My opinion is that practice is better than no practice, even if your habits are less than perfect and your accuracy suffers because of it.
Not only does training make you a better shooter, it also makes the use of a gun more instinctive and natural. I have found at any range, folks are ready and willing to help if asked.
The nightmare of having to defend yourself and your family is bad enough, but if an unintended person is wounded or killed, obviously your plan or lack of plan was flawed or poorly executed. Accidents happen, some are more serious than others, but most can be reduced if practice is frequent.
But a defensive and survivor mindset is more important to arrive at before a weapon is chosen.
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