Bore-up/PSG tightbore/barrel suck

Ok, so Im playing with the idea of increasing the inner barrel of my SR16
IMHO, the SR16 seems unbalanced with the full stock and short front.
so in my head I thought about removing my M4 tightbore and replacing it with a 590mm PSG1 tightbore and adding a 230 to 250mm silencer to the front end.
I know some have done this in the past and wanted to know how it works.

so I belive my M4 inner barrel is 363mm long, so if I get a PSG1 inner barrel, at 590mm, 227mm of the inner barrel should extend out of the gun, toss on a silencer of atleast 230 or higher and I should be fine.

But then there is alot of talk about compression and barrel suck. I heard it suggested that a V2 M4(ported) cylinder cant push enough air for it, and that even a V2 M16(none ported) cylinder cant do it, and that you need a bore up kit. But I dont wanna go insane with fps by using a giant spring to push the bore-up kit(i heard you need around a 190%).

then on WGC I see this

KM - TN Coated Inner Taper Cylinder for Long AEGs For 400mm to 590mm inner barrel

anyone have any info on this product? such as does it work? does it need a new piston head(currently a systema duracon silicone piston head) higher spring?

solutions?

EDIT: Sorry, I didnt realize that Illusion answered that in another thread. thanks

[frag7]

hey, I'm thinking doing exactly the same but I expect my G&P mechbox with systema gears will support the longer barrel . Am I right, or should I stop right now ??

[Jim]

The G&P mechbox and Systema gears is irrelevant. The cylinder is your main concern, if you get a longer barrel you will have get get a proper cylinder to correspond with the longer barrel.

[frag7]

:banghead: that's right, of course :banghead:
Wht can you expect if you don't change the cylinder ? lost of fps only ? How much 5% or 20 ?
What if I change the cylinder then decide to go back with the short barrel ?

thanks

[Jim]

First what gun do you have? and is it the stock barrel lenght?

[frag7]

G&P M4 with stock barrel.
Just an idea to be able to play the "sniper " with my assault rifle, while waiting for my sniper gun.

[mcguyver]

the cylinder in your m4 is the exact same cylinder that's in my spr/a and it lookes alot like the prometheus ones (they use other prometheus parts already). my barrel is m16a3 length and i don't notice much if any performance differences between my spr/a and the m4. the spr may have better accuracy on paper, but in the real world of wind, temperature, terrain and the skills of the shooter, that little bit of accuracy improvement will probably not amount to much. and engagement distances should be a little longer considering the power of these guns and longer distances make for more difficult "sniping" roles even at the best of times and especially with an aeg. you're fieldcraft skills are the best weapon you have. blastyman has the most accurate and effective aeg's ever in is m14 and without his good field skills it wouldn't matter.

[frag7]

So does it mean that with my soon-brand-new mechbox and a longer precision barrel I can play a decent sniper ? My ghuillies are ready and the one for the rifle is in construction :mrgreen:

[mcguyver]

well that's a tough question. i don't know what your experience in airsoft is, but this is mine: being a sniper means you need to inventive, fearless and patient. as engaement distances don't outrange visual distances, it's easy to get spotted and attacked even though you may be approaching the effective range of a single shot or semi-auto gun. the best snipers will go sometimes for hours without any apparent movement and without firing a shot. this is far more patience than i have and my approach is more of the "brute force and overwhelming firepower" and less of precision instrument of battle. an aeg is designed more for the "firepower" end of things where as a high-powered bolt action like the kjw m700 is more a surgical tool. the credo "one shot-one kill" is more appropriate for a "sniper" weapon. an accurate gun that will allow you to indeed get "one shot-one kill" aeg's generally are not. that is reserved, generally, to the m700, m24, type 96 sort of guns. then comes the field skills, things like intuition about an enemy's potential movements and making sure you're in position to effectively strike, the ability to conceal yourself and move with good noise discipline and stealth to track and stalk your enemy. it all seems like more of a "lifestyle" choice for airsoft, but if you're good, you can be a very effective weapon. i've played against very good snipers and very nearly stepped on one he was so good at concealment. but he used a stock vsr-10 so his effectiveness was totally ruined by poor weapon choice. some guys may say a very good and powerful aeg will make a good sniper weapon, but i have my doubts. accuracy and power (500 fps minimum) are THE most important attributes to a sniper weapon and aeg's usually lack severely in both categories. but this is only my opinion based on my experinces and the fields we play on. others may have different scenarios and ideas that may be very effective for them.

