M4A1 Gen 8 Feed Problems after Mods

I have just upgraded the O-Ring to a green o ring and replaced the barrel to a fighting bros 350mmX9.5mmX7.0mm Barrel, now i seem to get occasionally multiple shots when quickly blipping the trigger, every few shots might get a shot where it is almost like its just falling out the barrel and also occasionally get a popping sound when firing. any ideas?

Kind Regards,

hey Jake welcome to GBF bro always happy to see new members joining and posting. anyways what gels are you using because I’ve got the FB barrel too but I opted for the 7.5mm because the 7.0mm was always out of stock and with that barrel you can only use the milkies as others are inconsistent with size.

Cheers Mr.Milkman, doesn’t seem to be much in the way of an answer in regards to my issue out there, good to know there is somewhere out there for some help. ‘Tis my first Gel blaster, was having plenty of fun with it until this, quite annoying. Mate I am using the gold labelled Milkies.

sorry I forgot to mention that sounds like a compression leak when they fall out .when it’s Multiple fire at once could be one or more of either problems.like worn out tappet plate Spring, ratio of your gears to fast for Tapper player so try a sector delay chip that happened to me aswell

Is there likely to be wear on those parts if it’s only been used 3 times? Only bought the blaster 3 weeks ago, I will have to check the compression as you mentioned as I have just replaced the seal.


i have been giving this some thought and asking around also.

tappet / return spring will also produce this - compression leak since the nozzle doesn’t move forward to seal and the mag feeds more in

pew pew becomes plop plop

i had a bit of a play around with it today and checked the compression, all seems great, changed back to the original plastic barrel and it seemed to resolve the issues more or less, could it be that the 7mm ID of the fighting bros barrel is just too small to actually work, has anyone else used them in this size?

Iv tried the x-force tactical 350x7mm tight bore with similar results going to try the 7.5 as refitting standard barrel fixed problem

reading it all over again - compression ratio - recommend you calculate it.

if the ID were too tight and gels were getting stuck you’d either see a build up of ammo not coming out or the ones that did would be erratic in velocity.

if you’ve extended your barrel length (i’m preCoffee so…) you may have a lack of volumetric efficiency