Hi so I recently purchased the CYMA CM.518 M4 w/ custom muzzle brake use it for one game decided I wanted to upgrade it, put a m110 spring a hybrid tight bore 6.01 509mm barrel bull shark accelerator hop up and a suppressor, got it all setup nicely took it to last game was shooting 358 FPS at 1.28 jules with 0.32g BBS and as I decided it did not want to be DMR had to change back to original standard barrel and passed at 286 FPS at 0.78 jules on 0.32g BBS worked brilliantly had okay range and accuracy trigger kept locking up, so I'm wondering what can I do to stop the locking get better range and accuracy with out going over the AEG limit also what is the best battery to use for this gun it came with an 8.4 NI MH.
Moding my AEG
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Rogerborg
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When you say locking up, what exactly happens? It is happening on semi auto, full auto, or both? How have you been sorting it out?
Nah, those numbers don't make sense. 358fps with 0.32g would be 1.91J, which is well into Section 5 firearm territory.
286fps with 0.32g is 1.22J which is within the legal limit, but would actually be over the ~1.13J limit (typically expressed as 350fps with 0.2g) for auto guns at most sites. Great if they let you play, but it means they don't really understand energy. Or those numbers aren't right.
Anyway, on topic, it sound like you're already at or over the energy limit, so I'd just get the hop dialled in, let it settle down a bit, and keep the rubber clean. A tighter barrel might help, but for starters I'd give the stock one a good clean through with a cleaning rod, rag/paper and isopropanol (aka isopropyl alcohol aka rubbing alcohol).
Nah, those numbers don't make sense. 358fps with 0.32g would be 1.91J, which is well into Section 5 firearm territory.
286fps with 0.32g is 1.22J which is within the legal limit, but would actually be over the ~1.13J limit (typically expressed as 350fps with 0.2g) for auto guns at most sites. Great if they let you play, but it means they don't really understand energy. Or those numbers aren't right.
Anyway, on topic, it sound like you're already at or over the energy limit, so I'd just get the hop dialled in, let it settle down a bit, and keep the rubber clean. A tighter barrel might help, but for starters I'd give the stock one a good clean through with a cleaning rod, rag/paper and isopropanol (aka isopropyl alcohol aka rubbing alcohol).
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only in semi it just wouldn't let me pull the trigger had to go auto to clear it, and yes those jules are correct exactly what the crono was saying and when testing at first I had the gun firing close to high DMR low sniper range, and one way we got the jules down was by cutting down the 509mm barrel, my hopup and barrel is clean, and I think the bbs are bouncing because the inner barrel is near half the size of the gun even with out my suppressor added whole gun sits at 1.1m with stock in
Steveocee
AF-UK patch owner
- Oct 11, 2016
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Range & Accuracy - Buy a good replacement hop unit, bucking and TB barrel that is the correct size.
Locking - Full rebuild, the Cyma just wasn't designed to be run as a DMR. It's £100 brand new and no amount of cheap mods will make it shoot like a good DMR. A decent DMR build you are talking £600+ for something that can be regarded as accurate although you have clearly had some luck already, it won't last the test of time. Drop it back to AEG levels and use it as the beginner gun it is meant to be.
From your posts you are clearly not aware fully of legalities so you're a time bomb waiting to go off unless you get clued up.
Locking - Full rebuild, the Cyma just wasn't designed to be run as a DMR. It's £100 brand new and no amount of cheap mods will make it shoot like a good DMR. A decent DMR build you are talking £600+ for something that can be regarded as accurate although you have clearly had some luck already, it won't last the test of time. Drop it back to AEG levels and use it as the beginner gun it is meant to be.
From your posts you are clearly not aware fully of legalities so you're a time bomb waiting to go off unless you get clued up.
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Your right I'm not clued up lol why my mate who builds and mods did it for me, but I'm just tryna keep it AEG but perform like a DMR my main trouble is finding the right bore for the length of the gun, and the gun as it stands is AEG levels never wanted it DMR why I changed back to original barrel
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Asomodai
AF-UK patch owner
- Jun 14, 2017
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Physics states that's not possible. If it was then everyone would have done it.
There is so many things that you have stated that is just confusing or wrong. Really I would not use your mate to upgrade as he doesnt seem to have much of an understanding either.
I would just play more and learn more about upgrades before jumping straight into it as you have done.
The one thing I will say is that ditching the 8.4v nimh battery and using at least a 7.4v lipo or maybe a 9.9v life (Please do more research into how to charge these and what charger to buy, do NOT cheap out.) This will help with your locking up on semi issue.
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clumpyedge
AF-UK patch owner
- Aug 5, 2013
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Echo the above, Don't rely on your mate for info as it sounds like he is filling your head with all sorts of nonsense! if you are struggling with what you want to achieve from it (AEG that performs like a DMR is a bit farfetched) take it to a reputable tech who will tell you what sort of Hop/barrel/spring combo would be best for your platform to get the most out of it as a standard AEG and not a DMR.
Rogerborg
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Point of order, CYMA M4s and AKs come with 400fps+ / 1.5J springs as standard, and need downgraded for UK use. They're not magical, but they're not made of cheddar either.
And there's no magical (or cheese based) solution to making a ~1.13J AEG perform like a 1.6J+ DMR. You've got the power (or more) that you need, all you can do now is aim for hop and consistency.
What's wrong with the range? Is the hop set correctly? You'll want to set it so that it's slightly over-hopped (you can see the BB rise towards the end of its flight), then dial it back just a whisper. A very slight terminal rise confirms that you're not under-hopped.
