WE TA 2015, P90 review

[machgo]

 

The red arrow indicates where the first break happened on the factory part.  This is the weakest point.  When the bolt slams into the stop it rotates until it contacts a small ledge on the hop up housing. All the force is transmitted to the area indicated by the green arrow--but that area is marginally stronger than the area by the red arrow, thus it breaks at the red arrow.

 

The blue arrow indicates the area contacted by the BB follower in the mag.  There is a small "ledge" here.  It does not provide any support for the bolt stop as it does not contact the hop up housing.  In fact, this ledge can be completely omitted without any consequences.  Having said that, it may be possible to design a new part that utilizes such a ledge to absorb the force applied to the bolt stop.

[machgo]

 

This is my third, and most successful replacement part.  Notice the extra material forward of the pivot hole.  This extra material prevented the piece from breaking where the factory part did, but it cracked at the new weakest link--the spot indicated by the red arrow.  Again, this is where all the force is transmitted when the bolt stop rotates to contact the hop up housing.

 

The crack above the pivot hole happened after the crack below the hole...

 

 

[renegadecow]

You're forgetting the ledge on the other side, the one against the bolt face. And use nylon.

Edited April 6, 2016 by renegadecow

[machgo]

Not forgetting, but on the factory part the amount of material you are referring to is negligible.  In fact, it tends to bias the front of the bolt stop to the right as it slips past the edge of the hop up housing.  One of my designs incorporated extra material--more than stock--to absorb the blow of the bolt where you are referring.  Unfortunately, there is so little space available, due to the nozzle, that not much more can be added.  Add in the fact that I have only the most primitive machining capability--I'm using a drill press as a milling machine. 

 

I settled on the materials I chose because of cost and availability.  Nylon is my next choice if I can find it cheaply enough.

[renegadecow]

I whittled mine from a bone folder using a sharp knife and a drill. The stock part slips to the right because it's fairly loose. I made mine tighter so the shelf on the bolt face and the shelf with the spring share the load.

[CaptCalvin]

Why don't you give this a try:

Just pay attention to the extra shelf I added to where the part contacts the bolt carrier. The spring area only looks like that now because my hop unit broke when I made the bolt stop out of metal but didn't have that added shelf. If you add that shelf the portion that you pointed to with the green arrow will never even touch the spring "tray" on the hop unit. That's a plastic piece I'm using in place of the metal on the hopup unit that broke off and it held up fine.

Edited April 6, 2016 by CaptCalvin

[bankz5152]

Poly carb and nylon are hardly expensive A4 size sheet off ebay is around £10.

 

 

 

on my phone, my spelling will suck

[machgo]

Why don't you give this a try:

Just pay attention to the extra shelf I added to where the part contacts the bolt carrier. The spring area only looks like that now because my hop unit broke when I made the bolt stop out of metal but didn't have that added shelf. If you add that shelf the portion that you pointed to with the green arrow will never even touch the spring "tray" on the hop unit. That's a plastic piece I'm using in place of the metal on the hopup unit that broke off and it held up fine.

 

That's interesting.  I won't try making one of metal, but I may incorporate that notch in my next try.

[Vasriotaep]

Hello, happy to discover this forum and this topic.

 

It's too late to speak more (00:38), but if you have feeding issue, the only way I find yet to fix the problem is paste something on the top of the part 84/85, where the bbs release button should be pressed.

 

Edited April 6, 2016 by Vasriotaep

[renegadecow]

Are you sure it's not the bbs because if the issue is the bb catch not being depressed far enough you should have no feed at all and not just the occasional jam. I found this out when working with a mate's unit and was convinced padding that area was the solution until I used my bbs in his mags.

[Vasriotaep]

I tried many different kind/brand of bbs without result, without this fix, I just can shoot one single bb.

 

If you want some informations, I made a review

I made a part about the reliability problem.

I'm currently working on the reliability because until now, impossible to make the part 2 (shooting test) with a so bad quality gun

[LJ.NL]

I tried many different kind/brand of bbs without result, without this fix, I just can shoot one single bb.

 

If you want some informations, I made a review

I made a part about the reliability problem.

I'm currently working on the reliability because until now, impossible to make the part 2 (shooting test) with a so bad quality gun

 

 

Nice video, thanks!

Edited April 7, 2016 by LJ.NL

[bankz5152]

Whats the reliability issue?

 

As for the magazines replace the bottom o ring and the top o ring with nitrile ones, I have done this and they no longer leak. Only had 1 magazine leak from the release valve and did the same as you, left them soaking in silicone oil for 24 hours. I havnt found a way to get the oring out or back in for that matter to replace it. 

