Section 3.

Paragraphs 10-12


10. General

a. The tools, gages, and fixtures used in the inspection, disassembly, and repair of the U. S. rifles, M1, M1C (sniper's), and M1D (sniper's) are classified as tools, gages, and fixtures requisitionable for issue; tools, gages, and fixtures nonrequisitionable for issue; and common tools.

(1) Tools, gages, and fixtures authorized for issue, described and illustrated in the following paragraphs, are listed in SNL B-20.

(2) Nonrequisitionable tools, gages, and fixtures are not listed in Standard Nomenclature Lists. If such equipment is desired, it is to be made up locally.

(3) Common tools, screw drivers, drifts, pliers, hammers, stones, etc., which are normally used in maintenance and repair, are standard to maintenance organizations and are listed in appropriate Standard Nomenclature Lists.

b. All field service inspection gages must be returned to Springfield Armory, Springfield, Massachusetts, or Rock Island Arsenal, Rock Island, Illinois, once a year to be checked.

c. This section presents nomenclature, federal stock numbers, and description of the tools, gages, and fixtures. Use of the tools, gages, and fixtures is described in detail in Sections 5 to 7, inclusive.

11. Requisitionable Tools, Gages, and Fixtures


(1) Gages for third, fourth, and fifth echelons (fig. 8).

(a) Gage, breech bore (41-G-28). The breech bore gage is used to determine wear of the bore at the origin of the rifling. This gage has ten graduations, each of which corresponds to 0.001 inch of wear. The tenth graduation or point marked "REJECT" is equivalent to a bore diameter of 0.310 inch, since the zero graduation is 0.300 inch. Use of this gage is described in paragraph 9c.

(b) Gage, gas cylinder diameter (41-G-198-425). This gage is of the plug type. It is relieved on two sides in order to check for out-of-roundness as well as for oversize diameter. The gage checks only the origin of the cylindrical portions of the gas cylinder, as this portion has been found to be the one that determines whether or not the cylinder allows the weapon to function properly.

(c) Gage, no-go, barrel diameter at gas port (41-G-236). This gage is used to check the diameter of the barrel at the gas port.

(d) Gage, no-go piston (41-G-236-85). This gage is used to check the diameter of gas piston.

(e) Gages, headspace. The headspace gages are used to check the distance between the shoulder of the chamber and the face of the bolt. Headspace gages are of three sizes namely: 1.940 inches (41-G-200-75), 1.946 inches (41-G-200-100), and 1.950 inches (41-G-200-130) in length, and have been revised to privide a 45 degree bevel of the heads.

Note: Only headspace gages having beveled heads will be used in the

inspection of U.S. rifles, M1, M1C (sniper's), and M1D (sniper's).

The gages are also provided with a clearance cut for the ejector, which eliminates the need of removing the ejector to check the headspace. If other gages not having the clearance cut are used, the ejector must be removed before a check of the headspace is made. Use of the headspace gage is described in paragraph 9c.

(2) Gages for fifth echelon only (fig. 9).

(a) Gage, alining, barrel, with pin (41-G-13-350). The barrel with pin alining gage is used to check the alinement of the barrel to the receiver. Paragraph 22c gives details on the use of this tool.

(b) Gage, firing pin protrusion (41-G-182-350). The firing pin protrusion gage is used to check the protrusion of the firing pin beyond the face of the bolt.

(c) Gage, spring, operating rod, with 5- and 11-pound weights (41-G-358-300). This gage is used for gaging the load and free height of the operating rod spring.


(1) Tools for third, fourth, and fifth echelons (fig. 10).

(a) Bolt, field test (41-P--1587). The field test bolt is used in conjunction with the headspace gages to determine whether the chamber, bolt, or bolt lug seats in the receiver are worn.

(b) Punch, rear sight pinion (41-P-3788). The rear sight pinion punch is 3 inches long and has a diameter of 0.057 inch. It is used to stake the rear sight elevating pinion to prevent loss of the rear sight nut when in service.

(c) Reflector, barrel (41-R-2331). The barrel reflector is used to provide a light-reflecting surface for visual inspection of the rifle bore. It is placed in the chamber and, by holding the rifle so that the light is properly reflected, the bore, including the chamber, can be examined.

(d) Tool, combination, screw driver, wire brush and bolt, assembly and disassembly (41-T-3086-80). This tool, as the name implies, is a combination of tools which may be used to perform the following operations in the rebuilding of the rifle:

  1. Remove and replace the gas cylinder lock screw and various other screws, and seat the rear sight base.
  2. Extract the cartridge case.
  3. Remove pins and assemble the extractor
  4. Assemble or disassemble the extractor and ejector without removing the bolt from the rifle.
  5. Clean the chamber of the barrel.
  6. Install the extractor spring and plunger.

(2) Tools for fifth echelon only (figs. 11 and 12).

