Open chamber WE M4/Scar/PDW/G39/l85

[Boyso]

On the same basis, I've been looking at Ratech help pages on the PDW and they say to shave plastic off the nozzle. But every other tutorial I found, including the one I linked don't ask for any destructive mods. And my gun works fine...

[Eien]

Originally Posted by turok_t

No, dont apply brute force. After you remove the very small aluminum pin that holds the two halves of the nozzle, look for the crease (cross section of the nozzle) that splits the nozzle in two. Rotate both halves until they come apart.

Thanks turok, got it off

[kullwarrior]

Originally Posted by Boyso

On the same basis, I've been looking at Ratech help pages on the PDW and they say to shave plastic off the nozzle. But every other tutorial I found, including the one I linked don't ask for any destructive mods. And my gun works fine...

It has been reported that short barrel gun will experience lower fps without the shave. However, the conversely is true for long barrel gun (If you shave it the fps will become too high and beyond NPAS' range)

[Boyso]

Sooo, for a M4A1-Carbine lenght rifle, I keep it as is?

[Eeyore]

Originally Posted by Boyso

Sooo, for a M4A1-Carbine lenght rifle, I keep it as is?

Yes.

[juicy]

I've had mine as long as CTAC has had his - I guess that was early July or something like that. We both had better results after teflon taping the hop up rubber/inner barrel assembly with 1-3 wraps to create a better air seal.

My nozzle spring unhooked itself and crushed itself to pieces 1-1.5 months ago. Been running it without a nozzle spring and it works fine, minus the time when the crushed nozzle spring was still in my BCG. Any ideas on what I can use to replace mine with?

My nozzle/piston head o-ring tore a chunk out of itself when my nozzle spring went. Not too bad in terms of blowback, but I do notice I get a little more wasted gas spraying out when it cycles. No biggie, IMO.

I found WE hop up rubber < TM hop up rubber < Falcon double point green rubber. Still not quite up to what I wanted from it, going to be trying both PDI-Raven and RA Tech 6.01 barrels at some point or another. Not happy with the stock brass barrel. But, uh, any ideas what hop up rubber will work best?

Tried using a G&P plastic buffer, worked good till it beat its way into my buffer tube spacer and my BCG was getting locked up all the way to the rear in my buffer tube. Will get a KA or G&P buffer tube spacer kit to further test this, however I did notice slightly less perceived recoil, tiny bit higher ROF, and much less drain on the gas system.

Found that my RA-Tech NPAS when adjusted to sub-380 fps in a M4A1 length barrel tended to inhibit the cycling of the BCG to the point of it not quite properly chambering a BB reliably.

Haven't screwed around too much with trigger group, just put in TSC ambi safety set as I have just gotten too used to that. Not quite as crisp/precise in terms of fire selecting as the stock WE one. Sometimes have semi being a burst of auto till I release a tiny bit of pressure on the selector. I do find that the open bolt kit's trigger group to work way better. Hammer at least hasn't beaten itself to a pulp yet. Seems to work more reliably too, even with sear or whatever being worn down - can put selector on safe even with hammer not cocked... gah, kinda annoyed at people touching my GBBR and treating it like an AEG.

Oh, and WE mags suck. They dry out/blow out seals way too fast. Sometimes even when they're kept gassed with low pressure, they end up leaking in my gear bag. Kinda sucks, but oh well, they're cheap.

[turok_t]

Originally Posted by juicy

My nozzle spring unhooked itself and crushed itself to pieces 1-1.5 months ago. Been running it without a nozzle spring and it works fine, minus the time when the crushed nozzle spring was still in my BCG. Any ideas on what I can use to replace mine with?

You can get some from hardware stores or have them custom made. They are called “extension springs”. They wont have it Crappy tire, Home Depot or home hardware. I advise you NOT to get springs that are too stiff or else you will be consuming more gas. If your spring is really stiff, you may possibly snap the uber thin aluminum pin in the nozzle (the pin that secures one end of the extension spring)

Originally Posted by juicy

I found WE hop up rubber < TM hop up rubber < Falcon double point green rubber. Still not quite up to what I wanted from it, going to be trying both PDI-Raven and RA Tech 6.01 barrels at some point or another. Not happy with the stock brass barrel. But, uh, any ideas what hop up rubber will work best?

RA-tech barrels work fine. I would use King Arms hicapa nozzle (red). I got an increase in FPS using these parts with Teflon mod.

Originally Posted by juicy

Tried using a G&P plastic buffer, worked good till it beat its way into my buffer tube spacer and my BCG was getting locked up all the way to the rear in my buffer tube. Will get a KA or G&P buffer tube spacer kit to further test this, however I did notice slightly less perceived recoil, tiny bit higher ROF, and much less drain on the gas system.

