Velocity by Barrel Length of Various Calibers

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This page will examine barrel length to velocity differences for various calibers. We'll mostly stick to common calibers, but others will likely be added as well. But first, the concepts will be discussed below. The data will follow.

How Does Barrel Length Affect Velocity?

It is well-established fact that the length of a firearm's barrel will affect velocity (and therefore muzzle energy and even trajectory) to varying degrees. This is because the longer the propellant has had time to burn, the more of its maximum effect on the projectile can be utilized. Otherwise, energy will be wasted and propellant will likely burn off outside the barrel.

Why Does Barrel Length Affect Velocity?

This can depend on a number of factors, such as burn rate of the propellant, bore diameter, and probably others as well. The same caliber gun with the same barrel length could even show different results. For example, two revolvers of the same caliber and barrel length could differ in their amount of cylinder gap, allowing one to waste a bit more energy than the other. Likewise, semi-automatic or fully-automatic firearms will typically have lower muzzle velocity due to some of the propellant's energy being bled off into the gas system to work the action, and this can vary by individual firearm as well. Some guns, such as Heckler & Koch's integrally suppressed MP5SD are actually designed to bleed off excessive gas pressure to make sure any rounds they fire will remain subsonic! However, that is an edge case and can mostly be ignored as it pertains to the topic at hand.

We'll note various barrel lengths and load data on various calibers, from various sources.


.22 Long Rifle

Data for .22LR shown below is sourced from Ballistics by the Inch. A number of popular loads from major manufacturers were tested.

Barrel Length CCI 27 gr. CPHP CCI 29 gr. CPRN CCI Stinger: 32 gr. CPHP Remington Yellow Jacket 33 gr. (truncated cone, CPHP) Remington Viper 36 gr. (truncated cone CP) Remington Golden Bullet 36 gr. CPHP CCI Mini-Mag 40 gr. CPRN Winchester Super X 40 gr. RN CCI Velocitor 40 gr. CPHP Aguila Sniper SubSonic 60 gr. LRN
18" 1158 1114 1510 1407 1342 1181 1212 1250 1366 903
17" 1116 1060 1502 1396 1304 1178 1206 1227 1376 903
16" 1130 1094 1489 1398 1306 1185 1207 1251 1340 900
15" 1133 1083 1496 1369 1305 1178 1211 1241 1336 879
14" 1096 1103 1483 1334 1294 1163 1224 1222 1349 883
13" 1098 1071 1496 1381 1296 1147 1183 1248 1341 891
12" 1089 1074 1476 1334 1293 1167 1221 1235 1335 892
11" 1092 1079 1463 1360 1280 1180 1210 1223 1338 881
10" 1115 1065 1452 1304 1270 1150 1169 1193 1316 859
9" 1092 1042 1430 1315 1267 1129 1169 1203 1275 868
8" 1092 1048 1396 1271 1212 1101 1158 1191 1268 857
7" 1060 1056 1367 1284 1229 1073 1139 1162 1244 820
6" 1049 993 1321 1249 1165 1063 1101 1133 1093 824
5" 1029 1014 1286 1214 1156 1009 1097 1070 1172 796
4" 956 948 1191 1113 1104 984 1014 1043 1120 762
3" 907 893 1129 1045 998 890 948 965 1026 726
2" 861 860 974 945 875 846 856 862 882 663


9mm Luger

Also known as 9mm Parabellum, 9x19mm, etc. Data is from Ballistics by the Inch.

Barrel Length Cor-Bon 90 gr JHP +P Cor-Bon 115 gr JHP +P Cor-Bon 125 gr JHP +P Cor-Bon 115 gr DPX Federal 115 gr JHP text Federal 135 gr Hydra-Shok JHP (low recoil) Federal 105 gr Expand'g FMJ Federal 124 gr Hydra-Shok JHP Federal 147 gr Hydra-Shok JHP Speer 124 gr Gold Dot Short Barrel
18" 1754 1543 1449 1458 1297 1194 1370 1231 1038 1395
17" 1766 1550 1421 1455 1320 1207 1381 1250 1096 1400
16" 1740 1525 1430 1476 1295 1185 1358 1243 1073 1379
15" 1768 1536 1392 1416 1304 1194 1364 1244 1090 1375
14" 1767 1532 1405 1440 1295 1182 1372 1241 1090 1390
13" 1738 1517 1477 1427 1281 1183 1343 1237 1081 1378
12" 1716 1514 1385 1380 1282 1184 1273 1225 1081 1361
11" 1690 1496 1372 1391 1268 1166 1318 1212 1059 1360
10" 1647 1474 1372 1379 1253 1167 1314 1211 1067 1338
9" 1663 1476 1369 1377 1238 1161 1307 1212 1055 1345
8" 1634 1458 1366 1366 1234 1145 1278 1180 1047 1329
7" 1619 1446 1329 1350 1223 1136 1258 1161 1040 1316
6" 1566 1402 1312 1332 1188 1113 1235 1131 1030 1284
5" 1539 1372 1282 1315 1166 1085 1194 1115 1007 1259
4" 1444 1316 1226 1265 1094 1039 1140 1061 951 1203
3" 1345 1245 1170 1215 1029 976 1074 988 902 1108
2" 1215 1134 1061 1132 948 909 985 900 837 1074

Optimal Barrel Length For 9mm?

Based on the data above, it appears that almost all loads tested got their greatest percentage increase in velocity up until about a 7" barrel length. Velocity did of course increase further with longer barrels, but to a much smaller degree. For example, going from a 4" barrel to 7" (a 3 inch difference), every load got well over a 100 fps increase in velocity. However, going a full 10 inches longer up to a 17" barrel gained most of the tested loads under 100 feet per second in velocity. In fact, going from a 17 inch barrel up to 18 inches, actually LOST velocity in all but two of the loads, although the decrease was negligible.

It appears that overall, the optimal barrel length for something like an AR-15 pistol build, SBR, or similar setup, is about 7 to 8 inches for maximum efficiency and handling. If you still wanted to maintain an ultra-short setup with a suppressor, you could go even shorter with barrel length, as the additional length of the suppressor will increase velocity. Even at 7-8" barrel, the additional length of a suppressor would still allow the pistol or SBR to remain more compact than a 16" barrel. A 7" barrel with a 7" suppressor would still give an overall length of 14 inches. If you were looking for a rifle setup, there appears to be no major reason to go above the federal 16" barrel requirement, unless local laws differ, or whatever the case may be.


.460 Rowland

The .460 Rowland data below is sourced from Ballistics by the Inch.


Barrel Length Cor-Bon Hunter 230 gr. JHP 18" 1356
17" 1366
16" 1354
15" 1352
14" 1342
13" 1344
12" 1314
11" 1293
10" 1335
9" 1303
8" 1299
7" 1273
6" 1261
5" 1208
4" 1124
3" 1082
2" 974