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Barrel blanks

   

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Polotovary hlavní

Barrel blanks


COLD FORGING of RIFLE BARRELS

Forging Machine

Our hammer forging process is based on the GFM machines. These machines are known as radial forgers because the hammers move in linear, radial lines as shown in Figure 1. This forging technology was developed in Germany prior to World War II and continued after the war by GFM of Steyr, Austria.

 

Material of barrel

For cold forging of rifle barrels it is recommended to use a highly pure material. In order to achieve a material of such a pure degree it is normally re-melted once or twice in an electric furnace and then vacuum degassed. Impurities in steel have a negative influence on the deformation characteristics during cold forging.


Common barrel materials:

  • 32 Cr Mo V 1210
  • 21 Cr Mo V 511
  • 42 Cr Mo 4
  • 14 Ni Cr 14
  • 50 Cr V 4

Heat treatment

The material strength of the barrel blank lies between 750 and 1050 N/mm2.
After cold forging normally the strength of the barrel material increases by approximately 10%
After forging the barrel should again be stress relieved to make sure that during further processing no stress can be released which would negatively influence shooting accuracy.
An addition heat treatment (quenching) according special costumer demand is possible.
 

 

Available calibers

 

Caliber
 

 Bore   mm

 Groove/Choke mm Twist mm Bore In Groove /Choke In Twist In Outher shapes
r.4,5 4,44 4,60 450 0,175 0,181 17,7 H
r.5,5 5,44 5,60 450 0,214 0,220 17,7 H
6,35 6,17 6,35 254 0,243 0,250 10,0 C
7,65 Brow. 7,65 7,82 250 0,301 0,308 9,8 E
9 mm Lug 8,82 9,02 250 0,347 0,355 9,8 E

9 mm Brow

 8,84 9,04 250 0,348 0,356  9,8 E
.40 S&W 9,91 10,17 406 0,390 0,400 16,0 F
.45 AUTO 11,23 11,43 406 0,442 0,450 16,0 F
17 Rem 4,27 4,37 229 0,168 0,172 9,0 A
17 HMR 4,27 4,37 229 0,168 0,172 9,0 A
.204 Ruger 5,08 5,18 305 0,200 0,204 12,0 B
22LR 5,38 5,58 406 0,212 0,220 16,0 A

22 Hornet

 5,51 5,64 406 0,217 0,222 16,0 B
5,56 × 45 mm 5,56 5,69 178 0,219 0,224 7,0 B
22WMR 5,56 5,69 406 0,219 0,224 16,0 A
223 Rem 5,56 5,69 305 0,219 0,224 12,0 B

221 Rem

 5,56 5,69 305 0,219 0,224 12,0 B
222 Rem 5,56 5,69 356 0,219 0,224 14,0 B
22-250 5,56 5,69 356 0,219 0,224 14,0 B
243 Win 6,02 6,17 254 0,237 0,243 10,0 C
6,5 x 57R 6,45 6,70 260 0,254 0,264 10,2 C

6,5x55SE

 6,50 6,73 220 0,256 0,265 8,7 C
270 Win 6,86 7,04 254 0,270 0,277 10,0 C
7x64 6,98 7,24 220 0,275 0,285 8,7 C

7x57R

 6,98 7,24 220 0,275 0,285 8,7 C
7x57 6,98 7,24 220 0,275 0,285 8,7 C
7x65R 6,98 7,24 220 0,275 0,285 8,7 C

7mm Rem Mag
 

 7,04 7,21 241 0,277 0,284 9,5 D
300 Win Mag 7,62 7,82 254 0,300 0,308 10,0 D
30-06 Sprg. 7,62 7,82 254 0,300 0,308 10,0 C
308 Win 7,62 7,82 305 0,300 0,308 12,0 C
7.62x39 7,62 7,92 240 0,300 0,312 9,4 C
300 WSM 7,62 7,82 254 0,300 0,308 10,0 D
8 x 57 IS 7,89 8,20 240 0,311 0,323 9,4 D
9.3x62 9,00 9,28 360 0,354 0,365 14,2 D
9,3x74R 9,00 9,28 360 0,354 0,365 14,2 D
375H&H 9,30 9,55 305 0,366 0,376 12,0 D
416 Rem Mag 10,36 10,57 356 0,408 0,416 14,0 D
416 Rigby 10,36 10,57 420 0,408 0,416 16,5 D
458 Win Mag 11,43 11,63 356 0,450 0,458 14,0 D
458 Lot 11,43 11,63 356 0,450 0,458 14,0 D
shotgun gauge 12 18,30 0,00 0 0,720 0,000 0,0 I
shotgun gauge 12 -choke 17,4 18,30 17,40 0 0,720 0,685 0,0 I
shotgun gauge 12 -choke 17,6 18,30 17,60 0 0,720 0,693 0,0 I
shotgun gauge 12 -choke 17,8 18,30 17,80 0 0,720 - 0,0 I


Outher shapes of typical barrel blanks
 

Group

Description

Typical caliber

Diameter Max [mm]

Diameter Min [mm]

Length [mm]

Shape[mm]

Material
A rimfire rifle .22 LR 26 19 620 conical C 45
B lite rifle 222Rem. 28,5 20 620 conical 42 CrMo4
C medium rifle 308W 30 23 630 conical 15 230
D Magnum rifle 458W 37 26,5 645 conical 15 230
E gun 9Luger 36,5
 		 36,5 523 cylindrical 15 230
F gun 40SW 36,5 36,5 530 cylindrical 15 230
G gun 45 AUTO 35,5 35,5 565 cylindrical 15 230
H air gun cal. 4.5 18,6 18,6 485 cylindrical + choke C 45
I shot gun Gauge 12 28 28 700 cylindrical/choke 42CrMo4