Why would you get a plastic buffer (besides reduced gas consumption) for a part that gets impacted so hard and that travels with such high velocity? I suggest getting a RS buffer or use the one from RA tech. Some RS buffers are similar in weight to the RA tech (refer to my guide). The tradeoffs in having a plastic buffer (ie. reduce gas consumption) is not worth having it worn out so quickly. Also, you can also use washers that fit inside the buffer tube so your BCG doesn’t get locked up in the buffer tube.

Found that my RA-Tech NPAS when adjusted to sub-380 fps in a M4A1 length barrel tended to inhibit the cycling of the BCG to the point of it not quite properly chambering a BB reliably.

Originally Posted by juicy

Sometimes have semi being a burst of auto till I release a tiny bit of pressure on the selector.

Probably the selector is sliding off the safety detent pin from the recoil of the gun. I recall the safety detent pin is rounded, which doesn’t secure the selector as much as a RS detent pin ($2.00) which is more cone shaped that provides more s tability.

[Coresair]

Hello all, I had a question regarding ambi mag catches/releases.

searching the forum I found this : http://www.airsoftcanada.com/showthr...bi#post1095343

Originally Posted by Karma_

Also, Prime makes an ambi mag release for the PTW and WA, do any of you have any idea if it would work in the WE? I don't see why it wouldn't.
EDIT: So I took my mag release off my PTW to see if it will work in my WE and it does so there you go. For those other lefties out there, here's an option. Now we need an ambi selector.

would this hold true in OB versions, I currently own a 416 and I was wondering if it would still fit!


ALSO, I was wondering if you guys had any ideas/suggestions: I want to install the short inner barrel from an "untabbed" (without those dreaded tabs) OB kit. Would any of you know how I could mod this part so it would fit? Buying a whole new kit would be easier but since I already got this one I'd rather take a shot at it before anything!

thank you for your time!

[turok_t]

Originally Posted by Coresair

Hello all, I had a question regarding ambi mag catches/releases.

searching the forum I found this : http://www.airsoftcanada.com/showthr...bi#post1095343



would this hold true in OB versions, I currently own a 416 and I was wondering if it would still fit!


ALSO, I was wondering if you guys had any ideas/suggestions: I want to install the short inner barrel from an "untabbed" (without those dreaded tabs) OB kit. Would any of you know how I could mod this part so it would fit? Buying a whole new kit would be easier but since I already got this one I'd rather take a shot at it before anything!

thank you for your time!

Yeah the magazine catch would most likely work, as the OB and AWSS lower receiver is the same.

What do you mean by "Tabs" on the inner barrel?

[Coresair]

Originally Posted by turok_t

Yeah the magazine catch would most likely work, as the OB and AWSS lower receiver is the same.

What do you mean by "Tabs" on the inner barrel?

Thanks!

The tabs I'm refering to are located on both sides of the the hop up chamber, sorry for the confusion.

[Eien]

Curious here.. anyone tried the Ra-tech inner barrels for OB? Issues? Fitment?

[Fox62]

Originally Posted by Eien

Curious here.. anyone tried the Ra-tech inner barrels for OB? Issues? Fitment?

No issues, but I don't think it's really all that good. I have a 440mm 6.01 barrel on my SCAR DMR. Wish Ra-Tech made 6.03/6.05, which I believe are usually better (perhaps they are making them now?). In any case, I'd go for the Falcon ones, the Ra-Tech looks horribly finished, and the results haven't been very impressive, not terribly bad though, probably won't be replacing it anytime soon.


Fox.

[technosnob]

Is anyone having feeding issues?

I seem to get double feeds when using fully loaded (30 bb count) and even short count loads (25-28 bb's). It does not happen all the time but it happens!!!

I have installed OB kits into both of my M4's. One is a full length M4 the other a CQB. Npas installed in both.

[mr_nuts31]

I wondered if anybody else heard the news but it seems that WE has made some changes to the open bolt PDW here:

WE "Gen-3" PDW conversion kit - YouTube

[m102404]

Preamble:
Eeyore was generous enough to reach out to a bunch of us for critique and comment (aka T&E) on the Open Bolt (OB) Kit. A number of us have been heavy users of the WE platform...some since they were first available.

Over an extended period of time, the WE platform has been put through its paces. Bench time, training/range work, skirmish, milsim. Mixed shoot 'em up games and milsims that could be described as designed for gas guns.

The most recent testing/training session had approx 18-19 shooters.

