must correct the sear angles on either or both the trigger tip and hammer notch. Not until you are sure that the trigger functions properly and is safe should you harden the trigger and hammer. In the final honing of the sear surfaces after hardening be careful not to alter the angles or round the edges. Use a medium to medium-heavy tension spring for the triggers (this spring is under the trigger lever) and it should be of a length and adjusted so that at least a pull of two pounds is required to move the trigger alone. With the hammer cocked the trigger pull should be at least three pounds. The sear engagement, the angle of the sear and the pressure from the trigger spring including the angles of the safety notches, must be such that no matter how smartly the action is closed the hammer will stay cocked, this must be tested and if the safety does not hold when the action is closed very rapidly, or if the sear does not hold when the safety is disengaged, corrective measures must be taken. The testing should include snapping the action closed with safety removed and again with the safety in place but with the trigger tied back with tape or with a bread wrapper tie. These corrections may include one or more of the following: increasing the angle of the sear notch on the hammer, increasing the sear engagement of the trigger with the hammer, increasing the trigger weight of pull by use of a stronger or longer spring or adjusting it to give more tension to the trigger lever, increasing the angle of the safety notches and/or using a stronger safety spring.

The firing pin need not be the last thing of this action to make and install, but it should not be fitted until after the extractor parts have been fitted and the hammer fitted. We have shown two methods of installing firing pins for centerfire cartridges, plus one for rimfire. The first method we describe is the preferred Mann-Neidner method shown at left in Fig. 3-16. For the centerfire firing pin installation (Figs. 3-7 & 3-8), proceed as follows: Spot the location for the firing pin tip hole using a special center punch (which you make) that fits through the flash hole of a cartridge case the rifle is chambered for. Align the breech block in a drill press vise and drill a 3/16" hole through the breech block from front to rear. With a 1/4" end mill replacing the drill, bore this hole to within 1/8" of the hammer nose recess. Follow this by boring the hole for the bushing with a 7/16" end mill 1/4" deep, replacing the end mill with a 1/2x20 tap and tap threads in the hole. Finish the thread tapping with a bottoming tap. Now make the bushing as shown (Fig. 3-16, left) only longer than needed in front and make it so it bottoms cleanly, after which it is dressed off flush with the breech block face and finished. This bushing can be made from the threaded end of a 1/2x20 S.A.E. bolt and such a bushing need not be hardened further. Otherwise, make the bushing from drill rod or tool steel so it can be hardened. Now two small shallow holes must be drilled near the outer edge, opposite each other, and a spanner wrench made to fit these holes so the bushing can be removed for installation of the firing pin.

Now make the firing pin (Fig. 3-16, left). The tip end must be a snug but bind free fit in the 5/64" hole made for it. Make the tip longer than needed. Make the rear stem of the firing pin 3/16" and make it longer than needed. The firing pin must move at least .060", and ideally it should not move much more than this. Trim the firing pin by holding it to the rear and filing its tip flush with the breech block face. Now trim to correct length by filing the stem so that when the firing pin is fully depressed by the hammer the tip protrudes .055" to .060". The end of the tip is then rounded and polished. Round the large end slightly and then harden and temper the firing pin.

For the alternate method of firing pin installation see Fig. 3-16, right and Fig. 2-9 in Chapter 2. For a detailed description and full instructions on how to make this firing pin see Chapter 2.

With either method, the firing pin should be a snug fit, yet must not bind—it must move quite freely. The retractor spring need not be very strong but it must be sufficient to positively retract the firing pin after a cartridge is fired and the hammer is cocked. Also, drill a 3/32" gas vent hole through the right side of the breech block into the retractor spring recess area of the firing pin hole, as marked G.V. on Fig. 3-13.

The hammer fall should be halted by the support wall (A in Fig. 3-5) in the receiver and not by the firing pin or by the hammer nose contacting the breech block or retainer nut. In the fitting of the firing pin it may be necessary to shorten the hammer nose.

Although not at all critical, we suggest making the tang as shown. We silver-soldered the smaller diameter threaded rod to the larger tang and the larger tang to the plate. If necessary, the larger diameter tang can be bent near the plate in order to correct for or compensate for the stock drop. The screws to attach the tang to the receiver should be 10x32 or equivalent.

Woodworking Tools and Installation Tips

Woodworking Tools and Installation Tips

There are a lot of things that either needs to be repaired, or put together when youre a homeowner. If youre a new homeowner, and have just gotten out of apartment style living, you might want to take this list with you to the hardware store. From remolding jobs to putting together furniture you can use these 5 power tools to get your stuff together. Dont forget too that youll need a few extra tools for other jobs around the house.

Get My Free Ebook

Post a comment