physicsnerd 139 Posted November 21, 2011 Report Share Posted November 21, 2011 (edited) After spending some time taking apart my S12 (learn something new every time I do that) I got to thinking about the thread about the extended barrel hoods on the 2011 manufactured S12s. With that said, I was curious about the feed angle of the different types of magazines that are available. On hand I could look at an Izzy 2, 5 and 8; a SGM 2 and 12; and an MD 20. What I found surprising was the amount of variance with these different magazines even when they were manufactured by the same factory. For example, the Izzy 8 seems to have a lot less clearance with 2 3/4" shells than the 5 or 2. I took picture pairs to share with you all to give you an indication of the amount of clearance you may expect with different manufacturers of S12 magazines. Of course the obligatory disclaimer of your mileage may vary is quite apt here since there are many variables within one gun let alone all of yours so take this for what it is worth. When I am not having mag catch or extractor pin issues I have not had an issue with any of these magazines. Izzy 2: -------------------------------------------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------------------------------------------- Izzy 5: -------------------------------------------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------------------------------------------- Izzy 8: Continued in post 2. Looks like if you reply to your own thread before anyone else it auto combines them! SGM 12: -------------------------------------------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------------------------------------------- SGM 2: -------------------------------------------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------------------------------------------- MD 20: Edited November 21, 2011 by physicsnerd Quote Link to post Share on other sites
CFOofEVIL 8 Posted November 21, 2011 Report Share Posted November 21, 2011 Excellent idea for a thread. Thanks for the pictures and info! Quote Link to post Share on other sites
yooper14.5 84 Posted November 21, 2011 Report Share Posted November 21, 2011 Interesting.... Were the shells all the way back in the feedlips when you took those pictures? I'm gonna have to look at my magazines. Thanks for posting this. Quote Link to post Share on other sites
gunfun 3,931 Posted November 21, 2011 Report Share Posted November 21, 2011 (edited) Interesting. Thank you for posting with pictures. Most of us don't have access to the pricey imports. (although maybe the new legal changes will help?) For me personally the only reliability issues i have had since getting the gun tuned in is having a couple of surefires modded for the JT magwell wear down on the front edge. I built one of the two mags this happened to up with epoxy, but it is clearly still wearing. I have been considering sleeving it with thin steel like shimstock or something to reinforse the edge and give it a skidplate. That creates enough slop that maybe 1/100 shells will snag on the lower portion of the barrel hood. Now I am inclined to compare the magazine feed angle to my unmodified saiga. maybe I should be looking at adjusting the position of the magwell instead. I just went and checked my two. Measuring by precision calibrated eyeball micrometer from the back edge of the upper hood extension to the foremost top edge of a 2 3/4" shell: IZ 109 with JT magwell and surefires. (5) 10rd (1) 12rd. 12:rd ~1/4" (no problems with this mag feeding. wiggle allows for about 1/32 of movement at shell, but pushing naturally wants to stay more centered) 10rd worn then built up: 1/8" no play. 10rd: 3/16" 1/32" play Ditto, worn: 3/16" to 1/4" ish with play. Early EAA IZ 108 bone stock (until I get some play time around christmas Since all the mags fit great in my other gun without the magwell, I am inclined to dress the mag release when I convert.rather than fit the mags.) : Factory 5: 1/8" (looks centered on the barrel) surefire unmodified w/ serials to gun penciled in: 1/8" snug fit, not play without making it. surefire unmodified very tight fit: 3/16" Keep on shooting 5 clone: 1/8" actually gets stuck, and requires deliberate force to remove. Edited November 21, 2011 by GunFun Quote Link to post Share on other sites
physicsnerd 139 Posted November 21, 2011 Author Report Share Posted November 21, 2011 Interesting.... Were the shells all the way back in the feedlips when you took those pictures? I'm gonna have to look at my magazines. Thanks for posting this. Yes they were. I played around with chambering a round by hand (since I obviously had the BCG out!) and saw that the spring in the Izzy 8 is strong enough that as the shell rises to be ready for chambering it would be unlikely to move around enough to catch on the barrel hood. The SGM 12 has less spring pressure when it is close to empty and I could see how the shell may be jostled such that it *may* catch on the hood. However, to get that much play it would already need to be pretty far forward in the magazine AND get rotated upward for that to happen. Probably explains why, fingers crossed, I have not seen it happen! Quote Link to post Share on other sites
leadsled 40 Posted November 24, 2011 Report Share Posted November 24, 2011 SGM 8 round. Quote Link to post Share on other sites
physicsnerd 139 Posted November 24, 2011 Author Report Share Posted November 24, 2011 SGM 8 round. Thanks for posting. I will have to compare it the next time I have access to my 8s. Looks like the shell is well positioned. Quote Link to post Share on other sites
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