Heavy Bullets-Small Caliber????????????????

P

pyscodog

Active member
This is a question that has always left me scratching my head. A 223 shooting a 70,77 grain bullet. WHY?? I guess I'm just to old school. I just think if I want to shoot a 77 grain pill, I'll load up the 243. What am I missing here? A 40 grainer at 3700 or a 55 at 32/3300 and a 70/77 around 2600-2800. Load the same grain bullet in a 243 and your back up around 3400. I'm confused. Educate me if you will. Anybody else ever question this??
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It's all about ballistic coefficients which won't mean much unless you are going long range--500+ yards. The slower, high bc bullets will over take the lighter, lower bc bullets at extended range. More importantly, the high bc bullets drift less in the wind. Again this is more drastic at longer ranges. A Hornady 75 gr .224 A-max has a bc of .435. A 75 gr .243 V-max has a bc of .330. The 40 gr .224 V-max has a bc of .200. Basicly, the higher bc bullets shed their velocity less quickly and are deflected less in the wind.

You can run the numbers through any good ballistics program at realistic muzzle velocities and see the difference. The advantage of the higher bc bullet will become apparent after 500 yards. For shooting at "normal" ranges, the lighter and faster bullets will serve you just as well unless the wind is blowing a gale.
 
I got the muzzle velocities off Hodgdon's web site and ran them with the previous bc's through JBM. 100 yard zero and all atmospheric conditions the same. Windage is based on a full value 10 mph wind.

Bullet/velocity 400 yard drop/wndg 600 yard drop/wndg
75 gr .224/2900 -27.9/12.9 -84.5/31.8
40 gr .224/3660 -23.4/24.5 -88.9/67.2
75 gr .243/3440 -20.2/14.1 -65.5/35.4

By 500 yards the 75 gr bullet already has less drop than the 40 gr bullet even with a 760 fps disadvantage at the muzzle. The 75 grain .243 does have the drop advantage (If I had hedged my bets with .22-250 velocities rather than .223 velocities, it would have passed the .243 at just over 900 yards.) but, in every case, the windage is less for the higher bc 75 gr .224 bullet regardless of velocity. We can range our target almost perfectly but we can never be absolutely certain of the wind speed/direction.

 
Using the data from tt35 above, It would take the 22-250 using the 70/77gr bullets 900yds to catch up with the 243. I think thats what I read.

I guess if you plan on doing all your shooting beyond 900yds, your slightly better off with the 22-250! Shorter ranges, advantage 243.
 
I think you missed the wind, Don. But, again, if you're not shooting far enough to matter, a light bullet will still work almost as well for you depending on how hard its blowing.
 
Originally Posted By: tt35 We can range our target almost perfectly but we can never be absolutely certain of the wind speed/direction.




We have a winner!!! Drop is VERY similar in most conditions & rangefinders are very good nowdays. Not paying attention to the wind, you miss a groundhog with a light fast bullet, hit him "good enough" with the heavy.
 
It's not really a fair comparrison what Tim listed (with tthe .243" bullet going 3400). The 75 gr .243 is comming out of a totally different case. Put that much powder behind the .224 75gr and you really see the difference.
 
You dont see the point of the heavier bullets in .224 becouse you have a .243. I dont, so the heavier bullets give me great down range performance for a whopping $18. Make since now?
 
Less twist, less bearing surface, less friction, less wear.

More twist, more bearing surface, more friction, more wear.......
 
Originally Posted By: ackleymanDon't ever forget that fast twists with heavy bullets eats barrels...choose your poison.

Yep, if a guy shoots alot ,it might be a concern. Wear one out change it out. The average hunter will not have to worry about this.
 


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