chainring Posted February 18, 2011 Share Posted February 18, 2011 I've run a few mag clamps before, and always been irritated by noticing that it moves over time. I don't have to have safequeens, but I don't appreciate the shiny mar that is left behind as the clamp migrates toward the end of the barrel - sometimes only to be stopped by a vent rib leg. So, I've often thought about how to stop it. Heard electrician's tape, locktite, salt water, machined grooves, etc. but wasn't impressed by the efficacy of any of them - other than the machined groove, which isn't really an option. A parallel (and often red-headed stepchild) hobby of mine is bicycling, and my roadbike is a carbon frame with a carbon seatpost and bars. While inspecting my newly installed bars several years ago, I noticed a red greasy substance and was a bit surprised. Under normal circumstances, carbon bars are a problem to keep adjusted and tight, because the surface is slick and relatively fragile, which keeps you from clamping them very tightly. Grease didn't seem like a good idea at all, so I mentioned it to the shop. They informed me that it was not grease, but a substance called Carbon Assembly Paste. It was basically a collection of TINY plastic balls in a paste. Smear a bit on the carbon to be clamped and the little plastic balls compressed and gripped the microscopic texture of the clamping surfaces and increased frictin fantastically. Claims of 30% reduction in torque specs were common. It works, too, because my seat posts and bars never moved, and the paste is a common ingredient at any bike shop these days. It took a couple years for me to make the connection, but I'm betting that the same substance could be used to good effect between one's mag clamp and barrel/mag tube. I stopped by a bike shop today and got about a teaspoon squeezed into a plastic baggie, and I'm going to try it over the next few weeks on my 870. I welcome any of you to do the same thing, and get back to us on whether it works. One tube would be enough for a whole forum's worth of mag clamps, so it's hardly worth buying some unless you shoot with a big group of guys or are willing to mail everybody a little baggie of it! Which I might do if it seems to be effective. Some tubes are as much as $25, and some as cheap as $4. Probably not a dime's difference in effectiveness. Anyway, it's not going to change the face of shotgunning in America, but it seems like it might be a fix for a common little problem with long-extension competitive or HD shotguns. Figured I'd throw it out there so we could get some T&E. http://www.competitivecyclist.com/review-lubricants/Tacx-Dynamic-Carbon-Assembly-Paste_388.html http://jensonusa.com/store/product/CM407B09-Fsa+Carbon+Seatpost+Installation+Compoun.aspx Link to comment Share on other sites More sharing options...
GentlemanJim Posted February 18, 2011 Share Posted February 18, 2011 All of the clamps I have used slipped Except the Nordic clamps!! They stay where you put them Jim Link to comment Share on other sites More sharing options...
chainring Posted February 18, 2011 Author Share Posted February 18, 2011 Nordic is good stuff, but slipped nicely on my sister's 1100. Looking forward to trying this fix on it. Link to comment Share on other sites More sharing options...
DocMedic Posted February 18, 2011 Share Posted February 18, 2011 (edited) What I end up doing was taking a small amount of duct tape and placing it under the clamp where the loading tube part is. hasn't slipped at all. Edited February 18, 2011 by DocMedic Link to comment Share on other sites More sharing options...
StealthyBlagga Posted February 18, 2011 Share Posted February 18, 2011 My method is a bit more involved, but has proved very robust over years of hard use: 1) Disassemble the clamp and apply grease/vaseline liberally to anything that has to move (like the clamp screw). 2) Wrap the barrel and magazine tube with Saran Wrap. 3) Thoroughly degrease the surface of the clamp that touches the barrel/magazine. 4) Mix up some 5-minute epoxy resin and smear a layer on the inside of each clamp half where they touch the barrel/magazine. 5) Gently install the clamp on the barrel/magazine (i.e. over the Saran Wrap) and let the epoxy cure. 6) Disasseble and clean up (excess epoxy can be removed with a razor knife). Discard the Saran Wrap. The layer of epoxy will hold up to the high temperatures of the barrel, and will supply enough friction to prevent the clamp sliding without the need to over-tighten. You are welcome Link to comment Share on other sites More sharing options...
