6.5x47 or 7WSM/284?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by gunderwood, Sep 23, 2010.

  1. gunderwood

    gunderwood Active Member

    Jul 7, 2009
    I'm thinking of building a new long range hunting rig. Probably medium weight/contour 24-27" barrel. Not sure about actions yet as I'm in the inital planning phase. Open to suggestions. Contemplating the 6.5x47 Lapua pushing a 140gr Berger hunting bullet or a 7WSM or 284Win pushing the 180gr Berger.

    The BCs are pretty close, 6.5/140 is 0.612/0.313 while the 7mm/180 is 0.659/0.337. Definate advantage for the 7mm, but at the expense of more recoil for only 7.6% better G7 BC. Velocity wise they are again close, 2800fps give or take. Of course actual velocities depend on barrel length etc, but for practical hunting purposes I'm of the opinion these cartridges are very close. If you disagree feel free to chip and let me know where I have errored.

    1. Terminal ballisitics: If both bullets are very similar and impacting at similar velocities, what are your thoughts on game killing power? The 7mm will retain energy better due to the extra 40gr and a slight edge in BC. Quick estimates for a MV of 2800fps shows 6.5mm having 700ft-lbs at 1000 yards and 7mm having 1000ft-lbs.

    2. Barrel life/recoil: 6.5x47 is much more efficient. It accomplishes 90%+ of what the 7mm's do, but uses just under 40gr of powder to do it, while the 7mms are in the mid-60s for 7WSM and mid-50s for 284Win.

    I'm leaning toward the 6.5x47, but am not sure how much killing power I'd be giving up on larger game at long ranges. Thoughts?

  2. bigbrother

    bigbrother Well-Known Member

    Nov 28, 2003
    IMO, even though I'm a little partial to the 6.5 I would use the 7WSM if you're planning on shooting the 180 Berger out of it. While .04 doesn't seem like a lot, it starts to make a difference 700 yards and further. I also think pushing the 180 at 2800 is a little optimistic with 284 case out of the barrel lengths you're looking at.

    IF you were pushing the 180 vs the 140 at the same velocity you would most certainly notice a difference at long range in killing "power".

    This being said, it completely depends upon what you are shooting at and how far realistically you want to shoot it. If you're talking smaller sized deer targets and smaller under 1000 yards, take your pic and make the most accurate gun you can. If you're talking larger deer and up at 1000 yards and over, I think you should look at something completely different.