Wide Bore Barrels on VSRs and Gbbrs

[kojak]

Here's the FPS data from my M4 AEGs; both have notched cylinders (65mm unported length), all testing done with .32g BBs:

 

Wide bore barrel: 6.23x260mm

Tight bore barrel: 6.03x300mm

 

High power/wide bore: 330 FPS (1.61J) 

High power/tight bore:  377 FPS (2.10J)

Low power/wide bore:  269 FPS (1.07J)

Low power/tight bore:  317 FPS (1.49J) 

 

On a more subjective note, while the 6.23 barrel does shoot tighter groups it's not necessarily worth the overpowered gearbox with all its drawbacks; hopup tricks have a much greater and more and cost effective benefit.  

[3vi1-D4n]

At what range, how much tighter is the group?

[renegadecow]

Thanks! Power reduction does seem drastic and as you said, on an AEG it would mean having to stress out the gearbox more for less muzzle energy. Makes me doubt in applying it to a VSR then, but looks very much promising on my GBB AK. It won't mean having to put more strain and I'm using a restricted nozzle now for cqb which can be adjusted to compensate for the energy loss.

 

edit:

Forgot to ask what hop up you have on both uppers. Asking for hard range data might be too much but if your two uppers have different hop designs it could affect or possibly be the cause in the difference in precision.

[Rob15]

IF is the word.  But worth a try   Similarly graphite BBs also work.

If indeed, I suspect getting a thin coating would be quite difficult, if I were to try it myself I'd probably try and thin the micrometer blue enough with something like cleaning alcoho tol then spray a fine mist down the barrel with an airbrush and wait for the alcohol in it to evaporate, no idea if that'd really work though but it's the best I can think of.

 

From my brief stay there they also treat people who play milsim, use Systema guns, gas guns or even low/mid cap mags as BS.

Ha, I remember when I released my airbrake piston heads for sale a few years ago and ASM was viewable without an account, some people over there (Hunter Seeker being one iirc) looked at the photo of the airbrakes and said "That can't work, it's not tapered". Never been much inclined to register there if they judge the performance of a product on a photo, mindyou it still amazes/depresses me how many people still think an airbrake can only be used in semi-auto only AEGs.

[3vi1-D4n]

 

Ha, I remember when I released my airbrake piston heads for sale a few years ago and ASM was viewable without an account, some people over there (Hunter Seeker being one iirc) looked at the photo of the airbrakes and said "That can't work, it's not tapered". Never been much inclined to register there if they judge the performance of a product on a photo, mindyou it still amazes/depresses me how many people still think an airbrake can only be used in semi-auto only AEGs.

 

Hey engineering minds tend to be "know it all".  I know I have made comments like that before LOL

 

Off topic, but the cycling thing (semi vs auto) depends on the efficiency of the airbrake.  Once I made a very effective airbrake and it not only dropped 40fps the deceleration was so good the gears started to grind before piston returned to battery.  I put a few holes in the airbrake and it worked fine after that..

[Stuey]

Engineering minds aren't exactly great on social engineering.  I am one such example myself.

 

There's not being social, and there's not being a complete twat.

 

Interesting kojak's seeing a consistent ~0.4 J drop between tightbore and widebore. Good to see some hard numbers.

[kojak]

At what range, how much tighter is the group?

 

I can't say for sure; unfortunately I live in the city and have to make a special range trip to put rounds on paper.  But in practical use I'd estimate it adds 10-15 yards to the distance I feel comfortable scoring precise hits on semi rather than relying on burst fire.  I'll try to collect some actual groups soon, but I need to finish my DMR first so I can compare all of my custom guns at once.  

 

Thanks! Power reduction does seem drastic and as you said, on an AEG it would mean having to stress out the gearbox more for less muzzle energy. Makes me doubt in applying it to a VSR then, but looks very much promising on my GBB AK. It won't mean having to put more strain and I'm using a restricted nozzle now for cqb which can be adjusted to compensate for the energy loss.

 

edit:

Forgot to ask what hop up you have on both uppers. Asking for hard range data might be too much but if your two uppers have different hop designs it could affect or possibly be the cause in the difference in precision.

 

The hopup design is the same on both, though they were set in the field for a flat arc on the high power lower, so probably could have been dialed down for a slightly higher FPS on the low power one.  BTW that lower is tuned for 1.6J using a standard M4 length tightbore.  

 

There's not being social, and there's not being a complete twat.

 

Interesting kojak's seeing a consistent ~0.4 J drop between tightbore and widebore. Good to see some hard numbers.

 

Keep in mind that my tightbore is also 40mm longer.