CYMA CM048m - Patrol Base

[JVacation]

Hello,

 

Recently my CM048m order from Patrol Base arrived. It's a Christmas present to me but I gave it a quick test fire and fps check before it gets wrapped up. With the hop fully off it is firing 0.2g at a max of 310fps.
Does this seem a bit low or do you think that's about right? I will get round to upgrading the bucking, nub and barrel in the future as standard so hopefully that will help.

 

Cheers

[snuff]

That's fine,use it then decide if you need or want the extra fps.It may drop more when you add hop.I always play with any aeg standard before I "improve " it in case there are any underlying issues.

[Lozart]

1 hour ago, JVacation said:

Hello,

 

Recently my CM048m order from Patrol Base arrived. It's a Christmas present to me but I gave it a quick test fire and fps check before it gets wrapped up. With the hop fully off it is firing 0.2g at a max of 310fps.
Does this seem a bit low or do you think that's about right? I will get round to upgrading the bucking, nub and barrel in the future as standard so hopefully that will help.

 

Cheers

 

It's a bit low but within the tolerance of what is quoted on their listing (330fps +/- 10%). A tightbore barrel will probably bring it up a bit but it's fine to use as is for now. Run it for a couple of games and decide what it lacks then.

[Adolf Hamster]

might also want to check with the hop set- sometimes having the hop completely off will result in lower readings. you want to start with it completely off and go up in small increments until you find that sweet spot where the bb is going pretty straight and not flying upwards too much, it'll be good to get familiar with adjusting it as sometimes in-game being able to tweak slightly can be handy for getting some shots to land (eg turning it down to drop rounds behind a barrier).

 

once you have it set, the thing to check would be shot-shot consistency, see what range of velocities you're getting (eg 305-315fps) as that's a gauge of how good the airseal is.

 

as mentioned, good to just run it for a couple of games, get familiar with how it's shooting and get an idea of what areas you might want improved, no point going all out for extending range if your playstyle means you rarely use it.

[Rogerborg]

Agreed, it's playable, and I wouldn't change the spring until you've done everything you're going to do outside of the gearbox, and shimmed and re-lubed inside it.

 

Definitely chrono with some hop on, I've also seen slight rises when adding hop (before it reduces again).

 

Oh, and the usual new-gnu advice, put some silicone lube up the nozzle, give it some time to seep into the o-ring while you clean out the barrel and hop rubber, then blow the lube out the nozzle before re-assembling.

[BigStew]

As has been said chrono it when it is set for actually use. Also more power doesn't mean greater range. Set your hop use your site range and if you can regularly hit centre mass at 50m your not going to see a noticeable difference by upping power.

[Rogerborg]

19 minutes ago, BigStew said:

Also more power doesn't mean greater range

 

The usual technical objection that with sufficient hop up, more energy does mean more maximum range. But I agree that consistency is much more important or else you'll be lobbing BBs 5m further but hitting everything except what you're aiming at.

[BigStew]

9 minutes ago, Rogerborg said:

 

The usual technical objection that with sufficient hop up, more energy does mean more maximum range. But I agree that consistency is much more important or else you'll be lobbing BBs 5m further but hitting everything except what you're aiming at.

I should maybe re phrase that a 30/40 FPS  increase will give a small increase in range that is not worth the money/effort if you are getting 50m accuracy out the box.

[Adolf Hamster]

34 minutes ago, BigStew said:

I should maybe re phrase that a 30/40 FPS  increase will give a small increase in range that is not worth the money/effort if you are getting 50m accuracy out the box.

 

certainly it wouldn't be enough to warrant the risks associated with opening the thing up with limited teching experience. first rule of teching is make sure you have a reliable backup gun before you start messing with it.

 

in the early stages the money would be better spent on other accessories. for example i'd find a bunch of midcaps and an odin (with adapter) would increase enjoyment more than putting the money into making the gun shoot a bit better.

 

but then i really, really hate hicaps.....

[BigStew]

12 minutes ago, Adolf Hamster said:

 

but then i really, really hate hicaps.....

Gone completely the other way got sick of overly heavy belt rigs and switched to drum mags.

[Adolf Hamster]

44 minutes ago, BigStew said:

Gone completely the other way got sick of overly heavy belt rigs and switched to drum mags.

 

whatever floats your boat i suppose.

 

point is, there's more than just the gun performing optimally that makes for a good days pewing.

[JVacation]

Cheers guys, Ill do the basic upgrade for the time being of the ML bucking and nub. Ill run it for a few days and see how it goes. The external quality of the RIF is actually unreal for the price point and I am led to believe that the internals are very good too.

[BigStew]

18 minutes ago, JVacation said:

Cheers guys, Ill do the basic upgrade for the time being of the ML bucking and nub. Ill run it for a few days and see how it goes. The external quality of the RIF is actually unreal for the price point and I am led to believe that the internals are very good too.

Cyma is pretty much the biggest game in town these days and have been constantly upping their game for the last 10 years or so.

[Adolf Hamster]

46 minutes ago, JVacation said:

Cheers guys, Ill do the basic upgrade for the time being of the ML bucking and nub. Ill run it for a few days and see how it goes.

