.540 OD .302 ID SCH80 1/4 pipe fits .3 bore, .308 Bullet, &
.471 Base, .473 Rim,
"fits" .875"OD .469"ID 6 gauge "7/8" tube &
or .840"OD .464"ID SCH160 "1/2" pipe via reducer/coupler

7.82 mm or .308" is the bullet diameter

7.62 mm or .300 refers to the internal BORE before rifling &
the raised helical barrel ridges or lands of a rifled gun barrel
from the wiki CSV to HTML table
Name Bullet Case length Rim Base Shoulder Neck OAL
.30 Pedersen 7.82 (.308) 19.76 (.778) 08.48 (.334) 08.48 (.334) N/A 8.43 (.332) 30.38 (1.196)
.30 Carbine 7.798 (.307) 32.77 (1.290) 09.14 (.360) 08.99 (.354) N/A 8.41 (.331) 41.91 (1.65)
7.62×40mm Wilson Tactical 7.82 (.308) 39.8 (1.565) 09.6 (.378) 09.6 (.377) - - 57.15 (2.25)
.30 Remington 7.82 (.308) 52.3 (2.06) 10.7 (.422) 10.7 (.421) 64.14 (2.525)
.303 Savage 7.82 (.308) 51.2 (2.015) 12.8 (.505) 11.2 (.442) 10.5 (.413) 8.5 (.333) 64.01 (2.520)
.30-40 Krag 7.82 (.308) 58.674 (2.31) 13.84 (.545) 11.608 (.457) 10.541 (.415) 8.585 (.338) 78.74 (3.10)
7.62×51mm NATO 7.82 (.308) 51.05 (2.01) 11.94 (.470) 11.84 (.466) 11.35 (.447) 8.58 (.338) 69.85 (2.75)
.308 Winchester 7.82 (.308) 51.18 (2.015) 11.94 (.470) 11.94 (.470) 11.53 (.454) 8.74 (.344) 69.85 (2.75)
.30-03 Springfield 7.835 (.3085) 64.52 (2.54) 12.01 (.473) 11.94 (.470) 11.2 (.441) 8.64 (.340) 84.84 (3.340)
.30-06 Springfield 7.835 (.3085) 63.35 (2.494) 12.01 (.473) 11.94 (.470) 11.07 (.436) 8.628 (.3397) 84.84 (3.340)
30 BR 7.82 (.308) 38.41 (1.512) 12.01 (.473) 11.94 (.470) 11.66 (.459) 8.33 (.328) 58.00 (2.283)
.300 Savage 7.82 (.308) 47.5 (1.871) 12.01 (.473) 11.96 (.471) 11.3 (.446) 8.6 (.339) 66.04 (2.60)
7.5×54mm French 7.82 (.308) 53.59 (2.11) 12.24 (.482) 12.19 (.480) 11.2 (.441) 8.64 (.340) 75.95 (2.99)
7.5×55mm Swiss 7.77 (.306) 55.499 (2.185) 12.598 (.496) 12.548 (.494) 11.481 (.452) 8.484 (.334) 77.47 (3.05)
.300 Weatherby Mag 7.82 (.308) 71.75 (2.825) 13.49 (.531) 13 (.512) 12.5 (.492) 8.53 (.336) 90.47 (3.562)
.308 Norma Mag7.82 (.308) 65.0 (2.56) 13.5 (.531) 13.0 (.513) 12.4 (.489) 8.6 (.340) 83.82 (3.30)
.300 H&H Mag7.82 (.308) 72.4 (2.850) 13.5 (.532) 13.0 (.513) 11.4 (.450) 8.6 (.338) 91.40 (3.600)
.300 Winchester Mag 7.82 (.308) 66.55 (2.62) 13.51 (.532) 13.03 (.513) 12.42 (.489) 8.61 (.339) 84.84 (3.34)
.30 Newton 7.823 (.308) 64 (2.52) 13.3 (.525) 13.3 (.523) 12.5 (.491) 8.6 (.340) 85 (3.35)
300 Precision Rifle 7.833 (.3084) 65.53 (2.580) 13.51 (.532) 13.513 (.5320) 13.080 (.5150) 8.66 (.341) 93.98 (3.700)
60KPSI 7.62 NATO vs 62KPSI . 308 Winchester