RA-Tech WE M4/M16 nozzle

[turok_t]

Originally Posted by unknownvariable

How was the fit for the nozzle guide on the side?

I just got my nozzle (part of the complete bolt kit), and the nozzle guide on the side just falls out when handling the bolt carrier. I had to swap in a plastic one from my stock bolt carrier.

yeah its a bit loose, try to put some light glue to hold it in place..

I got word from RA-Tech regarding the difference between the first compared to second batch of the nozzles.. this is what they said:

"The first batch is sold out. First batch is processed by tumble polishing and second batch is by sandblasting"

[TPM001]

Just got one of these (the nozzle/bolt carrier combo) from airsoftparts. I must say, I'm quite impressed with the build quality and finish. The nozzle is the bead blasted version. The nozzle fits inside the bolt carrier perfectly and the nozzle slides freely (albeit slower than the plastic nozzle due to weight). This combo is definitely much heavier than the stock. I'll have to test how it affects rate of fire. I'll also do an fps test. My hope is that I get a stable 360 fps and a stable 400 fps. I'll try it on both an M4 CQBR and a 416.

I've been waiting for this upgrade for a long time. I must have chewed thru 15 nozzles ($400) waiting for this thing. I hope it's worth the wait....

[turok_t]

Originally Posted by TPM001

Just got one of these (the nozzle/bolt carrier combo) from airsoftparts. I must say, I'm quite impressed with the build quality and finish. The nozzle is the bead blasted version. The nozzle fits inside the bolt carrier perfectly and the nozzle slides freely (albeit slower than the plastic nozzle due to weight). This combo is definitely much heavier than the stock. I'll have to test how it affects rate of fire. I'll also do an fps test. My hope is that I get a stable 360 fps and a stable 400 fps. I'll try it on both an M4 CQBR and a 416.

I've been waiting for this upgrade for a long time. I must have chewed thru 15 nozzles ($400) waiting for this thing. I hope it's worth the wait....

I wish they had more of the tumble polished version, they looks alot better, too bad ratech isnt making that version anymore (cheaping out?). You might need to install the regular NPAS as i hear the one that comes with the aluminum nozzle is not consistent (i tried it myself too)

[TPM001]

Originally Posted by turok_t

I wish they had more of the tumble polished version, they looks alot better, too bad ratech isnt making that version anymore (cheaping out?). You might need to install the regular NPAS as i hear the one that comes with the aluminum nozzle is not consistent (i tried it myself too)

Might require modding to do that. I can already tell the NPAS valve in the aluminum nozzle is completely different from the one made for the plastic nozzles. When I get home, I'll open her up and take some pics.

From the onset, it looks like the built in NPAS in the aluminum nozzle is actually two separate pieces which are pressed together by the valve spring. There appears to be a flaw in the design because sometimes, the "head" of NPAS will not mesh well with the "tail" after being separated and coming back together. This could cause a lot of variances in the flow.

As you know, the NPAS valve for the plastic nozzle is actually a single contained unit. The flow would be more consistent.

I'll do some quick tests first before trying to mod. But since you've already mentioned it, it's stuck in my head and I'll end up trying to mod it anyway.

[TPM001]

Interesting. I tested in my WE M4 CQBR with decent results:

Using 0.25g BBs and a V2 mag:

400
391
386
386
381
386
387
382
381
385

The NPAS was open but not at it's widest position. I'm going to do more tests.

[SHaKaL]

Just ordered one from Airsoftparts. Can't wait to see the result with my XM 177 (plan to make this gun my workhorse as i like it size and lightness).
But seeing the result from you guy's, I'm confident that it will be gamable even in hot weather.

Any break or defects from firing it, yet?

[TPM001]

Some initial observations:

1) the aluminum nozzle and steel bolt carrier combo is heavy and shows in the noticeably slower rate of fire.

2) aluminum nozzle fits well in the stock aluminum carrier ( with the steel guides). In fact, the nozzle moves more freely in there. I much prefer the overall performance in the stock aluminum carrier.

3) Clockwise turn of NPAS = more fps

4) don't open NPAS too wide (i.e dont turn all the way clockwise) or function will be impeded. Remember, gas must be able to flow behind the NPAS valve.

5) there appears to be a sweet spot for the NPAS where you can achieve very stable results. Mine is where it's set at 385 fps with .25g BBs. More testing needed tho.

6) aluminum nozzle works well in the M4 CQBR. Works really well in the 416.


I still need to fine tune the nozzle. I still must achieve my objectives of stable 360 fps on .20 and 400 fps on .20.

[SHaKaL]

Thanks TPM001

[Stealthee]

Thanks for your report.

[TPM001]

As suspected, the NPAS in the nozzle is very different from that of the regular open bolt design.



Here's a closer look:



The part on the right (the tail) controls the fps. The part on the left (the head) is free floating and held in place by a spring.

At rest, both the head and tail parts "mesh" together allowing gas to flow both toward the front of the nozzle and also to the rear of the nozzle. The gas pressure building at the rear pushes the head forward against the spring until it goes so far as to "seal" the front of the nozzle thus stopping all gas flow to the front of the nozzle. All gas now flows to the rear of the nozzle and into the bolt carrier which moves back past the trigger assembly and disengaging the firing pin, stopping the gas flow.

The more you open the NPAS on the tail part (ie counter clockwise turn), the further forward you push the head in the nozzle. FPS is reduced because it will take less time for the head to seal the front of the nozzle and stop the gas flow towards there. Less gas flow = lower fps.

Now the problem with this design is that it is possible for the head to misalign with the tail as it returns back to rest position. If that happens, the head would be too far forward and your next shot would have significantly lower fps, until it is realigned again.

[TPM001]

That said, this misalignment doesn't appear to happen often and I am happy to report a very positive experience with the aluminum nozzle. My shots are very consistent (9 shots out of 10). Definitely a keeper.

[TPM001]

I guess theoretically, we can replace the head piece with the regular NPAS valve. The principle should be the same, as long as you open up the tail piece such that some gas pressure is allowed to build up behind the NPAS valve. This all assumes, of course, that the regular NPAS valve actually fits inside the aluminum nozzle.

I'll give it a try and report back.

[Basic-Wedge]

Keep up the good work. It seems like you'll have this all sorted out by the time I get mine.

[TPM001]

Ok. I confirm that the regular NPAS unit doesn't fit inside the nozzle. Too big. Looks like we're stuck with this design, for better or for worse.

Someday I might think about cutting off the prongs on the head piece. They only exist to aid with the NPAS adjustment (without needing to jam a screwdriver inside the valve opening). But for now, I'll live with the design.

[turok_t]

Originally Posted by TPM001

Ok. I confirm that the regular NPAS unit doesn't fit inside the nozzle. Too big. Looks like we're stuck with this design, for better or for worse.

Someday I might think about cutting off the prongs on the head piece. They only exist to aid with the NPAS adjustment (without needing to jam a screwdriver inside the valve opening). But for now, I'll live with the design.

Ill see if I can come up with a solution/a mod for the old npas to be installed in the new nozzle....ive got a lot more nozzles coming in.