Min amout of knockdown force at 700yrds?

[justgoto]

Originally Posted by .280fan

Regardless of range,

Exactly! It would be the same at 100 or 3000.

[trebark]

Originally Posted by JWR07

I decided to use a 270wsm with 140gr accubonds. Iam going to push it at 3150fps. Now given thevelocity and Nosler published BC (496) and using hanloads.com ballistic calculator I should have 1969fps and KDE of 1205 at 700 yards. I think that even though the numbers are just computer numbers this should be ok for whitetails out to 700yrds, boar out to 300yrds and bear (southeastern black) out to 150 to 200yrds.

1970fps....1205lbs...you're good to go.

[bigngreen]

I shot a mule deer buck at 340yds with the 140 Accubond starting out at 3340fps and there is no doubt that I would shoot any animal in the lower 48 with it after seeing the terminal performance and recovering the bullet out of the dirt.
At the speed I'm running them I'm keeping them to around 800yrds, I'm a little unsure if the Accubond will open up enough to deliver that energy so I am working with the 140 Berger also. It shoots 2.5 inches higher at 100yrd zero than my Accubond load so it works perfect.
The bullet speed and construction will determine you max range, I've shoot quit a few deer out at 350-400 yrds with a cal that only has 600-800 of energy and it did a wonderful job but the bullets were delivering 100% of that energy in the vitals, if I had shot a bonded bullet they would have not delivered hardly any energy and just poked through.
Decided on a particulat rifle yet?

[JWR07]

The rifle is going to be custom built 270wsm by Clay Spencer of Spencer Barrels. Here are the specs.

Action - Kelbly Atlas Repeater
Trigger - Shilen standard (set at 2lbs)
Recoil lug - Holland's
Barrel - Spencer 1-10 twist in (Shilen #6 LT varmint profile) 24"
Stock - MCM Tac Hunter w/ edge tech
Bottom Metal - HS detach mag
Base - Kelbly's
Rings - Kelbly's double screw
Scope - Leupold 6.5x20x40lr
I can't wait till this rifle is done.

[trebark]

Originally Posted by JWR07

The rifle is going to be custom built 270wsm by Clay Spencer of Spencer Barrels. Here are the specs.

Action - Kelbly Atlas Repeater
Trigger - Shilen standard (set at 2lbs)
Recoil lug - Holland's
Barrel - Spencer 1-10 twist in (Shilen #6 LT varmint profile) 24"
Stock - MCM Tac Hunter w/ edge tech
Bottom Metal - HS detach mag
Base - Kelbly's
Rings - Kelbly's double screw
Scope - Leupold 6.5x20x40lr
I can't wait till this rifle is done.

This opens up a whole new conversation...why 270WSM? 270 bullet selection and BC are not great. The 7mm WSM I would think would be a better choice. Great bullet selection and great BCs

[JWR07]

I choose a 270wsm becasue I already have lots of .277 bullets for a 270ihmsa. This is bacisly a 300 savage with the shoulder moved back. I am getting about 2500 with it out of a 22" barrel with 140gr bullets. This is my go to rifle for light weight carrying. But I need a rifle for stand hunting over a power line right of way that I have clear shots out to approx 700 to 800 yards. Also in the 7mm vs 270 debate I have always used a 277 cal never seen the need for a 7mm.

[JWR07]

FYI just running the numbers on a 7mm 140 accubond vs a .277 140gr accubond, the numbers favor the .277 if both use a velocity of 3150. If we go to 3186 for the 277 and 3200 for the 7 the numbers still favor the 277with 1814fps and 1023fpe at 820yrds. The 7 @ 820 is 1798fps and 1005fpe. So why not get the most with a 140gr bullet. (all numbers are using Nosler numbers in Hanloads.com ballistic calculator) FYI even if you run the 7mm at noslers max it still comes up 1810fps and 1018fpe.

140gr .277 BC .496 max & 3186 max fps
140gr .844 BC .485 max & 3218 max fps

per Nosler "minimum velocities for reliable expansion 1800fps"