After that, it's all about consistency, which means a clean hop rubber and barrel and decent BBs - and you're already making a good call by using 0.32g.
At the end of the day though, whatever you do, you'll be within a few yards range of any other decently set up AEG on the site.
EvilMonkee
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- Feb 17, 2014
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As always, with airsoft guns, leave it alone till it breaks. 'Upgrades' arent worth the time if you have zero clue what you are doing (as seems self evident) and especially so on a £100 CYMA. Play, enjoy the game, learn then look at your weapon.
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Nothing is bad about the range as it current setup just more can always be helpful but my main worry is the nine consistency, and tbh I have loads of money to splash out on any gun I just really liked the CYMA design that's why I got it
Nick G
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But those joules are not correct, so either your mate is misreading the chrono or not testing with .32s 358 fps with .32 is way past the legal limit for an AEG and is definitely not 1.28j
Rogerborg
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To expand on the above, those Joules figures look like (but aren't quite[*]) what you'd get at 358 and 286 fps using 0.2g BBs.
0.2g is what most sites use for chronoing, and what they assume when they talk about fps limits. What they should talk about is energy limits, not fps limits. A heavier BB has more energy than a lighter BB with the same speed, right? So when they say "350fps limit", they generally mean "350fps with 0.2g which is about 1.13J". And they should say that, but often don't. But what matters is the energy, not the raw BB speed.
So to be absolutely clear, if your AEG was flinging a 0.32g BB at 358fps then it wasn't just a little over the typical site limit of ~1.13J, it was way, way over at 1.9J. If it's full auto capable then it's technically not even an airsoft gun at that energy (1.3J limit for auto, 2.5J for semi/bolt), which means that (by default) it's a firearm, and a Section 5 prohibited firearm at that, which is a big no-no. It's very unlikely to be an issue, but I do want you to be aware of it.
tl;dr version: if you're shooting 0.32g BBs, and your site's energy limit is the typical ~1.13J, then your muzzle velocity should be under 276fps.
If your site doesn't explain this, or worse, doesn't even know it, then that's very disappointing, but sadly not unknown.
[*]358fps with 0.2g BBs, that would be ~1.18J.
286fps with 0.2g would be ~0.76J.
See: http://www.asiaairsoft.com/index_topic.php?did=23&didpath=/23
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Site setup rules and my gun was tested on .32 as that's what I'm using only. Joule Limits updated to Full Auto - <1.3j / MED0 (+/- 360 on .20), Semi DMR - <1.7j / MED20 (+/- 420 .20), Sniper - <2.4j / MED30 (+/- 500 .20) All weapons will be chronod with heavy weight bb's next month for Joules, so be prepared! no exceptions, you will not be able to play with that gun if you cant get below the limit.
Nick G
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well something is wrong 'cos a .32 BB traveling at 358 FPS isn't 1.28j No matter how convinced you are that that is what your gun was tested at those figures are impossible so either the FPS is wrong or the BB weight is wrong . Get it re tested by someone who knows what they are doing, if you are not confident to work on your own gun get it to someone who is. By the sound of it your mate hasn't got a clue, especially if he is quoting you those figures.
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Thoes are the figures from game day that's was tested by the cronos on site not by my friend
Rogerborg
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This is from your site's published rules? If so, they need kicked up the arse, for a couple of reasons.
First, because those numbers are just wrong. 360fps (109.728m) with a 0.2g BB isn't 1.3J, it's 1.2J. (well, 1.20402J). Likewise, 420fps with 0.2 is 1.64J not 1.7J and 500 is 2.32J, not 2.4J.
Don't take my word for it, that's physics.
KE=1/2 m v2 as per https://www.calculatorsoup.com/calculators/physics/kinetic.php or https://airsoftnation.co.uk/fps-calculator/
They need to sort themselves out and decide whether they're chronoing with those Joule limits, or with 0.2g BBs and those FPS numbers. They're not the same.
Second, because 1.3J is also bang on the legal limit for a fully auto gun to be classed as an airsoft gun. Worse, the legal definition is the energy that its "capable of" producing using "any missile". So if you turn up with a gun that can spit out your BB of choice at exactly 1.3J with the hop set bang on, then chances are it could produce over 1.3J with a heavier or lighter BB (or a steel or lead 6m BB - "any missile") or with the hop set differently.
That's why most sites use a lower limit, generally 1.13J for AEGs and 2.3J for bolties, to give a safety margin.
Sorry to bang on about this, and it's not aimed at you, but at the site. It's really not hard to get this right, and it's literally their job. How are you supposed to stay on the right side of the site rules and the law if they don't even know themselves?
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Nick G
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then they didn't set the chrono up for .32's, probably left it set for .20's Which site was it ? bit worrying if they don't know how to set their chrono up
If you've got plenty of budget I would suggest you buy yourself a chrono, they aren't expensive and they are a vital bit of kit when you start doing any work on your guns. And if you chrono it yourself you will have a proper baseline figure.
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- Thread starter
- #19
the site is Imperium Airsoft and they are cronoing for jules when I told him I was using .32 only he had to get a number for it from a data sheet, I didn't look at that
Nick G
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looks like he has misread his table. Assuming the FPS is correct it looks like he has still read the .20 figure. His fault if he has passed a hot gun as ok to play, but assuming your gun will still fire full auto it is way beyond the legal maximum for the UK , not good if they cant get their act together chronoing the guns , and even worse if they are allowing illegal guns to be used on site. This may be useful , still get yourself a chrono though.
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