Husqvarna Model 310s were not inexpensive guns back in the day. From the 1929 A.F. Stoeger catalog --

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I had the chokes opened on my 12-gauge to .010" and .020", .005" and .010" might have been even better. My post WW-II 16-gauge is still very tight and a Remington Express #5 in the left barrel accounted for the longest Pheasant in my memory.

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