Snakeeyes75

I made this myself out of a pair of Nuprol Mesh goggles (£15) plus a generic mesh mask (£12) and a couple of grip ties:
 

I made this myself out of a pair of Nuprol Mesh goggles (£15) plus a generic mesh mask (£12) and a couple of grip ties:
 

Or just use a bolt sniper or a jbbg springer
 
use what you want - within reason
play how you like - within reason also
 
I play for fun, have a laugh, trying not to fall ar$e over tit, seeing if my gun will last the day and thinking I need to get into shape
Actually I'm in shape - a big old ball shape that often thinks to myself in lethal weapon style......
 
I'm too old for this $hit - but wtf is still a laugh

I'm really baffled by the need for high ROF guns? I have a TM Scar which I run on a 7.4 lipo, I've had no issues in full auto running mid caps. Does everyone enjoy wasting money spraying foliage thinking there's someone behind a bush? (ooh err). I've been sniping for the last 5/6 months and my whole attitude has changed to now find that 1 or 2 well aimed shots is far batter than 50 "Sprayed" shots. I've now put a 5x mag scope on my Scar and again I'm finding that i'm wasting far less ammo now that I can see where my BB's are landing.

Well you need to take a fair bit off to allow the gun to slide in. I took tiny bits off at a time and just kept trying the gun. I needed to take a bit off the inside further down but did so with a file and sandpaper. Be careful though you don't want to break the holster.

Sure thing, here you go. 
 

Ok thats fine, if you want to go all out here is what you want to buy:
 
Orga Magnus 6.23 inner barrel
HSA ER HOP + EM NUB (get a good tech to install these) (Use 0.36-43g BB's)
Promithius perfect hop chamber
Promithius hard bucking
Speed trigger
HSA barrel stabilising kit
Polarstar red nossle
Redline airsoft poppet shim set.
 
This guy knows what he is doing, have a look at his build:

Yeah, I have made some plans to build a custom one of these at a fraction of a the price.

Hey, I feel building a polarstar DMR would be a bit of a waste of money, but I am all for a HPA setup. There is a polish site called mancraft offering a semi auto HPA system for about £160. From what I have seen this is as consitant as a polarstar (amped airsoft video on youtube I think), just with the right regulator and is dead silent too.
 
If you are looking for a DMR base then I would definatly recommend the A&K SR25 - a great body to build from. A tip would be to look at some polish sites to find it as last time I saw you could get it for £160. Combined with a scope, and harris type bipod you have the externals done. Another plus is the rails as they allow you to lock down the outer barrel. It is the gun used in this thread: http://www.airsoftsniperforum.com/43-longrange-aegs/892-holy-grail-building-your-dmr-aeg.html
 
Once you have got the A&K SR25 and installed the mancraft engine, you only have the hop system left to go. Firstly, you don't need to spend a fortune for a great hop unit, I would recomend the lonex. Seondly the bucking, again I would go for the lonex 70d bucking as in my opinion it does the job better than any other bucking.
 
Now this is were it gets complicated, you could go full out with ER hop's, LBR mod and PDI barrels, but in the most part these are for those who are trying to squeeze every liitle bit of peformance out of there DMR and are very difficult to install, however the peformance is phenominal (e.g. headshots at 300ft +). You proberbly don't want to go down this road.
 
 
What I would reccomend is a Promithius 6.20 inner barrel, it uses an extend flat hop hop system and an wide bore, it is also relitivly cost effective (don't use the bucking it comes with, just flat hop the lonex). A HSA barrel stabilising kit, very easy to install drop in upgrade and EM nub for the flat hop.
 
This would result in great peformance, with only very easy modifications needed and the build is quite cheap, this is an estimated build total:
 
Mancraft HPA system £160
A&K SR25 £150
Lonex chamber and bucking £20
Promithius 6.20 barrel £35
HSA EM nub and BSK £20
Nuprol 0.43g BB's - watch out you will get insane joule creep.
 
Total: £400 - The price of a polarstar engine.
 
Of course you need a reg and tank - for this I recomend a ninja SPL tank and a ninja regulator (import these from america)
 
Also if you wanted to go down the route which involves heavy modding, contact me as I can do all of it.
 
