Rifling Cutter Head

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Rifling Cutter Head

clean, with no metal cuttings or other foreign material present while checking this clearance.

That was the easy way to obtain a barrel. If no barrel blanks or chamber reamers are available when you have a need to make this gun, you will have to make the needed tools to drill, ream, and rifle the barrel yourself.

Around almost every town of moderate size, there is a gunsmith or some serious gun nut who has removed one or more barrels from some of the bolt action military rifles to rebarrel them to a caliber he considers more suitable. If you can acquire one of these old discarded barrels, you are a third of the way home. The hole will undoubtedly be drilled, ready to ream and rifle. This does not mean that you can take any old .22 barrel, or barrels from low intensity calibers, and rework them. These would not last long enough to make the project worthwhile. Barrels used for such cartridges as the eight by fifty-seven millimeter, .303 British, 30/60, and 7.62 are the kind you want.

It might be a good idea, at this time, to define exactly what is required for the barrel we need. The nine millimeter Luger or Parabellum cartridge requires a bore diameter of .346 inch to .350 inch. The groove diameter will be .354 inch to .358 inch. The rifling twist may be anywhere from one turn in nine and one-half (9.500) inches to one turn in sixteen inches. The chamber diameter should be .397 inch at the breech and .382 inch at the forward end of the chamber, with a depth from the bolt face of .745 inch. These measurements should be as precise as possible. The barrel may have as few as two grooves to as many as you care to make. However, in this particular instance, a four or six groove barrel is recommended.

A section of military rifle barrel, or a length of suitable steel (automobile axle material is often acceptable) should be cut to a length at least one-half inch longer than the finished barrel length. If you are only making a few barrels, a simple rifling head can be made by casting a lead slug around a steel rod. The rod should be notched and slotted to keep the slug in place before inserting tjie bore. When you have the rod and slug inserted, mark the bore to insure inserting it again in the same position. Then carefully push the slug out of the barrel and cut a slot in one of the grooved impressions in the slgg, (one of the raised ridges). This slot will accept a simple hook type rifling cutter as shown in the drawing. Cellophane shims are used under this cutter until the cutter removes a tiny amount of metal when replaced in the barrel and pulled through. Pull the

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cutter through each groove, removing it and rotating it to the next groove until the complete circle is made.

Then add another shim and make another cut through each groove. This should be repeated until the proper groove diameter is reached, after which the bore should be reamed to size and lapped as described later in this chapter.

This is a very slow, drawn out means of rifling a barrel. If possible, you should take a close look at the hook-type rifling cutter shown in the drawing. This cutter may be rotated at the proper rate of twist by a spiral groove cut in a suitable rod or by casting a lead slug around a rod inside a barrel with a proper twist rate. This cutter is used in the same way as in the previous description, making a cut through each groove before raising the cutter. However, with this set-up, the bore is reamed to the proper diameter before the rifling cutter is used, so considerably less metal must be removed by the rifling cutter.

Regardless of the rifling method used, the bore must be reamed to size. This is best accomplished by chucking the barrel blank in the lathe and by drilling the bore out with progressively larger drills, beginning (assuming we started with a .30 caliber hole) with a "P" size drill of .323 inch diameter, followed by a "Q" and then an "FT drill which measure .332 inch and .339 inch respectively. An eleven-thirtyseconds inch reamer will get the bore diameter up to .3438 inch, after which a reamer will have to be made to finish it to the proper size. A 23/64 inch reamer is .3594 inch and may be ground or stoned to ream the hole to .346—.350 inch. This is a reather difficult process and really should not be tried unless you know what you are doing.

It is also possible to grind a pilot that will just enter the bore on one end of a three-eighths inch square lathe cutting tool. Grind and stone the square body to the proper size, then blaze an extension to the end and push or pull it through the revolving barrel. It must be fed very slowly, using plenty of lubricant; as should be done with all cutting, drilling, and reaming operations.

After the bore is reamed to the proper size and rifled, it should be lapped to remove any fine wire burns or chips left from the barrel tools. This may be done by casting a lead slug, some two to four inches long, around a rod inside the bore. Push the slug almost all the way out of the bore, and coat it with a mixture of oil and fine emery flour. The unoccupied portion of the bore should also be coated with oil through the opposite end. A stop should be inserted in each end of the barrel to insure against accidentally pushing or pulling out the

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LOCK KOTS

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Rifling Hook Cutters

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lapping plug. This plug should never be removed from the bore until its work is finished. The lap should now be pulled (and pushed) back and forth through the bore for about ten minutes, with additional abrasive and oil being added frequently. After the lap is removed, the barrel should be cleaned thoroughly with gasoline and patches, and then examined. If more lapping is needed, the old lap should be melted off the rod and a new one made. Do not try to put the old lap back in the barrel.

The drawings show, in addition to the rifling heads r

Finished barrel with lock nut in place.

an^j lapping rod, how to make a ball-bearing handle. This handle should be used both with the rifling head and the lapping rod so that each may follow the rifling . twist freely.

It is hoped that you will be able to secure barrel blanks of the proper size if and when you need one. However, this business of drilling and rifling your own barrel or barrels is a fascinating and rewarding operation. And as knowledge and experience are gained through practice and experimenting, quite reliable barrels may be obtained in this manner.

Finished barrel in place in the receiver.

Rifling Hook CutterRifling Cutter Head

Chapter Six Trigger Assembly

A trigger and sear housing may be formed by bending one-eighth inch sheet stock to shape. However, it may be considerably easier to saw or grind one side of a section of angle iron (bed frame material is ideal for this) to the proper width and then to weld a flat piece to the side. This will form a box shape which should be left open at the top. The inside dimensions of this housing should be five-eighths inch wide by one inch deep with a finished length of eight inches. Make it at least eight and one-fourth (8.250) inches long to allow a little space for fitting. Weld a plate of the same material across one end to form the rear end of the trigger housing.

Beginning two and five-eighths (2.625) inches from the outside rear of the housing, make an opening three-eighths inch wide by three-fourths inch long in the bottom surface by drilling two three-eighths inch inter connecting holes. Following that, file the sides and ends to a rectangular shape. The trigger will project through the hole thus formed.

The trigger guard may now be made from a strip of one-eighth inch by one-half inch steel. Bend it to the shape shown in the drawing or to a reasonable facsimile, and weld it in place on the bottom side of the housing, over the trigger opening.

The top of this box, which fits against the bottom of the receiver, should be filed to match the contour of the receiver as closely as possible so that when the takedown bolt is drawn up tight, the two pieces will fit to-gethertclosely, keeping the joint as dust and dirt-proof as possible.

If three-eighths inch inside diameter steel tubing is available, two pieces should be cut to a length approximately two inches long. The length of these is not crit-

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Responses

  • david
    How make hook cutter for rifling barrel?
    8 years ago
  • Quintino
    How to make cut rifling head?
    8 years ago
  • Christi
    How to make barrel rifling head?
    5 years ago
  • mackenzie
    How to build an adjustable hook style rifling cutter?
    1 year ago
  • brian
    How to build an adjustable rifling head?
    7 months ago

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