WETTI/AWSS - M4/SCAR/HK416 - Technical Summary Thread

m102404 · September 28th, 2009, 17:39

Buy more than one NPAS kit when you get a lead on it!?! I'll gladly pick one up from you.

A buddy just got his NPAS SCAR nozzle in the mail today and is dropping it off tomorrow. I'll fiddle a bit with it this week.

Tys

Karma_ · September 28th, 2009, 17:59

Quote:

Originally Posted by Hata

Which one did you buy from airsoftbuddy?

which NPAS you ordering? the one for M4 or SCAR? I can't find anywhere selling the one for M4. I msg RA-Tech from GGI but no reply yet.

The charging handle is called Steel Charging Handle. No brand given, $39. It's solid, just need to file the gun a bit.

I sent RA Tech an email yesterday and got a response this morning. Maybe I'll order a few then. I know this will be a hot item.
*Edit - It's the NPAS for the WE M4.
Have any of you installed the chrome tightbore? WGC has them in stock but until I hear if they're that much better I'll hold off on getting one.

KEVORKIAN · October 1st, 2009, 23:32

Quote:

Originally Posted by m102404

A buddy just got his NPAS SCAR nozzle in the mail today and is dropping it off tomorrow. I'll fiddle a bit with it this week.

Tys

I actually spent some time indoors today testing out the SCAR's. I'm not convinced that I need to install the RA-Tech NPAS kits I got last week...both guns chrono at 335-340 fps using .20g with propane!!! Both are out of the box set-ups!
I will do further testing with the RA-Tech NPAS once my Bomber aluminum bolts arrive!

Anyone else have a chance to do some chrono tests?

Nabisco_Lobstrosity · October 2nd, 2009, 12:37

My stock* WE AWSS SCAR-L chronoed at 385-425fps with 0.25g BB's when I used Propane. It's no longer a question for me if I will install the NPAS to lower my FPS.

* The only part that isn't stock is the reinforced Firing Pin Stop.

NVC · October 2nd, 2009, 12:45

My Scar out of the box was chrono at a local field in the 375-380ish range.

m102404 · October 2nd, 2009, 13:30

Inital chrony (room temp 19-20C...all on propane) was:
WE M4 AWSS - M4A1 length inner - 540fps w/ 0.20g BBs
WE SCAR - stock - 399-401fps w/0.20g BBs
WE M4 AWSS - stock inner cut down to CQBR length (extends just beyond the threading of the 10" barrel section), CO2 Nozzle (looks just like the SCAR one) - 401fps w/0/20g BBs

I have not chronied yet with 0.25/0.28/0.30 or used duster yet. I hope to chrony both setups with some variations late this weekend.

Griff just got his NPAS valve...I'll detail it shortly. One of my prototypes look seems very similar to it in function.

Tys

Griffin · October 2nd, 2009, 14:24

Quote:

Originally Posted by Nabisco_Lobstrosity

My stock* WE AWSS SCAR-L chronoed at 385-425fps with 0.25g BB's when I used Propane. It's no longer a question for me if I will install the NPAS to lower my FPS.

* The only part that isn't stock is the reinforced Firing Pin Stop.

For the reinforced Firing Pin stop send a PM to Warchild over at Arnies or here. I know that his group in New York made bunch of them and was selling the extras they had. I have one ebing sent to me already hopefully it will get here soon. Not like I needed it but grabbed it for when the day it does break.

KEVORKIAN · October 3rd, 2009, 02:04

Alrighty, I just received a third WE SCAR (ordered in error) and I tested it out with the chrono...out of the box it shoots 375-380 fps with .20 bb's.

Here are my serial numbers for each of my SCAR's:

1.) Black WE SCAR #0000029 - shoots 335-340 fps
2.) Tan WE SCAR #0000638 - shoots 335-340 fps
3.) Black WE SCAR #0000185 - shoots 375-380 fps

Hata · October 6th, 2009, 10:28

Anyone already order or received M4 NPAS valve??

m102404 · October 6th, 2009, 10:56

I got Griffon's NPAS SCAR valve in my shop right now. If you have the "new" M4 chamber the nozzle with fit a M4...they're both the same nozzle (the type that looks like the Scar nozzle).

