Glad you went Prommy, for I while there I thought you were going to go Crazy.
Some like them but in testing I did not.
Before you get super excited and throw all your packaging away; roll the barrel on a flat surface and check it's true/straight.
Also inspect the crown/barrel exit for any little burrs.
95% of the time Prommy are bang on but sometimes there's the odd lemon
So last night i received my Prometheus 6.03mm tightbore 370mm inner barrel, with my Laylax hop up arm in hand i decided to have a go at install them in the MTR16.
Managed to get the receivers apart, BCG out, flash hider, front rail and faux gas block, EASY.
Then came a hour of headache (is it really airsoft modding if there is ever no headache? ?) I spent the best part of an hour trying to remove the first castle nut with an armourers wrench and heat gun. Only once the receiver itself was too hot to handle with bare hands would the first castle nut move, they it was a simple pull of the next piece AND then ANOTHER FREAKING CASTLE, BIGGER THAN THE LAST!!! I had to heat the receiver up so much i was worried shit would start melting, how much thread glue did TM use, a whole bottle ?
Second Boss castle nut removed, and some wiggling for the outer barrel and finally i could access the hop.
I decide to measure the width of the Laylax one and compare it to stock, both were 6.75mm wide perfect. New barrel in (checked for QC and it was spot on), new hop arm in and reassemble which thankfully didn't take too long.
After all that the result, FPS wise a bit disappointing, didn't get the FPS improvement i was hoping for.
STOCK on .20g BBs she was firing around 1 to 1.1 joules or about 330 to 335FPS
Upgraded barrel and Hop Arm i was getting 1.2 joules or around 355 to 360FPS
I was hoping at least to hit 380 to 400FPS and then use the NPAS to dial it up further.
So some questions:
Was i expecting too much going from a 250mm to a 370mm inner barrel?
Should that extra 120mm length have made a bigger difference or is it what you would expect?
My only reason is that when i owned a KWA Vector, stock it was shooting 380FPS, but screwing on the suppressor (which acted as a 150mm inner barrel extension) pushed the FPS to over 450FPS
As for range and accuracy i cant tell as i have a tiny garden, but i hope i didn't lose too much of the fairy dust in the hop, i was very careful.
My NPAS hopefully will arrive soon so i am hoping i can volume up the MTR 16 to output at least 420 to 430 FPS.