More FPS out of WE SCAR (Open Bolt)

Fox62 · July 30th, 2011, 17:02

As I said on other posts, I'm at about 470 FPS (2.05 joule) on my SCAR DMR, my goal being 500. I stopped using my NPAS, since I get more FPS out of the stock valve (I thought I might actually need the NPAS to lower from 500 and something after all the upgrades...wrong). I currently have a 440mm/6.01 precision inner, Falcon hop up rubber, the hopup and inner are tightly sealed with teflon tape. I tried changing the floating valve spring for a heavier one (the one which comes with the Dyna Piston Head set), and while it obviously reduced the efficiency of the mags since it was releasing a lot more gas (my CO2 mags didn't even work - they died after two or three shots, the gas one was about 1/3 as efficient), it didn't do anything for FPS, if anything, it lowered them. What was more strange is that I saw a lot of gas physically come out of the front of the gun with this spring (which doesn't happen with the other), so it would appear that there's a lot more gas being sent to the BB, but it goes to waste, and the BB is propelled before this extra gas can have any effect or something like that. I can't really think of another way of explaining it, because there IS more gas being sent, it's just not being used to propell the BB.
Any ideas on what's going on with the stronger spring? Another way I haven't thought of of getting it shooting faster?

Thanks, Fox.

Ross · August 10th, 2011, 15:11

Huh. I thought falcon only made hop ups for the closed bolt system. I have heard of some people using propylene in their gas guns to increase fps. I have also heard from them that it puts more pressure on the square mag gaskets. Which makes the mag more prone to leaking. This guy uses propylene. ‪RA-Tech WE M14 Airsoft Gun Details Section8 Scotland‬&rlm; - YouTube

If you want the gun to cycle faster, you can add washers to the recoil spring. That should send the bolt back faster. Not too much strength though, or you'll lose the bolt catch function. You can also make sure that your bolt and bolt carrier is greased up properly to reduce drag.

Can you tell me how you sealed your hop up with Teflon tape? Would that increase the pressure or something?

Fox62 · August 10th, 2011, 18:24

Quote:

Originally Posted by Ross

Huh. I thought falcon only made hop ups for the closed bolt system. I have heard of some people using propylene in their gas guns to increase fps. I have also heard from them that it puts more pressure on the square mag gaskets. Which makes the mag more prone to leaking. This guy uses propylene. ‪RA-Tech WE M14 Airsoft Gun Details Section8 Scotland‬&rlm; - YouTube

If you want the gun to cycle faster, you can add washers to the recoil spring. That should send the bolt back faster. Not too much strength though, or you'll lose the bolt catch function. You can also make sure that your bolt and bolt carrier is greased up properly to reduce drag.

Can you tell me how you sealed your hop up with Teflon tape? Would that increase the pressure or something?

LOL, yeah, I've used propylene. The FPS sky rocketed, but the gas mag would work like ****.
No, Falcon makes an (awesome) hop up bucking for the open bolt system, and in a couple of weeks I should have the field results I've been really waiting for.
Teflon tape should stop any kind of gas escape between the bucking and the inner barrel; many snipers and DMRs I know have done it to maximize efficiency and make it less prone to leaking in the future. The teflon should be applied to tie the bucking and inner together, at the end of the bucking, as if it were regular tape glueing the parts together.

Fox.

PugsleyAdams · August 10th, 2011, 18:38

You're trying to get 500fps using what weight of bb? With my closed bolt scar using .25's I get around 450fps with the stock valve which works out to around 500fps with .20's!

Fox62 · August 10th, 2011, 18:59

Quote:

Originally Posted by PugsleyAdams

You're trying to get 500fps using what weight of bb? With my closed bolt scar using .25's I get around 450fps with the stock valve which works out to around 500fps with .20's!

I know, and that's what I'm trying to get. But I'm at about 425-30 with .25, and that's tops. So I'm 30 FPS off the mark. And again, we're talking tops, I wish I was a bit over 500 to have that headroom. I just replaced the whole bolt with a brand new one for testing purposes, got to chrono still, but I'm not expecting a huge difference.

Fox.

PugsleyAdams · August 10th, 2011, 19:27

I forgot to say that my entire scar is stock and I'm getting the fps you want, maybe I just got lucky....or unlucky(according to everyone I shoot with it) depending on which end your on! If you have a longer inner barrel (than the stock inner) then maybe your hop-up is pushing down on the bb too much and that's why the fps is a bit low. You have almost twice as long as my inner so you should be getting a bit more you'd think!

Ross · August 10th, 2011, 21:04

I get 435 on .25s. Not sure what that converts to for .20

Thanks for the info fox. When you say the gas mag would work like shit, what do you mean? Like it runs out fast?