I would modestly describe the experience level of those involved as high. Professional trainers, LE, senior mods/hosts/players, gun docs and guys who who "just" pull triggers. For good or for bad...these guys are not ones to pull punches. What works...works....what doesn't gets put aside.

To be fair...MUCH more T&E time to date has been put into the closed bolt (aka CB, aka Brass Tube) system. However, it did not take much to realize the shift in the wind of what was coming. First with the G36, then subsequent models (i.e. PDW being offered in both formats), then the conversion kits.

**NOTE**
I fully realize that there have been comments from more than a few other ASC members across the country so far as how good/reliable/etc...the OB is. They are valuable comments and should be weighed in with anyone's consideration of this system.

This writeup, and I, should not be seen as the be-all/end-all. Simply put, there are many, many others out there who are far better builders/gun docs and shooters than myself....they simply don't write much on the forum . This writeup is intended to summarize their observations and experiences.
********

Part 1: Short Background & Summary (for those with ADD)
The WE Open Bolt Conversion Kit has been available for a number of months now. As with any new system, everyone holds their breath a bit to see how it will perform and hold up to the rigors of regular use.

In summary, the open bolt (more correctly the "open chamber") system works very well, appears to be quite durable and offers some notable improvements over the closed bolt (aka closed chamber).

Significant Improvements (vs. CB system)
1. Crispness of the cycling action
2. Hopup application
3. Gas efficiency
4. Asthetics of not seeing anything in the ejection port when the bolt is rearward (personally I don't care much about that....)

NOTE: Both the PDW and M4 platforms were tested, the G36/L85/AK less so and will be excluded from comments,...and unless specified, each point will apply to both systems (note...Nozzle and Piston are used interchangeably)

Part 2 - Installation

- The installation of the OB system into either platform is very straightforward. Although there is a near complete lack of Step by Step documentation, the process is simple.

- There is little that can be misaligned or installed incorrectly, most pieces being a "swap out old part, install new part process". Care should be taken to ensure that the receiver insert for the inner barrel on the M4 is aligned nicely before everything is tightened down....this is not an issue with the PDW kit.

- WE M4 and PDW mags continue to be plagued with leaking seals and valves. While some of this can be remedied by using gasket sealer (only Loctite Blue Silicone Gasket sealer was used) on the rear main seal (aka backplate), replacing the fill valves with Madbull Replacement Grenade fill valves (turned to diameter on lathe to fit the mag body) and keeping some gas and silicone oil in the mag...these are inherent mag design issues and not a result of the closed -> open conversion.

- magazine conversion is straightforward and only requires that some care is taken not to have the top gas seal (rubber boot) twisted/pinched. Removing or retaining the plastic "filler" block at the end of the mag spring does not seem to affect function negatively at all.

* The PDW installation could not be easier...with the bottom two hex screws removed, the entire "front end" is simply swapped for the old unit.
*** the PDW Kit's return to battery spring is technically deflating...a seemingly band-aid fix. The recoil guide rod and spring setup in the RATech replacement bolt is much more of a "proper" design...and it's no wonder that the Gen3 WE PDW will be like that right out of the box.

* The M4, especially if you have aftermarket rails and such, requires more front end disassembly. In many setups the front sight/gas tube needs to be removed so that the delta ring assembly can be removed.
* The M4 assembly continues to suffer the loosening of the outer barrel from the receiver, but this is not directly attributable to the Open Bolt kit. The stock assembly has an Oring positioned there to facilitate a crush fit.
* aftermarket M4 charging handles may not work as their end profile may cause the bolt to bind when fully chambering
** Not related to the CB/OB at all, but worth noting...the stock reinforced cast "part #66" seems to be holding up very, very well. Many of the weapons that came with them stock have not suffered failure at all.

3. Operation

- both platforms operate very nicely and I would say that there are no issue encountered that would not otherwise be present with other GBB guns. Worn feed lips, overly applied hopup, dirty systems will cause feeding/functional issues.

- in our most recent test/training day there were an even mix of CB and OB weapons present (and a couple of very well built Magnas)...one CB suffered a significant failure attributable (jamming) to the gas/hopup system...a few other suffered significant failures (failure to actuate gas) due to trigger mech/mag issues.

- the action of the open bolt system seems to be "crisper" than the close bolt system. Both in cycling speed and sound. There is a sharper snappiness to the action in both semi and full auto. The is a notable decrease of the "gas cloud" that was apparant with the CB system.

- Overall reports indicate that reverting back to "normally oiled gas" (i.e. just a couple of drops now and then...like a GBB pistol) is absolutely fine with the OB system. This in and of itself is a large contributor to the solid out-of-the-box accuracy improvements of the OB system.

