Bore, Groove and Twist Specifications
The
specifications below are drawn from CIP, SAAMI and other sources and are the
guidelines we use for manufacturing our bullets. If your rifle has been rebarrelled, check
with the supplier of the new barrel whether the barrel conforms to the original specification. Examples of
errors that can occur would be to replace a 7x57 or 7x64 barrel with a 7mm
Rem Mag barrel. We have seen 404 rifles with .423 barrels as well as .418 barrels, 6.5
Swedish Mausers with .264 Win Mag barrels and so on. The Case Length column contains the maximum case length. The
trim length is shorter and varies according to the caliber.
Twist Rate By Manufacturer
Caliber |
Bore mm |
Groove mm |
Twist mm |
Case Length mm |
Bore Inches |
Groove Inches |
Twist Inches |
Case Length Inches |
177
Rem |
4.270 |
4.370 |
229 |
45.62 |
0.168 |
0.172 |
9.0 |
1.79
|
.204 |
5.029 |
5.169 |
305 |
47.24
|
0.1980 |
0.2035 |
12.0 |
1.85
|
5mm
Rem Mag |
5.070 |
5.190 |
305 |
N/A
|
0.1996 |
0.2043 |
12.0 |
N/A
|
5.6
x 35R |
5.350 |
5.580 |
360 |
35.5
|
0.211 |
0.220 |
14.2 |
1.40
|
22LR |
5.380 |
5.580 |
406 |
N/A
|
0.212 |
0.220 |
16.0 |
N/A
|
22
Hornet |
5.510 |
5.640 |
406 |
35.64
|
0.217 |
0.222 |
16.0 |
1.40
|
22
PPC USA |
5.530 |
5.660 |
355 |
38.48
|
0.218 |
0.223 |
14.0 |
1.52
|
5.6x57
|
5.540
|
5.690
|
250
|
56.70 |
0.218
|
1.224
|
9.8
|
2.23
|
5.6x57R |
5.540 |
5.690 |
250 |
56.70
|
0.218 |
0.224 |
9.8 |
2.23
|
224
Wea Mag |
5.540 |
5.690 |
356 |
|
0.218 |
0.224 |
14.0 |
|
223
Rem |
5.560 |
5.690 |
305 |
44.70
|
0.219 |
0.224 |
12.0 |
1.760
|
5.6x50Mag
|
5.560
|
5.690
|
350
|
50.00 |
0.219
|
0.224
|
13.8
|
1.97
|
5.6x50Mag/R |
5.560 |
5.690 |
350 |
|
0.219 |
0.224 |
13.8 |
|
220
Swift |
5.560 |
5.690 |
356 |
|
0.219 |
0.224 |
14.0 |
|
222
Rem |
5.560 |
5.690 |
356 |
|
0.219 |
0.224 |
14.0 |
|
22-250 |
5.560 |
5.690 |
356 |
|
0.219 |
0.224 |
14.0 |
|
219 Zipper |
5.560 |
5.690 |
406 |
|
0.219 |
0.224 |
16.0 |
|
5.6x61 SE v H |
5.580 |
5.760 |
220 |
61.00 |
0.220 |
0.227 |
8.66 |
2.40 |
22 Sav |
5.610 |
5.740 |
305 |
|
0.221 |
0.226 |
12.0 |
|
240 Wea Mag |
6.020 |
6.170 |
254 |
|
0.237 |
0.243 |
10.0 |
|
243 Win |
6.020 |
6.170 |
254 |
51.94 |
0.237 |
0.243 |
10.0 |
2.049 |
244 H&H |
6.020 |
6.220 |
255 |
|
0.237 |
0.245 |
10.0 |
|
25-35 |
6.350 |
6.500 |
