.308 Win 168SMK seating depth

[Monday shooter40]

Just asking before I start my own assumptions and process. Is there a known seating depth node for the 168gr SMK in 308 winchester? I can touch the lands with about 1/3 of the bullet in the neck, so I've got A LOT of room to go backwards.

Any advice is appreciated.

 

[Bill Norris]

In my custom build Rem 700 I'm setting them @ .005 OTL. BUT, every rifle is different and it may not be what your rifle likes. CAUTION, I worked up my load from a lower charge to find max. Please work up your load and watch for pressure signs.

 

[Straightshooter1]

Just asking before I start my own assumptions and process. Is there a known seating depth node for the 168gr SMK in 308 winchester? I can touch the lands with about 1/3 of the bullet in the neck, so I've got A LOT of room to go backwards.

Any advice is appreciated.

Because there so many variables (like barrel contour, barrel length, powder burn rates, chamber dimensions), there's really no particular seating depth that's in any way universal. I will have one seating depth for one powder and a different seating depth for another. For example, for my 168 SMK's I use 40.5 gr AR-Comp with a COAL of ~ 2.858", which is .036" off my lands. For IMR-4064 it's 42.3 gr with a COAL of 2.866 and .038" off the lands. I started at .010 off the lands and I'm simply off the lands this much due to throat erosion.

You might just want to start at .010" off the lands and work up an OCW test to find the best powder load then work the seating depth to fine tune the load. Or, better yet, just start further from the lands to find a good powder load as the amount of jump really isn't important as a good seating depth that works due to good "barrel time".

 

[Monday shooter40]

Because there so many variables (like barrel contour, barrel length, powder burn rates, chamber dimensions), there's really no particular seating depth that's in any way universal. I will have one seating depth for one powder and a different seating depth for another. For example, I use 40.5 gr AR-Comp with a COAL of ~ 2.858", which is .036" off my lands. For IMR-4064 it's 42.3 gr with a COAL of 2.866 and .038" off the lands. I started at .010 off the lands and I'm simply off the lands this much due to throat erosion.

You might just want to start at .010" off the lands and work up an OCW test to find the best powder load then work the seating depth to fine tune the load. Or, better yet, just start further from the lands to find a good powder load as the amount of jump really isn't important as a good seating depth that works due to good "barrel time".

I guess I should have asked for a known zone or window. I know every barrel and chamber has its own likings.

 

[Sandstorm]

My Krieger 4 grove using RL15
and fhe 168 bullet likes a .083 jump
and my buddies like more than.100 out
You never know till you start working up your loads..

 

[snert]

I bought cases of Federal 168 GM for our multi-jurisdictional swat team. Without exception it shot at .5 MOA or better in every rifle, both factory Rem 700 and multiple customs. When I bought a 700 Varmint Special in 308, I simply grabbed a factory fed GM and set my OAL to it using a 168 MK.

I have never tried to fiddle from there, and it shot fine. I am sure I could play and maybe get better, but I have never tried. (I don't even have the length written down as I use that factory round as my "dial in" on my die. Interestingly, the 155 Palma shoots great at that OAL too.)

 

[Zero333]

168 don't really care much about the distance to the lands. Load one at 2.800" and measure it to the ogive and do the same to the rest matching the ogive measurement. Simple. That's why many still shoot it after so many decades and so many much better bullets ballistics wise.

 

[Sandstorm]

I like 43.5gr Varget in mine Zero333.....dont they fly well indeed.

 

[Zero333]

I like 43.5gr Varget in mine Zero333.....dont they fly well indeed.

43.5 Varget is my normal load. However it was quite a hot day out so I figured 43.4 might do the trick just as good. I don't mind taking chances. This time I got lucky

 

[Beiruty]

3-shots 0.28 MOA
5-shots 1.5 MOA

No-seating depth tune

 

[Beiruty]

168gr SMK at 2.808" over 42.8gr of Ram TAC.

 

[Beiruty]

Rifle
A $350 Howa 1500 308 22" skinny (sporter) actioned barrel in a $225 choate AL chassis embedded stock.