rhino Posted August 11, 2007 Report Share Posted August 11, 2007 Right, thought i'd finally get round to doing one of these. As everyone knows i've never been a fan of the "Sticky-out" magazines favoured by the Maruzen Ca870 range and the subsequent clones that followed thereafter. So, i thought i'd stick this here for people who'd like to modify their JT3 shotguns to use the G&P 22 round short magazines currently available for the Maruzen CA870 range. FIRST THINGS FIRST... This cheap and relatively easy mod is for the JT3 shotguns (Benelli clones - pistol grip and full stock models) This WON'T work on the Double Eagle shotguns (CA870 clones) due to the magazine feed being different. WHAT YOU'LL NEED... small phillips head screwdriver (depending on what stock version you have), you may need a slightly wider headed Phillips head - for reference, this was performed on a pistol grip version. Small roll of black masking tape (available at any budget £ store or DIY shop) and a stanley knife (watch those fingers now!) AWAY WE GO... The G&P CA870 22 round short magazine. On the front of the magazine (not here because it's already been sorted) is located a small piece of plastic which sticks out slightly. With the stanley knife, carefully cut it off so that it looks like the above picture. next bit is to find out how to get the magazine to sit in correctly. If you put the magazine in now, it won't lock in properly. This is because on the short magazine there is a small catch located near the bottom at the back of the mag. Currently, it won't fit because there is nowhere for that tiny bit to click into (if you look at the above picture, the circled section shows where that small part on the back of the magazine has to lock into) GET 'EM OFF... (OO-ER... ) *Ahem* Right, next bit is to take the stock or pistolgrip off (pistolgrip for this one) and remove the plastic cover and the ejection port (after taking the grip off, it should just slide off) Next part is a bit fiddly (don't lose them screws now!!!) As shown on the above 2 pictures, remove the screws that the arrows are indicating (4 silver - 2 each side) and carefully push out the silver pin (circled in both pictures - doesn't matter which way it comes out) and carefully pull the trigger guard away. TRIAL AND ERROR... This is the most fiddly bit really (not hard, just got to get it right) Grabbing your black insulation/DIY tape, take a fair sized piece off (about 7" or so) and fold it over and over until you get a small square made from the folded tape. The arrow on the above picture shows where to put the small piece of tape (inside the guard just short of the back of the shell hole) Now when it comes to putting the guard back on (as shown above) the guard will bulge down slightly and replacing the screws in the middle section gets a bit tricky. Put the 4 silver screws back in (not too tight... don't want to strip the threads now do we?) You should now have a small gap at the rear of the shell hole. Place the magazine in and press it up. Does it click into place? If not, either add more tape to make the gap wider or remove the tape to make the gap smaller. Once the mag sits comfortably in the well, try firing a few rounds with it to make sure it's feeding right. Yes? If not, then there's too much tape there and you'll have to remove a bit more. On the above picture, the white dots show whereabouts the gap should be... and this picture shows where the tape should be on the inside of the trigger guard (red dots) If the magazine sits in fine and is feeding well, put the silver pin back in (see pics 3 and 4 if you're not sure), replace the ejection port, receiver cover and pistolgrip/stock and there you have it. You'll note that even though the triggerguard bulges down slightly, it's hardly noticable and you can finally use those G&P shorty magazines without your shotgun resembling an Enfield. FINISHED RESULT Ian "Rhino" Leonard Link to post Share on other sites
fanta101 Posted August 11, 2007 Report Share Posted August 11, 2007 Genius guide. Really well done finished product you got there. This question may be a bit off topic but it reminds me: Would a G&P flash-light pumping handle (fits for Maruzen 870s) fit on a Tanaka 870? Link to post Share on other sites
rhino Posted August 11, 2007 Author Report Share Posted August 11, 2007 hmmm.... not sure. Might do with some modification. Not had the chance to get one of the Tanaka shotties yet, so i wouldn't like to say for certain. Link to post Share on other sites
Edmiles Posted August 11, 2007 Report Share Posted August 11, 2007 Good article, may give it a shot when/if I get mine. Link to post Share on other sites
rhino Posted August 11, 2007 Author Report Share Posted August 11, 2007 no probs, if you get stuck drop me a PM Link to post Share on other sites
the_viral_phantom Posted August 11, 2007 Report Share Posted August 11, 2007 Very helpful, thanks again. Viral. Link to post Share on other sites
Edmiles Posted August 11, 2007 Report Share Posted August 11, 2007 Oh and I forgot to say, does the original mag still work with it? I'd assume not but I thought I'd ask. Link to post Share on other sites
rhino Posted August 11, 2007 Author Report Share Posted August 11, 2007 yes it does. That was the first thing i made sure. Tried both of the short magazines i bought for it and then tried the original mag that came with it. Works flawlessly. In a sense, the modification doesn't affect the original magazine in any way. All the mod does is put a small gap in the rear of the feeding well so that the catch on the rear of the short magazines can lock in (whereas the standard magazine is released by pressing the button on the side of it.) Link to post Share on other sites
skattergunn Posted February 7, 2008 Report Share Posted February 7, 2008 Awesome guide. I just picked up one of these and am wanting to do this mod, but can't seem to figure out how you got that stock off(I have the full stock version). Any help is greatly appreciated. Link to post Share on other sites
rhino Posted February 7, 2008 Author Report Share Posted February 7, 2008 i had the same problem, but Belladonna told me how to do it. Basically you have to stick a straight edge screwdriver between the shoulder stock rubber and the stock and pry it off (it's a royal pain, but don't be frightened of gving it some force) Once you manage to pry it off, it's just a case of unscrewing the long bolt and taking the stock off completely. Hope that's some help. NOTE: I also found a way to make it easier to get the stock off for future use. I'll put it up in a bit when i get a chance to take a pic. Link to post Share on other sites
skattergunn Posted February 7, 2008 Report Share Posted February 7, 2008 Fantastic! Just got it off. Many Thanks to you, Rhino. Link to post Share on other sites
rhino Posted February 7, 2008 Author Report Share Posted February 7, 2008 no probs. Camera just died on me so i'll have to use the text version of the stock mod. It's pretty simple really. After you've got the end cap off, find out where the bolt goes into the stock and mark it on the end cap. Next, get a large enough drill bit (or a spade bit that's just slightly larger than the head of the bolt)drill a hole and then attach it back to the stock (make sure that the hole is large enough to allow the head of the bolt to be pulled through it.) You should now be able to unscrew the entire stock without having to mess around prying the stock end cap off (yes, there's an obvious hole now in the end of the stock but it doesn't affect performance in any way) If i can get some decent batteries after, i'll try and take a few pics to show what i mean Link to post Share on other sites
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