Sierra 168 or 175 gr. HPBT MatchKing for 1:12 .308?

[Kristian_Jensen]

Sierra 168 or 175 gr. HPBT MatchKing for 1:12 .308?

Rifle: Remington 700 with Lothar Walther 25" chambered in -308

http://www.lothar-walther.com/brcms/...bild4405_2.jpg

ØD1 = 0.940"
ØD2 = 1.240"
L1 = 6.0"
L2 = 26" or 28"

Does the 7gr. difference matter or should I just pick what's available to me?

 

[NovaHunter]

How far are you shooting?

If you are shooting 800 yards or less than the 168 will be fine. If you need to shoot to 1000 then I would try the 175's.

Also, take a look at the TMK's. The 168 TMK is super sonic to 1000 yards.

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[Kristian_Jensen]

So, beyond 1000 you'd reccomend 175.... i see there are also 175 TMK

Are they to be preferred over the HPBT variants?

 

[NovaHunter]

The 168 SMK is a great bullet, it just starts going trans sonic and destabilizing near the 1000 yard mark. 800 yards and in it is a great bullet. I shoot it out to 600 yards all the time.

If you are going to shoot 1000 yards, look at the 175 SMK or either 168 or 175 TMK's. The TMK's have a better BC than the SMK, which will help you if it is windy.

I think your 1:12 twist will stabilize the 175's, but you might want to check with Sierra's specs to make sure. My .308 rifles are all 1:10, so don't have any experience with a 1:12 .308.

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[Supersubes]

These bullets are nearly identical except for their boattail design, resulting in one being slightly heavier. The 7 grain weight difference doesnt mean much. The final muzzle velocity will be quite close for each of them. Then it comes down to bc, and the 175 wins there. Aside from your gun preferring one over the other, the 175 is the obvious choice. Dont sell yourself short though. There are perhaps a dozen other bullets that would be suitable. The hornady 178hpbt comes to mind, or the many 155's that nearly match the sierra 175 bc(but go faster).

Here's the jbm stability calculator. Punch the numbers in and see if your barrel will stabilize whatever bullet you like. Youre looking for an sg or 1.5 or greater.

http://www.jbmballistics.com/cgi-bin/jbmstab-5.1.cgi

Depending on where you live (top of a tall mountain perhaps?), you can get away with shooting a longer bullet.


This is berger's quick reference chart. At the far right is a recommended twist rate. It's based upon the heaviest air one could shoot it, which may not apply to you.

http://www.bergerbullets.com/pdf/Quick-Reference-Sheets.pdf

 

[03psd]

My LTR had a 12 twist. It shot 168 SMK wonderfully. I tried a bunch of different 155 Scenar loads and never got satisfactory results. I also tried 175 SMK and got decent results but not so much better then the 168gr bullets at my available distance <600y that I could justify the cost difference.

 

[Kristian_Jensen]

Thanks. I'm going for the 175

 

[Centurion123]

1-12 and 175smk works fine, even from my 20" barrel. The 175 is the better choice.

 

[jtake]

My AIAE III is 1:12 24". It likes both 168 and 175 smks, but 175 shoots slightly better.

 

[Devildog]

I shoot the 175's, if your a reloader look into the new Nosler 175 rdf's. I havent used them yet but ran the numbers through my ballistic calculator and if the posted bc's by Nosler are correct it may prove to be a better choice then Sierra's 175hpbt. I'm ordering some to try out. Good luck

 

[flyright]

I just received my order of the Nosler 175's (200 of them). I've found the weight not as consistent as the SMK's. The Noslers are between 174.8 to 175.6 but the ogives are very consistent +/- .001 on about 20% with 80% just about identical - this seems to be better than SMK's. I'll punch some holes soon and report back.