A Beginner's Guide To Barrels, Flat Hop and R-Hop
There is a lot of mis-information surrounding airsoft parts, such as inner barrels and hop up modifications, and predictably so, airsoft teching can be confusing in the early stages. So, to dispel some of the mis-information and rumors on the topic, I thought I'd write a coherent article regarding hop up and barrel modifications, specifically inner barrels, R-Hop and Flat Hop.
First things first, I strongly recommend you read u/Argoms [post on Recommended Brands/Parts] (http://www.reddit.com/r/airsoft/comments/29h0sw/recommended_brandsparts_list/) before you read this, as it covers a lot of good stores, brands, sites and parts.
- Barrels:
What is it that makes a good barrel? Well, there are a lot of things that factor into a good barrel. You don't necessarily have to go out of your way to order a $60+ Prometheus or PDI barrel to get great results. I took some relatively popular barrels and compared them side by side.
[From the bottom up, they are: ACM stainless steel 6.03mm (often branded as "Matrix"), G&G aluminum 6.06mm Combat Machine barrel, Madbull aluminum coated 6.03mm, VFC 6.04mm brass, ACM 6.05mm brass.] (http://i.imgur.com/QasbW2C.jpg)
Barrel Length
Let's get the big one out of the way first. In terms relative to range and accuracy, barrel length doesn't mean anything. That's it. If you'd like to factor in FPS and air voluming, be my guest, but those things don't really effect range and accuracy so directly, only how quickly the BB gets there and how quickly it loses the air behind it as well as velocity consistency. If you have a decent air-seal and a roughly correct volumed cylinder port, you should be fine. This being said, correctly voluming the barrel to the cylinder is crucial to consistent FPS, which aids tremendously in 250ft+ ranges. A 400FPS gun may be able to range 250ft, but a 500FPS gun will certainly reach it in a more timely and consistent fashion.
Barrel Windows -
One of the biggest factors when it comes to barrels in R-hopping or flat hopping is the window. [There are 3 main barrel cuts: straight wide, straight slim, and angled.] (http://www.pohrani.com/f/1V/WB/36cw6rhW/r-hop-tutorial-04.jpg) The first two are great for flat and r-hop, but I'd avoid slant-windowed barrels all together. [You can see here that each of these barrels have been displayed from largest to smallest window.] (http://i.imgur.com/hjdroRg.jpg) Notice how the stock ACM barrel has the largest window of all of them and the Matrix Tightbore has the smallest, despite being an aftermarket "upgrade" barrel. Barrel window size is a massive factor when R-Hopping especially. If your contact patch only protrudes through a small slit in the middle of the barrel window, you're only going to get decent results.
Bore -
I'm about to drop a huge truth bomb...[barrel bore barely matters.] (https://youtu.be/POAThtQEqi0?t=8s) Whether it be 6.08mm or 6.01mm, barrel bore is damn near inconsequential when compared to hopup. Without getting too heavily into it, 6.05mm to 6.02mm is the perfect bore for most guns. If you want a more consistent FPS, pick up a nice tightbore and have a field day :) Of course, wide-bores are a whole other story (basically, a cloud of air carries the BB out, but they're only suitable for HPA guns and occasionally, high FPS bore-up AEGs). That being said, the main reason you see a huge increase in range and accuracy with tightbores is...
Barrel Consistency and Smoothness -
The best thing a barrel can be is smooth and consistently straight.
"But Hitler, I don't have $20 to spend on a Madbull or ZCI barrel, what do I do?" Lets just say that your cleaning rod, some cloth, 15 minutes, some scissors and some rubbing alcohol and maybe some brass polish are your best friends :) That goes for all barrels, tightbores included.
Material factors into this a lot as well. The obvious reason is the weight of the barrel (for reducing rattle in the outer barrel). One of the many reasons why the Combat Machine barrels are certifiable hot garbage is that they're made of thin, cheap aluminum. On top of that they're not anodized and they're not slick at all.
An example of an aluminum barrel done right is the Madbull Black Python 6.03mm. It has a very nice hard Teflon based coating and is extremely smooth and, though the aluminum may not be much thicker than the CMs, the coating more than makes up for it.
Stainless steel and Brass barrels are more than heavy enough and are often thicker than aluminum barrels. On top of that, the stainless steel's bore is always more consistent due to the tighter tolerances needed when machining steel.
If your barrel rattles about in your outer barrel (which most do), [head down to your local hardware store and pick up some Plumber's/Teflon tape for 50¢] (http://i.imgur.com/SUnrGT0.jpg). Wrap it around your barrel (and bucking if needed) after it's been inserted in the hopup chamber and wrap it around your barrel in a "barber shop pole" pattern.
Crowning -
[As you see here] (http://i.imgur.com/VH3LV67.jpg), these barrels vastly differ in terms of depth of crown (notice I added a ZCI 6.02mm stainless steel barrel, I didn't include it in the window part due to the fact that it has an R-Hop patch installed) The VFC and the ACM stock barrel having the most (despite watch the picture shows) and the Combat Machine barrel having...none. What does this mean? Not too much, sadly. Crowning can have a huge effect on FPS and consistency, but it doesn't really matter if your crown is 0.5mm or 5mm deep, they all serve the same purpose and that purpose is very minimal. As long as your barrel has some crowning, you're good to go.
