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Last Updated on :
August 16, 2015

Mauser Action Truing

The action of Mauser Rifless has stood the test of time. It has proven that it is one of the most Safe, reliable and accurate firearms ever built. Although to achieve a precision rifle and to greatly improve on the mausers accuracy the action can be trued. Which consists of squaring the Receiver face, lapping the bolt lugs and lapping the bolt face. The lapping can be done at home with the proper tools and knowledge, however Squaring the Receiver face needs to be left to a skilled gunsmith with a metal lathe.


Lug Lapping - The Mauser bolt lugs locks in the receiver when closing . The amount of metal that makes contact between the bolt lugs and receiver is where lug lapping comes in . Lapping the lugs provides more metal to contact the lugs and receiver and improves the squareness of the mating of those surfaces. It is accomplished with a lug lapping tool which can be made or bought and it is available from Brownell's, Midway or your favorite gunsmith supply store. It works by threading the lapping tool into the receiver [ the barrel threads ] and applying lapping compound [ or vallve grinding compound ] to the lugs of the bolt and rapidly opening and closing the bolt. This increases metal to metal contact and when finished assures the lugs are both firmly against the receiver when the bolt is closed. you will be able to tell how much contact is being made by the nice shiney spots on the lugs . I like to have around 70 to 80 percent contact area. you can over do this and possibly lap to much i wouldnt suggest going for more than 70 percent .


Bolt Face Lapping - The face of the bolt is where the head of the cartridge makes contact with the bolt. By lapping and squaring this surface it insures that the cartridge is in full contact and stress free and in-line with the chamber of your barrel. This is performed with a bolt face lapping tool also sold by Brownells or Midway [ and can be made as well ]. By inserting the bolt face lapping tool into the threads of the receiver with the bolt closed and applying compound to the face of the bolt, use a hand held drill which rotates the tool and squares the face of the bolt improving accuracy greatly. again you can over do this go slow.


Squaring the Receiver Face - The receiver face is the metal that comes in contact with the shoulder of the barrel [ which is the surface the barrel mates with allowing the barrel to be tightened]. Squaring this surface insures when the barrel tightens up it is 100 percent squared and inline with the receiver. This is accomplished by putting the receiver on a mandrel and using a metal lathe, remove as little as possible of metal to insure the face is squared. As stated above this is best left to a competent gunsmith even if you have a lathe as the smith will know the tolerances of the metal and not damage the heat treated [ hardened ] surface.


Lothar Walther

NM Collector


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Disclaimer, This is an Informational website intended only as an aid to help and/or entertain the Firearm community, this site is not a buisness Mauser Central is a hobby page only. All firearm repair or modifications should be done by a qualified gunsmith. If you hurt or kill your self or someone else this website is in no way to be held responsible ! As I am telling you now gun repair is meant to be done by a gunsmith this site informs you of some tasks a gunsmith may perform. All copyrights belong to Mauser Central or the rightful owners thereof .
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