178 gr. Hornandy AMAX and BTHP loads

[Big Bad Bob]

Self explanatory title.

What are your favorite loads for 178 gr. Hornandy AMAX and BTHP in .308 and .300 WSM?

I Recently acquired boxes of each bullet and wanted to started working up a load in each. I have had great results with both calibers in the 168 gr. BTHP.

Wanted to hear yalls results, thanks.

 

[kelbro]

Near book max of IMR4064 and Varget for the .308 does very well for me.

 

[Jasper1573]

I load them the same as Sierra 175s, but add .2 additional grain of powder for the extra bullet weight. Nothing scientific about the additional .2 grain of powder, it just makes the 178s shoot the same as the 175s from my Rem 700 308...YMMV

 

[amlevin]

I know that this tread has a few cobwebs on it but I thought I'd toss in a comment anyway.

I find that the Hornady 178 gr A-Max can be loaded using the same charge weights as both Nosler and Sierra HPBT's in my rifle.

Here's a recent group at 300 yards from a .308 I built around a 24" Benchmark 5-C barrel on a Remington 700 action.



(the "On Target" measurements are for the 4 shot group excluding the first shot which I dismissed as a flyer since the next four were "true".)

It was during a load workup. The "flier" was actually the first shot of the group and the next four shots dropped into the ragged hole. I was using my recently purchased Bullseye Target Camera System to record the shots and it's fun to "replay" the pics of the target showing the sequence of hits

The load that produced this group was 42.4 gr IMR-4064 in a Winchester case with a Wolf LR primer. Bullet was seated to yield a case head to ogive measurement of 2.243" with the COAL ~2.860" Speed for this load was 2718 avg.

I also discovered another accuracy node with just over a full grain more IMR-4064 with same case, primer, seating depth. It was 43.7 gr and yielded 2780 fps avg. The SD was a little lower but the group size was larger yet still sub .250 MOA. Might consider the faster load for longer ranges where I need the extra speed to make the distance.

Again, this was not a 100 yard group but a 300 yard group and needless to say, I love the 178 A-Max. Bought another 500 yesterday afternoon.

BTW, this isn't a Benchrest Rifle, just a Tactical/Varmint style shot from a bipod with a "beanbag" rear rest.

 

[ArchAngelCD]

I load them the same as Sierra 175s, but add .2 additional grain of powder for the extra bullet weight. Nothing scientific about the additional .2 grain of powder, it just makes the 178s shoot the same as the 175s from my Rem 700 308...YMMV

Usually less powder is required with a heavier bullet to match the performance of a lighter bullet. Why do you use additional powder with a heavier bullet?

 

[Havok7416]

Near book max of IMR4064 and Varget for the .308 does very well for me.

There ya go!

I load them the same as Sierra 175s, but add .2 additional grain of powder for the extra bullet weight. Nothing scientific about the additional .2 grain of powder, it just makes the 178s shoot the same as the 175s from my Rem 700 308...YMMV

I'm also curious about this.

 

[amlevin]

There ya go!



I'm also curious about this.

It was stated that the extra powder was required to get the SAME performance as the lighter bullets. Not unusual if one is trying to get the same speed.

Also, the Hornady 178 A-max has a different bearing surface measurement than the SMK/Nosler CC so it may handle the extra charge weight well, without increasing pressures above the limits.

 

[AlliedArmory]

In my old R700 SPS-V I ran 44.2gr Varget with a 168SMK and it shot between 1/4 - 1/2MOA rested at 100yrds pretty consistently. Same results with a 178 Amax but dropped the charge down to 44gr and still had an avg of 2690fps.

In my newer Tikka T3 Tactical 24" barrel, I run 44.8gr Varget with a 175SMK and it shoots lights out with a avg speed of 2730fps in LC Match brass.