"The definitive "go to" bucking:
I've owned four or five of these in the past and they've always worked very well. During wet, dreary and sub-zero weather, these things continue to work with excellent range and accuracy. I've successfully installed these in Echo 1's, VFC's, King Arms, (of course) G&G, etc. The only things I've had trouble installing these in a KWA's 2GX hop up units, but that's KWA for ya.
I got approximately 230ft of consistent, accurate range in an JG G36c using a 300mm tightbore inner barrel with great air compression at a consistent 400FPS on a freezing day
The simple enlargement of the nub works great
Reliable (it takes hundreds upon thousands of rounds to kill these, it's like a cheating player who doesn't want to call their hits)
Fits well in many hop up units
Consistently good quality
Doesn't work well with H-nubs or X-nubs
A common question I see is: "should I get this or Prometheus Purple Bucking?" The only reason to get the Prommy over this is if you like purple and you hate having money to buy more upgrades. 10/10
"This item is great, but I have to share a set with you guys. Before this set (including this item), my gun had a roughly 3 foot spread at 100 feet. wtf right? Single fire was a pipe dream, I have been forced to play "spray and pray", which is both ineffective, and goes through ammo about 100x faster. I mean i would burn through 3000-8000 rounds PER GAME, and rarely hit anyone, unless they were 50-125. Now i go through about 1000 rounds tops unless i really want to suppress someone, and i easily kill anyone within 250, and push to 300. Not only am I more lethal, but it's more cost effective since i go through a 5th of a bag, rather than 1-2 bags. My gun now shoots a 1 foot group at 200 feet... Omfg it's amazing. Now i'm a single fire player. It's an entire new world, and I got all the parts from evike.com. Before these upgrades I was at 450 fps, so you think my grouping would be better than 3 feet at 100 feet away. After these upgrades it might be about 460 (mainly cause an extended inner barrel) (by the way all of my shooting is just standing fire, so it's likely even more accurate then that if prone/propped up/in a gun vice).
The main concept to accuracy, is to have no movement in the barrel, hop up, hop up bucking, etc, and all of it needs to be 100% consistent. If there is even 1/100th of an inch of movement somewhere, it can throw off your grouping by a lot! So on you tube when you see them trim the bucking so it's smooth on the inside, DON'T do that. You want that notch so it doesn't slide around. The more solid of a fit around the bb your hop up has, the more consistence upon leaving barrel aka more accurate it'll be. This entire set is 97.50 (before coupons, after coupons it was about 76$ for me). I recommend this set up for 450 fps buildings. Using it in a cqb with a shorter barrel will still increase accuracy a lot, but it won't be sniper range (push to 300 feet). A 320 fps with 8 inch barrel might be 200 feet, push to 225-250. I don't know cause I don't have a CQB build, but that's my estimate. You'd lose roughly 100 feet worth of range/accuracy. I use .28 bb's and make sure you get "precision grade" not match grade, not generic brands, get precision. This means they are about 5.96mm in diameter, and they are ALL the exact same diameter/shape. match grade is i think are made 5.86-5.94 or something. This means the entire bag is inconsistent, meaning they won't be 100% accurate. Generic brands are far worse. Weight wise for my 450 fps build you can try .3, maybe even .32, but no more than that. I like .28's cause they are still great for this build, and .28 is the heaviest weight before a major price jump for the bbs. Now here is the process/parts you will need.
1st is a good hop up. I believe in metal hop ups both because they are more stable, more reliable, and they last longer. I mean a plastic hop up might not seem to wiggle much, but even the smallest of movement can translate into a +5 inch larger grouping at 200 feet. "I used the ASG Lonex Ultimate Aluminum One Piece Hopup for M4 / M16 Series Airsoft AEG". This hop up comes completely disassembled which was intimidating to me as I've never done more then put in inner barrels, and new motors. Trust me though, it isn't rocket science. Worst case if you have an airsmith friend, this entire set up will take them less than a half hour. Put that together but don't use the hop up spacer that comes with it. Use the 3rd component.
The 2nd and one of the most important pieces is the hop up spacer. I use the "Angel Custom CNC "H-Hop" Hopup Spacer For All Airsoft AEG (Set of 2 / Black & Clear)". Most hop up spacers are a soft rubber or plastic, and flat across. This means they "flex" against the bb. While this is a good concept in theory since it'll hug against more surface area of the bb, trust me it's bad. "Flexing" is inconsistent. One bb might fit through perfectly, another one just slightly less perfectly. I mean it can be like 1/10th of a mm in difference, but again this can easily throw off your grouping by +5 inches at 200 feet. These hop up spacers are hour-glass shaped, so they still fit around a bb very well. The key difference is they are a hard plastic. So they don't wear down as fast, and they are completely consistent. Every bb goes through not perfectly, but the exact same as each other, and that's what counts!
The 3rd component is the " G&G Hopup Bucking for Airsoft AEG w/ Cold-Resistant Material" A friend recommended this bucking, and now I understand why. For one it's a slightly better fit on the barrel, but this slightly better fit means better grouping/air seal. Second, it is durable material. It won't wear out as fast as most other bucking. It's basic friction. The hop up pushes the bucking against the bb, so with every bb that runs through, it gets more and more worn down.
The 4th is a good inner barrel. I got the "Angel Custom G2 SUS304 Stainless Steel 6.01mm Airsoft Tightbore Inner Barrel (455mm / AEG)". This barrel is godly among the barrel world. For one the packaging it comes in is literally perfect. I mean just the package is a very hard plastic that it free floats inside, and evike put an additional card board tube around that. Don't know why cause it's already nearly indestructible, but evike takes care of its products even in shipping. The length 455mm is just a hair under 18 inches. With my build, that's literally just to the end of the suppressor, roughly 1/8th inch from the end. PERFECT! This barrel is a tank, it's very durable. I mean you can literally swat someone with it repeatedly, throw it back in your gun, and it'll still run like a dream. Also it has no finish on it, meaning it won't wear over time. Nothing to wear. My gun has a mock suppressor, but either that or a barrel/flash hider, one thing that is very important. Tape around the end to increase the outer diameter of the inner barrel, until it fits snug inside the outer barrel/suppressor. The point of this is to make it have no wiggle. The less wiggle=more accuracy. This can literally effect your gun so much that it'll take your accuracy from 18 inches at 200 feet. To 10 inches at 200 feet. Keep in mind this is from a standing position. Note you can go with a shorter barrel, it's likely that range will drop about 10-20feet for every 1 inch shortened in the barrel, but this length barrel is recommended for only 450fps and up, and with good internal compression (nozzle, cylinder, piston head, etc). The concept is that with such a long barrel, you need that air to be forced through fast enough to get it through the barrel fast enough, that it won't be sucked back by the vacume. Longer barrel means more air in it meaning more vacuum it creates, so the bb has to go through it fast before it is sucked back. And you need good air seals cause if your cylinder leaks at all, it means though the air might still push through at 450 fps, it won't be as much air. Longer barrels need every bit of that air.
Last but certainly not least, is an item you can't find on evike, but any walmart or home depot/lowes should have some for cheap. It's called "teflon" tape, this is very thin tape that fits to the shape of almost anything. You want to put this between your inner barrel and the front of your hop up (where that metal ring goes) and anywhere else that is loose. If it has enough space, wrap some in. I also wrapped some on the end of the outside of my hop up, against the inner barrel. This is to help secure the hop up against the inner barrel, secure the entire set up inside the outer barrel, and help with air compression.
I highly recommend this set up, built this way, with these exact parts. If you have a stock gun (even a high end kwa, G&G etc are still "stock" guns) you will notice a world of difference.