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Need Help With Runaway M1

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I've had my Savage M1 for a few months and it consistently runs away in both full and semi. In full, it often keeps shooting 5-10 rounds after I release the trigger. On semi, it shoots full-auto and pretty much acts the same as on full, shooting 5-10 rounds after I release the trigger. I've tried it with a couple of different kinds of ammo but the problem continues. If I dry fire the gun on full and keep the trigger depressed, the bolt will keeping cycling by hand. If I dry fire the gun on semi and keep the trigger depressed, the bolt will catch the sear with each cycle, requiring me to release the trigger and depress it again to cycle the bolt. Since the gun seems to function fine when dry firing like this, is it that the recoil spring is too stiff and isn't allowing the bolt to travel far enough rearward to catch the sear? Any ideas are appreciated because I am going through a lot of ammo like this!
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Found this while looking for something else.. in the TCN Apr. 1998 issue


Does your W/H tend to burst fire on the semi-auto setting? Odds are that the rocker or the pivot pin holes aren't in quite the right location. Most frequently the pivot pin hole is out of vertical alignment (usually too low). There are two solutions. First, build up the top of the rocker with weld and then re-shape it to its 0 original profile (effectively raising it up into contact with the bolt's T- slot while on the semi-auto setting). At the same time make sure that the rocker isn't too tall now so it doesn't contact the bolt while on the full-auto setting. This approach allows you to save your original W/H trigger housing but will keep you from being able to drop-in an unmodified replacement rocker in the future. Second, if the pivot pin hole is also out of front-to-rear or left-to-right alignment, the easiest fix is to completely replace the W/H trigger housing with one from a WW II GI parts set. The GI housing was gauged when it was made for correct dimensions - I'm not sure that can be said of all of the West Hurley production guns.


This seems to be the problem you are talking about...

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Thank you for the info so far. Aside from part identification, I'm a novice with Thompsons, so please bear with me. Before I try changing out a bunch of parts (which I don't have or know how to do yet), let me show you what I am looking at on the rocker pivot, sear, and bolt so we can maybe narrow this down a little more.






I don't know what a "good" rocker pivot is supposed to look like--is this one too worn?


If I do need to start changing out parts, can anyone recommend a good, detailed guide for disassembling the lower receiver? Thanks.

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I bought the DVD of the US Army Tech Films on the Thompson on Evilbay. It has been very very helpful in showing how to completely disassemble and reassemble my Thompson even with out tools.. I highly recommend getting one. I've seen them on Gunbroker as well...


The internal parts are not that hard to get nor too expensive if you need to replace them. I can't tell if they need it by the photos.


Good Luck...

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From the description given, the rocker seems to be working just fine. The problem (runaway) is cause by the sear not engaging the bolt to stop its motion. This could be caused by something (including grime) hindering the sear movement or broken springs. This should be evident in manipulating the trigger and sear with the frame removed.


If weak ammo is used, the bolt will not be driven back far enough to catch the sear. If something is hindering the recoil spring (such as kinks or debris in the bolt hole) it could slow the bolt. A bent or twisted receiver could also. A bent magazine might impede bolt movement.


It sounds like you need to get the instruction needed to completely disassemble the gun and clean it thoroughly (a CD is available from this board). Look for things that are obviously wrong. If the problem persists, get some hands on help.


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