Chinchaga Bullets

Some ballistic coefficients for 257 caliber bullets and muzzle velocities at which data was recorded
257/180 2600fps G7 0.358
257/163 2666fps G7 0.328
257/150 2761fps G7 0.337
257/141 2745fps G7 0.332
257/135 2909fps G7 0.300

Stability twist requirements:
257/180 (1:7” twist)
257/150, 163 (1:7 twist)
257/135 (1:8” twist)

Test rifle 1:6 twist Jury barrel Red Deer, Alberta. Chambered 257 SAUM. Bob Galloway, Rocky Mtn House (Custom GunWorx) chambered it and threaded to a Pierce Precision Receiver.

Please post any questions to my email:
[email protected]

375/430ST bullet. Heaviest 375 I can make. Needs at least 1:10 twist. Length is 2.153”, Boat tail is 0.348”, nose is 0.887”, bearing surface is 0.918” G7 BC 0.564

New bullet. 308/264ST. 1.846”long, 0.918” bearing surface, boat tail 0.190”, nose length 0.728”. Minimum twist 1:9”, 1:8” would work best

308/242GR with steel ballistic tip. Length 1.734”, bearing surface 0.810” long, boat tail 0.190”, nose length 0.728”.
9.5” twist will stabilize, 9.0” or 8.5” twist will be better. Similar bullet, same profile 236GR G1 0.694. G7 0.385.