[renegadecow]

From the FB convo, his hop-up has a mind of its own past 30m.

[bankz5152]

hmmm interesting. Easily solved new hop rubber & nub

[Vasriotaep]

Whats the reliability issue?

 

As for the magazines replace the bottom o ring and the top o ring with nitrile ones, I have done this and they no longer leak. Only had 1 magazine leak from the release valve and did the same as you, left them soaking in silicone oil for 24 hours. I havnt found a way to get the oring out or back in for that matter to replace it. 

 

Thank for the oring tips, I will check if my fix with silicone seal doesn't work. 

 

About issue, I had for the moment :

-Gas leak with all mags => Not fixed yet

-BB doesn't feed without pushing down the mag => Fixed by paste a part of plastic on the top of the part 84/85, but for how many time?

-Double feed => Fixed by sanded the part 98

-Trigger in semi-auto too hard => Fixed with a piece of plastic

-Mag position not align with the internal gas tank valve => Fixed with a piece of plastic on the butt

-Absolutely poor performance (30m maximum) => Not fixed yet, I change the nub and I will see

[renegadecow]

So bored out of my wits that I'm actually wishing for something to break. That or more mags, but from a combat load perspective, 150 rounds plus 40 from the 5-7 is more than plenty for me.

[Brigg]

Would aluminum be a good material for these bolt stops? Or would something like 6061 be too soft as well?

[renegadecow]

I think softer is better. Use something hard like steel and it's likely to break something softer.

[rusTORK]

Would aluminum be a good material for these bolt stops? Or would something like 6061 be too soft as well?

You may use aluminum to test an idea. It's soft metal and easy to modify. If it will work with aluminum, move to steel.

[CaptCalvin]

I wouldn't recommend it unless you know your idea won't lead to damage to the hopup unit. I was lucky the damage to mine can be worked around. If it had been the pivot point that broke it's pretty much toast. Replacement/upgrade units still aren't out there as far as I'm aware.

[Brigg]

I would automatically assume a steel catch would damage everything it touches in a WE gun. Which is why I asked about 6061. I don't have a p90 yet but it's not out of the question. So it's worth thinking about these things beforehand. I didn't want to be one of the early adopters for this one, considering its relatively unique features.

 

Chances are when I do get one, the first thing I'll do is start machining parts.

[renegadecow]

You could always go with a nylon catch, proven and easy to mill. That or a steel hop chamber.

[Vasriotaep]

Issues update :

-Gas leak with all mags => Tried with silicone seal and it seems it works! But as the conception of valve is strange on these mags, I will make a tips video if it's confirmed!

-BB doesn't feed without pushing down the mag => Fixed by paste a part of plastic on the top of the part 84/85, but for how many time?

Works, but maybe too much. The plastic part 2mm high, I load two bbs at once because of this, and bbs could jump into the gun when I change the mag. So I will change it by a 1mm plastic part. Should be good.

-Double feed => Fixed by sanded the part 98.

Still no problem, if I consider the new double feed problem is due to the previous fix.

-Absolutely poor performance (30m maximum) => Not fixed yet, I change the nub and I will see. 

A small improvement by using the stock nub again but with a better position, more centered. Now, at 30m, I'm pretty sure to touch someone, and I think I can touch until 40m but not more. The double feed problem doesn't allow me to confirm that. I'm sure another rubber can provide really better performance

[renegadecow]

FINALLY! Something broke. Well, not really broken, just wear related problem I guess. Actually it's more of a niggling issue than a problem. Basically, if I let go of the trigger real slow the hammer overrides the sear and falls completely. It still works if I let go of the trigger like I normally do, but I thought I ought to address this early on. Even when new I already noticed that the engagement of the sear and disconnector against the hooks of the hammer were very little as in they weren't engaging the full surface area of the corresponding parts but merely half if not a third of it. What I did was file certain parts on both the sear and disconnector so that they engage fully.

 

On the sear, I took away about 0.5mm off the length of the steel post (top most circle) which acts as a spacer between it and the disconnector. I also took away off its heel (circled far right) so the sear is allowed to move back a bit more.

On the disconnector, I filed off a bit off the bottom of the protrusion (far left) which also makes it lean more forward in conjunction with shortening the sear's steel post.

 

You can see below just how much material I had to file off, which isn't much at all.

 

With these modifications the sear and disconnector engages completely against the hammer. While this translates to a longer trigger pull and reset in theory, because of the heavy trigger spring it is not a distinguishable difference at all.

Edited April 11, 2016 by renegadecow