Bullet weight, velocity and BC......trade offs??

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Dan B, Feb 17, 2006.

  1. Dan B

    Dan B Well-Known Member

    Messages:
    290
    Joined:
    Jan 16, 2002
    For setting up a gun to handle shooting inside of 500 yards...which do you choose...lghter bullet, less BC but higher MV or heavier bullet, more BC and less MV. The caliber is a .284 Winchester (1 in 9" twist barrel) and the game I'm after is elk. I know that the most accurate load is ultimately the winner but please read on.

    I'll be testing the 140gr AB, 154gr SST, 160gr AB, and 162gr SST (and A-Max for target shooting). I've compared the book numbers for velocity and kinetic energy but I'm looking for actual experience. I know that heavy for caliber bullets are the ticket for LR shooting...lower initial velocity but better retained downrange energy. But at shorter range (0-500yd) is the heavier bullet and higher BC (160gr to 175gr bullet) significantly more beneficial or am I better off w/ more velocity and higher impact speed from a lighter 140 to 150gr class bullet?

    Educate me!!
     
  2. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

    Messages:
    6,848
    Joined:
    Jun 12, 2004
    Dan B,

    Wind drift is the first thing you need to worry about when hitting a target at longer ranges. It is true that lighter, faster bullets will often match the heavy slower bullets out to 500 yards in wind drift and generally will shoot even flatter.

    The problem is that when the bullet gets on target, we need the bullet to do alot of work. In the case of the 284 Win, we need the bullet to do ALOT of work because there is not an over abundance of velocity or energy from this chambering at 500 yards.

    That said with the proper bullet there is certainly plenty but for a dedicated elk rifle at 500 yards it is on the lower end of what I would recommend.

    Of the bullets you list, I would pick first the 160 gr Accubond. I believe Hornady offers a 154 gr Interbond as well. That would be a much better choice then the SST for elk. Deer, thats another story but for elk, use the bonded core bullets in this weight range.

    175 gr bullets are really to heavy for the 284 class of rifle in my opinion. The 160s offer plenty of penetration, better velocity and fit this case size better. The key is the bullet you use, the 160 Accubond would be very hard to beat if it shoots well in your rifle.

    Just my opinion,

    Kirby Allen(50)
     

  3. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

    Messages:
    6,848
    Joined:
    Jun 12, 2004
    Dan B,

    Wind drift is the first thing you need to worry about when hitting a target at longer ranges. It is true that lighter, faster bullets will often match the heavy slower bullets out to 500 yards in wind drift and generally will shoot even flatter.

    The problem is that when the bullet gets on target, we need the bullet to do alot of work. In the case of the 284 Win, we need the bullet to do ALOT of work because there is not an over abundance of velocity or energy from this chambering at 500 yards.

    That said with the proper bullet there is certainly plenty but for a dedicated elk rifle at 500 yards it is on the lower end of what I would recommend.

    Of the bullets you list, I would pick first the 160 gr Accubond. I believe Hornady offers a 154 gr Interbond as well. That would be a much better choice then the SST for elk. Deer, thats another story but for elk, use the bonded core bullets in this weight range.

    175 gr bullets are really to heavy for the 284 class of rifle in my opinion. The 160s offer plenty of penetration, better velocity and fit this case size better. The key is the bullet you use, the 160 Accubond would be very hard to beat if it shoots well in your rifle.

    The main thing in your post that will determine which bullet you should use is the word "ELK". These are tough critters. For deer hunting, the 140s and 150s are fine, for elk, use the 160s and you will be much happier with the results, especially if a big heavy shoulder happens to get hit!!

    Just my opinion,

    Kirby Allen(50)
     
  4. 41mag

    41mag Well-Known Member

    Messages:
    752
    Joined:
    Feb 7, 2005
    Personally I would go with the 154 or the 160gr AB with the latter getting probably more attention. However the best shooting one would win out.

    The advantage you will get with either will be better penetration than with the 140gr., (IMO), especially at the longer ranges. Yes the 140gr AB is designed to do some great stuff, but it is still a 140gr. In the 154, I might give the SPBT a try over the SST, just due to experience with them both. The SST is a great bullet however it seems to open up pretty quickly on the lighter game we have shot with it, where the standard SPBT penetrated a little deeper before really getting into the bigger wound channel. Granted I am also shooting them from a 7 mag as well as a 280 Rem. Also, our deer over here are nothing like an elk, but we have also used both on hogs with very similar results. I can promise you that the hogs are a GREAT test meduim for bullet preformance. They have it all, tough hide, big bones, and a tenacity for hangin in there even after being hit by a truck load of energy.

    The 160gr AB would to me seem to be best suited. I know your not going to get blistering speeds from it, however, with the range you specified you will still be well within a realm of good penetration and accuracy. IT should hold together quite well and get well within the vitals on most any decent shot you might attempt. Even with a solid shoulder hit the heavier 160 will still have the remainder of the shank pushing it on through and into the vital areas.
     
