How far off lands for 178 Amax in 308?

[pcschwenke]

I've been shooting a 175 SMK load with 47.5 gr of 2000MR for a while with great results, but decided to try the 178 Amax. To my surprise, the Amax loads (with no adjustments to the seating die) didn't group well. I've been pushing the bullet out further to 2.925" (0.040" off lands) and it worked better but groups with 2000MR were still about 1". The same seating depth with RE15 produced groups under 1/2 MOA. My next step is trying the Amax at 0.005 & 0.010" off the lands. Haven't tried them yet though. Anyone have any suggestions? I'm also trying to work up loads similar to the one above but using Lapua & Winchester brass for matches. I know the Lapua has a much smaller internal volume than the Winchester and have backed off my loads by 0.5 grain. My former loads where with Federal and Hornady brass.

What's the best distance from the lands you have tried with the 178 Amax? Any suggestions for loads with the 2000MR & lapua brass?

Thanks,

Paul

 

[BCP]

Re: How far off lands for 178 Amax in 308?

I shot a lot of 178amax in my last 308 AR and 2.78 was best in that rifle. When I used 2000MR it was 47.5 win brass and 2.8.

I would try 2.8COAL and 46-46.5

 

[vinsonr]

Re: How far off lands for 178 Amax in 308?

Mine are loaded at 2.81, with a long jump and go into .3" groups. 178 bthp's on the other hand are proving more difficult to find the right seating depth.

 

[doubled]

Re: How far off lands for 178 Amax in 308?

178 A-MAX seemed to be a very jump tolerant bullet in my experience; I was jumping .020 to start and never changed my seating depth for over 600 rounds. when I rechecked my OAL i had .030 of throat erosion so I was essentially jumping .050. I noticed no change in accuracy from the initial .020 jump.

I would recommend you use a hornady OAL gauge; load them to .20 off and run a ladder or OCW test; find a node and then play with seating depths.

 

[scott123456789]

Re: How far off lands for 178 Amax in 308?

I thought I just read a guy here claiming that the 178gr wouldn't jump more than .020 off lands.

 

[vinsonr]

Re: How far off lands for 178 Amax in 308?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: scott123456789</div><div class="ubbcode-body">I thought I just read a guy here claiming that the 178gr wouldn't jump more than .020 off lands. </div></div>

Likely the 178 bthp's

 

[redbullitt]

Re: How far off lands for 178 Amax in 308?

Mine jump just fine. Havent had any effect on accuracy with changing the oal really. Gotta agree they seem pretty ok with a bit of jump.

 

[Rob01]

Re: How far off lands for 178 Amax in 308?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Vinson</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: scott123456789</div><div class="ubbcode-body">I thought I just read a guy here claiming that the 178gr wouldn't jump more than .020 off lands. </div></div>

Likely the 178 bthp's </div></div>

The 178 BTHP jumps just fine as well. I am betting it has more to do with the rifle and chamber.

 

[pcschwenke]

Re: How far off lands for 178 Amax in 308?

Thanks for all the responses. I thought for sure this thread was a dead...

This past weekend I messed with loads 2.820" - 2.960" OAL and found at 2.955 (0.010" off the lands) was the most consistent. I also noticed that the 178 A max seems to like slower velocities as well. At around 2550 fps, I got my best groups with Reloader 15. I've yet to find a load with 2000MR and this bullet worth pursuing. I'll try cutting back to 45.5 grains of 2000MR and work up to 47 and try again. I'll give a OCW another go. A while back I found a great load for the 175 SMK and 2000MR (RE15 as well) with Federal & Hornady brass. In the pursuit of the perfect load, I bought Winchester and Lapau to try. Loads with the Winchester are close to the others but, the Lapua has not been so fortunate. I need to reduce the loads as mentioned above and do the OCW test again. Seems like the Lapua need to be reduced by atleast 1/2 grain.

Shot 15 different loads last week burning up previous reloads and different bullet styles. My Father-in-law gave me about 3-4 hundred of eaof the 150, 155 palma, 180's, and 190 SMKs.

Paul

 

[Gosu]

Re: How far off lands for 178 Amax in 308?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: pcschwenke</div><div class="ubbcode-body">
This past weekend I messed with loads 2.820" - 2.960" OAL and found at 2.955 (0.010" off the lands) was the most consistent. I also noticed that the 178 A max seems to like slower velocities as well. </div></div>I am having absolutely the same results, slower has been better.

 

[Rob01]

Re: How far off lands for 178 Amax in 308?

Try Varget. You will get more velocity and the groups are fine at higher velocities. I run them around 2700fps.

 

[pcschwenke]

Re: How far off lands for 178 Amax in 308?

Rob01, What type of groups are you getting with Varget? I tried Varget with the 175 SMK & 168 A-Max and it produced groups worse than RE15 & 2000MR by 3/8". The nodes are very large with 2000MR but groups were consistently smaller with RE15. Seemed like my gun just didn't like Varget. Since my groups were not great, I kept my left over loads for warming up the barrel. Last time I was out I shot the final 9 pcs of a load with the 175 SMK & Varget. All 9 shots were easily under an inch. Not sure if it was because of lower outside temperatures or if the barrel was now broken in. As mentioned above, I will give Varget another shot! Bought several pounds of 2000MR I need to use up first.

gosu, glad it's not just me!


Paul

 

[Rob01]

Re: How far off lands for 178 Amax in 308?

1/2 MOA or better. Some guns are different and like different powders. I must have missed you mentioning you tried Varget but I only saw RL15 and 2000MR. Just mentioned Varget as another option.

What powder charge were you using before? Min/Max for Varget and the 175/178 is listed as 42/45grns on Hodgdon's site.

 

[pcschwenke]

Re: How far off lands for 178 Amax in 308?

Rob01, I don't have by log book with me but, I think that I started around 42 and went up to close to 46 with the 175 SMK. Still no pressure signs. I'll double check this later when I get home.

Paul

 

[Rob01]

Re: How far off lands for 178 Amax in 308?

That's fine as long as you knew the range. Some people keep the powder charge super low because they are looking at a manual like Sierra which lists 42grns as the max with Varget and the 175/178. Sometimes running them super slow can effect accuracy in a bad way.