Tippmann M4 owners thread

[RostokMcSpoons]

Ah, what the hell. I can't find one of these here already, so I'm going to be bold and create this, as a collection point for questions and knowledge sharing. 

I've just bought a used M4 V2.

It's not yet working as I'd like... When I tried it on the range yesterday I was only getting 30-35m of range.  When I chrono'd it the reason became clear... 150fps!

Cue some confusion as to how to adjust the power output on the gun, as the manual only covers the v1 model, and it's changed in the v2.  (Turns out it's the grub screw that's at an angle in the larger plastic part of the bolt)

I think it started all the way in, reducing power to the minimum (the previous owner used this mostly in cqb I think so may not have noticed?). I didn't really know what I was doing so had to keep talking everything apart, tweaking the setting then putting it back together and re-chronoing.  I think eventually I got flustered enough to start turning it the wrong way.  

Anyway the peak FPS I reached was still just 260 with 0.28g BB's.  Need to be up near 280-290 I think, but more importantly the gun (if healthy) should be able to go waaaaaay past that.

I've now taken the gun apart again in my house and can see what I'm dealing with, confirmed the air chamber was not blocked by the screw at all. So does that mean I've got an air leak elsewhere?  Is there anything else I should be looking at?

Edit: Tested on the chrono in my house, it's varying between 240 and 280 FPS.  It'll go a few shots at one level before jumping up or down to another.

Oh yeah. At the moment it's running without a selector switch as it fell off and got lost when I was doing all the adjustments on the range.  So it's stuck on full auto.  I need a new one of those too ?

 

[RostokMcSpoons]

Thinking about how I'm losing air, I wondered if there should be a barrel spring on my gun.   So I've just pulled the inner barrel out.  No spring, but then I've looked at the Tippmann M4 manual (for the v1) and there's no spring shown in the exploded diagrams.

However, it did show I've got a damaged hop rubber.   It seems the gun likes to damage the end of it...

View attachment 87647

... it's split a little on both sides.   I'm not sure if that damage is enough to account for the low and variable velocity though.

(The original rubber was deformed on the right hand side, creating a nub of material that made the BB's curve to the right)

Is this a sign that the nozzle isn't aligning correctly?

It does look very slightly low and to the left when viewed here:

View attachment 87648

edit:
I put the gun back together, but first I wrapped some PTFE tape around the hop rubber (at the muzzle end of it)
My gun has had the 'dwell mod' done to it, so for shits and giggles I screwed that in a bit too.
And when I chrono'd it (no hop applied now)... it's still variable.  But perhaps a little better?

View attachment 87651

 

 

[Adolf Hamster]

those torn lips will absolutely ruin the consistency, tbh i'm almost surprised it's not worse than it is.

if it's tearing the lips like that then something mustn't be right, and nozzle as you're already thinking seems like the likely culprit, maybe going too far forward?

 

[RostokMcSpoons]

those torn lips will absolutely ruin the consistency, tbh i'm almost surprised it's not worse than it is.

if it's tearing the lips like that then something mustn't be right, and nozzle as you're already thinking seems like the likely culprit, maybe going too far forward?

When the 'bolt' travels forward, it goes up against a solid block that is effectively part of the upper receiver... I'm sure I could shim that in such a way as to back the nozzle off a little.
The problem is the gun could eat quite a hop rubbers before I get it right ?

 

[Adolf Hamster]

When the 'bolt' travels forward, it goes up against a solid block that is effectively part of the upper receiver... I'm sure I could shim that in such a way as to back the nozzle off a little.
The problem is the gun could eat quite a hop rubbers before I get it right ?

if you're gonna try shimming if you start out over-shimming, then drop it down until you get decent air seal? that way the nozzle is too far back rather than too far forward.

kinda the opposite of trimming a nozzle where you shorten in little increments to be sure not to take too much off.

that is, assuming there isn't some trick to the system that we don't know.

 

[RostokMcSpoons]

I've had another look at the hop rubbers, to do a bit of 'forensic analysis'    The original one has that slightly folded lip that caused the curving is otherwise undamaged.  It looks like a Macaron Yellow, for reference, so quite soft.  The cheapo one I replaced it with, which feels as hard as nails and could probably survive WW3 (which might be handy), is completely pristine.
The Guarder Clear looks 'unhappy'.   So yeah the nozzle might be 'doing something' to the rubbers, but hopefully it's a matter of fine margins.  Rather than trying to shim the nozzle, could I shorten it  a tiny bit?

I put the cheapo hop rubber back in.   It might not be soft enough to hop heavy BBs, but it ought to keep a good air seal.  And things are getting 'interesting' in that I've dialled out the Dwell Mod grub screw, and with that I've seen the FPS reach as high as 380.
But the consistency is still all over the place.  
I messed around with the hop (re-applying some) and the Dwell screw some more, and the last few shots got figures of 297-326.    I've got the feeling I'm not a million miles away from it working properly... but I might need a new O-ring or something to make it happen.