[frag7]

I'm not afraid of the tactical side of playing "sniper" : that's my way of fun :mrgreen: I'm just concern by the technical part. My mechbox is on surgery by now, so it's a good time to change the cylinder if neccessary.

Anyway I outrange everybody on the field so I think it's a decent base, I just want a longer barrel to gain a little accuracy and range. And one day, maybe, I'll go with a M700 Takedown :shock:

[ILLusion]

Originally Posted by Droc

Ok, so Im playing with the idea of increasing the inner barrel of my SR16
IMHO, the SR16 seems unbalanced with the full stock and short front.
so in my head I thought about removing my M4 tightbore and replacing it with a 590mm PSG1 tightbore and adding a 230 to 250mm silencer to the front end.
I know some have done this in the past and wanted to know how it works.

so I belive my M4 inner barrel is 363mm long, so if I get a PSG1 inner barrel, at 590mm, 227mm of the inner barrel should extend out of the gun, toss on a silencer of atleast 230 or higher and I should be fine.

But then there is alot of talk about compression and barrel suck. I heard it suggested that a V2 M4(ported) cylinder cant push enough air for it, and that even a V2 M16(none ported) cylinder cant do it, and that you need a bore up kit. But I dont wanna go insane with fps by using a giant spring to push the bore-up kit(i heard you need around a 190%).

then on WGC I see this

KM - TN Coated Inner Taper Cylinder for Long AEGs For 400mm to 590mm inner barrel

anyone have any info on this product? such as does it work? does it need a new piston head(currently a systema duracon silicone piston head) higher spring?

solutions?

EDIT: Sorry, I didnt realize that Illusion answered that in another thread. thanks

Your first assumption is correct in that you won't need a bore-up kit with heavy spring - ASSUMING: that you are upgrading for a 590mm PSG-1 inner barrel.

There is also a 650mm PSG-1 inner barrel for PSG-1's with internal silencer. THIS is the inner barrel that will give you greater upgrading headaches.


I used that exact cylinder that you show up there in my SPR mk12 mod1 which has a 590mm Prometheus 6.03mm tightbore.

It's shooting 420fps, which is pretty much the same as when I was using that same cylinder with a 6.03mm 509mm inner barrel. Full auto tests through the chrony show no variation in velocity.

Originally Posted by frag7

hey, I'm thinking doing exactly the same but I expect my G&P mechbox with systema gears will support the longer barrel . Am I right, or should I stop right now ??

As long as your mechbox can support the cylinder (and the G&P one does), then yes, you can do the same modification.

Originally Posted by frag7

:banghead: that's right, of course :banghead:
Wht can you expect if you don't change the cylinder ? lost of fps only ? How much 5% or 20 ?

That depends on what spring you have in there as well as what cylinder you have in there now.

Originally Posted by frag7

What if I change the cylinder then decide to go back with the short barrel ?

I suggest you read the thread in the general forum regarding matching cylinders with inner barrels:
http://www.airsoftcanada.com/showthread.php?t=20534

To sum it up, your velocity won't be as high as if you had a matched cylinder, and to add to that, you'll be adding more impact stress to your gearbox. Although the G&P gearbox is supposedly a "reinforced" gearbox (compared to stock Marui), it's still a v2 gearbox which is poorly designed. It can still crack under heavy stress and in certain conditions.

Originally Posted by mcguyver

the cylinder in your m4 is the exact same cylinder that's in my spr/a and it lookes alot like the prometheus ones (they use other prometheus parts already). my barrel is m16a3 length and i don't notice much if any performance differences between my spr/a and the m4.

Unfortunately, the Prometheus cylinders are only rated up to 550mm length inner barrels, ie, Sig550, the longest Marui AEG inner barrel available with "standard" cylinder length (standard meaning v2, 3 & 6 gearbox).

A different cylinder will be required to go to 590mm, which is what this discussion is about.

[Blastyman]

btw I am using a 590mm barrel with a m4 cylinder and so far I haven't noticed many issues. Thing chrono's about 420 on semi or full auto.

Though I do have a full cylinder I plan on putting in next time I have the gun apart.