As noted above, this is not my line of work.
But the New Jersey and Puff were a fun topic in RVN.
Please note the last line.
“Approximate Barrel Life 3a 395 rounds”
NOTE 3a READS:
^HC rounds at 2,525 fps (770 mps) were 0.74 ESR and at 2,000 fps (610 mps) were 0.09 ESR. The Target rounds at 1,800 fps (549 mps) were 0.08 ESR, but it is noted that this gun could fire 2,860 Target rounds before exceeding liner life.
http://www.navweaps.com/Weapons/WNUS_16-45_mk6.php
Projectile Types and Weights 1a AP Mark 8 Mods 0 to 8 - 2,700 lbs. (1,225 kg)
HC Mark 13 Mods 0 to 6 - 1,900 lbs. (862 kg)
HC Mark 14 Mod 0 - 1,900 lbs. (862 kg)
Bursting Charge AP Mark 8 - 40.9 lbs. (18.55 kg)
HC Mark 13 - 153.6 lbs. (69.67 kg)
HC Mark 14 - 153.6 lbs. (69.67 kg)
Projectile Length AP Mark 8 - 72.0 in (182.9 cm)
HC Mark 13 - 64.0 in (162.6 cm)
HC Mark 14 - 64.0 in (162.6 cm)
Propellant Charge 2a Full Charge - 535 lbs. (242.7 kg) SPD
Reduced Charge - 295 lbs. (133.8 kg) SPD or SPDN
Reduced Charge Flashless - 315 lbs. (142.9 kg) SPCG
Muzzle Velocity Full Charge - New Gun
AP - 2,300 fps (701 mps)
HC - 2,635 fps (803 mps)
Full Charge - Average Gun
AP - N/A
HC - 2,525 fps (770 mps)
Reduced Charge - New Gun
AP - 1,800 fps (549 mps)
HC - 2,075 fps (632 mps)
Working Pressure 18.0 tons/in2 (2,835 kg/cm2)
Approximate Barrel Life 3a 395 rounds
Read footnote 14a. Towards the bottom, it says approximately 1500 rounds for the liner. Very interesting about how rounds through the barrel increased exponentially. I’m not sure, but I think it is the liner that needs replacing, not the barrel.
http://www.navweaps.com/Weapons/WNUS_16-50_mk7.php#ammonote14
The site you quote is for the 16 inch/45 caliber Mark 6 naval gun on the North Carolina class. The Iowas use a 16 inch/50 caliber Mark 7. 395 rounds is correct for the Mark 6, but not for an Iowa.
USS New Jersey is an Iowa class.