Tbb; FPS Changes (Seeking Advice Specifically From TM Scar Owners)

[THE FNG]

Hi all,

 

So I've been on a bit of a research and fps boost mission lately.

I've been looking at my array of Rifs on my rack and looking at giving a few a slight fps boost BUT they are all Marui and I dont want to open the gearboxes and let out the fabled marui magic dust.

 

Project A: TM high cycle Aug

I got a stock aug in a trade and it was firing around 250-260 fps. 

I have swapped out the stock barrel for a zci 6.02 340mm barrel and a maple leaf rubber and omega nub and seen an increase up to 295-300 fps! Much better and no extra stress on the gearbox as I beleive it falls within the cylinder volume ratio.

 

Project B: Scar H

I have a Laylax (Prommy) 6.03 363mm barrel and hitting 302 fps on the dot almost every shot.

My query: I put this barrel in before I knew that different cylinders had different ports and therefore effects on barrels. Would this length be ok based on the stock marui cylinder or would it be detrimental?

 

Project C : Scar L

Completely stock.

I have a 6.03 300mm madbull tbb lying around to play with and was debating whether it was worth trying this for a night fps boost to 300+

 

Project D : 416

I had a stock tm 416 with a stock tm 363mm barrel that was initially a placeholder (I beleive it was that length) that I sent to firesupport for a fix (bolt release had stopped and trigger contacts were worn) and service. I asked whilst they had the gearbox open to see what the fps was and to try to get the fps to around 335. 

It came back to me and I did a quick chrono and it was 335 on the dot for about 5 or 6 shots.

I have since re chronod today and to my surprise, hit around 10 shots at 335, then dropped to a 300 fps shot, then a few more at 335, then hit a 351 shot, then generally settled around the 335-345 mark with the occasional stray.

I put the augs stock 260(?)mm barrel and added a slight amount of hop tension; it settled around the 330-340 mark.

 I belive that the hop rubber may have been slightly off centre causing some fps fluctuations. I will be changing the hop rubber for a maple leaf as I think the stock rubber is also slightly worn and flayed at the barrel end.

I need to spend an afternoon playing with the hop rubber and barrel to see if it is hop/seal issues that's giving such a fluctuation. 

Of note; fire support had left the new springs wrapper I'm the box and I'm sure it was an m110 which I thought was too hot for 350 fps limits, bit it could have just been any wrapper used to wrap up the old spring.

 

 

My ultimate question;

What barrels (length and diameter) would people recommend for the Scars to get me at a good 300+ fps that wouldnt add stress to the gearboxes?

It's a hard science to nail down "what am bestest gun barrel for bestest fps" due to so many factors. I'm just trying to get a good list of peoples experiences that I can use to help make some decisions with.

 

I'm sorry if it's a very nooby question; i confess to being a bit of a tech divvy and i struggle with numbers!!

 

Tl;dr tm ngrs scar users; what tbb have you switched to and what fps differences have you seen?

 

[Adolf Hamster]

i've never attributed a notable fps change on an aeg from just the barrel itself, at least assuming that they're decent barrels in good clean condition and aren't damaged.

 

i'd say its more likely what you're seeing is an improvement of air seal, either via changing the hop rubber, reseating everything during the swap, or the aftermarket barrels pushing the feedlips slightly back against the nozzle.

 

in terms of voluming, aeg's tend to have a bit of lee-way, funny me and duck were discussing this in another thread recently.

 

if you're for buying a new barrel to change, i'd say stick to the original length (or at least as close as you can get). the ZCI 6.02 stainless barrels are pretty damn good performers for the price, although for the premium end i'm still a sucker for a pdi 6.01.

[Misery]

@Adolf Hamster check negs latest video on facebook bud

[Adolf Hamster]

18 minutes ago, miserydrift said:

@Adolf Hamster check negs latest video on facebook bud

 

see the part of my post saying "assuming it's a decent barrel"

 

it's the sad truth of this hobby that even branded parts can be pretty terrible *cough*madbull*cough*

 

 

[Misery]

[THE FNG]

1 hour ago, Adolf Hamster said:

i've never attributed a notable fps change on an aeg from just the barrel itself, at least assuming that they're decent barrels in good clean condition and aren't damaged.

 

 

in terms of voluming, aeg's tend to have a bit of lee-way, funny me and duck were discussing this in another thread recently.

 

I've seen some interesting results with inner barrels.

First time I saw fps change was with a classic army ump.45; I swapped the stock 200mm inner barrel for a 363 6.03 madbull barrel. It went from 325 fps to 375! 50 fps increase.

 

My scar H went up 5 or 10 with a barrel length Increase up to 363mm with the prommy/laylax. 

 

Aug has had a 30 fps increase with a 100mm+ increase.

 

I put the same madbull 363mm in a cyma p90 and that went up around 30 fps+ iirc.