203 |
|
0.250 |
0.256 |
8.0 |
|
25-06 |
6.350 |
6.530 |
254 |
63.35 |
0.250 |
0.257 |
10.0 |
2.494 |
250 Sav |
6.350 |
6.530 |
356 |
48.56 |
0.250 |
0.257 |
14.0 |
1.912 |
257 Wea Mag |
6.360 |
6.530 |
254 |
64.75 |
0.250 |
0.257 |
10.0 |
2.549 |
6.5x65RWS |
6.450 |
6.700 |
200 |
65.00 |
0.254 |
0.264 |
7.9 |
2.56 |
6.5x57 |
6.450 |
6.700 |
200 |
65.70 |
0.254 |
0.264 |
7.9 |
2.59 |
6.5x68 |
6.450 |
6.700 |
250 |
67.50 |
0.254 |
0.264 |
9.8 |
2.66 |
260 Rem |
6.500 |
6.710 |
229 |
51.69 |
0.256 |
0.264 |
9.0 |
2.035 |
264 Win Mag |
6.500 |
6.710 |
229 |
|
0.256 |
0.264 |
9.0 |
|
6.5x55 Sw Mau |
6.500 |
6.730 |
220 |
55.00 |
0.256 |
0.265 |
8.7 |
2.17 |
Caliber |
Bore mm |
Groove mm |
Twist mm |
Case Length
mm |
Bore
Inches |
Groove
Inches |
Twist
Inches |
Case Length
Inches |
6.5x54 M Sch |
6.480 |
6.780 |
200 |
53.65 |
0.255 |
0.267 |
7.9 |
2.112 |
270 Win |
6.860 |
7.040 |
254 |
64.52 |
0.270 |
0.277 |
10.0 |
|
270 Wea Mag |
6.870 |
7.040 |
254 |
|
0.270 |
0.277 |
10.0 |
|
7mm Wea Mag |
7.020 |
7.210 |
254 |
|
0.276 |
0.284 |
10.0 |
|
7mm Rem Mag |
7.040 |
7.210 |
241 |
|
0.277 |
0.284 |
9.5 |
|
7-08 |
7.040 |
7.210 |
241 |
|
0.277 |
0.284 |
9.5 |
|
280 Rem |
7.040 |
7.210 |
254 |
|
0.277 |
0.284 |
10.0 |
|
7x61 Super |
7.000 |
7.220 |
229 |
|
0.276 |
0.284 |
9.0 |
|
7x57 |
6.980 |
7.240 |
220 |
57.00 |
0.275 |
0.285 |
8.7 |
2.244 |
7x64 |
6.980 |
7.240 |
220 |
64.00 |
0.275 |
0.285 |
8.7 |
2.520 |
275 HV Rigby |
6.970 |
7.250 |
203 |
|
0.274 |
0.285 |
8.0 |
|
275 Belted NE |
7.040 |
7.280 |
255 |
|
0.277 |
0.287 |
10.0 |
|
280 Ross |
7.050 |
7.300 |
220 |
|
0.278 |
0.288 |
8.7 |
|
7.5x55 Swiss |
7.540 |
7.770 |
270 |
55.6 |
0.297 |
0.306 |
10.6 |
2.189 |
300 Lapua Mag |
7.620 |
7.820 |
240 |
|
0.300 |
0.308 |
9.4 |
|
300 H&H |
7.610 |
7.820 |
254 |
|
0.300 |
0.308 |
10.0 |
|
300 Win Mag |
7.620 |
7.820 |
254 |
|
0.300 |
0.308 |
10.0 |
|
308 Norma |
7.620 |
7.820 |
254 |
|
0.300 |
0.308 |
10.0 |
|
30-06 |
7.620 |
7.820 |
254 |
|
0.300 |
0.308 |
10.0 |
|
30 R Blaser |
7.620 |
7.820 |
305 |
|
0.300 |
0.308 |
12.0 |
|
308 Win |
7.620 |
7.820 |
305 |
51.18 |
0.300 |
0.308 |
12.0 |
2.015 |
30-30 Win |
7.620 |
7.820 |
305 |
|
0.300 |
0.308 |
12.0 |
|
300 Wea Mag |
7.630 |
7.820 |
254 |
|
0.300 |
0.308 |
10.0 |
|
300 Sav |
7.620 |
7.820 |
305 |
|
0.300 |
