Of course the NRA does not officially promote legalization of armor-piercing bullets and automatic weapons! They merely balk at legislation that, in THEIR view 'might' serve as a pathway to restricting any significant access to any weapons their members wish to own!
On paper, they look reasonable... on a practical basis, the rules they are willing to allow have little effect on illegal practices. IF there are unlimited legal guns available, those will be acquired illegally by folks who shouldn't have them.