Airsoft FPS

This is the ultimate guide to Airsoft FPS (muzzle velocity) issues.

What is the airsoft fps term?

The muzzle velocity, expressed in fps (feet per second) is the muzzle velocity of airsoft replicas. It is the speed that the BB has when it leaves the barrel of the airsoft gun.

Many people believe, the more fps an airsoft replica has, the better. To some extent it is true, but here are the bare facts.

The fps in airsoft means only that a certain BB will have a certain muzzle velocity. In most cases for most replicas it is measured for 0.2 g BB, but be sure to check it. If you find a suspiciously cheap replica with high fps, it probably means it was measured on 0.12 g BB and on 0.2 g BB would have less fps.

The fps also means that the BB fired from this replica will have a specific kinetic energy, calculated from the formula E=m*V²/2, where m is the mass of BB (0.2 g for example) and V is the fps. The more the energy of the BB, the longer range you can shoot. And the more pain you will cause when hitting someone.

fps vs range in airsoft

Yes, the bigger the fps for a replica, the longer it's range may be!

But the range is not determined only on the fps of an airsoft replica. The range is determined mostly by the hop-up system of the replica. This system rotates the BB so it will not fall on the ground after flying 20 meters.

A cheap replica may have large fps, but that does not necessarily means it has long range. It is not said it might be used as sniper rifle!

fps vs accuracy in airsoft

fps does not determine accuracy. Accuracy depends on the lenght of the barrel and the quality of the hop-up system. If you install tightbore (precise inner barrel) for your electric airsoft replica, it will slightly increase your fps (by 5-10 fps or so) but will surely increase the accuracy of your replica.

To be honest, the bigger the fps, the smaller the accuracy. Try using 0.12 g BBs in your AEG of 300 fps and you will see what I mean. To use this high muzzle velocity you need to use heavier BBs, for example the 0.2 g BBs are recommended only for replicas that have less than 300 fps! For 400 fps you should use 0.23-0.25 g BBs, for sniper rifles of 540-550 fps you should use 0.36-0.43 g BBs. Lighter BBs will be fired in random directions.

Guys from ASGShop.pl broke my mG36's hopup chamber

Last saturday I wrote a post on how my mG36 got home from tuning and repairs in ASGShop.pl broken. Now it is a good time to add some more details to the story.

On 18th, right after I posted an article, I mailed the guys from ASGShop to tell them the replica doesn't work.

Yesterday (on 23rd) I mailed them once again, as I didn't get any answer. Couple hours later I got a reply that my e-mail was forwarded to the guy who worked on my replica.

The guy called me today around 11 AM on my cellphone but I had another phonecall at work, so I didn't answer. I tried to call him back in a couple of minutes, but the phone was not answered (the message on their answering machine says the phone support works from noon). He eventually called me three hours later.

I told him that the I found one piece of hop-up / barrel assembly (the spacer I mentioned on the earlier post) lying somewhere in the box that held the replica. We discussed for a moment and he said that it is not possible that this part disconnected itself somehow while the package was being moved. He told me that if I feel like I may try to take a look at the hop-up assembly and fix it by myself. As all I want is to have my replica firing as soon as possible, I agreed. I am familiar with this mechanism as I tried to replace the inner barrel by myself.

So I came home and started working on the mG36. The first step was to remove the magazine nest (sorry -- don't know if this is the right word, I mean the part you put magazine in) and what I saw told me something is very wrong with the hop-up chamber. I saw this:

From Airsoft from Poland photos

On the photo above you can clearly see that there's a broken hop-up chamber and that the hop-up bucking (rubber) is broken as well. You may also see that the spacer I mentioned earlied is gone (no big mistery here -- I found it in the cardboard box). So I disassemblied it a bit more to remove the barrel and hop-up chamber.



You can see that the rubber is also damaged. The moving nozzle made a small cut on the lower part of the rubber. You can also see what happened to the hop-up chamber.

But the latest discovery was worst. Not that I did't expect it, though...



This is the part of the hop-up assembly where the spacer is supposed to go. On the original G36 barrels there are two notches that hold the spacer in place. You can see it perfectly on the photos here (a guide to G36 hop-up disassembly). The fourth photo shows the spacer (pointed with the red arrow). On the 8th and 9th photos you can see the notches on the inner barrel.