  5. Dan B

    Dan B Well-Known Member

    Messages:
    290
    Joined:
    Jan 16, 2002
    Kirby...I was asking so I can start gathering components for the XP that you signed for yesterday. I know the .284 Winny is on the light side but w/ a 160gr bullet and some calculations I have ran, it will still deliver over 1500 ft.lb. at 500 yards. Sufficient for "calendar" shots...broadside, relaxed and unsuspecting. I'm fully aware that it won't drive a bullet from stem to stern...and that's ok. The gun will be shot a lot (in matches and deer hunting) and I want it to last a while (hence the .284 vs the 7WSM)...then once I'm comfortable at shooting beyond 500yds then I'll jump to the 7WSM.

    Sounds like a 154gr IB or 160gr AB will be the first to scoot down the tube of my APS XP-100.

    Opinions is what I'm looking for. Thanks fellas......Dan
     
  6. Michael Eichele

    Michael Eichele Well-Known Member

    Messages:
    3,829
    Joined:
    Jan 6, 2003
    You wont be dissapointed with the 160 AB for what youre trying to accomplish.

    Try the 162 AMAX for deer ect.. but stick to the AB's for elk.
     
  7. Bart B

    Bart B Well-Known Member

    Messages:
    2,483
    Joined:
    Dec 25, 2005
    It's about a toss up regarding what's more important at 500 yards for accuracy; wind bucking ability or accuracy. But I would choose accuracy because one can learn to read the wind and make corrections for it but you can't make corrections for accuracy after the ammo's loaded.

    And unless you can shoot a 160-gr. spitzer boattail bullet out of your .284 Win. at 3000 fps, you'll not get 1500 ft. lbs of energy at 500 yards. One might get 2800 fps from a .284 Win. using a 160-gr. bullet but I doubt it unless the barrel's 26 or more inches long.
     
  8. Aussie

    Aussie Well-Known Member

    Messages:
    250
    Joined:
    Apr 29, 2004
    I have a 7mm WSM and wouldn't tackle elk sized game at 500 yards with it let alone a .284 .
    You're talking 7mm RUM territory IMHO .
     
  9. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

    Messages:
    6,848
    Joined:
    Jun 12, 2004
    Oh yes, Now I am on the same page!!!

    Bullet recommendation still stays the same, rifle or handgun, me personally, the 160 gr Accubond or one of Richards Wildcat Bonded Cores would be my first choice to try.

    As mentioned, the most accurate bullet that will do what is needed is the best choice.

    Kirby Allen(50)
     
  10. wapiti13

    wapiti13 Well-Known Member

    Messages:
    521
    Joined:
    Mar 8, 2004
    Dan B, What length barrel are you having built? What velocity are you projecting? Just curious.
     
  11. Dan B

    Dan B Well-Known Member

    Messages:
    290
    Joined:
    Jan 16, 2002
    Bart...I'm plugging in a 162gr bullet (.625 BC) at 2700fps and 8500ft of elevation gives 1700+ ft. lbs of energy at 500 yards. A 154gr (.525 BC) at the same velocity will give 1509 ft. lbs. Both loads will also give approx 10MOA of drop at 500yards which will work great against my Burris Ballistic Plex in the 3-12x32 LER scope. I'm not trying to cause a ruckus...just asking to opinions to verify my calculations (and theories) or shorten my effective range.

    The barrel length will be seventeen inches on an XP-100 that Kirby is going to build. I'm getting 2600fps from a 7mm-08 using 154gr SST's and 16.75" of barrel. I'm hoping that more capacity will get the 154gr IB or 160gr AB to the 2700fps mark.
     
  12. Bart B

    Bart B Well-Known Member

    Messages:
    2,483
    Joined:
    Dec 25, 2005
    Dan, what 162-gr. hunting bullet has a BC of .625?
     
  13. Dan B

    Dan B Well-Known Member

    Messages:
    290
    Joined:
    Jan 16, 2002
    Bart...my mistake...the 162gr SST is .550 but still generates over 1600 ft. lbs. at 500 yards. And still over 1500 ft. lbs. at 575yds. I want to run the numbers w/ the 160gr AB but can not find the BC.

    All I hunt with is specialty handguns so I am used to dealing w/ lessened energy and more arching trajectory. I'm not trying to turn a .284 Winny into a 7RUM...and I'm willing to limit shots to what the guns is capable. There are certainly more capable elk cartridges...and I own several in rifles...but I'm not a monster capacity case kind of shooter and this is my first elk hunt with a handgun. I've dumped them with a bow and rifle w/o a problem. That's why I'm asking for input.

    Thanks.......Dan