§241.4. Application of tolerance for “diameter of head.” — Inbound Citations

(1) Having determined the errors of each dimension and given to each its proper sign (see § 241.4), add the errors on the effective diameter of head and the distance between heads algebraically and multiply the result by 1.67 (or 5/3). Then add this result to the error on the circumference of bulge algebraically. If the result obtained is not greater than the tolerance given above, then the barrel is within the tolerance allowed; if the result is greater than this tolerance, then the barrel is not within the tolerance allowed.