Why am I shocked? I tried to replace the barrel in my mG36 some time ago. I bought some long barrel that didn't fit because of those notches. And being aware of that (and since the precise barrel for G36 was not available at ASGShop.pl at the time I sent them my replica for tuning) I told them to install any precise barrel that will fit. Well... seems the guys decided that the barrel without notches is as good as the original. But they were wrong. I thought of this last week -- this is why I wasn't surprised. :(

I don't care! I am going to send them the replica tomorrow and phone them on monday (will probably e-mail them some of the photos as well). I suspect they will repair it as a part of their warranty, 'cause they have simply no other choice.

But I am going to write this whole story down on the biggest polish airsoft community's bulletin board. I would let one mistake go, but two mistakes are too much!

mG36 at home, but broken

Recently, when I used the phrase "my favorite ASG shop" I meant the asgshop.pl. It changes today! They aren't my favorite airsoft reseller anymore, 'cause they screwed up my replicas twice. The AUG was first (the guy who repaired the replica didn't replace the broken engine) and now the G36 is broken...

And what's the most hilarious in this whole story? I think I know what is the problem as I almost forseen it...

Two years ago I tried to replace the inner barrel for my G36. At that moment it was difficult to purchase a proper barrel since it wasn't available at any of local airsoft shops. So I bought some 509mm-long barrel for AUG and M15s. But I couldn't install it, as it had notches in wrong places. The notches are used to hold the barrel to the hop-up chamber.

When I unpacked the replica from the box, I found a small piece of hop-up assembly. This part - spacer - stopped me from installing the barrel when I tried it. On this photo you can see when this spacer goes on the barrel, it is the place where the notches are. I the notches are somewhere else, you can't install the spacer. And the spacer is very important as it: holds the barrel from sliping out of the hop-up chamber and holds the hop-up adjusting wheel from moving to the front.

Okay, so I took the mG36, plugged charged battery and then tried to fire the replica. It made some noise, as the gearbox worked. But the BB wasn't shot. The BB wasn't fed to the hop-up chamber and wasn't shot. I rotated the replica upside down to make sure there is no trouble with the high capacity magazine. Nothing changed. So I thought maybe the hop-up is set on high BBs turning and then I turned the adjusting wheel to the other side. Nothing changed, but the adjusting wheel moved a bit to the front of the replica.

As the mG36 doesn't work, it's going back to asgshop.pl for further repairs.

mG36 is ready

On thursday a guy from my favorite airsoft shop called me and we spoke for a while about my mG36 replica I sent for repairs and tuning.

He said that he installed the parts I asked for (precise inner barrel, 6.04 mm by Systema, and sealed air nozzle) and tested the replica on the chronograph. I wanted the replica to have around 350 fps -- enough for playing with guys that have 400 fps installed, but not very much). And I thought that after this barrel and nozzle installed it’ll have something close to that (330...340 fps maybe), since the G36 from Classic Army has 315 fps in stock!

Do you want to know what were the results from chronograph? A shitty 290 fps! I was stunned when I heard that.

It seemed that there was no other choice than to change the power spring. I asked the guy what caused such poor results. He said that the cylinder - cylinder head - piston head set is not very airtight and the spring looks weak. He suggested to change the spring go M100 and new cylinder with both heads made from aluminum. When I approved those parts to be installed, he asked me if I didn’t want to have the M110 instead as it’ll give me something close to 400 fps. Of course I agreed...

On friday he called me again. He installed the M110 and the other parts I mentioned above. He checked the replica on chronograph again and had result of 390 fps. That’s more than enough, I think...

Would you guess how much I’ll be charged for this tuning? PLN 460, amount equivalent to $170.

But hey, if the mG36 is supposed to be an light support weapon (as it’s real steel MG36 counterpart), it must have better range and accuracy than typical ASG replica...

Tuning questions

About two weeks ago I started thinking about getting one of my replicas tuned. At this moment the MP5K and mG36 are full-stock (I mean the gearbox, not the body, bipod, battery and other stuff). AUG has the "silent" set installed, more info can be found in the post about the silenced AUG. But it does have significantly better muzzle velocity than stock replicas, I believe it's got something aroung 350 fps. (Mamut's CA870 after his tuning has 410 fps on 0,2g BBs and 380 fps on 0,3g -- meaning that the light BBs don't gain all the energy the power spring can give).

