Typical FPS Increase From Tight Bore Barrels - ?

[Uncle Pauly]

(Posting this in the Gas Guns forum as it's specific to GBBs...)

I'm thinking of fitting a Prometheus tight bore barrel to my Tokyo Marui MWS. Specifically, I'll be replacing the stock barrel - which I think is 6.08mm diameter - with one measuring 6.03mm diameter (barrel length will remain unchanged at 250mm).

I'm aware that the tighter bore will increase FPS, but I'm struggling to find any information about how much the FPS increase is likely to be. Anyone got any experience of this that they'd be able to share?

PS: I don't have access to a chronograph at home and am too tight-fisted to spend £50 just for the sake of testing this

Cheers for any input.

 

[P4radox]

Just arrived my maple leaf czjet 6.04x250mm barrel the increase was around 15fps on 0.3g (302/317fps)!

But the TM inner barrels are beat down the most of the

wonder-barrels (I just changed because I use ML buckings which are more compatible with the same brand at the barrel mouth), though Ive already tried that Promi/laylax 250x6.03mm on my previous mws really good quality but hadnt seen the big magic (same shaped barrel mouth as on the TM one) !

I hope its gonna serves you!

 

[Uncle Pauly]

Just arrived my maple leaf czjet 6.04x250mm barrel the increase was around 15fps on 0.3g (302/317fps)!

Thanks for the input! Yeah, the Prometheus barrel I have seems to be a drop-in replacement for the original Marui one - the bucking fits the barrel mouth no problem.
 

15fps increase would be fine in my situation, so I’m hoping the new 6.03mm barrel produces a similar result ?

 

[AlphaBear]

Just arrived my maple leaf czjet 6.04x250mm barrel the increase was around 15fps on 0.3g (302/317fps)!

But the TM inner barrels are beat down the most of the

wonder-barrels (I just changed because I use ML buckings which are more compatible with the same brand at the barrel mouth), though Ive already tried that Promi/laylax 250x6.03mm on my previous mws really good quality but hadnt seen the big magic (same shaped barrel mouth as on the TM one) !

I hope its gonna serves you!

Hey P4radox, You're get 317 fps using a 0.3g bb with just a barrel upgrade?

 

[P4radox]

Hey P4radox, You're get 317 fps using a 0.3g bb with just a barrel upgrade?

Yes ,thats happened!

But I use AngryGun mpa nozzle ,so I just turned back under the limit!

View attachment 62531

View attachment 62532

 

[P4radox]

Thanks for the input! Yeah, the Prometheus barrel I have seems to be a drop-in replacement for the original Marui one - the bucking fits the barrel mouth no problem.
 

15fps increase would be fine in my situation, so I’m hoping the new 6.03mm barrel produces a similar result ?

Yes ,but that means around 380-390fps/0.20g/on propane without npas!

 

[Uncle Pauly]

Yes ,but that means around 380-390fps/0.20g/on propane without npas!

Holy crap! Yeah, I read that wrong ?

So you got the equivalent of +50-60 fps from just switching to a 6.04 bore barrel? Wow. I had no idea it could have such a difference.

I’ve since bought a chronograph (arriving this week), so I’ll report back on the Prometheus 6.03 barrel once I’ve had chance to test it.

 

[Uncle Pauly]

A quick update…

I’ve now tested and chrono'd two Prometheus tight bore barrels in my MWS: one measuring 250mm and another longer at 370mm (both 6.03mm bore).

Set up: Abbey Predator gas; SixG Super Nub; standard MWS bucking; 0.2 BBs.

• Short barrel: MWS shoots at average velocity of around 300-310 fps (0.2 BBs)
  
• Longer barrel: average velocity is around 315-330 fps (0.2 BBs)
  

Less ‘oomph’ that I anticipated, but that’s all good as I was hoping to remain site safe (<350 fps). The Prommy marketing blurb mentions that users can expect around 10 fps boost, and my results seem broadly consistent with that.

Accuracy seems great, or rather, no change from the stock MWS magic (6.08mm bore barrel, I think). Still able to hit a head-sized target at around 30-40m with good consistency when shooting 0.32 BBs. Have yet to test it out at longer ranges.

TL/DR: based on my own experience, the Prommy 6.03mm barrels seem to give a nice boost of 10-20 ‘free’ fps with no apparent loss of accuracy. Worth it for the money? Probably not… but that’s airsoft all over, right? ?