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.
Similar Posts:
- Book Review: A New Ballistics Resource from Bryan Litz
- New Editions of Applied Ballistics Books
- Big Bore Basics with Bryan Litz — From .338 to .50 Caliber
- Litz Field-Tests BCs of Sierra Tipped MatchKings
- Second Edition of Litz Applied Ballistics Book Announced
Share the post "30 Caliber vs. 7mm for Long Range — Litz Offers Analysis"
Tags: ballistics, BC, bullet, Litz
The winner of the 2009 Steel Safari shot a 7mm WSM (180gr Berger VLD). The only .30 calibers present were a handful of .308s (top 308 was 7th place) and one .300 WM. The top 10 positions were totally dominated by 6’s 6.5’s, and 7’s. -z
As an F-Class shooter where muzzle brakes are not permitted, I think the choice for long range is between 6.5mm and 7mm, not 7mm and .30 cal.
To be fair to the .30, the main problem is that none of the major bullet manufacturers are making them with high BC. The sectional density of the 240grn SMK shows that it COULD be made with a higher BC than the 180 Berger. Perhaps there is some other limiting factor which makes this impractical.
Alan,
I completely agree that the problem with heavy .30 caliber bullets is that they’re poorly designed. The Hornady 208 Amax, Sierra 210 MK, and Berger 210 VLD and BT are not bad options in the 210 grain weight class, but 210 isn’t really a heavyweight for .30 cal.
I know at least 1 bullet maker (wink) who’s working to fill the nitch for well designed heavy .30 caliber bullets.
Bullet availability will dictate the success of a caliber within it’s application. Look at .277 caliber. Right between 6.5mm and 7mm. Why isn’t .277 caliber considered a ‘competition’ option? Because it’s traditionally a hunting round, and all the bullets made for .277 are designed around that application.
All that’s needed to bring the .30 caliber back into the forefront of LR competition are some well designed ‘true’ heavyweight bullets (around 230 grains). For some applications, the recoil will still be prohibitive, but in other applications it won’t matter.
-Bryan
Sir, if you make a high density tungsten cored .30 cal you would exceed their present BC limitations without increasing overall bullet length; heavy, short with more case capacity… Now, make the 6 and 7mm with a tungsten core and you will have a strong winner.
Mark Caracci
As this article has been brought back to the fore, it is worthy of mentioning that Matrix Bullets in Canada has indeed approached the .277 caliber with an eye towards a very high BC match round, and they have done so in the form of a 175 grain bullet, with an average anecdotal G1BC of .700, based on the testing that has been done by Long-Range Bechrest testers. They have also started producing a 165 in this caliber as well.
It will offer a nice change from the rampant supply problems with quality 7mm bullets, and it will be nice to compete with something very different.
Compared to the 1st edition the book by Bryan Litz it now contains data for 60 additional bullets (my counts):
cal .224: 4
cal .243: 7
cal .264: 7
cal .270: 3
cal .284: 9
cal .308: 22
cal .338: 8
For six “old” bullets additional measurements were done to improve the reliability of the data. All 236 bullets (except one) have their dimensions shown in a drawing. The larger page size was used to add for each bullet a table of stability for typical twist rates of the caliber.
In a time of more or less fictional advertised ballistic data, the book by Bryan Litz is really invaluable.
He explains long range ballistics in a plain, easy to understand way.
The software is, contrary to most commercial programs, not overloaded with features, but very straightforward to use. I my view it is ideal for the beginner.
I just ordered some Berger 230 grain Hybrid Tactical OTM .308 bullets for testing. The G7 BC is .364 vs. .345 for the 7mm 180 Hybrid. It remains to be seen if the additional recoil is a problem in a 22 pound rifle.
Like to see something in a .257 diameter VLD about 123 grains or better.
Variety is the spice of life!
I shoot a .300 WSM in High Power Long Range and like the 210 gr. bullets. I’ve shot well with 220 and 240 grain pills, but they give me headaches now when I shoot them. The 210 does not. I hope Berger doesn’t stop with their .30 cal. improvements at 230 gr. There’s still a market for the 210!
With respect to a tungsten core, Powell River Labs produced such in a .22 cal 87gn during the early 90’s. The OAL is around 1.004″. They performed well during testing at Oak Ridge, had a high BC but an even higher price, $1.00 per bullet. Don’t know if they continued or ever produced for other calibers. My interest in these dropped rather quickly simply due to the price.
As a long time 7mm user I fail to understand why we bother with 30 cal, apart from habit. The 7mm is head and shoulders above the 30 cal in performance and has none of those annoying habits the 6.5 has at long distance.
“Market forces” (whatever that really means) seem to keep the 30 cal afloat. I know when I started in 7mm the supply of projectiles was impossible and now it is much better. I hope in 5 years time we will see more choice of bullet weights in this caliber.