Back bore?

Adironduck

What does it mean to "back bore" a shotgun barrel and how does it improve patterning?

Tailgunner1954

A back bored barrel is oversized (larger ID) than a standard barrel, can't tell you exactly how much. The shot isn't as crunched together and the string is slightly shorter. One other thing that improves patterning is to relieve the forcing cones, lenghting the time/distance for the shot to get to bore size. By not deforming as many pellets patterns tighten up (fewer deformed pellots = fewer fliers)

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Some guys like a mag full of lead, I still prefer one round to the head.

gunnut

deformed pellets? Hevi-Shot is not even close to being uniform, however nothing I mean nothing will pattern like it! Why is this?

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He Dog

Gunnut, I am not familiar with heavi-shot, but shot deformity is the primary cause of flyers in the pattern and shot stringing, where some shot reaches the target well behind the front shot. It is indeed caused by shot compression at the rear of the shot column, and is worst in shells with long shot columns, like .410. That is why .410 patterns so poorly most of the time. Deformities are also caused by contact with the barrel/choke, though modern plastic shotcups have almost eliminated that problem. In any event, shot that is not round, but is flattened or obturated simply has more resistence and slows faster. If heavi-shot is round but different sizes, that would be no different that mixed shot loads, like turkey loads with 4 and 6 shot.

gunnut

He-Dog, Thanks for your reply. I truly understand what you are saying, however hevi-shot is of different sizes and shapes. It is denser than lead do you think this explains its patterning? Check out remington.com or hevi-shot.com.

The Nut

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