Several customers have raised questions on this subject, the following is straight from the factory.
On single stage recoil spring guns (all guns except Titans & Sigma) it's 15-18lbs. Titans & Sigma9 it's 21-24lbs. Production dept advises no need of different tension springs necessary for +P ammo. Warning: DO NOT use +P ammo in pistols with stainless barrels.
Any pistol unit regardless of caliber which the slide is stainless, the barrel that goes with it will NO longer be 416 stainless, but will be match with barrel 4140 in MIRROR CHROMED FINISH. This is for durability purposes, since 4140 is no doubt tougher and more reliable than stainless. You know based on experience with ATI before. We are recommending to make this necessary change for long-term sake, not just because we want to. Kindly explain to the buyer. 4140 metal on a crucial part such as a barrel is more dependable in terms of longevity and safety. So any black- slide unit pistol, barrel will be 4140 black, any stainless-slide unit pistol, we match it with barrel 4140 in mirror chromed finish (actual appearance almost the same as stainless). Barrel breakage is more rare to happen in a 4140 steel barrel "than" a stainless barrel. This way we can avoid future complaints, manufacturer and buyer are all happy.
Once again, this minor change is for any next coming p.o. This is a "long term improvement" for everyone. Just a heads up info for you. Website specs wordings will be changed soon.