- all weapon functions remained operational (i.e. bolt release, select fire, racking/etc)

- hammering shots in both rapid semi and strings of full auto have been fine and reliable. When running a fully gased mag on full auto...it seems to be less common to get to the point where the action fades out due to the lack of gas pressure as the mag depletes.

* on one PDW the bolt catch/release was intermittently activated when firing (both semi/full) and would lock the bolt back with rounds remaining in the magazine. While this can occur in any setup...it only happened on this one weapon.

4. Wear and Tear, Fit/Function, Adjustments

- both systems seem generally durable.

* In one instance the bottom of the PDW bolt carrier needed to be filed/ground down so that there was enough clearance to cycle the action. No issues with the RATech bolt kit...no issues like that with the M4 kits.

* As with many GBB pistol systems...the bottom "foot" on the piston that "kicks" a BB out of the magazine and pushes it into the chamber is subject to damage from the magazine if it is inserted into the weapon forcefully while the bolt is closed. There is no issue with the closed bolt system as the brass tube is substantial. The ideal practice would be to lock the bolt to the rear, insert the magazine and let the bolt go forward to chamber a round. However, in regular use, that is often not the case and mags are inserted with the bolt both to the rear and forward....and so far it does not seem to be an issue with damaging the open bolt piston.

* Resting the magazine on the floor (surface was hardwood) when shooting prone did not hang up any of the rifles.

* while the BB is inserted a fair bit into the chamber of both weapon systems, it seems that a chambered BB will tend to fall out if the muzzle is not pointed downwards with an OB system. If the mag is still in, there is a high degree of probability that the BB will fall back and into the bolt area. This will cause a jam, and/or potentially break something, if the bolt is allowed forward. The instances where the bolt was let forward with a loose BB in there did NOT result in any catastrophic breakage or damage....but I'd be conscious of it.

* the hopup adjustment on the PDW is simple, effective and easy to manipulate.

* the hopup adjustment on the M4 is effective, simple but not as easy to adjust. Manipulation of the hex grub screw with an allen key, both from the ejection port and from "below" if the receivers are separated, is cumbersome and time consuming.

* an alternative method for the M4 adjustment is to use either an elongated screwdriver with the proper hex bit...or secure a piece on an appropriately sized allen key to the end of a rod (e.g. expoxy one to a rod, etc)...open the receivers, remove the bolt and access the hopup adjustment from the rear of the upper receiver. It is much easier and fairly precise.

- both hopups seem to hold their settings quite well

- there were more than a few malfunctions throughout testing...and they are still being reviewed. Mostly due to the magazines/feed lips.

* the nozzle return spring on one M4 failed and thus the nozzle does not "flick back" as it is supposed to do so when the bolt is rearward. Like a GBB pistol...this does not affect the actual function, but is rather a cosmetic thing (the piston is still visible in ejection port). Nothing was done to "fix" the issue, the gun was run as-is and did not fail.

* while the PDW hopup assembly seems very well assembled, the M4 hopup seems very, very sloppy in comparison. The molding of the two hopup/chamber halves do NOT capture the inner barrel very well and allows a lot of wobble, twisting/movement. This can be tightened up by applying wraps of "plumbers tape" to the inner and then assembling the hopup unit.

* both systems seem to offer a ~50% increase in gas efficiency vs. the closed bolt system

- the open bolt mags are easily loaded if your loader has a GBB mag tip. Nobody bothered with the little adaptor boot that is included with the kits.

- the feed lips of the open bolt mags stand much less proud to the top of the mag than the closed bolt mags...and while they may still break, they should be less prone to breakage.

- the top gas seal of the OB mags are ramped such that the nozzle interacts with a jam fit when fully forward...this provides an excellent gas seal between the mag and the nozzle.

- the front of the feed lips of the open bolt mags seemed to get chewed up a bit (in PDW)...but once marred they didn't seem to wear any further.

- the stock "out of the box" accuracy is greatly improved with the Open Bolt system. The PDW kit (short barrel) returned excellent consistency and accuracy. Stock iron sights. 5-30' shot standing/prone freehand. Propane and quality 0.30g BBBastard BBs.

- likewise the M4 setup was very consistent...although tuning in the hopup was a major hampering to testing. A well cared for and slightly modded M4 OB was a real tack driver.

** NOTE: Not related to OB/CB specifically...somewhat surprisingly there were no RDS failures throughout the last testing/training session. The optics used ran the gamut from a RS Specter to clones. Historically GBBRs will shake the internals of a clone RDS to bits...some last longer than others, but in general they will die. I reverted to shooting with only iron sights for the past 2 years as I can't stomach trashing expensive clones. On the other hand one of the guys is on his 7th or 8th RDS for his GBBRs.....