0.308 |
12.0 |
|
7.62x39 |
7.620 |
7.920 |
240 |
38.70 |
0.300 |
0.312 |
9.4 |
1.524 |
7.62x54R |
7.620 |
7.920 |
240 |
|
0.300 |
0.312 |
9.4 |
|
303 BR |
7.700 |
7.980 |
254 |
|
0.303 |
0.314 |
10.0 |
|
8x57J |
7.800 |
8.070 |
240 |
|
0.307 |
0.318 |
9.4 |
|
8x64 |
7.800 |
8.070 |
240 |
|
0.307 |
0.318 |
9.4 |
|
8x64S |
7.890 |
8.200 |
240 |
|
0.311 |
0.323 |
9.4 |
|
8x68S |
7.890 |
8.200 |
280 |
|
0.311 |
0.323 |
11.0 |
|
Caliber |
Bore mm |
Groove mm |
Twist mm |
Case Length
mm |
Bore
Inches |
Groove
Inches |
Twist
Inches |
Case Length
Inches |
8mm Rem Mag |
8.000 |
8.200 |
254 |
|
0.315 |
0.323 |
10.0 |
|
8x57JS |
7.890 |
8.200 |
240 |
|
0.311 |
0.323 |
9.4 |
|
8x60S |
7.890 |
8.200 |
240 |
|
0.311 |
0.323 |
9.4 |
|
318 WR |
8.070 |
8.380 |
305 |
|
0.318 |
0.330 |
12.0 |
|
318 Rimless NE |
8.070 |
8.380 |
305 |
|
0.318 |
0.330 |
12.0 |
|
338 Lapua Mag |
8.380 |
8.580 |
254 |
|
0.330 |
0.338 |
10.0 |
|
8.5x64 |
8.380 |
8.590 |
254 |
|
0.330 |
0.338 |
10.0 |
|
340 Wea Mag |
8.380 |
8.590 |
254 |
|
0.330 |
0.338 |
10.0 |
|
338 Win Mag |
8.380 |
8.590 |
254 |
|
0.330 |
0.338 |
10.0 |
|
350 Mag Rigby |
8.890 |
9.060 |
305 |
|
0.350 |
0.357 |
12.0 |
|
9x57 |
8.780 |
9.060 |
360 |
|
0.346 |
0.357 |
14.2 |
|
35 Winchester |
8.890 |
9.090 |
355 |
|
0.349 |
0.357 |
16.0 |
|
35 Remington |
8.890 |
9.090 |
406 |
|
0.349 |
0.357 |
16.0 |
|
35 Whelen |
8.860 |
9.070 |
406 |
|
0.349 |
0.357 |
16.0 |
|
350 RemMag |
8.860 |
9.070 |
406 |
|
0.349 |
0.357 |
16.0 |
|
358 Norma |
8.890 |
9.100 |
305 |
|
0.350 |
0.358 |
12.0 |
|
9.3x64 |
9.000 |
9.280 |
360 |
|
0.354 |
0.365 |
14.2 |
|
9.3x62 |
9.000 |
9.280 |
360 |
|
0.354 |
0.365 |
14.2 |
|
9.3x57 |
9.000 |
9.280 |
360 |
|
0.354 |
0.365 |
14.2 |
|
9.5x57 M.-Sch. |
9.270 |
9.620 |
300 |
|
0.365 |
0.379 |
11.8 |
|
375 Wea Mag |
9.350 |
9.530 |
305 |
|
0.368 |
0.375 |
12.0 |
|
378 Wea Mag |
9.320 |
9.530 |
305 |
|
0.367 |
0.375 |
12.0 |
|
375H&H |
9.300 |
9.550 |
305 |
|
0.366 |
0.376 |
12.0 |
|
.375 WR |
9.300 |
9.550 |
305 |
|
0.366 |
0.376 |
12.0 |
|
9.5x66 SEvH |
9.300 |
9.550 |
305 |
|
0.366 |
0.376 |
12.0 |
|
408 Win |
10.150 |
10.330 |
356 |
|
0.400 |
0.407 |
14.0 |
|
408 Chey-Tac |
10.185 |
10.363 |
330 |
|
0.401 |
0.408 |
13.0 |
|
450/400 N.E. 3" |
10.160 |
10.410 |
381 |
|
0.400 |
0.410 |
15.0 |
|
405 Win |
