rangerguy Posted July 16, 2013 Share Posted July 16, 2013 I installed a +7 nordic tube on my Jm 930, trimmed the spring to 12" past the end of the tube. The gun run flawless but there is a whole lot more spring tension now which makes it harder to load. I relize the new spring is thicker than the factory. Can I cut the spring down past the recommened length to reduce the pressure without running into reliability problems? What lenghts are you guys running? Any help would be appreciated. Link to comment Share on other sites More sharing options...
rtr Posted July 16, 2013 Share Posted July 16, 2013 12" is what is recommended. That extra spring tension will be reduced some as you use the gun and as your brain gets used to feeling the stiffer spring. I recommend you don't cut it. Link to comment Share on other sites More sharing options...
prc77 Posted July 16, 2013 Share Posted July 16, 2013 12" is the shortest spring length that I would go. Reliability could easily be an issue going shorter. Make sure the mag tube and follower is super clean. I use a product called Dricote its silicone free. Spray some down the tube, let it set a minute. Wipe it down with a clean, lint free wipe on a 12ga brush. Super slick, dry. Works for me Link to comment Share on other sites More sharing options...
Nuke8401 Posted July 16, 2013 Share Posted July 16, 2013 +10" on my 930 turkey with either my 8 or 10 round setup. I seem to recall others going to +9. Less tension = easier to hand cycle, less chance of FTF, and less chance of double feed. Since the shell stop is moved by contact from the bolt carrier through a lever/spring; the more tension from the mag tube spring the more likely FTF while either shooting or hand loading. In some cases high mag spring pressure cases double feed when the shells come out of the tube faster than the shell stop can move back into place. I got to +10 by trimming the spring until I could hand cycle with a full tube and also buffed the shell stop parts and very slightly stretched the shell stop coil spring. If in doubt, springs are cheap, buy 2 and cut one until the gun malfunctions with only one shell left in the tube. I might R&D this just for the heck of it, I have an extra spring. Link to comment Share on other sites More sharing options...
T Bacus Posted July 16, 2013 Share Posted July 16, 2013 (edited) If you want to run the lightest spring possible Nuke8401s advice is good. Get two of the same spring, cut one to 10" and test. If it still runs cut to 9" and test again. Repeat until the gun stops feeding. Then cut the second spring 2" longer than the first when it failed. When I put the the Carbon Arms mag tube on my Versa it had a +1 extension and I cut the spring to 12" past the end of the tube. I later changed to a +2 extension which reduced the length of the spring past tube to about 9". I did not replace the spring and have had no problems. Edited July 16, 2013 by T Bacus Link to comment Share on other sites More sharing options...
Thecelt Posted July 16, 2013 Share Posted July 16, 2013 So you recommend a dry lube? Why silicone free? 12" is the shortest spring length that I would go. Reliability could easily be an issue going shorter. Make sure the mag tube and follower is super clean. I use a product called Dricote its silicone free. Spray some down the tube, let it set a minute. Wipe it down with a clean, lint free wipe on a 12ga brush. Super slick, dry. Works for me Link to comment Share on other sites More sharing options...
rangerguy Posted July 16, 2013 Author Share Posted July 16, 2013 (edited) Good advice nuke. I ordered a couple spring today and am going to do some R@D and trim an inch at a time. I have gotton a couple double feed only when hand cycling. Edited July 16, 2013 by rangerguy Link to comment Share on other sites More sharing options...
Nuke8401 Posted July 16, 2013 Share Posted July 16, 2013 I believe the nordic instructions say 10-16 past the tube. Most likey this is generic to all extensions they sell. I would be interested in what failure would result from a weak/too short spring. I would imagine the shell would jam between the tube and the lifter. Still might R&D this my self. Link to comment Share on other sites More sharing options...
rangerguy Posted July 16, 2013 Author Share Posted July 16, 2013 I just tried putting the factory spring in the new extension and it sticks out 9 inches past the +7 extension. Hand cycled fine. Gotta wait for the baby to wake up too test fire Link to comment Share on other sites More sharing options...