 

tbh i wouldn't even go that far initially, nowt wrong with the ml macaron+omega combo but no sense cracking open a brand new gun (and voiding what passes in airsoft for a warranty) until you've got a clear benchmark and goal as to what you want to improve.

 

 

[Ebeneezer Goode]

22 hours ago, Adolf Hamster said:

 

tbh i wouldn't even go that far initially, nowt wrong with the ml macaron+omega combo but no sense cracking open a brand new gun (and voiding what passes in airsoft for a warranty) until you've got a clear benchmark and goal as to what you want to improve.

 

 

Wot 'ee sez, guvna.

 

Skirmish it a couple of times to get a feel for it before ripping it apart and tinkering.

 

Most CYMA AKs in that range are superb as standard, apart from cleaning the barrel you shouldn't have to do anything IMO.

[Tactical Pith Helmet]

On 15/12/2021 at 14:55, Adolf Hamster said:

 

tbh i wouldn't even go that far initially, nowt wrong with the ml macaron+omega combo but no sense cracking open a brand new gun (and voiding what passes in airsoft for a warranty) until you've got a clear benchmark and goal as to what you want to improve.

 

 

I bought two 4 series AKs last week.  They will remain virgins until I've ascertained that they are basically sound.  Then ML and barrel and that's about it.  

 

Even their 3 series are pretty damn good these days.  

[JVacation]

Been giving a better try today at shooting at a range of 40-50 metres using 0.28.

 

Gun is definitely struggling a bit. I don't currently have my chrono to check but it's obvious that the power is not where it needs to be. I have a feeling patrol base most likely cuts more off the spring to be "safe" instead of trying to get to the ideal power.

 

I have ordered some new o rings and a o ring nozzle to see if there is an issue with the airseal first. Will then check the chrono before deciding if it needs a new spring. 

 

Will let you know how it goes. 

[Ebeneezer Goode]

40-50m? I'll be amazed if you can get any kind of reasonable accuracy at that range...

 

Be aware your velocity will drop with heavier pellets. 310 on .2s seems average and I wouldn't worry about that. When you day the gun is "struggling" what do you mean, is the cycling laboured, crap range, not shooting straight...?

 

Out of interest what battery are you using?

[JVacation]

21 minutes ago, Ebeneezer Goode said:

40-50m? I'll be amazed if you can get any kind of reasonable accuracy at that range...

 

Be aware your velocity will drop with heavier pellets. 310 on .2s seems average and I wouldn't worry about that. When you day the gun is "struggling" what do you mean, is the cycling laboured, crap range, not shooting straight...?

 

Out of interest what battery are you using?

 

Sorry I should of clarified. I was using a garden 40-50m long and it's dropping around 30m. Increasing the hop anymore just causes a jam and I can't overhop 0.28 at all which should be somewhat possible. 

 

The gun seems to cycle fine just doesn't have the power. Last time when I did chrono it did seem to have a 15 fps deviation too. 

 

I think cracking it open and checking airseals and putting a oring nozzle on first is a good starting point 

 

Also I'm using a 7.4 turnigy lipo from hobbyking. 1500mah.

 

 

Edited December 31, 2021 by JVacation

[EDcase]

Could help to get in there and clean it up as well as re-shim.

O-ring nozzle is good as long as it fits properly (length and not too tight)

 

You could also try polishing the inner barrel.

(Presume you already cleaned the barrel...)

 

 

 

Edited December 31, 2021 by EDcase

[JVacation]

11 minutes ago, EDcase said:

Could help to get in there and clean it up as well as re-shim.

O-ring nozzle is good as long as it fits properly (length and not too tight)

 

You could also try polishing the inner barrel.

(Presume you already cleaned the barrel...)

 

 

 

 

Had a response from PB today saying that it's very rarely that they receive them firing them hot. I take it they come from Taiwangun then and they do the downgrade for PB as their "low" option (310).

 

If the airseal work doesn't help significantly what strength of spring would you recommend? 

[Ebeneezer Goode]

If the range is a bit meh and there's a deviation in fps, sounds like a leak. I'd send it back to them and get them to check and fix. Seals will probably sort it.

[Rogerborg]

On 31/12/2021 at 15:25, JVacation said:

I think cracking it open and checking airseals and putting a oring nozzle on first is a good starting point

 

Yup, an o-ring nozzle and replacing the stock [clarification] piston o-ring resulted in a rock solid air seal on my CM.516.  A bit of silicone grease and I was seeing a had-to-check-it-twice 1.3J out of an M100 spring and a ZCI 229mm barrel.  Air seal is king, I had to drop to an M90 and even then it's nudging 1.14J.

[Ebeneezer Goode]

Seen the same issue on my LT M4. A bit of reassembly did the trick.

[SSPKali]

Yep, the air nozzles on the Cyma AKs is the one weak point but easy and cheap to fix.

 

One other thing to watch out for is the only chrono that matters is the one at the site you are playing at that day! 
 

My MP5 was 335-337fps on 0.20g at home but 351-352fps at the site. Bugger. Same with my GBBR but that was easier to dial down the gas valve.

 

Snipped a coil off the spring and all good now. I figure mine is reading about 5% under (or theirs is over, but that argument won’t get you anywhere) and work from there.