 

[Adolf Hamster]

i'd be hesitant about shortening the nozzle, if this were a drop-in engine in a donor chassis then yes nozzle length is a thing to worry about but as this is an all-in one platform we should be able to assume the nozzle is the correct length.

feels like it's an issue with how it's been assembled, but exactly what i don't know.

 

[RostokMcSpoons]

An update and a request...
The request is that I'm sure someone here posted an advert offering a nozzle block (without the dwell mod) for sale here earlier in the year.  I sent an offer via the message button but never got a reply.   And now I can't find the ad.   (Perhaps it was on another site, my memory is shite)   If that person happens to read this - please contact me!

After a second message sent off to Tippmann via their website, I got a reply back from Dave at KoreOutdoor.com.  I've not had time to try his suggestions, indeed I've asked for some advice regarding the lube as I don't want to have anything combusting in the gun :]  

Here are his notes, maybe someone else will find this useful

(I would take issue with his comment about +- 15fps being acceptable, I've just been firing a few shots through the DE, and that's +-2fps!)
 

Just been sent your email from yank land

We’re based in Crowborough, TN6. And are Tippmann in the UK & Europe

+- 15 fps doesn’t seem too bad, but can hopefully be dialled in a little bit more


The first thing I would do is oil the valve, a lot of owners don’t do this often enough and you’ll notice a bigger difference in performance.
If you put a few drops of our oil lubricant down the ASA before airing up, this will oil the orings in the valve creating a better seal. Chances are you may need to put a fair bit down there and blast on full auto for a while to spread the oil out enough as it’s not been done before.

A couple of drops on the rear bolt & oring also will help
I would also check that the rear oring is the correct size. A lot of people just buy generic orings which are either the wrong size, hardness or material for the application.

We haven’t had any issues with the front bolt (nozzle) not aligning, might be a case of taking the screw out holding the drive assembly in (front bolt, powertube & valve and rear bolt) and reinstalling

As you said the bucking will contribute to the fps variance, I would ensure this is sitting correctly, as sometimes they come in not sitting flush so the feed lips are too far into the gun and cause issues

Make sure the TDC isn’t damaged also, worth unscrewing and checking the nub is okay and screws up and down smoothly.

Let me know how you get on with that, if not I can get a price for some orings & oil for you.
Bucking, I would go aftermarket for best results – a lot of users are suggesting the ASG Madbull Shark Red (I believe), if not a standard G&G green is a good all-rounder. But totally up to preference

Otherwise there’s not much more to them!

Thanks,
Dave

 

[RostokMcSpoons]

Sorry to bump my own thread, but hey ho...

Well I just decided to try out my gun to see what it's shooting at right now... and things have perhaps taken a turn for the much, much worse.  But as I'm trying HPA for the first time, maybe it's just a 'thing'.  Knowing my luck.. it's not.
 

Basically I went through maybe a hundred rounds of BBs in single shot with chrono attached.   It seemed to be being 'respectable' in the velocity variance - a few outliers at 350 and 390 but mostly at 365-375.  Too hot for skirmishing, but it's just testing.
I thought I'd give a few bursts on full auto, to check the RoF.   This is when things went South on me...  the RoF seemed quite variable.  Then it started firing in bursts.   Then semi-auto started firing in full auto, and eventually it went full run-away firing at ever faster rates until it sounded like a very fast fart, and just kept going until I shut the valve.

The gun still seems to function in that I can cock it and the trigger won't fire on safe, but does on single and full auto.  But when I reattach the air and turn it, it goes run-away full auto again.

The only thing I can see is the air pressure in the tank is quite low (less than 1k.... maybe 800psi?) but I think that's surely enough to make the gun function properly.  And I can't imagine people wanting to use HPA if it does that just because it's low on air!

So have I got a shagged gun?   What's the fix?

Edit: Oh thank Gaaawd.  Yes, low pressure can cause "the fart of death" where the sear doesn't engage and it does the run away thing.   Not very user-friendly but something I can watch out for!

 

[Old man Jay]

I had the nozzle for sale but removed the advert, I have a few other bits and was going to put it up as a set, does your v1 have either the hard recoil buffer spacer fitted ? or the dave air saving device ? if either of these are fitted its best to remove them and start afresh. This will make dialling in your fps a lot easier.

what barrel is in it ? I had a pair of madbull blue shark hop rubbers that actually worked fantastic in mine and they were cheap, hopped .3 no issue. Although the macron yellow should also be fine. Its easier to cut the end off the hop feed lips if you feel the nozzle is ruining them. 

Depending on who did the dwell mod you can put a bit of grease around the screw to stop leaks.

