StrangeRanger Posted July 7 Report Share Posted July 7 My MP34 has occasional failures to feed which might be related to the very light spring rate of the magazine springs. I think that it's entirely possible that during their 90 year life they have taken a set. They have a free length of right at 11-1/2". If someone who has a good running MP34 could measure the free length of their mag springs it would help me diagnose the problem Link to comment Share on other sites More sharing options...
huggytree Posted August 27 Report Share Posted August 27 Aren’t mags pretty cheap. Easier to just buy a few more mags? gun has such a slow rate of fire that spring has to be really weak not to feed 550 rpm Link to comment Share on other sites More sharing options...
tommyboy Posted August 28 Report Share Posted August 28 On 7/7/2025 at 1:53 PM, StrangeRanger said: My MP34 has occasional failures to feed which might be related to the very light spring rate of the magazine springs. I think that it's entirely possible that during their 90 year life they have taken a set. They have a free length of right at 11-1/2". If someone who has a good running MP34 could measure the free length of their mag springs it would help me diagnose the problem Years ago, Sarco sold reproduction MP34 mags and they all had a really light spring tension right from new. Definitely not manufactured with the correct spring tension. Link to comment Share on other sites More sharing options...
zavrit Posted August 31 Report Share Posted August 31 (edited) I replaced my MP34 magazine spring with one from an Uzi magazine and it fits great. Functions perfectly when shooting. Much better than the original weak spring. You can see in the photo how much longer the Uzi spring is compared to the MP34 spring. Edited August 31 by zavrit Link to comment Share on other sites More sharing options...
StrangeRanger Posted August 31 Author Report Share Posted August 31 Uzi springs were the first thing I tried. They wouldn't fit inside the MP34 follower. I've got some MP40 springs coming from Wolff. They may need a little trimming but I think they may work Link to comment Share on other sites More sharing options...
zavrit Posted August 31 Report Share Posted August 31 Additional photos of the Uzi spring with MP34 follower. Maybe your Uzi spring is different than the one I use? Link to comment Share on other sites More sharing options...
StrangeRanger Posted August 31 Author Report Share Posted August 31 (edited) Mine is a skosh bit wider and won't fit between the sidewalls of the MP34 follower: they only interfere by a few thousandths but they do interfere. The wire gauge is also just thick enough that the free end won't snap under the tab on the follower. I could bend the tab slightly and would do so if the Uzi spring would otherwise fit but it doesn't FWIW my Uzi mags are all Bundeswehr surplus. Edited August 31 by StrangeRanger Spellling Link to comment Share on other sites More sharing options...
zavrit Posted August 31 Report Share Posted August 31 Interesting. The spring I use is from an IMI magazine. Keep us posted on the MP40 Wolff springs. Thanks. Link to comment Share on other sites More sharing options...
StrangeRanger Posted August 31 Author Report Share Posted August 31 I tried Sten springs and they're close but just a little bit narrow. They're readily available and I could probably trim then and make them work but I think the MP40 springs might be a better fit. I'm not losing sleep over finding a fix Link to comment Share on other sites More sharing options...
StrangeRanger Posted September 8 Author Report Share Posted September 8 (edited) You are absolutely right. Uzi springs will fit. I missed the fact that Uzi springs are not rectangular; they are slightly trapezoidal. I was trying to install them with the high end of the coil to the rear of the follower matching how the original MP34 springs were installed. Unfortunately this put the wider part of the Uzi spring in the narrower part of the MP34 follower where it simply would not fit. Turn them around and they drop in. Going to order a pile of Uzi springs to refit my mags I wonder if it would be advisable to trim half a coil off the Uzi springs to keep the high end to the rear BTW The MP40 springs fit and seem to work well if trimmed to 10-5/8" OAL but they are nowhere as close a fit as the Uzi springs Edited September 8 by StrangeRanger Link to comment Share on other sites More sharing options...
zavrit Posted September 9 Report Share Posted September 9 Thanks for the update. I would not cut the spring. I turned my spring so the high end is at the rear. It doesn't matter the angle of the spring at the bottom. Link to comment Share on other sites More sharing options...
StrangeRanger Posted September 9 Author Report Share Posted September 9 On my springs the high end is the narrow side of the trapezoid. If I turn it towards the rear the front is the wide side and will not fit inside the follower I'm going to order some springs from Wolff. Maybe they'll be like yours and there won't be an issue. Link to comment Share on other sites More sharing options...
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