So I decided to put some money in my airsoft replica tuning.

Since MP5K cannot be used with battery larger than 1200mAh 9.6V (after small modification of some kind), I decided that MP5K will remain as it is now.

So the decision is to choose between tuning AUG and mG36. I wanted to get muzzle velocity around 420-430 fps. Tunned by ASGShop.pl both replicas are upgraded to this level by installing:

• M120 power spring
  
• super torque up gear set (Classic Army)
  
• reinforced bearing guide with bearing (Deep Fire)
  
• reinforced cylinder, cylinder and piston heads (the latter with bearing) and nozzle (Deep Fire).

Since AUG has already got both bearing guide, gear set and the bore-up cylinder set installed the tuning will eventually be only to put power spring inside. I have the Classic Army 170% power spring (I got it free of charge when buying G36) so it seems that this entire tuning will be for free (only the costs of installing all the parts...).

Later I decided that I will not put money in AUG. Why? I am afraid that the battery I have (8,4V 1200mAh) will not be enough to "fuel" this replica.

So I decided that I'll send my mG36 to ASGShop and order the 420-430 tuning. But instead ot all the reinforced cylinder-piston parts, I'll install the bore-up. It should cost similar amount of money but I believe I'll gain few more fps. Addiotionally I'll send them back the barrel I ordered and ask them to send me the one that'll fit (more about barrel troubles is written in mG36 phase III upgrade - day one.

mG36 - one step back

I wrote couple of days ago (in post MG36 phase III upgrade, day one) that the barrel I could not be properly attached to the rest od the replica. What I wanted to express is that there's one part of hopup chamber that holds the barrel to the chamber which doesn't fit because the barrel has notch in different place that the original one.

I removed that barrel on saturday and installed the original one, that's why I titled this post "one step back". :)

Yesterday I had my first chance to test the replica during airsoft game. We played it inside one of abandoned tractor factory buildings. What I noticed yesterday:
- the replica is now better balanced since the heavy battery is now installed inside the stock,
- the stock cannot be folded because of the battery iside (that's why the 3300 mAh battery for this stock has different cell setup).

Here's a photo of my replica at it's current state of upgrade.

From G36 and its m...

By the way -- I just noticed why the stock had different connector on the cable, that's because the battery had the same T-type plug. I wonder why they couldn't use the standard small or large plug?

Yesterday I also got a chance to attach the C-magazine to my replica. See below...

From G36 and its m...

One of the guys had the G36 with STAR grenade launcher and that magazine. The grenade launcher looked nice but the effect of launching all the BBs inside was...poor (in my humble opinion).

mG36 phase III upgrade - day one

Today I decided that I'll install the parts I receieved yesterday, ordered earlier this week (stock, barrel), the sealed nozzle I bought few months ago and a 170% Classic Army spring I got with my replica.

I decided that the first thing to replace will be the stock because that was my main purchase. I tried to remove the original stock in order to attach my new purchase. I didn't have the proper hex key to remove the hinge. So the stock will have to wait for it's turn.

This was not a good day for the G36 tuning. First of all I didn't have all the tools required for such a work and I ordered parts that didn't fit my replica well. ;)

Since I removed the gearbox and magazine socket to see how to attach the stock wiring to the gearbox (I still have no f--king idea!) I had an opportunity to remove the inner barrel and install the precise one. So I removed the outer and inner barrel and the entire metal part that holds the hopup together. I dismantled that part and the hopup itself. When I got my hands on the barrel and compared it to the one I bought (designed for M14, not G36!) I saw that it has the vertical incision (that holds the barrel in place and doesn't allow any motion in axial direction) was in different place. This means that the barrel is not properly connected to the rest of the replica.

Without having the stock installed I didn't want to replace the inner parts of the gearbox - i.e. nozzle and power spring. This is because I wanted to have first the 9.6V battery installed which I can't install without the stock.

Parts to mG36 phase III arrived

Yesterday I got the parts I ordered -- precise barrel and battery stock. Too bad I don't know how to connect the wiring to the stock.