Also pay close attention to your hop unit, I assume its a replacement tdc job, may be worth pulling it out and checking it over.

also check the feeding manually to make sure there isn't to much resistance for the bolt when loading a round.  

 

[RostokMcSpoons]

Hi!  Thanks for solving the mystery for me ?

Mine is a v2 so it has the tdc hop as standard. It has a tight bore barrel in it at the moment.. Ive got a few guns where I could swap similar length barrels and go back to a standard bore, see how that works out.

Is had the dwell mood but nothing else (as far as I can tell / what I've been told) 

Madbull seem to be the preferred hop rubber, I'll order one!

 

[Old man Jay]

you might find a standard bore barrel a good start, might alleviate some of your fps inconsistences, also may solve your hop rubber issue. worth a punt to rule out the tight barrel.

 

[RostokMcSpoons]

Just put some lube through the system and swapped the O-ring on the bolt over.  Also filed down a little plastic inside the nozzle from the where the dwell mod screw goes in.

Just fired a few dozen 0.20g BBs through it to see how consistent the fps is now, and it's still inconsistent.  

But not unusably so?

It's varying from 390-420 but the majority are at 405.  It's set pretty much at max power I think with no hop applied, so I think there must be something still wrong as it surely ought to be capable of quite a bit more.  But it's getting better.
I'll try a different barrel.

 

[RostokMcSpoons]

I have had another go at fettling my Tippmann sort-of-recently, and it's still not right.

1) The TDC hop is ...

View attachment 116100

Yes.  Proper.   It's spinning right round like a record, baby.  Not engaging with a thread to actually apply any downward pressure.  Either the thread the hop screw has stripped, or it's gone walkies altogether... I'm sure it used to be fine, but it ain't now!

Edit:  Oh dear, I think I was being a noob.  I just found a video explaining how the TDC hop works.  I may have a loose grub screw preventing it from working properly.  I'll go check!

2) The Rate Of Fire is a bit pants.  It must be chugging along at 10-12rps or something.  I've seen videos of Tippmanns ripping along very nicely at above 15rps.   Maybe I need a different bolt or recoil spring to achieve that, but I suspect it's more the set up or a problem...?

3) Semi Auto doesn't work properly.  If I have the full auto working, then the semi auto tends to occasionally spit out 2 or 3 BBs.   If I turn the RoF down to the point that semi is reliable, then I basically end up with full auto also working as semi!

I have already contacted Dave Sutton at Kore Outdoor UK, who I believe are the UK distributor for Tippmann parts?  He suggested some lubrication which I did already... so looking for any other hints or tips!

 

[RostokMcSpoons]

Apologies if this is boring-as-shit, but I feel I have to document this as I seem to be very good at learning stuff about this gun, going a few months without touching it, forgetting some of that information, and having to start (effectively) from scratch. 

So, having said that - good news... I meddled with the RoF valve and the power output valve, and by hook / crook / sheer luck the darned thing started to fire better on semi AND full auto.
I took it along to the skirmish on Saturday really actually hoping to use it 'in anger' for the very first time.

(People have told me that Tippmann's are finicky to set up, it looks like you need to balance the valve settings for them to work together properly)

Well, the hop up just still wouldn't play ball, so it got left on the bench.    The best I got it was that out of 10 BB's fired, 5 or 6 would hit the sky, 1 or 2 would fly flat, and the rest would arc towards the ground.

But I've now made some more progress.    I've tweaked the RoF and power even further so it's now spitting out 0.28's at 290fps, showing a great deal more consistency.  And the RoF has bumped to (guesstimate) 15rps. 

I took the hop cylinder out

zView attachment 119961


and looking closely at it I realized it has, I think, a custom nub.   Instead of the 'pencil eraser'  lump ,shown on the photo of the stock unit above, it's got a shape rather like a horse's saddle with a shallower 'ramp' on one side than the other.  It's like an even fancier version of an Omega nub.  I think I've now oriented it correctly (it rotates freely on the unit, so there's every chance it wasn't straight-on originally). 

The TDC adjustment screw now works smoothly and with a consistent resistance when adjusting it, because I also oriented the cylinder to ensure the grub screw engages with a recess within the groove (not shown in pic, unfortunately), so there's no longer any chance the unit will be rotated instead of increasing or decreasing the height of the nub.

Annoyingly I won't have the option of checking the true accuracy of the gat at skirmish range until next year, but I guess if I get all the BB's hitting within a few inches at 15m then it'll prove the hop is properly engaged... tomorrow will be the first chance to have a try at that.

I'm really excited because, damn it, this thing is really fun to shoot    

Edit:  Fecklity-feck, it really seems to be working!  I can now adjust hop successfully - it'll over-hop 0.28's visibly at 15m, and I can dial it all out or even - get this - set it correctly.

So it groups!  I have a usable Tippmann at last.  Yay!   My joy is unconfined!