It's a beater, so $70-80 for a cheapie M4 barrel that weighs about 1.7 lbs, and then take a dump in the restroom to lose some weight. Wanna splurge a little, go for a chrome lined barrel at $130-$140ish. Drop to a 14.5" barrel and lose another 4 oz or so, bringing the barrel weight to 1.5 lbs with a standard M4 profile that won't go flaacid on you.
....and no, I refuse to buy chinese crap. They've done enough crap to my other business with counterfeit products.... %@#^#$ copycat chinese motherf*ckers.
BTW. Did I mention I despise the Chinese? I'm ethnic Chinese but no I'm not from f*cking China, that crappy shithole of a "commie" country.