10.290 |
10.490 |
356 |
|
0.405 |
0.413 |
14.0 |
|
Caliber |
Bore mm |
Groove mm |
Twist mm |
Case Length
mm |
Bore
Inches |
Groove
Inches |
Twist
Inches |
Case Length
Inches |
416 Rem Mag |
10.360 |
10.570 |
356 |
72.39 |
0.408 |
0.416 |
14.0 |
2.85 |
416 Wea Mag |
10.360 |
10.570 |
356 |
73.99 |
0.408 |
0.416 |
14.0 |
2.91 |
416 Rigby |
10.360 |
10.570 |
420 |
73.66 |
0.408 |
0.416 |
16.5 |
2.90 |
404 Jeffery |
10.410 |
10.620 |
420 |
|
0.410 |
0.418 |
16.5 |
|
404 Rimless NE |
10.410 |
10.620 |
420 |
|
0.410 |
0.418 |
16.5 |
|
10.75x68 |
10.450 |
10.750 |
420 |
|
0.411 |
0.423 |
16.5 |
|
444 Marlin |
10.770 |
10.920 |
965 |
|
0.424 |
0.430 |
38.0 |
|
45-70 |
11.430 |
11.580 |
508 |
|
0.450 |
0.456 |
20.0 |
|
450 Rigby |
11.430 |
11.630 |
420 |
|
0.450 |
0.458 |
16.5 |
|
460 Wea Mag |
11.430 |
11.630 |
406 |
|
0.450 |
0.458 |
16.0 |
|
458 Win Mag |
11.430 |
11.630 |
356 |
|
0.450 |
0.458 |
14.0 |
|
470 NE |
11.850 |
12.050 |
533 |
|
0.467 |
0.474 |
21.0 |
|
475No2NE31/2" |
12.060 |
12.370 |
457 |
|
0.475 |
0.487 |
18.0 |
|
505 Gibbs |
12.550 |
12.800 |
406 |
|
0.494 |
0.504 |
16.0 |
|
50 BMG |
12.690 |
12.940 |
250 |
|
0.500 |
0.509 |
9.8 |
|
50 BMG |
12.690 |
12.940 |
381 |
|
0.500 |
0.509 |
15.0 |
|
12.7x70 Sch |
12.700 |
12.940 |
450 |
|
0.500 |
0.509 |
17.7 |
|
500 Jeff |
12.700 |
12.970 |
508 |
|
0.500 |
0.510 |
20.0 |
|
500 N.E. 3" |
12.700 |
13.000 |
381 |
|
0.500 |
0.512 |
15.0 |
|
550 Magnum |
13.720 |
13.970 |
457 |
|
0.540 |
0.550 |
18.0 |
|
577 Snider |
14.230 |
14.580 |
508 |
|
0.560 |
0.574 |
20.0 |
|
577 NE |
14.550 |
14.780 |
762 |
|
0.573 |
0.582 |
30.0 |
|
600NE |
15.340 |
15.570 |
762 |
|
0.604 |
0.613 |
30.0 |
|
700NE |
17.480 |
17.780 |
737 |
|
0.688 |
0.700 |
29.0 |
|
GS Custom Bullets, situated in Port Elizabeth
on the East Coast of South Africa, manufactures solid copper, turned, monolithic
bullets for hunting and sport shooting. These bullets are used by hunters on
several continents, hunting from the smallest of antelope to the largest of
dangerous game, using the smooth HP bullet, as well as the more popular HV, FN
and SP bullets with the patented drive band concept. GSC bullets are configured
for the highest possible ballistic coefficients. SP bullets are mainly used for
sport shooting. All GS Custom Bullets are coated.