(a) Reamer, extension (41-E-452) (fig. 11). The reamer extension group is used as a guide or fixture in reaming the headspace. Refer to paragraph 22d for detailed use of this tool. It consists of five parts:

  1. Adapters, reamer (with locking nut) (long and short). A reamer adapter is assembled to the reamer and locked by the locking nut. The adapter is the connecting piece for the universal-jointed extension unit. Adapters are furnished in two lengths to allow the use of reamers after they have become shortened as a result of repeated sharpening.
  2. Wrench, adapter assembling. This tool is used to assemble the reamer adapter to the reamer and hold it while the locking nut is being tightened.
  3. Guide. The guide is used as an alinement piece and as a stop for the reamer. It is secured in the receiver by a thumb screw having a point on the threaded end. Tightening the thumb screw forces a guide back against the locking lugs, which is necessary to insure uniform headspace reaming.
  4. Extension, universal-jointed. This unit is provided with a tapered square shank to be used with a brace.

(b) Reamer, carbon steel, hand, headspace (41-R-498). (See fig. 11.) This reamer is used for reaming headspace when rifles are being rebarreled. It is used with headspace reamer extension as described in (a) above.

(c) Wrench and fixture, barrel and receiver, disassembly (41-W-3875). (See fig. 12.) This fixture and wrench are used in disassembling the barrel and receiver assembly. The barrel is passed into the fixture, muzzel end first, and located so that the rib on the barrel stops against a shoulder in the fixture. This fixture holds the barrel firmly while the receiver is turned counterclockwise with the special wrench.

(d) Wrench, windage screw knob (41-W-3852). (fig. 12). The windage screw knob wrench is an adjustable split socket which can be adjusted to fit tightly on the elevating knob or windage knob. A crank is attached to facilitate rotating the rear sight knobs when disassembling and assembling the rear sight.

(e) Wrench, gas cylinder lock, assembling (41-W-1496-250). (fig. 12). The gas cylinder lock assembling wrench is used to remove an extremely tight gas cylinder lock and is designed to fit the contours of the gas cylinder lock. This wrench is intended to be used for assembling the lock to the rifle.


(1) Fixtures, assembly, barrel and receiver (41-F-2987-250) (Fig. 13). This fixture is used to draw the barrel in correct relation to the receiver in order to prevent binding of the operating mechanism of the rifle and to position the barrel properly so front sight will have correct relation with respect to rear sight. It is equipped with clamping facilities to hold the receiver in a fixed position; a pointer and an index, which are attached to splined portion of barrel, are provided to assure correct alinement when draw is made. For detailed use see paragraph 22c.

(2) Fixture, assembling, bolt (41-F-2987-260) (fig. 13). The bolt assembling fixture is a clamp used to install the extractor in the bolt. It can be held in a vise or permanently fastened to the armorer's bench. The bolt, with its component parts, is clamped in place in the fixture. The fixture is designed so it will aline the cut in the ejector with the extractor hole in the bolt, making it possible to install the extractor.

(3) Fixture, assembling, ejector, with spindle, Nos. 2, 3, and 4, and bushing Nos. 6, 7, and 8 (41-F-2987-270) (fig. 13). This fixture is used for assembling the ejector, extractor, and rear sight springs to their respective components.

12. Nonrequsitionable Tools, Gages, and Fixtures

a. DRIVER, LOWER BAND (Fig. 14). This tool is used to seat the lower band. It is to be made up locally and from hard wood. Cover the ends with leather to provide a surface that will not mar the finish of the ferrule. Figure 14 shows a dimensional drawing from which the tool may be constructed.

b. WEIGHTS, TRIGGER PULL (fig. 15). Four weights of 4 1/2, 5 1/2, 6 1/2, and 7 1/2 pounds respectively are used to check trigger pull. (See fig. 4). Each of the weights should be provided with a rod which is long enough to clear the stock so that the pressure will be exerted parallel to the axis of the bore and rigid enough to retain an L-hook bend not less than 2 1/4 inches long when supporting the weight. Figure 15 is a dimensional drawing from which the weights may be constructed.

c. PLIERS (Fig. 16). The pliers are used to assemble or remove the band on the rear hand guard.

d. FIXTURE, TRIGGER HOUSING ASSEMBLING (Fig. 17). This fixture is used to seat the trigger pin when assembling the trigger housing group.

e. ROLL SWAGING (Fig. 18). The swaging roll is a rolling tool used to swag the metal of the barrel eliminate looseness of barrel in receiver.

f. GAGE, HEIGHT (Fig. 19). The height gage is used to measure the depth of the cut when modifying the operating rod. (See para. 22a.)

g. GAGE, DEPTH (Fig. 20). The depth gage is used to measure the fillet cut and is provided with a scribe line to ascertain the starting point of the cut.

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