seasam Posted March 28, 2013 Share Posted March 28, 2013 (edited) I opted to remove the rail on my m4 and thought I'd share... -Rail screw holes are M4x.75 NOT #8-40 (8-40 is what I used, but do so at your own risk - read further) -Screws should be no more than .130" long to match receiver thickness I purchased these two plug screws, either one will work: -Brownells hex plug: 080-534-002WB $16.99 http://www.brownells.com/gunsmith-tools-supplies/small-hardware/metal-screws/hex-plug-screws-prod21185.aspx -Brownells slotted plug: 080-533-840WB $8.99 http://www.brownells.com/gunsmith-tools-supplies/small-hardware/metal-screws/plug-screw-kit-prod792.aspx Personally I thought the hex screw looked best, even though they were pricey. I was worried the hex plugs might be a shade too long as the receiver seemed to be 1/8" but they fit perfect. Other options on Brownells include a positive stop screw and a SS option. I secured these screws with Loctite 243 as it supposedly works better if oil contamination is present... and I already had some 243 from my titanium carriercomp mag install (thx Unobtanium for the 243 insight). I'm sure any blue loctite would do the job though. All in all probably a huge waste of time for this, but I like the cleaner m1 type look with the rail out of the way. Plus I was bored. [ATTACH=CONFIG]2048[/ATTACH][ATTACH=CONFIG]2047[/ATTACH][ATTACH=CONFIG]2046[/ATTACH][ATTACH=CONFIG]2045[/ATTACH][ATTACH=CONFIG]2044[/ATTACH] Edited March 29, 2013 by seasam updated for rail fastener thread size Quote Link to comment Share on other sites More sharing options...
benelliwerkes Posted March 28, 2013 Share Posted March 28, 2013 (edited) I opted to remove the rail on my m4 and thought I'd share... -Rail screw holes are #8-40 thread (thx Mesa Tactical) I purchased these two plug screws, either one will work: QUOTE] The M4 screws are METRIC not SAE......using the 8-40 screw is going to re-configure the threads. They feel like they fit because a steel screw is being used to "re-thread" a shallow aluminum threaded hole. IF you try to go backwards now your factory screws will not fit properly. We have already documented how aftermarket wannabe rail screws that are shipped with some rails, do not fit, even metrics that are shipped, however they too are usually the incorrect pitch specifications. Edited March 28, 2013 by benelliwerkes Quote Link to comment Share on other sites More sharing options...
seasam Posted March 28, 2013 Author Share Posted March 28, 2013 thanks for the insight and correction! I will say that the 8-40 screws did work for me in this case as they are not being used as a fastener. I encountered no resistance and do not believe that the threads were reconfigured. Had they been torqued down, the result may have been different. I'm happy with what I have so I don't think I'll try getting different screws to see if it makes a difference. If anybody else has tried metric screws please chime in. Quote Link to comment Share on other sites More sharing options...
StrangerDanger Posted March 29, 2013 Share Posted March 29, 2013 I looked around on McMaster-Carr and Fastenal, but didn't see much that would work for the .75mm thread pitch. It's kind of an odd ball size. The closest I found was 6mm in length, which is kind of long for your needs. They'd need to be ground to the length you need. Since there is no lip on a set screw to bottom against, you'd have to lock them in place with a threadlocker. http://www.mcmaster.com/#set-screws/=m32hxp Quote Link to comment Share on other sites More sharing options...
seasam Posted March 29, 2013 Author Share Posted March 29, 2013 I looked around on McMaster-Carr and Fastenal, but didn't see much that would work for the .75mm thread pitch. It's kind of an odd ball size. The closest I found was 6mm in length, which is kind of long for your needs. They'd need to be ground to the length you need. Since there is no lip on a set screw to bottom against, you'd have to lock them in place with a threadlocker. http://www.mcmaster.com/#set-screws/=m32hxp thanks for the suggestion... yeah mcmaster usually has it all, but I guess this size is too far out there. m4x.7 or m6x.75 .... close but not close enough. the other option is some sort of plastic plug like Benelli uses in their other models, but I don't think that's any easier to find. I tried (caplugs, stockcap sites). I know for sure my threads weren't ruined with the 8-40 when I put them in - loose if anything, but who knows when I try to take them out now that they're loctited in place and I have to use actual force to remove them. I think I'll just leave them and call it a day. and never sell my m4. hah. I'm at least glad benelliwerkes posted on this, because I could not find out what the damn size of those screws were from online searching. I just don't have the tools myself... so thanks again man. Quote Link to comment Share on other sites More sharing options...
Hookster Posted March 29, 2013 Share Posted March 29, 2013 Hey Seasam!....Beyond all the thread tech talk....I like the look! Quote Link to comment Share on other sites More sharing options...
seasam Posted March 30, 2013 Author Share Posted March 30, 2013 Hey Seasam!....Beyond all the thread tech talk....I like the look! thanks, yeah I like it. went and shot last night - everything seems fine, loctite did the job. Quote Link to comment Share on other sites More sharing options...
StrangerDanger Posted March 31, 2013 Share Posted March 31, 2013 Another option would be to put a small bead of black silicon in the hole. If the holes are desired at some point, you could easily dig it out. Quote Link to comment Share on other sites More sharing options...
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