overbore

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From over- + bore.

overbore (not comparable)

1. (firearms) Such that the capacity of the burning cartridge powder is greater than the volume within the barrel.

overbore (third-person singular simple present overbores, present participle overboring, simple past and past participle overbored)

1. (firearms, transitive) To modify so that the capacity of the burning cartridge powder is greater than the volume within the barrel.
2. (automotive, of cylinders or the engine containing them) To bore out more than is usual for the design; especially, to bore out to a degree that pushes the limit regarding the wall thickness of the casting.
   • 1985, George Philip Hanley, Stacey Pankiw Hanley, The Marmon Heritage: More Than 125 Years of American Production of World Renowned Products : Marmon, Marmon-Herrington, Marmon-Herrington All-Wheel-Drive Ford‎^[1], Doyle Hyk Publishing Company, →ISBN, page 40:

     The Model F engine was an overbored variation of the larger engine first applied to the Model D the previous year. This made it considerably oversquare: 5 inch bore (4.625 on the D) and 4.5 inch stroke displacing 353 cubic inches. It was rated 32.4 SAE horsepower, produced 35 at the same conditions and 40 maximum.

overbore

1. simple past and past participle of overbear

• overrobe