By far the easiest and safest way would be to have the gun overbored, opening it up about ten thousandths. Over boring is very popular these days on new guns and doesn't involve any of the pitfalls encountered with striking the outside of the tubes. If anything, over boring is likely to improve patterns and reduce felt recoil. I like Skeet's Gun Shop in Talequah, Oklahoma (918-456-4749) for this type work.

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