Here's the How-to from my guide, including my replacement pin upgrade:
The oem linkage pin is 5mm dia and peened or possibly melted at one end which you can clearly see. If you need to remove it for whatever reason you’ll need to drill it out. A 3/16” bit works well, just try to be careful not to damage the hole of the barrel block. I drill a smaller hole first which is easier to get centered, then use the 3/16. I drill down ~.050", then I use a punch to drive it out. The reasoning for the dia and depth is to avoid damaging the hole in the barrel block. The hole is tapered as seen in the pix, so if you drill it as described then use a small punch and it will force the pin out without damage. My punch is made from the straight shaft of a 3mm Allen wrench with one end partially tapered to self center in the drilled hole. To install a new oem pin I drill a ~3/32” dia hole in the small end, maybe 3/32” deep, then using a center punch I expand it. You need to have the pins head well supported, like with an anvil or something very heavy and hard, and protect the gun and pin from damage while you do this. It doesn’t need to be flared much, just enough so it can’t come out, and it’s nice if it’s tight enough that it doesn’t rattle around. If you don't have a punch you make one from something (I think old Allen wrenches are great for this) or use a #2 phillips. A phillips will leave an obvious X mark but it's also much easier to do than a punch. Since this step will be difficult to do for most people I'd say give a punch a try, then if that fails use a phillips. I did one like this and it doesn't look bad w/ the X, but it's not great either. Imo the best looking way to resolve this, is the following: I prefer to make a reusable press-fit pin, which is also great if you plan on taking it out again in the future. A press fit pin will need to be custom fit, and I use the shaft of a drill bit to make it. In the pix I used a #6 bit as a donor, which was ~.203" dia, and I sanded it down to ~.201". It's not easy to sand down hard steel like that so I suggest you get a bit that's as close as possible to start. The example bit in the pix was made in china so it was rather uneven/out of round so the main reason I sanded it down that far was to make it more even. Quality US bits are much more even so less, if any, sanding is needed. A 13/64 might work and be easier to find that # bits, but the shaft dia of drills vary and may be too small. Depending on brand you might need a fatter #5 bit to make it work. To sand the bit smaller I simply chuck it into a drill backwards, wrap sandpaper around it and spin. Ideally you'll just be making the bit smoother and any fitting will be done by making the hole bigger. Again, I only sanded the above bit because it was nasty chinese crap and out of round, and sanding it took much less time than going to the store for a nice one. The bit/pin can be bigger than oem by many thou, it just means you have open up the holes in the barrel block and cocking linkage more. So using that .201" pin I only had to sand the hole in the block ~.001-.002", and open the linkage hole ~.0005". Basically the pin just barely didn't fit the linkage so I opened it up just a hair to work, no more, which is perfect because now it doesn't rattle. The hole in the block you sand little by little until the fit is just right, meaning tight enough so it will never come out until you hammer it out, and loose enough that you can hammer it in and out without too much trouble. To help get that fit you can put a long (~4mm?) gradual bevel on the pin before you cut it to it's final length, which will be your guide for sanding the hole. So using my example .201" pin I'll say sand so the very end is ~.198" or so. Now I can tell when my hole is close and I can try hammering it in as I get closer to I know when it's right. Once the fit is good you cut the beveled part off when cutting to final length. You don't need or want the hole in the barrel block to be super smooth, so I think ~180 sandpaper would be good for both quicker cutting and a good finish for said press fit. The length of the pin should be ~.500" long so it will fit nicely at the bottom of the tapered holes on each side for a sweet clean look. The block of a typical B18 is ~.615", so with the oem tapered holes it would be rather ugly and the space around them will collect dirt. The one in the pix is .500" and I think it looks pretty sweet. You can see I beveled the ends of the pin so it goes in smoothly, but if you don't like the looks of it then at least make sure the edge of the pin is burr free so it won't dig in/scrape when installing. I suggest at least a little bevel on the side going in, but up to you. If the bit has stamped numbers in the shaft, like mine had a big "#6", you'll want to smooth its high spots down or it could cause unnecessary wear on the cocking linkage. I'd also rotate said spot to a position that won't be scraping on the linkage during cocking, like at the top. Since the pin is harder than the linkage you should put the finest finish on the pin you can. I think I used 1000 sandpaper but 600 is fine. It's not required but the rougher the finish the more wear you'll get. Even if it were a 180 finish it will probably never wear out, but I figure I'll make an effort to make it better and stay snug. The hole in the linkage should be rougher, maybe 320 to 220? That way it'll hold lube better and wear into the pin better. Another nice thing about a removable pin is you can actually prep those surfaces, dry lube them and get grease in there, both during install and later as you see fit. I recommend dry lubing the pin and linkage surfaces, if you have it, then a liberal qty of dry lube/grease mix over that because the linkage is under a lot of pressure when cocking. Or you can use moly paste, which is one of the few places I'd use that stuff.
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