I installed the nozzle/rod to his bolt 2 nights ago. It's machined as nice as any of the other valves. The kit comes with the adjustment tool, e-clip, rod and nozzle (inc. float valve and spring). He just got the Bomber lightweight bolt yesterday. We'll get that into the rifle later this week.

Check the two allen screws that hold the bolt to the guide rail (not the spring guide). Unless loctited down, they'll loosen off and there'll be a lot of play in the bolt...and thus the nozzle. The nozzle lip with clip the edge of the cylinder...and I think that this transfers a bit of a shock to the nozzle, and it's weakest part is the standoffs of the inlet gas holes. Too much force or repeated impact (either misalignment or jams) and they might crumple. Anyway...that's my theory.

On my M4...I removed the hard white plastic spacer from behind the nozzle and replaced it with a piece/section of rubber that was just a hair longer than the plastic spacer. My wild ass guess is that if there is a bit of give as the bolt comes slamming forward...the rubber will deaden the shock of the impact a bit. In the event of a jam...there'll at least be a bit of give, hopefully taking a bit of the sting out of it. I test fired 1 long burst of FA just gas...and 3 mags of bbs. Seemed to work fine.

RATech NPAS comments
- the spring is the same as the others, but the end piece that goes across the diameter (hard to describe, but if you've seen one, you'll know) of the spring is not there. It's just a normal tubular spring.

- the "adjustment tool" is just a bent piece of tubing that has a allen key grub screw screwed into the end of it (so the head of the grub screw becomes the socket of the tool). Ingeniously simple...and it works.

- The adjustment screw in the nozzle is very nicely made...looks like an M5 screw...it looks a bit bigger than a M4. It has a white o-ring in one part of the threading...I suppose so it doesn't travel too far towards the rear of the nozzle.

- I'll take another look at the rods...but I think that the threaded portion of the stock rod extends a few threads more into the nozzle than the rod that came with the NPAS kit....perhaps for more of an adjustment range? maybe because the flange of the adjustment screw takes up space.

- the e-clip that comes with the RATech kit is silver...whereas the stock one is black. I didn't mic them...but the silver one seems a split-hair thicker. This is good because it removes play from the piston body/bolt lockup.

I just set it in a random position and test fired so far...17deg, 420fps w/0.20.

I might swap it into my M4 CQBR....it's easier to pop the M4 bolt out and twiddle the adjustment than it is to do that with the SCAR. If anything gets loose from taking it apart and reassembling endlessly...I'd rather it be my M4 than his SCAR.

Now...pre-mature comments.
1. You're going to want to loctite the screw. It's not a "nylon-nut" style of thing where it'll hold in whatever setting you leave it at. That said, it's stiff now...but who knows as the rifle shakes and rattles as it shoots.

2. I've mucked around with solid spacers screwed onto the rod. They hold...but each spacer needs to be tuned to each gun's nozzle/setup. So not easily adjustable for temperature variations. I have one setup for 330fps and the other for 360fps. A bit on the low side...but they should work for indoors/outdoors warm-hot days.

3. I've mucked about with dilling/tapping a screw through the stock float valve...that works too. The setup needs to be tweaked to make it usable...but it's essentially the same thing as the NPAS nozzle.

Adjusting these things is going to be fiddly. Aim for a 20-30fps lower than max limit as a safety margin...record some temp/fps readings throughout the day to get a baseline for your setup.

Karma_ · October 7th, 2009, 01:39

Quote:

Originally Posted by Hata

Anyone already order or received M4 NPAS valve??

Not yet. I hope it comes this week.

KEVORKIAN · October 8th, 2009, 01:18

I just installed a Bomber lightweight aluminum bolt and I have to say I'm impressed! Blow back is much crisper and the ROF has noticeably increased too!

More testing over the weekend when I have more time...

m102404 · October 8th, 2009, 11:01

Met with Griffon last night...and took his bomber bolt and WarStore CNC part 66? (the knocker delay piece).

The bolt is surprisingly light!

I'll pop it in tonight or Monday.