Hope this helps,
Charlie.

Lots of bollocks in this thread.
 
I'd say an M4 base is ideal, there are a lot of after market hop units that fit, the Fusion Engine can be installed with minimal effort and then you can make it look how you want as well as perform how you want.
 
The Fusion Engine's strongest suit is that it's consistent to within 1fps and doesn't suffer a trigger response hit when you ramp the power up.
Frankly, if you're blowing the best part of £700 on a Polarstar set up and you aren't making a DMR out of it, then you're just wasting the money. An AEG can cope with all other build types just as well, if you're looking for accuracy and range then P* blows everything non-HPA out of the water.
 
HPA is all about the shot to shot consistency, if you're buying one to spam it like a pleb then you're doing it wrong.
 
A mate of mine built a P* DMR using an AR base, he built the gun around the Fusion Engine rather than buying a base gun though.
 
The thing's a fucking beast, puts spring snipers to utter shame.
 
He's got some videos on YouTube, channel's called TheManCave I think. I'd link you but I'm on my phone.
 
I would personally advise against an SR25 base, because they're a 7.62 platform they traditionally have either an extended V2 gearbox and a standard hop, or a standard gearbox and an extended hop.
 
You can only get standard length V2 versions of the Fusion Engine, so you have to make up the rest of the space with the hop unit.
 
Either by getting a dedicated long hop unit - the G&G SR25 one is the only one I'm aware of - or by modding a standard hop to fit the larger space.
 
The former massively limits your hop unit options, whilst the latter opens you up to a world of arse pain with regard to making your modded unit properly air tight.
 
So just using an M4 base, where you can fit the Fusion Engine and choose from a massive range of high end, after market hop units, makes it all a lot easier.

HPA rigged GBBR for the best trigger response. WA is a good place to start or GHK.
 
Even a decent GBBR that isn't tapped is alright so long as the internals are up to scratch and the mags and gas are decent. Cooldown isn't a huge issue on semi so getting the fps consistent can be done with reletive ease.
 
Add a flat hop to the mix and you're golden.

Going to watch this thread closely!

I'd expect grown ups playing at soldiers with toy guns like usual airsoft, only taking it much more seriously.

Hehe, I bought a TM recoil, I use PTS Pmags which are "stunning". BUT, Pmags wont fit in the T4 ;(

I have had them a while I have some G&P metal mags will give them a try as well so all being well I am going back this Sunday will be trying them mags First I will try the mag it came with. Thanks to both of you for the reply and help What mags do you use

G&G Midcaps are a bloody nightmare with that gun. As a test try the hicap that came with it. I bet that's fine, G&G don't actually make a mag that fits the bloody gun! Stupid I know although some have said that you can either file the front/bottom lip of the magwell to help the mag fit in a tad looser OR file the front of each mag. Alt' buy different mags!
 
I used MAG brand mags but after a month I got the same issue! best option is to go into an airsoft shop and ask to try some different mags.
 
Sorry, not the answer you want, I ended up selling the gun as the hicap was the only mag that worked (Although it required more winding than most hi caps). It's a great gun when it's working so don't give up like I did. It really is a case of finding some decent mags for it though!

I use Military 1st for most of my gear. There might be others a bit cheaper but Military 1st have always given me good service.

Sandpit (ucap) allows you to chrono on the weight your using. Apocalypse also had no problem with it either.

To be honest, I'd have no problem trying max my gun's potential to what the rules allow. If they insist on chronoing with .2s then go with it. Hit 495 on that (a little leeway to be safe) and then swap to .43s. You won't have done anything wrong by their rules and you'll benefit from it, strictly speaking it may not be in the 'spirit of the rules' but then if they ignore joule creep then that's up to them. I'd just go for it, especially if you're doing a sniper rifle build.

But if I told them I was going to chrono with .2's but i'd be using .43's would that still be acceptable? It's being dishonest to a point but I can't complete if others are getting away with it!
 