- Buckings (and flat-hopping them)
Flat hop and R-hop aren't too picky when it comes to what bucking you use. I recommend any bucking that gets a good seal and is the appropriate hardness for your FPS. [Pictured here is a nicely done Lonex 70D bucking I flat hopped a while back] (http://i.imgur.com/TCOVCP9.jpg). My personal favourite is still the G&G Green.
[This is, by far, the best flat-hop guide out there.] (https://www.youtube.com/watch?v=TbK167v_8Pg) Basically everything you need to know about the procedure is explained in the video.
To sum up the video: flat hop gets a better contact on the BB resulting in better accuracy and much better range. Turn your bucking inside out, shave down the alignment ridge and nub, and use a flat nub of your choice (M-Nub and hopup arm mod is optional).
- Hop Up Units
Does your unit get good air seal? Does it house the bucking, nub and barrel well? Does it mesh nicely with the nozzle? Does it feed BBs well? Does it keep it's zero? Did you answer yes to all of these? Then use your current chamber and skip this section. If not, continue reading.
A common mis-conception with hop up units is that they help with range and accuracy. This is only partially true. Sure, they house the entire "range and accuracy" assembly, but they mostly effect consistency. If your hopup unit is not doing it's job well enough, swap it out (of course). Material, whether it be zinc, aluminum, or plastic, and whether it's CNC'd, cast, or molded, doesn't matter too much as a good chamber is a good chamber.
- Flat Nubs and M-Nubs
Another extremely important part of hopup modding is the nub used. The two most popular flat nubs are: [the M-Nub] (http://i.imgur.com/14pMJrb.jpg) and [the standard flat nub] (http://i.imgur.com/7Lb3xnA.jpg). The flat-nub shown here is a Modify Baton Ryosoku nub (often sold with a pre-flat-hopped bucking that isn't quite as good as most custom ones seeing as they keep the alignment ridge intact). The M-Nub is a custom-cut piece of pink eraser and can also be found in a professionally manufactured version on most airsoft parts sites such as Brill Armory or Clandestine Airsoft. I've had better results with the M-Nub in both R and Flat configurations seeing as it is softer and more flexible than the very stiff store-bought nub. In fact, the Modify nub is unusable with R-hop because it's so stiff. Another popular choice is the "bridge nubs" or "concave flat nubs". These suck. That is all. In all seriousness, the theory is great, but it's not very affective in practice, at least not when compared to the M-Nub or standard flat nub. Reason being is the contact patch is reduced and so the hop up has to be turned all the way on to be affective with a BB heavier than a .25g.
Refer to the flat hop guide in the Buckings section to learn how to make and use an M-Nub.
- The Fabled R-Hop o.o
R-Hop requires both modifications needed when Flat-Hopping with an M-Nub. It is essentially a more consistent contact patch (it does the exact same thing that flat-hop does, just a bit better). I highly recommend that you pick up an R-Hop Z-Kit from [Clandestine Airsoft.com] (http://www.clandestineairsoft.com/hs-armory-c-1_41_42/) or [Brill Armory.com] (http://www.brillarmory.com/index.php?main_page=product_info&cPath=37&products_id=121) (or any of the recommended parts sites on Argom's post) then move onto a 6mm IDx 10mm OD EDPM rubber tubing (found cheap on McMasterCarr) once you get the hang of things. Watch [this] (https://www.youtube.com/watch?v=WDtXRDfpdCM) video and read [this post] (http://www.airsoftillustrated.com/?p=2184) and be on your merry way. [Here's a pointless picture of one of my better R-Hops on a ZCI 6.02mm stainless steel barrel.] (http://i.imgur.com/1x8ZMtw.jpg)
Aaaaand, that's about it. Feel free to disagree, add something, and ask questions. Danks :) Also, I recommend you use .28g or .30g BBs with these modifications on AEGs shooting between 350FPS and 400FPS.
Edit: added info below on the Magic Box Miracle Barrel as per request from u/yahtzee5.
Hey mang, I think you need to give an honorable mention to miracle barrels. The general consensus around here states that they are to be avoided, but just a few weeks ago, some dude tried to drop some hard tech knowledge on me and told me to get a miracle barrel, so I believe that either
- we are all ignorant and are behind the times
- many masses of people are being deluded by business and YouTube celebrities So what says you? - yahtzee5
-
Ayyy, forgot to mention Miracle Barrels. In my experience, they're good barrels when paired with other mods. Problem is, I could take my pink eraser nub, a flat-hopped bucking, and a slightly polished stock barrel and out-perform it to the umpteenth degree. They're quite possibly the most overpriced airsoft part on the market as they're really just decent barrels with a weird piece of metal that helps with consistency on the bottom. Pretty much a bunch of marketing hype for a good product, but not one that's worth the price tag. If you have the money, it's good to keep in mind that Prometheus and PDI are beloved for a reason. Edit: You can't get great airseal when using a custom flat hop with it due to the little metal piece of the bottom needing the alignment ridge to keep tension. It's doable using the alignment ridge with an R-Hop, but I'd suspect it's not worth it. - Me ( ͡° ͜ʖ ͡°)
Posted Apr 13, 2015, 4:38 AM UTC · edited