Inner Barrel to Drop FPS

[concretesnail]

If a 407mm 6.02 inner barrel runs at 400fps on a .2g bb what length would be required for sub 350fps on a .2g?

 

[Nick G]

What platform ? AEG or gas ? if it's an aeg you are better changing the spring . You will also need to factor in what cylinder you have , ported or non ported . If it's gas lengthening the barrel will likly increase fps rather than reduce it.

[Rogerborg]

I'm guessing it's that G&G 308 MBR AEG.  If so, I agree, you're not going to get that sort of energy drop just from the barrel, and neither would I suggest trying to make the air seal worse.  If you want to turn it into site (and actually legally) legal AEG, I'd be throwing an M100 spring in and taking it from there.

[concretesnail]

2 hours ago, Rogerborg said:

I'm guessing it's that G&G 308 MBR AEG.  If so, I agree, you're not going to get that sort of energy drop just from the barrel, and neither would I suggest trying to make the air seal worse.  If you want to turn it into site (and actually legally) legal AEG, I'd be throwing an M100 spring in and taking it from there.

It is my 308 dmr.

an idea floated through my head. I have two rails, which mount the same way and wondered if I use a split outer barrel to make the length adjustable whether I could use a second hop and barrel to drop the length of the inner to a point where it would be 350 under and I could forgo the dmr med on sites which are smaller, effectively becoming a semi locked assault rif.

 

[Adolf Hamster]

36 minutes ago, concretesnail said:

It is my 308 dmr.

an idea floated through my head. I have two rails, which mount the same way and wondered if I use a split outer barrel to make the length adjustable whether I could use a second hop and barrel to drop the length of the inner to a point where it would be 350 under and I could forgo the dmr med on sites which are smaller, effectively becoming a semi locked assault rif.

 

 

You'd be better off with a second gun tbh.

[concretesnail]

7 minutes ago, Adolf Hamster said:

 

You'd be better off with a second gun tbh.

I did think that, just wondered if it was workable.

[Adolf Hamster]

52 minutes ago, concretesnail said:

I did think that, just wondered if it was workable.

 

If it was an hpa yes, you could swap uppers and just remember the pressure/fcu settings for each config.

 

But aeg it's more hassle than its worth.

[Cr0-Magnon]

When Negative Airsoft installed an ORGA 6.23 widebore barrel in my GR25, it dropped the FPS from 485 to 400. I obviously can't with confidence say what kind of results you'd achieve but these barrels are known to drop the FPS. It also gave it amazing range. He's mentioned in his videos that it was the best range and accuracy he's ever gotten.

[Adolf Hamster]

6 minutes ago, Cr0-Magnon said:

When Negative Airsoft installed an ORGA 6.23 widebore barrel in my GR25, it dropped the FPS from 485 to 400. I obviously can't with confidence say what kind of results you'd achieve but these barrels are known to drop the FPS. It also gave it amazing range. He's mentioned in his videos that it was the best range and accuracy he's ever gotten.

 

heard the wide bores were decent if you could get the volume for them, they tend to be more suggested to pair up with hpa systems than aeg's.

 

not surprising it's dropping the fps, it's an intentional air leak after all.

[concretesnail]

The wide bore barrels would be where I'd have been looking. It started as a thought process similar in theory to swapping uppers. As some outer barrels are made of two shorter sections and then a complete hop and barrel swap would effectively be a cheap version of a second upper.

[Rogerborg]

Huh, I hadn't thought of going wide widebore.  My mind was in the 6.01 - 6.08mm range, not the "carrot down a corridor" level.  Might be worth a try, but they don't come cheap versus just throwing a lower powered spring in.

 

How quick is your change?

[Adolf Hamster]

Suppose now i think about it this might not be the worst idea.

 

Wether it drops the fps enough and/or deals with the overvoluming (although on an aeg overvolume isn't too bad) at the desired length is the question though.

 

Still reckon a dedicated assault gun would be better, you'd get auto and much less faff to swap configs.

 

Plus who doesnt need an excuse to get a second gun?

[Cr0-Magnon]

54 minutes ago, Rogerborg said:

 they don't come cheap versus just throwing a lower powered spring in.

 

That'd definitely be the most economical option. Although if the gun in question is a DMR platform, just buy another because....well, needs must and all that.

The widebore barrels are more often used the other way round, where you'd install a stronger spring because of the FPS drop caused.

Edited June 28, 2021 by Cr0-Magnon

[concretesnail]

sorry for delay in replying here, work got in the way.

 

A spring swap isnt really workable as a quick option as, as G&Gs idea of a quick change spring is to dismantle all but the gear box shell. it would be much quicker to pop the upper off and have a complete setup of hopup and inner barrel to drop in and then remove a section of outbarrel, in the same manner as fitting a tracer or such like, or like the TM Scar H has a outer barrel section which isnt required.