cking Posted February 18, 2011 Share Posted February 18, 2011 Just clean all the parts put epoxy on the clamp, put it together, clean excess off with vinegar and little plastic scrapper and let dry. When comes time to take it off a smart rap with mallet it will pop louse. IF it won't come off just take hair dryer to it until it too hot to hold them rap it. Link to comment Share on other sites More sharing options...
want2race Posted February 18, 2011 Share Posted February 18, 2011 My Nodic clamp moves too. I've tried many things as well. Adding anything under the clamp, tape, loctite etc, changes the spacing between the tube and barrel. I could watch the barrel move as I attached the clamp. Carbon Fiber is more porus than steel but I'm curious about this stuff. I may just machine a very shallow groove in my mag tube and call it done. Link to comment Share on other sites More sharing options...
GentlemanJim Posted February 18, 2011 Share Posted February 18, 2011 hmm, Wonder why my clamps did not slip? I did clean the guns after every use, maybe more rounds would do it? I use rosin dust to clamp barrels when doing bolt rifles...I bet that may work Jim Link to comment Share on other sites More sharing options...
benny hill Posted February 18, 2011 Share Posted February 18, 2011 2 layers of masking tape on the tube & no move no more. Link to comment Share on other sites More sharing options...
mpeltier Posted February 18, 2011 Share Posted February 18, 2011 Bieng in to Bicycling myself, I use a piece of innertube cut the same length as the clamp, slipped onto the magtube under my Nordic clamp (yes mine would move also). Its less messy than any paste, cost less and locates the same place for the clamp on re assembly. Never a problem with clamp diameter or anything. It works perfectly. Link to comment Share on other sites More sharing options...
Pat Miles Posted February 18, 2011 Share Posted February 18, 2011 I'll have to pick up a tube of the carbon assembly paste. I can think of a dozen other things in the shop I'd like to try it on. May just turn out to be the greatest thing since sliced bread. Pat Link to comment Share on other sites More sharing options...
philg80 Posted February 18, 2011 Share Posted February 18, 2011 I am surprised no one puts a small piece of skateboard tape around their mag tube. The adhesive sticks to the tube leaving the gritty side out and the clamp grabs the grit. That is what I have done for years and no problems yet. Link to comment Share on other sites More sharing options...
GunCat Posted February 19, 2011 Share Posted February 19, 2011 hmm, Wonder why my clamps did not slip? I did clean the guns after every use, maybe more rounds would do it? I use rosin dust to clamp barrels when doing bolt rifles...I bet that may work Jim Rosin works well, as does a little bit of extra fine lapping compound. I've used both in similar situations. Link to comment Share on other sites More sharing options...
sirveyr Posted February 19, 2011 Share Posted February 19, 2011 I use small pieces of bicycle inner tube on my Hobo Tactical 870. Link to comment Share on other sites More sharing options...
rkgsmith Posted February 22, 2011 Share Posted February 22, 2011 Simple cure, just don't run a clamp at all. I never do and have never had a problem. Link to comment Share on other sites More sharing options...
T3P_Guy Posted February 22, 2011 Share Posted February 22, 2011 I just put some heat shrink tubing on the legs of my Nordic clamp (the ones clamp on the mag extension). I don't have to worry about over-tightening now, just snug it up and it will not budge. Link to comment Share on other sites More sharing options...
slowsure Posted February 22, 2011 Share Posted February 22, 2011 I use 600 grit sand paper cut into small tabs to go under barrel and clamp. Thin, works and simple like me. Link to comment Share on other sites More sharing options...
halogrinder Posted February 23, 2011 Share Posted February 23, 2011 what about some valve lapping compound? 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