30 Caliber vs. 7mm for Long Range — Litz Offers Analysis
Bryan Litz, Ballistician for Berger Bullets, has authored an excellent article on bullet design, What’s Wrong With .30 Caliber?. This story originally appeared in Precision Shooting magazine, and now can be read on LongRangeHunting.com.
In this article, Bryan analyzes the design of long-range bullets, from .22 to .30 caliber. He notes that while 30-caliber bullets can have very high ballistic coefficients, 30-caliber bullets must be very heavy to match the BCs of the 6.5mm and 7mm projectiles. As the chart below shows, it takes a 240gr 30-caliber bullet to match the G7 BC of a 180gr 7mm VLD. But most 30-caliber shooters don’t use those ultra-heavy projectiles because the recoil is excessive and because it takes a monster cartridge burning lots of powder to drive 240-grainers to optimal velocities. Litz notes: “Heavy recoiling rifles are harder to shoot accurately. Even if a shooter overcomes the mental aspect of heavy recoil, the ‘system’ is more sensitive to minor imperfections in shot execution. This may be another reason that drives .30 cal shooters down to the ‘middleweight’ 190-grain class bullets instead of the proportionally heavy 220-240 grain bullets.”
Litz concludes that the heavy 7mm bullets are a better choice than the biggest 30-calibers (except in unlimited weight “heavy guns” where recoil is not a factor.) Bryan writes: “Even a moderate 7mm chambering is capable of delivering 2800 to 3000 fps with the heavy 7mm bullets, much faster with magnums. The heaviest .30 cal bullet requires a big magnum just to get to 2800 fps. So the first problem is: you can’t get the heavy .30 cal bullets going as fast as the heavy 7mm bullets! Even if you could get the same muzzle velocities from the heavy .30 cal bullets, it would take much more powder to do it, barrel life would suffer, and you’ve only achieved parity with the 7mm. The various negative effects of the incredible recoil are really just the ‘nail in the coffin’ for the heavy .30 caliber bullets.”
Bryan’s Updated Second Edition Ballistics Book
If you are interested in learning more about bullet design and ballistics, check out Bryan’s book, Applied Ballistics for Long Range Shooting. This highly-respected resource, now in its second edition, includes experimentally-measured Ballistic Coefficient (BC) data for over 236 long range bullets of various makes. The new edition of Applied Ballistics was upsized to 7″x10″ and Bryan added two new chapters, while updating the existing chapters. Bryan’s book comes complete with a CD containing Version 2.0 of the Point Mass Ballistics Solver. CLICK HERE to order Litz’s book and CD for $49.95.
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