Tys

Hata · October 8th, 2009, 13:36

My new charging handle is finally on the way here.
Just wonder, what grease are you guys use to maintain your GBBR?

m102404 · October 9th, 2009, 18:41

I just use a dab of superlube on the bolt bearing...then shoot a mag or two of oily gas through it now and then. Dry gas might be better for the hopup performance...but the seals in the mags love to have some oil.

NPAS Kit pics

Adjustable valve, crunched nozzle (lower), stock nozzle (upper)

Adjustment tool/valve

Adjustable valve (right..partially unscrewed) and stock valve

Different lengths of threading on stock SCAR rod vs. RATECH NPAS kit rod

Homemade spacer

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October 2nd, 2009, 12:37	#19
Nabisco_Lobstrosity Trader rating Join Date: Jun 2006 Location: Charlottetown, PEI	My stock* WE AWSS SCAR-L chronoed at 385-425fps with 0.25g BB's when I used Propane. It's no longer a question for me if I will install the NPAS to lower my FPS. * The only part that isn't stock is the reinforced Firing Pin Stop. __________________ Nabisco Lobstrosity --------------------

October 3rd, 2009, 02:04	#23
KEVORKIAN Trader rating Join Date: Nov 2006 Location: Manitoba	Alrighty, I just received a third WE SCAR (ordered in error) and I tested it out with the chrono...out of the box it shoots 375-380 fps with .20 bb's. Here are my serial numbers for each of my SCAR's: 1.) Black WE SCAR #0000029 - shoots 335-340 fps 2.) Tan WE SCAR #0000638 - shoots 335-340 fps 3.) Black WE SCAR #0000185 - shoots 375-380 fps __________________ Kevorkian I SUPPORT THE USE OF SILICA BB BASTARDS!

October 6th, 2009, 10:56	#25
m102404 Tys Trader rating Join Date: Apr 2006 Location: Toronto	I got Griffon's NPAS SCAR valve in my shop right now. If you have the "new" M4 chamber the nozzle with fit a M4...they're both the same nozzle (the type that looks like the Scar nozzle). I installed the nozzle/rod to his bolt 2 nights ago. It's machined as nice as any of the other valves. The kit comes with the adjustment tool, e-clip, rod and nozzle (inc. float valve and spring). He just got the Bomber lightweight bolt yesterday. We'll get that into the rifle later this week. Check the two allen screws that hold the bolt to the guide rail (not the spring guide). Unless loctited down, they'll loosen off and there'll be a lot of play in the bolt...and thus the nozzle. The nozzle lip with clip the edge of the cylinder...and I think that this transfers a bit of a shock to the nozzle, and it's weakest part is the standoffs of the inlet gas holes. Too much force or repeated impact (either misalignment or jams) and they might crumple. Anyway...that's my theory. On my M4...I removed the hard white plastic spacer from behind the nozzle and replaced it with a piece/section of rubber that was just a hair longer than the plastic spacer. My wild ass guess is that if there is a bit of give as the bolt comes slamming forward...the rubber will deaden the shock of the impact a bit. In the event of a jam...there'll at least be a bit of give, hopefully taking a bit of the sting out of it. I test fired 1 long burst of FA just gas...and 3 mags of bbs. Seemed to work fine. RATech NPAS comments - the spring is the same as the others, but the end piece that goes across the diameter (hard to describe, but if you've seen one, you'll know) of the spring is not there. It's just a normal tubular spring. - the "adjustment tool" is just a bent piece of tubing that has a allen key grub screw screwed into the end of it (so the head of the grub screw becomes the socket of the tool). Ingeniously simple...and it works. - The adjustment screw in the nozzle is very nicely made...looks like an M5 screw...it looks a bit bigger than a M4. It has a white o-ring in one part of the threading...I suppose so it doesn't travel too far towards the rear of the nozzle. - I'll take another look at the rods...but I think that the threaded portion of the stock rod extends a few threads more into the nozzle than the rod that came with the NPAS kit....perhaps for more of an adjustment range? maybe because the flange of the adjustment screw takes up space. - the e-clip that comes with the RATech kit is silver...whereas the stock one is black. I didn't mic them...but the silver one seems a split-hair thicker. This is good because it removes play from the piston body/bolt lockup. I just set it in a random position and test fired so far...17deg, 420fps w/0.20. I might swap it into my M4 CQBR....it's easier to pop the M4 bolt out and twiddle the adjustment than it is to do that with the SCAR. If anything gets loose from taking it apart and reassembling endlessly...I'd rather it be my M4 than his SCAR. Now...pre-mature comments. 1. You're going to want to loctite the screw. It's not a "nylon-nut" style of thing where it'll hold in whatever setting you leave it at. That said, it's stiff now...but who knows as the rifle shakes and rattles as it shoots. 2. I've mucked around with solid spacers screwed onto the rod. They hold...but each spacer needs to be tuned to each gun's nozzle/setup. So not easily adjustable for temperature variations. I have one setup for 330fps and the other for 360fps. A bit on the low side...but they should work for indoors/outdoors warm-hot days. 3. I've mucked about with dilling/tapping a screw through the stock float valve...that works too. The setup needs to be tweaked to make it usable...but it's essentially the same thing as the NPAS nozzle. Adjusting these things is going to be fiddly. Aim for a 20-30fps lower than max limit as a safety margin...record some temp/fps readings throughout the day to get a baseline for your setup. Last edited by m102404; October 6th, 2009 at 11:06..

