Barrel is accurate.
Comes pretty much fully loaded if you want an M4/M16 look.
Body halves not best quality
To start this was my first marker. It realiable, accurate, quiet and easy to field strip.
The BT-4 Assault comes with a...
-14" M16 Barrel
-6 Postion Tactical CAR Stock
-Adjustable M16 Carry Handle.
This marker is tough and will take a major beating and still keep on shooting, however like I said above the quality of the milled body halves are low and the cheap plastic on of the handguards leave something to be desired. The Gun is also quite long at 33" it wieghs a good 10-12 pounds with a 20oz CO2 tank and Fully loaded hopper. The gun is pretty quiet though which is a plus.
The BT-4 Also fixes some of the issues that the 98 Coustom had, like the Trigger Frame is screwed onto the body, the feed neck is easily slide of the weaver rails [which are on the top and bottom of the gun.] There are also no built in sights, so you don't have to worry about some rear sight preventing you from moveing an iron sight all the way back to the end of the gun.
The are a lot less upgrades for the BT-4 than there are the 98 Coustom, some things will fit but others won't. There is no Ricochet Rocket Cock 2 system availble so the guns externals are exposed and paint will get into them. Field Stripping the marker is really easy, just remove the barrel, feed neck, and the iron sight, then unscrew the trigger frame, and 4 more screws and bam your looking at the internals.
This gun is a good woodsball gun, but if your looking for better quality get an A-5 or X7.
Overall 8 out of 10
Its a nice gun but leaves some things to be desired.