I used the npas to turn it down a bit so I can keep full auto on. At 400 fps I get about 200 foot range. I don't think I want anything better than that. So would you say your aftermarket hop up is better than the regular open bolt one? I noticed my hop up is decent, but it likes to lower or raise itself magically.

The Chad · August 10th, 2011, 21:07

Just my opinion but I suggest a hole about 4 inches from the end of the inner barrel. 1/16" bit. Make sure to bevel the inside of the hole and the inside of the end of the inner barrel.

Ross · August 10th, 2011, 21:15

what would a hole do mr chad?

The Chad · August 10th, 2011, 21:25

nvm the BBs are too light for what I was thinking about. Apologies.

Fox62 · August 10th, 2011, 21:31

See, Ross is on the same page as me. That's the FPS I'm getting, and he's got a longer barrel as well. Very strange.
Yeah, the speed was insane (I didn't have the chrono that day - I was out of gas and someone gave me some propylene they had, it was an unregulated game, anyway), but the speed was noticeably (visibly) a lot faster, ballpark 600-650 FPS, possibly more. But the mags would die on the fifth-seventh shot, and we tried charging them for different durations; sometimes they would die on the first shot. The cooldowns were pretty big as well. As for Daedalus using it, meh, what does a guy who lets Ra-Tech do the upgrades for him know

.
200 feet on .25? That's pretty nice. I'll be shooting with .36's and am aiming for 260, but I doubt I'll get at it, that's why I'm trying to squeeze up to the last FPS.
My hop up (bucking/rubber) is harder, and better suited for heavier BBs, .25's will just fly off into the sky, even at low settings, I get a lot more adjustment range using the 0.36's.

Fox.

ThunderCactus · August 11th, 2011, 04:15

It's a gas gun. Just use heavier ammo to get more FPS.
My WE PDW shoots 380fps on .20s, but when I use .28s it shoots the equivalent of 420fps on .20s.

Fox62 · August 11th, 2011, 10:55

Quote:

Originally Posted by ThunderCactus

It's a gas gun. Just use heavier ammo to get more FPS.
My WE PDW shoots 380fps on .20s, but when I use .28s it shoots the equivalent of 420fps on .20s.

That's very interesting. Why does it work like that?
It would also make chroning with 0.20's to know in which category you are (mandatory) pretty dumb, at least in regards to gas guns.

Fox.

t0aDe · August 11th, 2011, 11:19

Quote:

Originally Posted by Ross

I get 435 on .25s. Not sure what that converts to for .20

Thanks for the info fox. When you say the gas mag would work like shit, what do you mean? Like it runs out fast?

I used the npas to turn it down a bit so I can keep full auto on. At 400 fps I get about 200 foot range. I don't think I want anything better than that. So would you say your aftermarket hop up is better than the regular open bolt one? I noticed my hop up is decent, but it likes to lower or raise itself magically.

Here is a handy (hopefully) energy chart my friend!
http://img407.imageshack.us/img407/4...ctenergyta.jpg

ThunderCactus · August 11th, 2011, 14:51

Heavier BB's take longer to accelerate, so more gas pressure builds up behind it.

Gas guns create unique problems for chrono because of this, so they have to be chrono'd on the ammo they're going to use and that number converted to a joule rating or equivalent FPS of a .20
Gas guns also shoot way harder as the ambient temperature rises, so they need to be spot checked with a chrono as well.

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July 30th, 2011, 17:02	#1
Fox62 Banned Trader rating Join Date: Jun 2011 Location: Buenos Aires, Argentina	More FPS out of WE SCAR (Open Bolt) As I said on other posts, I'm at about 470 FPS (2.05 joule) on my SCAR DMR, my goal being 500. I stopped using my NPAS, since I get more FPS out of the stock valve (I thought I might actually need the NPAS to lower from 500 and something after all the upgrades...wrong). I currently have a 440mm/6.01 precision inner, Falcon hop up rubber, the hopup and inner are tightly sealed with teflon tape. I tried changing the floating valve spring for a heavier one (the one which comes with the Dyna Piston Head set), and while it obviously reduced the efficiency of the mags since it was releasing a lot more gas (my CO2 mags didn't even work - they died after two or three shots, the gas one was about 1/3 as efficient), it didn't do anything for FPS, if anything, it lowered them. What was more strange is that I saw a lot of gas physically come out of the front of the gun with this spring (which doesn't happen with the other), so it would appear that there's a lot more gas being sent to the BB, but it goes to waste, and the BB is propelled before this extra gas can have any effect or something like that. I can't really think of another way of explaining it, because there IS more gas being sent, it's just not being used to propell the BB. Any ideas on what's going on with the stronger spring? Another way I haven't thought of of getting it shooting faster? Thanks, Fox. Last edited by Fox62; July 30th, 2011 at 19:02..

