Forster Products
Home Page
Search
View Cart
Sale
Reloading Tools
Ammunition Measurement System
Co-Ax® Reloading Press
Reloading Dies
Reloading Die Sets
Power Adapter for Case Trimmers
Hollow Pointer
3 in 1 Cutter
Outside Neck Turners
Primer Pocket Chamfering Tool
Neck Reamer
Hot 100
Case & Cartridge Inspector
Primer Seater
Powder Measuring Tools
Deburring Tools
Bullet Pullers and Collets
Sizing Lubricants
Gunsmithing Tools
Universal Sight Mounting Fixture
Headspace Gages (Gauges)
Gunsmithing Screws
Gunsmithing Screwdrivers
Gold Inlay Filling Kit
Gunsmithing Accessories
Resources
Locate a Distributor
PDF Library / User Instructions
Forster Focus
Video Library
Forster ProStaff
Terms and Conditions
FAQ
Contact Us
About Us
Newsletter Sign Up
Catalog Request
Become a Fan on Facebook
Subscribe to Forster on YouTube
Follow Us on Twitter
Follow Us on LinkedIn
pinterest
 
8X57 Mauser (8mm Mauser)
Chamber Headspace Variation and Measurement

Background
SAAMI’s current Chamber and Cartridge drawing (ANSI standard) shows a 19° shoulder angle in the chamber. The earliest revision of this print showing 19° is dated April 21, 1980.

The shoulder angle in the 8 x 57 Mauser, however, hasn’t always been 19°.

A SAAMI/Winchester Repeating Arms print, New Haven, CT, dated November 12, 1938, shows a 20° 48’ shoulder angle. The last revision made on this 20° 48’ angle print is dated July 9, 1947.

It appears that the transition from the older 20° 48’ shoulder angle to the current 19° shoulder angle did not happen suddenly. Discussions with gunsmiths and collectors indicate that there may have been a 15 to 30 year period during which firearm chambers were manufactured to both shoulder angles.

Measurement and Gaging Implications
Headspace gages that are made to the current 19° shoulder angle will not properly check older 20° 48’ shoulder angle firearms. Because of the shoulder angle difference, a 19° gage does not match to the datum measurement point of firearms that are chambered to 20° 48’. A 19° headspace gage will appear as if it were longer because the 19° shoulder angle will contact the bore of the chamber before it contacts the chamber’s datum point.

Recommendation
Determine whether the chamber of a particular firearm is made to the current 19° shoulder angle or to the older 20° 48’ shoulder angle. This may be done by making a chamber casting using CERROSAFE® or a similar material.

Once the shoulder angle is confirmed, then obtain the correct headspace gages. Forster manufactures distinct gages for both the current standard 19° shoulder angle and for the older 20° 48’ shoulder angle chambers. Order numbers for the older 20° 48’ gages are:

  • GO Gage: HG8mmoldG
  • NO-GO: HG8mmoldN
  • FIELD: HG8mmoldF

 

 

 
 
 
DNV Forster adheres to ISO 9001:2008
Quality Management System Standards.
Forster Products' certificate
CERT-05739-2006-AQ-HOU-RvA is
accredited by independent auditor DNV.
FORSTER PRODUCTS, INC.
310 East Lanark Avenue
Lanark, IL 61046
PHONE: (815) 493-6360
FAX: (815) 493-2371
Internet Payment Gateway
©2014 All Rights Reserved