Miscellaneous

Selecting Cartridge and Caliber


Long Range Cartridge/Caliber Selection
by Lucas Beitner

Trying new cartridges is one of the most interesting aspects of shooting. Most every cartridge has its application or “place”. It seems many are   confused when it comes to selecting a cartridge and caliber. Questions like “what’s the best caliber?” are very common. No one likes to have their questons answered by another question (specifically “what are you using it for?”) but, there is no “best” caliber or cartridge. Application is the key. Here’s how I decide what caliber I want next (I say “next” because given enough time I’d no doubt have them all ). I’m lucky enough to be able to   reload my own ammo, If you can’t, the selection process is different. Those who don’t reload must take into accout ammo availability as well as cost. Cartridges like the 308 and 223 are very good when restricted to using factory ammo due to lower costs and availability of high quallity ammo. I’ve   also noticed the 308 generally comes from the factory with fast enough twist for fairly high BC bullets one would choose for long range shooting. If you do re-load, this is the basics of how I select what cartridge I want, specifically, with long range application.

Step 1) select a bullet.

I’d first decide how heavy a bullet you want to shoot, for vital shots on Elk 1200ft/lbs of engergy would be nice. 600ft/lbs is a good minimum for deer (These energy figures I read in the book “Hunter’s Guide to Long Range Shooting” by Wayne Van Zwoll, a fellow I trust to give accurate information). A   ballistic calculator can give you a good idea of the engergy available at a given distance. If you’re just punching paper this isn’t a factor. For long range, BC is paramount. For example if you want a 130gr bullet it would be foolish to use a 7mm .395 BC, when a 130 gr 6.5mm has a BC of .595. If these were fired at the same MV the 6.5mm would have greater energy at long range,not to mention superior ballistics and wind bucking ability. For my   personal use I go with the following (these will change with new bullets becoming available all the time):

6mm (.243″) up to 115gr
6.5mm (.264″) from 130gr to 140gr
7mm (.284″) 140gr up to 180gr
7.62mm (.308″)175gr up to 240gr
8.58mm (.338″) from 250gr to 300gr

Step 2) select a cartridge

You should now decide the ballistics/energy required for your application. Cartridge selection should be based on speed, and bullet BC’s. If you’re   only shooting out to 500yds it may not be wise to sacrafice too much speed to shoot a bullet with a higher BC. At 1000yds BC is extremely critical and   one may be well suited to choose a higer BC even if it requires you to sacrafice considerable speed. Spend time checking the possiblities with a ballistic caluclator. Be realistic with your expectations of muzzle velocity. It’s easy to come up with increadable results on a ballistic calculator. Check the recorded MV’s of more than one source. You may be able to match the results you read about, but your brass may become fatigued   quickly doing so. It may also be advisable to select cartridges that are common in competition as info on accurate load data, and quality components   will be more abundant. If you’re using a high quality hand-lapped barrel (especially the Benchmark Barrel’s 3 grooves I use) you are within in your rights to expect some decent MV’s.

Step 3) Compromise  

Now that you’ve found the “perfect” cartridge/caliber for your application (no doubt a super magnum) you need to compromise with…
1) Expected barrel life
2) Recoil you’re willing to tollerate
3) Weight (large magnums reqire longer barrels to explot their potential, and also subject you to carrying heavier ammo).
4) Novelty factor (there are many ways to get a desired result; in reality the 338 RUM gives up little compared with a 338 Lapua magnum. It’s the   novelty of the Lapua that makes it desirable to so many.)
5) Cost (100gr of powder per shot down range will empty your savings quick if you do much shooting.
Let me know if you find a good deal on .338″ 300gr SMK’s).
6) Availability of reloading components (no matter how good the cartridge, you’ll be up a creek if you can’t find brass anywhere).
Other things to keep in mind…

Make sure your barrel has a fast enough twist to stablize the bullets you plan to shoot. This is often the limiting factor in factory rifles for long   range use. If you’re building a custom rifle you can really exploit a caliber’s long range potential by getting the proper twist. In my experience some bullet makers don’t recomend a fast enough twist. Check what others are using to stablize specific bullets. Some cartridges require a longer barrel to exploit their capacity. If your barrel is too short for your cartridge, you may be simply wasting powder. If a short barrel/rifle weight is a priority for you selecty your cartridge accordingly. For example the WSM’s have been reported to give good MV with shorter barrels compared to the standard   magnums wich often sacrafice a great deal of MV if the barrel is not at an ideal length.