September 28th, 2009, 17:39	#16
m102404 Tys Trader rating Join Date: Apr 2006 Location: Toronto	Buy more than one NPAS kit when you get a lead on it!?! I'll gladly pick one up from you. A buddy just got his NPAS SCAR nozzle in the mail today and is dropping it off tomorrow. I'll fiddle a bit with it this week. Tys

October 2nd, 2009, 12:45	#20
NVC Trader rating Join Date: Jul 2009 Location: Edmonton	My Scar out of the box was chrono at a local field in the 375-380ish range.

October 2nd, 2009, 13:30	#21
m102404 Tys Trader rating Join Date: Apr 2006 Location: Toronto	Inital chrony (room temp 19-20C...all on propane) was: WE M4 AWSS - M4A1 length inner - 540fps w/ 0.20g BBs WE SCAR - stock - 399-401fps w/0.20g BBs WE M4 AWSS - stock inner cut down to CQBR length (extends just beyond the threading of the 10" barrel section), CO2 Nozzle (looks just like the SCAR one) - 401fps w/0/20g BBs I have not chronied yet with 0.25/0.28/0.30 or used duster yet. I hope to chrony both setups with some variations late this weekend. Griff just got his NPAS valve...I'll detail it shortly. One of my prototypes look seems very similar to it in function. Tys

October 6th, 2009, 10:28	#24
Hata Trader rating Join Date: Dec 2001 Location: 43.855477 , -79.509371	Anyone already order or received M4 NPAS valve??

October 8th, 2009, 01:18	#27
KEVORKIAN Trader rating Join Date: Nov 2006 Location: Manitoba	I just installed a Bomber lightweight aluminum bolt and I have to say I'm impressed! Blow back is much crisper and the ROF has noticeably increased too! More testing over the weekend when I have more time... __________________ Kevorkian I SUPPORT THE USE OF SILICA BB BASTARDS!

October 8th, 2009, 11:01	#28
m102404 Tys Trader rating Join Date: Apr 2006 Location: Toronto	Met with Griffon last night...and took his bomber bolt and WarStore CNC part 66? (the knocker delay piece). The bolt is surprisingly light! I'll pop it in tonight or Monday. Tys

October 8th, 2009, 13:36	#29
Hata Trader rating Join Date: Dec 2001 Location: 43.855477 , -79.509371	My new charging handle is finally on the way here. Just wonder, what grease are you guys use to maintain your GBBR?

October 9th, 2009, 18:41	#30
m102404 Tys Trader rating Join Date: Apr 2006 Location: Toronto	I just use a dab of superlube on the bolt bearing...then shoot a mag or two of oily gas through it now and then. Dry gas might be better for the hopup performance...but the seals in the mags love to have some oil. NPAS Kit pics Adjustable valve, crunched nozzle (lower), stock nozzle (upper) Adjustment tool/valve Adjustable valve (right..partially unscrewed) and stock valve Different lengths of threading on stock SCAR rod vs. RATECH NPAS kit rod Homemade spacer

WETTI/AWSS - M4/SCAR/HK416 - Technical Summary Thread

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