August 10th, 2011, 15:11	#2
Ross Trader rating Join Date: Nov 2009 Location: Winnipeg	Huh. I thought falcon only made hop ups for the closed bolt system. I have heard of some people using propylene in their gas guns to increase fps. I have also heard from them that it puts more pressure on the square mag gaskets. Which makes the mag more prone to leaking. This guy uses propylene. ‪RA-Tech WE M14 Airsoft Gun Details Section8 Scotland‬&rlm; - YouTube If you want the gun to cycle faster, you can add washers to the recoil spring. That should send the bolt back faster. Not too much strength though, or you'll lose the bolt catch function. You can also make sure that your bolt and bolt carrier is greased up properly to reduce drag. Can you tell me how you sealed your hop up with Teflon tape? Would that increase the pressure or something? __________________

August 10th, 2011, 21:04	#7
Ross Trader rating Join Date: Nov 2009 Location: Winnipeg	I get 435 on .25s. Not sure what that converts to for .20 Thanks for the info fox. When you say the gas mag would work like shit, what do you mean? Like it runs out fast? I used the npas to turn it down a bit so I can keep full auto on. At 400 fps I get about 200 foot range. I don't think I want anything better than that. So would you say your aftermarket hop up is better than the regular open bolt one? I noticed my hop up is decent, but it likes to lower or raise itself magically. __________________

August 10th, 2011, 18:38	#4
PugsleyAdams Trader rating Join Date: Nov 2009 Location: St. Catharines, Ontario	You're trying to get 500fps using what weight of bb? With my closed bolt scar using .25's I get around 450fps with the stock valve which works out to around 500fps with .20's!

August 10th, 2011, 19:27	#6
PugsleyAdams Trader rating Join Date: Nov 2009 Location: St. Catharines, Ontario	I forgot to say that my entire scar is stock and I'm getting the fps you want, maybe I just got lucky....or unlucky(according to everyone I shoot with it) depending on which end your on! If you have a longer inner barrel (than the stock inner) then maybe your hop-up is pushing down on the bb too much and that's why the fps is a bit low. You have almost twice as long as my inner so you should be getting a bit more you'd think!

August 10th, 2011, 21:07	#8
The Chad formerly LoveMyStubby Trader rating Join Date: Dec 2008 Location: SW ON	Just my opinion but I suggest a hole about 4 inches from the end of the inner barrel. 1/16" bit. Make sure to bevel the inside of the hole and the inside of the end of the inner barrel.

August 10th, 2011, 21:15	#9
Ross Trader rating Join Date: Nov 2009 Location: Winnipeg	what would a hole do mr chad? __________________

August 10th, 2011, 21:25	#10
The Chad formerly LoveMyStubby Trader rating Join Date: Dec 2008 Location: SW ON	nvm the BBs are too light for what I was thinking about. Apologies.

August 10th, 2011, 21:31	#11
Fox62 Banned Trader rating Join Date: Jun 2011 Location: Buenos Aires, Argentina	See, Ross is on the same page as me. That's the FPS I'm getting, and he's got a longer barrel as well. Very strange. Yeah, the speed was insane (I didn't have the chrono that day - I was out of gas and someone gave me some propylene they had, it was an unregulated game, anyway), but the speed was noticeably (visibly) a lot faster, ballpark 600-650 FPS, possibly more. But the mags would die on the fifth-seventh shot, and we tried charging them for different durations; sometimes they would die on the first shot. The cooldowns were pretty big as well. As for Daedalus using it, meh, what does a guy who lets Ra-Tech do the upgrades for him know . 200 feet on .25? That's pretty nice. I'll be shooting with .36's and am aiming for 260, but I doubt I'll get at it, that's why I'm trying to squeeze up to the last FPS. My hop up (bucking/rubber) is harder, and better suited for heavier BBs, .25's will just fly off into the sky, even at low settings, I get a lot more adjustment range using the 0.36's. Fox. Last edited by Fox62; August 10th, 2011 at 21:34..

August 11th, 2011, 04:15	#12
ThunderCactus Not Eye Safe, Pretty Boy Maximus on the field take his picture! Trader rating Join Date: Feb 2007	It's a gas gun. Just use heavier ammo to get more FPS. My WE PDW shoots 380fps on .20s, but when I use .28s it shoots the equivalent of 420fps on .20s.

August 11th, 2011, 14:51	#15
ThunderCactus Not Eye Safe, Pretty Boy Maximus on the field take his picture! Trader rating Join Date: Feb 2007	Heavier BB's take longer to accelerate, so more gas pressure builds up behind it. Gas guns create unique problems for chrono because of this, so they have to be chrono'd on the ammo they're going to use and that number converted to a joule rating or equivalent FPS of a .20 Gas guns also shoot way harder as the ambient temperature rises, so they need to be spot checked with a chrono as well.

More FPS out of WE SCAR (Open Bolt)

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