Fps Increase V Barrel Length

[BigStew]

Nothing showed up in a forum Search. so thinking about getting a pistol carbine kit for CQB (for TM M9 or Hi Capa based) and want to run an extended barrel, is there a rule of thumb or calculation for increase/decrease of FPS relative to barrel length or is it just a case of fit it and see? If I put a 300mm + barrel is going to be a likelyhood of it running hot or not? 

[Adolf Hamster]

i've not seen one.

 

it's related to the original length that the gun is gassed for, so adding 100mm to a pistol is gonna have a bigger impact than taking 100mm off a rifle.

 

if it's for cqb tbh i wouldn't even bother changing it, effective range of a tm pistol is more than fine for those kinds of distances.

[BigStew]

15 minutes ago, Adolf Hamster said:

if it's for cqb tbh i wouldn't even bother changing it, effective range of a tm pistol is more than fine for those kinds of distances.

More than likely. my main reason for a longer barrel was it to be in line with the outer barrel so that the BB doesn't ricochet.

[Adolf Hamster]

5 minutes ago, BigStew said:

More than likely. my main reason for a longer barrel was it to be in line with the outer barrel so that the BB doesn't ricochet.

 

shouldn't be too much of an issue.

 

if the bb path/outer barrel is deviating enough for that to happen then there are bigger problems at stake