Question on bullet performance on target shooting.

[NDAR15MAN]

For target shooting only. Question..... If you have a 69 gr bullet and a 50 gr bullet in 223 cal and they are both shooting the same Moa at 100 yards ( let's say 1 inch groups , exactly 1 inch groups with 0 wind on the day you are shooting targets ) . Can you make the assumption that you should always be shooting the heaviest bullet because it should ALWAYS perform better in any wind condition ? Even at 200 , 300 , 400 , 500 , 600 yards ? Thanks. Martyd

 

[CJ6]

Your wind reading skills and drop doping will be the determining factor with the lighter bullets. The higher BC (NOT WEIGHT) a bullet has the less drop/drift it has making it "easier" to cut the wind/drop.

 

[spclark]

Can you make the assumption that you should always be shooting the heaviest bullet because it should ALWAYS perform better in any wind condition?

You can but physics will prove you shouldn't in some situations.

One example: 6mm is a popular bullet diameter in several catridges. Some folks find Berger's 105VLD or their newer 105 Hybrid to perform better from 600 to 1,000 yards than D. Tubb's (Sierra-made) 115DTAC or Berger's own 115VLD.

It's not so much all about weight but how well a bullet's design performs at a speed you're comfortable shooting them.

 

[Highpower-FClass]

Discounting accuracy, BC and velocity are the determining factors. It is not possible to universally say that the heaviest projectile will buck the wind better, though at 'reasonable' velocities it often will. Take a 68 grain Hornady 223 projectile and shoot it at a slow poke 2500 ft/s and it will drift 3.4 MOA in a 10 mph cross wind at 300 yards. Then shove a case full of 24 grains H322 and shoot a 55 gr berger at 3300 ft/s and it will drift 3.1 MOA in a 10 mph cross wind at 300 yards.

So while a heavier projectile, of similar quality in the same caliber etc. will typically, or even most often, have less wind drift at a given distance it is not possible to say it will always be the case.

You can quite easily find out expected wind drift between two projectiles by using JBM ballistics calculator:
http://www.jbmballistics.com/cgi-bin/jbmtraj_simp-5.1.cgi

Plug in your first projectile and velocity, set max range to 1000 and zero range to 100. Click calculate. Look in Windage MOA column for your distance of interest. Go back and do the same for the other projectile and its velocity. This will give you a pretty good idea which will buck the wind better.

Of course this is only one of many many different factors of how well a specific projectile will do in your particular rifle at a particular distance but all other things being equal, the above will give you a good idea of wind drift for two different projectiles.

 

[Mozella]

As others have pointed out, bullet weight isn't the only important factor. BC and how fast you can launch them are equally important. If you want to know more about how to best balance, MV, BC, weight, and precision you might want to read Brian Litz's latest book which discusses this subject in some detail,
Modern Advancements in Long Range Shooting Vol. 2

 

[NDAR15MAN]

Thanks for the answers. A lot of sharp people here. Martyd

 

[Ned Ludd]

In general, it is fair to state that when loaded to equal pressure, the higher BC bullet will experience less wind drift. Realistically, what that means is that it is very difficult to get a lighter, lower BC bullet to outperform the heavier, higher BC bullet at safe operating pressure. Yes, you can push the lighter bullet much faster than the heavier bullet. However, it is typically not possible to push it fast enough to overcome the BC deficit without jacking the pressure way up, unless the BCs of the two bullets were fairly close to begin with.

In the example you gave above, I would generally try to shoot the 69s over the 50s, especially at longer distances, because they'll get blown around less. Frankly, neither one of those is a good choice past about 250 yds if you shoot where it's often very windy. Something in the 77-80 gr range would be a big improvement in terms of wind resistance IF your rifle could accommodate them, and IF they shot with good precision. It's important to note that you included the critical caveat in your example, in that the two bullet choices showed equal precision. This is often the deciding factor. A heavier higher BC bullet doesn't help much if you can't get it to shoot with good precision in your setup. Likewise, bullet cost and availability may be additional factors to consider.