How to prevent or fix excess recoil in Heckler & Koch Gewehr 3 pattern rifles.
by Marc Whitacre
Heckler & Koch GmbH Gewehr 3 pattern firearms (G3, HK-91, PTR-91), particularly those chambered in 308 Winchester or 7.62 NATO, have a widespread reputation for excessive, abrupt recoil. Excess recoil can make the gun very uncomfortable to shoot and lessen the life of the gun. This article will discuss the means of preventing or lessening excess recoil. I will assume the reader has access to one of the several HK repair or armorer’s manuals available online.
First, it is necessary to understand the mechanical principles of operation of the gun. The best article for this is a US Army study that is available online for free as iiBRL Memorandum Report No. 1953, A Comparative Evaluation Of The 7.62MM And 5.56MM, G-3 Assault Rifles published January 1969 by Thomas E. Carlson and David A. Golm at the U.S. Army Research and Development Center, Ballistic Research Laboratories. Aberdeen Proving Ground, Maryland (bit.ly/2Vfkr2k). Some of the information in this article comes from that study and anyone interested in the G3 should read it.
For purposes of understanding the recoil generated by the G3, the operation of the G3 action can be summarized as follows. First, the hammer falls and the firing pin strikes the primer of the cartridge, causing the powder to ignite and chamber pressure to rise. As the chamber pressure rises, pressure is exerted on the face of the bolt which is transmitted to the locking rollers which are engaged in recesses in the trunnion and also rest on an inclined plane (the locking piece), which is connected to the more massive bolt carrier. The shallow angle of contact between the rollers and the locking piece reduces the backwards pressure on the bolt carrier to about 1/3 of that exerted on the bolt.
The bolt does not…
Read more in the November 2021 issue.
Don’t miss a single issue. Subscribe now or renew your subscription.
For non-subscribers wanting free access, submit one free article to use on our site and we’ll send you a complete digital copy of any issue of your choice (April 2006 to current).