How does resident evil 5 improve its hit rate?

Don't use shotguns, OK shotguns. For example, M3 fired three bullets, but three bullets missed the enemy with 1, which will lower your evaluation. 14 bullet has a low hit rate of three tubes, so try to pass through with submachine gun. You can also use shotguns, but try to get close to the enemy and make sure that every bullet hits. I don't need a shotgun now. At least every level was marked with an S.