Yes! I realize this is a BIG BIG issue and most people are just avoiding it! I'm happy to play on either side of the answer, MED sort of solves the issue but I don't want to be the one guy that is adhereing to the rules when no-one else is

Only combat south let me use the weight I was using in the guns (and rightly so, especially in gas guns). Every other site including my main one insists on .2s which is pretty stupid imo, I turn my guns down sufficiently to make sure regardless but it doesn't take much to print out and laminate a conversion chart.

Ever since I started playing airsoft, and got involved in the whole game and science behind the guns and all this and that, to a deep enough level to understand it all, I have noticed joule creep.

But it's only as of late that I've started to see it earn a name, and a gathering of people who actually seem to understand what it is.

I first noticed it when I had an ICS L85 AEG, it was fitted with a 6.01mm tightbore barrel, 509mm long and fired .20s at about 360fps.
I noticed that when I loaded heavier ammo, my fps wouldn't drop by as much as the conversion charts said it would.

If you look at the equation used to work out muzzle energy, which involves the figures pertaining to ammo weight and speed, you'll notice that there's no mention of the length of the barrel, the bore width, or even the amount of pressure applied to the shot. Because it's just an equation, it isn't designed to be used in relation to airsoft guns, but it can be applied to them. As a result there are myriad variables it doesn't take into account, and this means that the conversion charts can be wildly inaccurate.

The conversion charts are simply that. They convert the muzzle energy into different weight and fps amounts. It's like an on paper reference to using scales. Adding more of one thing here will balance out this thing here.

The reality of it isn't so clear cut. Back when I first noticed it, the conversion charts said that loading .25s ought to reduce my fps by around 40, but I was seeing it drop by about 20. At the time I didn't realise that this would mean my muzzle energy was increasing, but it effectively meant that I was firing hot by around 20fps once I'd loaded the .25s. I was just counting my lucky stars that I was able to get away with having higher fps than the charts said I ought to be.

However, now I've owned gas guns for a year, and I've seen it happen a lot more extremely, I've come to realise that the ignorance of not understanding it could lead to someone getting hurt someday, so my aim with this is to try and help bring attention to joule creep, and bring attention to... not how to counter it, but how to play with it safely.

First, I'll try to better explain what it is and give an example of it.

Joule creep is the name given to muzzle energy which increases when the gun is loaded with a heavier weight of ammo. The name, joule "creep" is given because the energy, measured in joules "creeps" up without it necessarily looking as though the muzzle energy has increased.
It is common knowledge that adding heavier ammo reduces your fps, and many make the assumption that this drop in fps is a counter balancing effect which results in the muzzle energy remaining the same. You load .2s and chrono at 350, you load that same gun with .25s, you chrono at 315, muzzle energy remains the same. Right? Well, yes, sometimes.

Joule creep is caused by guns sending more pressure down the barrel than the barrel can contain. Let's set up a hypothetical scenario:

Gun A has a barrel which is long enough to contain 100% of the pressure that the mechanism sends down it in order to power the shot. So its cubic, volumetric capacity is large enough for all the pressure being sent down it to fit inside it.
If you fire a .2g BB through gun A, all the pressure will be used on the .2, the .2 will leave the barrel and there'll be no excess air leaving the barrel once the BB's free of it.
Adding heavier BBs to Gun A will see the conversion charts ringing true.

Gun B has a barrel which can't contain all the pressure sent down it to fire the shot. It's only big enough to contain about 50% of what gets sent through it to fire the shot.
So when loaded with a .2 it'll chrono at 350fps, but when the .2 is free of the barrel, it'll be followed out of the muzzle by 50% of wasted air.
This is a gun that will see a lot of joule creep, because now when you add a heavier shot, due to it taking longer to accelerate out of the barrel, it is present in the barrel for longer, which means some of that "spare" 50% can be applied to the shot, and because more pressure is building up behind the shot, it is actually increasing the power of it.
A .25 might use 60% of the air, a .30 75% a .46 95%... These are all just made up numbers to demonstrate the point, but can you see how a gun could gain power, that's muzzle energy, measured in joules. Kinetic, impact energy, that physically increases through the use of heavier ammo, all because the gun sends more power than required down the barrel.

