.308 past 500 yards, 168s vs. 175s

[markm]

Can you share any experience you've had with these bullet weights beyond the 500 yard mark?

(we're getting about 2515 FPS with 175s from our 20" Rem 700s)

[ICANHITHIMMAN]

Thats good speed what powder are you using? I ran a few boxes of the 175smk out of my 308 24" out to 1k with great results. Before switching to the AMAX. I never could get the 168g smk to stabalize to my liking out of a 1-10. I dont think it was ever designed to rotate that fast out to 1k.

I have sence stuck with the 175smk even in the 1-11 twist of my M1A.

Im on a heavy bullet kick now 208g AMAX its fun speeds are lower of course but the groups dont lie.

[markm]

I'm running 42.8 grains of Varget with the 175 set to magazine length in Lapua brass.

We get 2511 fps and 2513 fps out of My 700 and Pappabears 5R 700 respectively.

[sinister]

The 168 SMK was specifically designed for Olympic and International 300-Meter shooting. It was just incidental that they shoot well/OK to 600 yards (the US highpower National Match Course).

They tend to go trans-sonic around 850 yards when launched at around 2550-2600 fps. It helps to have a 1-10 or 1-11 twist.

The 155 SMK pushed out of a longer 28-30 inch barrel around 2900 fps is shot by many Palma competitors due to goofy British and Commonwealth laws (where you can own one rifle per specified purpose, specifically for long-range competition). If you can't show a need (and show you've actually shot or practiced that discipline in the last year) you lose your license. Communists.

The 175 SMK has the same ogive profile as the 155 but obviously is heavier, retaining velocity better past 1,000 yards when launched between 2550 and 2700 fps.

The 175 SMK or the current 180 Sierra Game King (with the older 180 Match King boat-tail) will probably give you better results if you're tending toward the shorter barrels. You can't exploit the benefits of the 168 and 155 ballistic coefficients if you can't launch them fast enough.

[Sensei]

168 grain OTM generally have more trans-sonic stability issues than similar mass AMAX or 175 grain OTM. Thus, I generally stick to 175 grain OTM for my long range shooting in 308.

Having said that, I do think that the TAP 155 or 168 grain AMAX is the best balance of long range accuracy and terminal performance.

[markm]

The 175 SMK or the current 180 Sierra Game King (with the older 180 Match King boat-tail) will probably give you better results if you're tending toward the shorter barrels.

Yeah... my trajectory chart shows the 175 staying super sonic to 1000.

We may give the 180s a try too. Thanks.

[Pappabear]

The 168 SMK was

They tend to go trans-sonic around 850 yards when launched at around 2550-2600 fps. It helps to have a 1-10 or 1-11 twist.

The 175 SMK or the current 180 Sierra Game King (with the older 180 Match King boat-tail) will probably give you better results if you're tending toward the shorter barrels. You can't exploit the benefits of the 168 and 155 ballistic coefficients if you can't launch them fast enough.

So, how far out do the 168's perform well in your opinion. 500? 700?
800? Where is the pretty hard and fast cut off? What can we reliably and consistently run the 168's?

Mine is 11.25 twist 20 inch. Marks is a 20 inch SPS, I forget the twist?

[markm]

Marks is a 20 inch SPS, I forget the twist?

1/12 Hammer forged barrel according to REM's site.

[ICANHITHIMMAN]

I dont even mess with the 168gSMK if you want a real edge and would like to stick with a match target type of bullet. I would look at the 175g Berger VLD, Bryan Litz has put alot of time into that bullet to up the BC and stabalize the transonic flight.

Also I'm not a Varget fan, that in its self means very little who am I right. Well I would give R15,VV-N540 a try and see if it pushes you speeds up I think it will.

If you realy want to go nuts look at the 208g AMAX or 210 VLD and some VV-N550 or R17.

[markm]

We ran a pound of R15 and didn't hit anything too exciting. We've also been messing with IMR 4064, but Varget performed more consistently in velocity between the two guns.

We might circle back to it sometime... now that I've got the bullet runout down and we have decent triggers in both guns.

I know people complain about lot to lot variations in Varget. I'm just burnt out on load development for now.