I believe the process outlined above is in a logical order, however, you may have a factory rifle or already have a rifle built. If this is the case   check your twist rate and test bullets that will work with your twist and give you favorable ballistics for your application. You may have to   compromise quite a bit, but when it’s time to replace that barrel get it right. When investing money into a rifle build, do the research necessary to   get it right. Keep in mind, new cartridges will often be hyped a great deal (some rightly so) especially on the internet. Don’t be tricked so easily.   There is no “magic” giving a cartridge supernatural performance. If a cartridge has a higher opperating pressure it may give excellent performance   per/grain of powder. If a cartridge neither withstands higher pressure, nor holds more powder than another, how can it give substantially higher performance? I won’t say it’s not possibe, but use common sense. I could find information on the internet to back any rediculous claim I’d want to make, but this doesn’t make me correct.There are some cartridges (with factory loads) that use powders not yet available to the public wich yeild excellent performance. You would not be able to duplicate this performance with your handloads.

Things will change. New bullets and cartridges are becoming available all the time. Recently the 6.8mm (.277″) has recieved a boost due to new high BC   bullets available from Berger (likely in response to new cartridges like the 270WSM and 6.8 SPC. Previously there was little intrest in this caliber for long range use, due specifically to bullet selection.
 
I’m not claiming this is the only or best way to go about cartridge selection. This simply outlines important factors that should be considered by   anyone deciding on a cartridge for practical long range use.

Discussion

  • Kirk T. Hindoien

    So – Reading the above, you say the higher the BC the better the bullet is for long range shooting. Even if you give up MV, the BC will help carry the energy further down range.

    Thanks,

    KIRK T.

  • Lucas

    Yes, basically. It depends on how far you plan to shoot and how much velocity you will be sacraficing. At shorter ranges, like 500yds, the highest BC bullet available will not give you the best ballistics. At 1 mile the highest BC (usually heaviest) bullet may infact give the best ballistics (depending on your cartridge). There are online ballistic calculators that will allow you to determine what’s best at a given distance. Also keep an eye on how much wind drift you’ll have with spcific bullets/loads. I find it easier to get the drop correct and more difficult to get the wind dope correct, especially when shooting across a canyon. If you have a question about a specific load/bullet combo I’d be glad to help. You can e-mail me at lucas@longrangeshooter.com

  • http://http://http://http://http://www.LongRangeShooter.com Mike

    Good article Lucas, very informative for those of us that are a little behind the times when it comes to modern calibres and their specific applications. I understand the 6mm/06 is a pretty good varmit round. Have you heard of anything on it? I was at Mels the other day dropping off my new RUM and he mentioned that my old Mauser action was usable. So, I have been thinking of making a 6.5/06 out of it until I heard about the 6mm/06 abilities. Something to consider….. :{)

  • Lucas

    Thanks Mike. If you’re going to keep it 500yds and less the 6mm-06 would have better ballistics for sure. If you plan to shoot out to 1000yds the 6.5-06 would get the nod. With a 6.5-06 you could shoot the 140gr Berger VLD’s (.640 BC) at nearly 3000fps, not that’s some good long range ballistics. Both of these cartridges are hard on barrels so it depends on how many rounds you plan to shoot. Larger bores allow better barrel life so the 6.5 would have a bit better life than the 6.

    The -06 cartridge has a ballistic twin, the 284. Therefore you may also consider the 6×284 and 6.5×284. It’s also posibble to use cartridges based on the 284 in short actions although depending on your reamer specs it could be difficult to mag feed with the high BC bullets.

  • Joe Perez

    Hi Mr. Lucas, I recently got into some semi long range shooting. I hand-load for 308,30-o6,and 22-250. Recoil is important to me. 308 would be my max. Can you suggest some of your favorite cal. 5 or 600yds would be max. Was looking at the 6.5-284. Also can you suggest some rifles under 2grand. Was looking at the Sav. Ba in 308 and their F-class bolt action. Thanks for any advice

  • http://none George A Brown

    I prefer 30-378 in 130 grain bullet at any range up to 600 yds

  • Steve

    Just getting started with a Browning BAR 300WSM, with a 4×16 vortex scope,wanting to shoot 700 yards for elk. What would be a staring point. I was going for a different gun to start with, put this one fell into my hand for cheap. not the best but maybe a possibility?
    Thanks in advance

  • http://longrangeshooter.com caleb

    sorry it has been almost a year since you posted this question. I am looking in to getting the site rebuilt and up and running.

    I think that would be an ok set up for out to 700 on elk. what do you shoot for range with it now? i would say quit shooting it at 100 and shoot groups from 200 up in range. when you get comfortable and tight groups start shooting cold bore shots at further range trying for a 1st round kill shot

  • Vincent Lowry

    Could anyone tell me where to find load data for a 6.5-300 wsm. Thanks.