Joule creep is therefore significantly more prevalent in gas guns than AEGs. This is because AEGs use pistons and cylinders. Cylinders can only contain x amount of air, and they can be ported to reduce the amount of air they send down the barrel. Generally a factory AEG will be fitted with a barrel and cylinder combo that more or less match the barrel and cylinder's volumetric capacity, which will prevent joule creep from happening.

Gas guns on the other hand, send significantly more gas down the barrel than required, simply by nature of the mechanism. It isn't something that can be reduced without it impacting the other performance characteristics of the gun.

The longer and tighter a barrel is in gas gun, the worse the effects of joule creep will be. A longer barrel means there's more enclosed space for the gas to expand in, and the tighter the barrel means there's less space around the BB for the gas to escape.

So I said I'd give some real world examples.

A few months ago I set up my gas L85 to chrono at just under 370fps on .20s, because that's my regular site's limit. My L85 at the time was fitted with a 509mm long, by 6.01 wide tight bore barrel.
Once set I changed to .28s which are what I generally run through it, and decided to chrono it again, just to gauge how much the fps dropped by.
To my amazement, it didn't drop. I got more or less the same reading. In the ballpark of 370fps on .28s... I thought I might've got my ammo or my mags confused, so I double checked, but nope...

According to conversion charts, a gun that chronos at 370fps on a .2 ought to drop to 312fps when loaded with .28s... But as I touched on above, this is because the equation assumes the same amount of pressure is being used to fire every weight of shot, but in gas guns, the heavier the shot, the more power gets applied to it. So My L85 therefore sends so much more pressure than it needs to down the barrel, that my fps remained the same because all the excess was making up for the drop caused by the weight increase.

So if I'd gone to field this, I would have been firing hot by around 60fps, which is a joule increase of about .40.

Today I thought I'd run the same test through my gas SCAR, so I chrono'd it on .20s, an average of 5 shots gave me a mean of 331fps.
Loaded it up with .3s and did the same again, mean average of 290fps.

According to conversion charts, 331fps on .20s ought to drop to 279fps, so that shows an increase in power of about 11fps from adding heavier ammo. Pretty significantly heavier too. My SCAR barrel is tiny too, I think it's 10" and it's not even a tight bore.
That's a joule increase of only .08 or so, so it's pretty damn insignificant, but it proves the point that longer and tighter barrels, as per my L85 can take much greater advantage of it.

Imagine if someone had a gas sniper, they set it up to fire at 500fps on .2s, it was fitted with a very long, tight as tight can be tightbore, and then they switched to .46s to play with...

Ouch.

So to be safe with your gas guns, ensure you look up the conversion charts, find the site's fps limits before you go, and work out what the limit will be on the weight you intend to use. Then when it comes to chrono, use the weight you intend to use, and set your fps to the limit you worked out. Conversion charts might not work with regard to the fps drop from adding weight being correct, but they are still correct in that x fps = x joules.

So as long as you're setting your fps using the ammo weight you intend to use, you'll be safely within the limits.

If you've read and understood everything I've just written out, or if you already knew about it, then help me spread the word. There are sites that ban the use of gas rifles because they don't understand the science behind the muzzle energy, or simply can't be bothered to deal with the need for people to chrono on the weight they say they're chrono-ing on. There are sites that force people to chrono using .2g BBs. This is ignorance, and it's potentially unsafe.

Given any opportunity joule creep needs explaining in a way that people can understand and pass on, because the more people know, the less silly rules and regulations they'll be stopping us from using the guns that we love, for the hobby we enjoy.

From the website
 

Yeah, all nice and airtight. The only time it lost a stack of power was when the cylinder head worked loose (I bought the proper tool to tighten it). The ASPUK head has an O ring plus I've PTFE taped the thread. I'm about 90% convinced that the problem has been the M150 ASPUK spring. Ive been bold and clipped 1 & half coil from the Laylax M170 and it's reading 490-500.6 (I put 100 BB's through it first). The question is now, how much will it lose?

Just a quick follow up to say my G18 Gaurder pieces arrived today, 9 days in total!