MarkCO Posted July 16, 2013 Share Posted July 16, 2013 When the spring gets too weak/short, the malfunctions vary based on the load, speed and hold. Sometimes, no shell even comes out, other times it gets trapped by the lifter part way out of the tube. Remember, when you trim a spring, you will get a bit of collapse over the first 100 rounds or so. I found that cutting a spring to 13" and running a match with it, it will end up about 12". I usually run about 11" as with 10", slugs and buck tend to have feed issues. Link to comment Share on other sites More sharing options...
abishai Posted July 16, 2013 Share Posted July 16, 2013 I just installed my Nordic +3 on my 930 SPX (7+1) thinking I'd get 8 in the tube, but Nordic will only claim 7. I bought the +3 on faith since numerous anecdotes at the range claim 8 is possible with the +3. So, technically, I can get 8 in the tube, but not with my Nordic spring. I trimmed the Nordic spring according to the directions, starting at 16" past the tube, iterating by 2" each time. Unfortunately, it never accepted the 8th shell (2 3/4"), and I ended up cutting it too short to feed anything properly. Out of curiosity I resorted to the factory spring (not sure if its a Choate or Mossberg spring), which extends 16" past the tube and is a slightly lighter weight spring, and it accepted 8 just fine. Only now I am having some feeding issues, probably due to the fact that this spring is too short, made for the Choat +2.Nordic advises I exchange the +3 for a +4. But before I do that, just wondering if there's any springs (brand and length) out there I should try that anyone has experience with perhaps hitting the sweet spot in this scenario. Thanks! Link to comment Share on other sites More sharing options...
rangerguy Posted July 16, 2013 Author Share Posted July 16, 2013 Who's spring do you use Mark? Link to comment Share on other sites More sharing options...
mpom Posted July 16, 2013 Share Posted July 16, 2013 Different Mark, but also running a 22" JM with a +2 Nordic extension. I cut down a Nordic spring to 8" beyond mag tube, no malfunctions. Just for grins I installed the factory spring, which sticks out quite a bit more but has thinner wire. Runs just fine and is significantly easier to load shells, so left it in place a couple of hundred shells ago. With a +7 or +8, I would follow Nuke's advice if factory spring does not work. Link to comment Share on other sites More sharing options...
MarkCO Posted July 16, 2013 Share Posted July 16, 2013 I only use Nordic springs. Link to comment Share on other sites More sharing options...
Thecelt Posted July 16, 2013 Share Posted July 16, 2013 I gotta measure the factory spring on my jm but by eye its easily 14" past the end of the nordic tube if not a little more. Link to comment Share on other sites More sharing options...
rangerguy Posted July 17, 2013 Author Share Posted July 17, 2013 My factory spring still sticks out 9" past the +7 extension. I shot one tube full of 11rds with no problems, gonna run a couple more tm. Makes for a lot easier loading. Link to comment Share on other sites More sharing options...
Nuke8401 Posted July 17, 2013 Share Posted July 17, 2013 At least with the 930 I would say each gun would be a little different (mag spring lenght/force) because of the way the shell stop interacts with the bolt/carrier and the differences in friction/force required to operate the shell stop. I would guess a slicker shell stop/parts with a stronger shell stop spring could tolerate higher mag spring tension but I'm guessing a mag spring on the shorter/weaker end of the scale that still allows the gun to function reliably would be the best set-up and perhaps the most reliable. If is were going to set-up a new 930 without polishing the shell stop or other work I would go with the shortest/weakest mag spring that lets the gun operate reliably. No brainer I guess. Link to comment Share on other sites More sharing options...
