Home Forums Hunting & Shooting Ask The Gunwriters 308win loads: 155grn Scenar and 155 grn A-Max- what am I missing?

Me and my bolt gun ground hog pards swear by the 175smk. Is there any other load for a 308?

What is the attraction to the 150ish loads> I am all ears but I don't honestly understand the thinking or have any experience with em.

Is it a flatter out the gate trajectory or something??? I dial but if I ain't gotta I can live with that ease of use too.

I thought the same, but run the numbers in a ballistic app and you will see why.

2950 mv out of a 24" barrel and outstanding accuracy with the scenar.

A pro may be along to correct me shortly, but this is the nutshell version of what I remember from all my reading and figuring on the topic.

The additional velocity from the 155, combined with excellent projectile design, leads to it being competitive with 175s even at long ranges. The 175s have higher BCs and lose speed more gradually, but have enough less to begin with that it kinda evens out, and an argument can be made for the lighter bullets.

The 175 seems to be falling off in efficiency as far as grains vs. velocity from the .308. The 168 may be better, but for historical reasons I don't quite understand or remember much about, one of the leading manufacturers at some point changed their boat tail angle to a steeper one, decreasing the BC. Everybody else has copied the draggier specs, so now most of the 168s are not as good at long range as most of the 175s, even though there isn't really a theoretical reason that has to be the case.

The 150-is weight range does seem to be a sweet spot for efficiency of the .308 cartridge.

I prefer the the 155g Lapua out to about 900 yards. Faster, less recoil, minor BC differences. The 175g SMK seems to remain more stable at the transonic/subsonic stage.

While a lot of bullet builders copied the 168g BT design, they also copied the 155 design which was borne from competition.

The 155 Scenar, 155 Palma and the 155g Dyer all have BCs that are very very similar to the majority of 168 BT designs but can obviously be sent faster out of the gate.

Now all they need to do is make a bonded version for us big game hunting, 308 calibre shooters...

You're referring to the Sierra 168gr MK. While it was designed as a "match" bullet it was never intended for long range use. The boattail angle is wrong, The bullet will tumble past 800 yards. To get the 155's to shoot inside of the 175gr SMK you have to push the lighter bullets really hard, like 3100fps+.

168gr bullets from other manufacturers (Berger, Nosler,...) don't have the boattail issue.

What you seem to be missing is the concept of what BC is and how it affects bullet flight.

The Scenar gives the 308 an additional 200 yards over the 175 SMK with less windage, and sometimes that is helpful, but you may not be shooting at targets at longer range so it may not make any difference to what you are doing.

A 308 is a lot more lead than I want to throw at small varmints close in anyway, other than Coyotes at extended range...900-1200 yards.

There's nothing wrong with the 175 Sierra, it gives most of what the 308 can do.