DMR accuracy issue

[cripto]

Hello all. I've been working on my dmr for about a year now. Here are the specs:
G&G Combat Machine m4 as a base
M150
100:300 SHS helical gears.
SHS metal piston head
SRC high torque motor
Steevofet
My own Flat hop, made with an eraser
It's firing nicely(a bit louder than I'd like) but the groupings are far from satisfying. At roughly 140ft, I have a grouping that fits withing a 3x3ft square. Some bbs drop before they even hit the target, and some are flying high or right and left. Are my expectations too high, or did I mess something up? I'm using Madbull .36 bbs. Any feedback is MUCH appreciated!

[Dominum]

What bucking did you use, and what barrel is in it?

[Skywalker]

Barrel? .... yeah thanks dom

[Star_folder]

Have you done anything to stabilize your outer barrel, or stabilize your inner barrel? Have you tested your compression?

As for the noise, have you adjusted the AoE in the gun?

[Dominum]

Are you using the stock chamber with no mods? They're not very good at holding the setting firmly, for one.

[cripto]

6.03 Madbull 509mm barrel. I'm using a systema bucking with the rubber nub removed. I wrapped the inner barrel in thin tape, making it more snug. The outer barrel...nothing done. The AoE I ajusted to the best of my ability...which might not be that great. Yes, stock chamber. Thanks for the feedback!

[Dominum]

Is the cylinder the stock ported cylinder?

[Skywalker]

Was the barrel brand new, or used previous? 3 foot diameter at that range is pretty rough, sounds almost like the inside of the barrel could be dirty/scratched.

[cripto]

Yes, it is the stock, ported cylinder. The barrel was bought used, but it doesn't look scratched or damaged...