Nuke8401 Posted July 17, 2013 Share Posted July 17, 2013 (edited) Ok, a little R&D this evening. 4 1/2" past the tube measured with the cap off and it runs great! A little background, I last cleaned my 930 before the FNH match last year and I have only shot maybe 10 slugs thru it since last fall. Today I took it out of the safe, put a few drops of M1 on the bolt, hand cycled and started testing. Measured my mag spring at 9 1/2" past the tube, pretty sure I cut it to 10" when I installed it maybe 1 1/2 years ago. Cutting an inch off at a time I shot 2 rounds from full 10+1 and then 1 in the chamber and one in the tube. I kept this up until I got to 4 1/2 inches. I decided to stop there and ran a mixed of 2 00buck, 2 fed high brass 6, 2 rem slugs, and the rest a mix of bulk rem and win 8s. As fast as I could shoot 11 rounds no failures.I will be shooting with some friends this sat and should get some significant rounds through it then.A few things I remembered when cleaning it after shooting today.1. Make sure the outside of the mag tube is clean. It is easy to think it’s clean because the carbon can be deceiving, you should end up with shiny metal, I use a scotch brite greeny.2. The piston rings are easier to clean if you soak them overnight in hops. I always use a wire wheel on a dermal.3. The first/large/wide piston ring can only be installed one way but the second ring can be installed backwards. I install the rings by installing the small ring in the large and then large on the piston, easy. The small ring should be held in place by the large ring. I also wire wheel the cylinder where the piston seats. 4. I use rem oil on everything just as a protectant after cleaning.5. I lube the tube, piston, all other parts with M1. I wipe as much lube as possible off the piston and rings before installing them.6. During a match I might put a few drops of M1 one the bolt as You would an AR.7. When installing the mag extension, install the coupling first and tighten Just beyond hand tight, then install tube. I used blue Loctite on the ext tube to coupling on mine and from then on remove the extension tube and coupling together. Concerning mag spring length, I did some simple some work (fluff and buff) on the shell stop and other parts so all guns would respond differently to different mag spring lengths.. Edited July 18, 2013 by Nuke8401 Link to comment Share on other sites More sharing options...
rangerguy Posted July 17, 2013 Author Share Posted July 17, 2013 That's 4.5 inches with a nordic spring Link to comment Share on other sites More sharing options...
Nuke8401 Posted July 17, 2013 Share Posted July 17, 2013 (edited) Added to above post. Edited July 18, 2013 by Nuke8401 Link to comment Share on other sites More sharing options...
Nuke8401 Posted July 17, 2013 Share Posted July 17, 2013 Yes 4 1/2" nordic spring works in MY 930. Link to comment Share on other sites More sharing options...
Thecelt Posted July 17, 2013 Share Posted July 17, 2013 Nuke, what have you had done to your 930? I just polished up the shell stop and chamber but no chance to test her out yet so I'm curious what you had done, if it made any difference, and do you have any pictures of the work? I'm wondering if I should polish up the ss a bit more. Link to comment Share on other sites More sharing options...
Nuke8401 Posted July 18, 2013 Share Posted July 18, 2013 (edited) See the "Mossberg 930 issues" thread and the " another 930 turned popper slayer" thread for shell stop work and other stuff. Besides the shell stop I just smoothed/polished the bolt and "carrier" = the flat piece the bolt sits on. No real metal removal. I did all the work myself. The only failures I have ever had were due to dirty piston/ rings. Edited July 18, 2013 by Nuke8401 Link to comment Share on other sites More sharing options...
rangerguy Posted July 18, 2013 Author Share Posted July 18, 2013 Thanks Nuke for the R@D. How much difference is there in the spring tension with the spring that short? I hand cycle 10 full tubes with the factory spring and shot 2 full tubes 11+1. Waiting on my new springs from Nordic to test there spring. Makes loading significantly easier with the factory spring. I have a match Sunday and we will see what happens. Link to comment Share on other sites More sharing options...
Nuke8401 Posted July 18, 2013 Share Posted July 18, 2013 (edited) There is significantly less tension at 4 1/2". Super easy to load. While I plan to test at 4 1/2", I have been running with a 9 1/2" spring. Depending on how the testing goes Saturday I might split the difference and run 7" or so to get the best of both worlds. I could see during a match where the extra spring pressure might be needed. Recoil works against the mag spring (forces the shell in the tube forward vice back) so maybe a tube full of slugs might FTF or even one slug left in the tube might FTF. It seems many people have problems with 930s and maybe more so the JMs, maybe I have been lucky but mine has run 100% after I figured out the piston/ring cleaning thing. Edited July 18, 2013 by Nuke8401 Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now