Widebore Barrels and FPS

[TheGrover]

Hey guys,

 

im looking to get an aftermarket barrel for my G5, and rather than buying a tightbore and pushing my FPS up, i would rather get a widebore like an Orga Magnus and just extend it into a suppressor.

 

is there any guide anywhere that outlines what kind of effect that a tighter/wider or shorter/longer barrel has on FPS? as i really want to keep my muzzle velocity where it is comfortably below site limits

 

Thanks chaps

[sp00n]

you would not believe how easy and hard is is to answer this lol

 

firstly lets make the assumption that you pistons cylinder is correctly ported for every length you use

 

generally as a rule of thumb longer barrels will increase you FPS (upto around the 500mm long mark on a v2 AEG) but not by massive amounts

a shorter barrel will reduce your fps ... but not by much

 

a tighter bore barrel will increase you fps, but not by as much as longer barrel

a wider bore *may* reduce your FPS, but not by a lot

 

the other thing to bear in mind this isnt an exact science, some people may get a + or - 50fps with the longer barrel, some may see a far less or no difference at all.

similarly a tight bore can give 30fps extra or none at all

 

i hope this helps some.

 

(on a side note i dislike tight bores totally, as my 1 encounter, well it had me buying a stock barrel!)

[ImTriggerHappy]

Hey guys,

 

im looking to get an aftermarket barrel for my G5, and rather than buying a tightbore and pushing my FPS up, i would rather get a widebore like an Orga Magnus and just extend it into a suppressor.

 

is there any guide anywhere that outlines what kind of effect that a tighter/wider or shorter/longer barrel has on FPS? as i really want to keep my muzzle velocity where it is comfortably below site limits

 

Thanks chaps

I have one a 6.23 and its great but it will seriously lower your fps. Be prepared to drop a new spring in at least. Other option is to look at P.D.I 6.05 and 6.08 barrels they wont mess with fps but will improve consistency.

[proffrink]

ITT: People not checking which subforum they're in.

 

With a 6.23 you can expect a 10-20fps decrease. Extending the barrel won't get you that much. Thankfully with GBBs there isn't the problem of having to make sure your cylinder is up to the task, but I would say that with the GHK G5 kicking out only 300fps bringing that down to 280 might not be the best idea.

 

I'd probably go for the tightbore if I were in your shoes. If you were around the 350 mark then I might say otherwise. A well manufactured tightbore will still give you an increase in accuracy (as well as the usual FPS bump) over many stock barrels, but the GHK ones are actually alright to start with.

 

I suppose a lot of this depends on the gas you're using too - Guarder powerful might give you 330-340, but if you're using Nuprol or some other green gas then you're likely hitting 300-310. Do you have a chronograph?

 

Edit:

Just to answer the whole question: Yes, a longer barrel will improve FPS too, but I don't have the knowledge to tell you whether a longer wide bore will stay at around about the same. My thought is that it would likely be a negligible - 5-10fps - drop, but again, I'd say if we're operating around the lower 300s then a tight bore barrel is going to give you that FPS kick and a bit more range (as well as marginally improved accuracy over the stock barrel).

[Spatch]

I take it none of you have taken reference to the rifle named in the original post, G5? That would be gas, not an aeg

 

Wide bores work very well in gas rifles, orga Magnus has been proven to be excellent in a G5

[ImTriggerHappy]

I take it none of you have taken reference to the rifle named in the original post, G5? That would be gas, not an aeg

 

Wide bores work very well in gas rifles, orga Magnus has been proven to be excellent in a G5

Good point didn't check. Go for the widebore. They are good in aeg's as well but take some work to get right I lost over 40 fps with mine compared to a stock barrel which is why I think PDI barrels are better in general for aeg's.

[TheGrover]

well the best Orga i can find is 260mm, 55mm longer than the stock barrel (dunno if its a 6.03 or a 6.08 or somewhere in between, though the DMR kit for the gun comes with a 6.03)

 

with an extra 55mm (which is over 20% of the stock barrel, i was hoping that the increased length would cancel out the loss in FPS due to the wider bore.

 

and since its GBB, i dont have to worry about cylinders or springs, just how the floating valve behaves in the nozzle.

 

if it turns out to produce less than 300fps, ill probably have to invest in either a high-energy nozzle to bring the power up, or an adjustable one, though i believe that the adjustable one may have issues, as i cannot find a single review for it and i dont know if the gun's cycling will move the setting over time

[Spatch]

The 'adjustable' nozzle is made by a French guy in a shed and is basically the standard nozzle with a screw in the side of it, not a huge upgrade, it's for bringing the fps down rather than raising it

[proffrink]

well the best Orga i can find is 260mm, 55mm longer than the stock barrel (dunno if its a 6.03 or a 6.08 or somewhere in between, though the DMR kit for the gun comes with a 6.03)

 

-snip-

If all else fails, try the Delta Strike barrels. I've had good experiences with them, and at 6.20 they certainly have a wide enough bore. They're also more readily accessible in the UK at different lengths. The only thing is the window is built for longer, flat hops (R-Hops primarily) so it might not be suitable.

[TheGrover]

ok, so ive fitted my WBB and just tried the high power nozzle for the G5 to see if i can bring the FPS back up. here are the muzzle velocities for different setups:

 

Stock barrel, stock nozzle - approx 290 FPS w/ 0.25g BB

WBB, Stock nozzle - approx 245 FPS w/ 0.25g BB

WBB, High power Nozzle - Approx 360FPS w/ 0.25g BB

WBB, High power nozzle and 144a gas - Approx 330 FPS w/ 0.25g BB

 

Clearly, the high power nozzle is too much for me. i tried it hoping for an extra 50FPS and i got an extra 100

 

Now ill have to swap the nozzles back and find another way of getting the FPS back to something sensible.., maybe joule creep will bring the FPS of 0.30s to something preferrable? time to get the tools out again!

 

EDIT:

 

Okay, swapping back to the Standard Nozzle gives me approx 260 FPS with 0.30s, only 20FPS under my calculated site limit of 350FPS with 0.20G BBs. i guess taking it apart and giving it some love found a little more power somewhere... does anyone wanna buy a high power nozzle for a G5?

[TheGrover]

okay, so ive just brought the chrono out again to do some testing. Im using Colemans propanein my room, its pretty warm inside, i guess a little over 20 degrees, adn my fps with a 0.3G bb is about 300 FPS at the start of the magazine (~15fps over the site limit for this weight) and by the end of the mag, its dropped to around 250 FPS (~35 FPS below the site limit). Im using the standard nozzle and widebore barrel, which in the past resulted in an FPS of around 245 on 0.25g BBs.

 

my question is: did i put the nozzle/bolt assembly back together well enough that the FPS has increased? i certainly lubed the hell out of the double O rings on the nozzle.

 

And: Will the FPS come down after a few hundred rounds anyway?

 

Im gonna put a couple hundred rounds through anyway just to see if it settles down, otherwise ill have to crack it again and do a little bit of subtle sabotage to reduce my FPS so that its under the limit at the START of the mag

 

Thanks guys

 

EDIT: Answered my own question, FPS is down to 20FPS below the limit

 

Job well done, now time for a celebratory skirmish...