Ruger American 308 Winchester 168 gr. Sierra MK HP

[Kent Goldings]

As you know, I’ve been working up a load for my 308. This week I tested 168 grain Sierra Match-King HP. I decided to use 40 grains of H4895.

The twist is that I loaded Starline 308 Match brass with small primer pockets. I have a supply of Remington 7 1/2 small bench-rest primers.

The results at the indoor 100 yard range were very promising. Accept for a few fliers that were probably my fault, the groups were nice.

I took the load to Catskill and took some chronography.


Im happy to finally have data on the muzzle-velocity sweet spot of this rifle. I shot the load out to long range. Despite poor weather this morning. The load performed well. But, the practical target range does seem limited compared to the 6.5 PRC.

 

[dsdmmat]

Need to up those velocities. If you are not showing any pressure signs. 168s should be good out to a 1000 yards but you have to be running about 2700FPS to keep it supersonic out to that distance.

 

[Kent Goldings]

Need to up those velocities. If you are not showing any pressure signs. 168s should be good out to a 1000 yards but you have to be running about 2700FPS to keep it supersonic out to that distance.

In theory, you are correct. But, this rifle is really sensitive to muzzle velocity. I’ve spent a lot of time wrestling with faster loads and accuracy really suffers. I’ve come to accept that this rifle has a speed limit.

 

[tony]

FACT. SR primers have less brizzance than LR. Under certain conditions (cold weather), using small rifle primers (as in this .308 case) and some difficult to ignite powders delayed ignition may occur.

Many years ago I experienced delayed ignition using .308 BR brass, Rem. BR primers and IMR 3031 powder.

My pet .308 load using standard primer hole brass was 39 grains of IMR 3031 and Sierra 168 gr. HPBT match bullet. I was using LC match brass and therefore reduced load by one grain to 39 grains as per recommendation (when using military brass) in my old Lyman reloading manual. It was superbly accurate.

 

[Kent Goldings]

FACT. SR primers have less brizzance than LR. Under certain conditions (cold weather), using small rifle primers (as in this .308 case) and some difficult to ignite powders delayed ignition may occur.

Many years ago I experienced delayed ignition using .308 BR brass, Rem. BR primers and IMR 3031 powder.

My pet .308 load using standard primer hole brass was 39 grains of IMR 3031 and Sierra 168 gr. HPBT match bullet. I was using LC match brass and therefore reduced load by one grain to 39 grains as per recommendation (when using military brass) in my old Lyman reloading manual. It was superbly accurate.

That’s useful information. I’ll be sure to use large rifle primer brass for loads I plan to hunt with.

 

[Tisto]

Just out of curiousity, what other powders have you tried ? Your "speed limit" may be self imposed. I have found that Benchmark yields superb results with very light bullets ( 110's and 125's) and that Accurate 2520 is excellent with 165 - 180 weights. Of course, all rifles are different, and you can play with different loads forever, sometimes never finding the magic combination.

 

[Kent Goldings]

Just out of curiousity, what other powders have you tried ? Your "speed limit" may be self imposed. I have found that Benchmark yields superb results with very light bullets ( 110's and 125's) and that Accurate 2520 is excellent with 165 - 180 weights. Of course, all rifles are different, and you can play with different loads forever, sometimes never finding the magic combination.

I might have a couple ounces of Benchmark. I like using it when I can find it. It’s fine stuff. Right now I have CFE 223, H4895, and IMR 4895.

As far as the speed limit being self-imposed, you could say that. I’ve just noticed a distinct lack of accuracy when I pushed the bullet faster. I’ve seen this with bullets of different weights. I’ve also seen it with factory loads. The gun really likes Federal Premium 168 grain Match. The box says 2600 FPS, but it clocks in around 2500 FPS.


This rifle is still essentially a sporting rifle. Even at the pokey 2500 FPS, a 150 grain bullet will have sufficient energy out to 300 yards. I probably would shoot deer or black bear that far away.

 

[Kent Goldings]

More load testing for the Ruger American 308. I loaded up the remainder of the Hornaday 168 Grain A-MAX. It has a reasonable BC, 0.475. Not quite at the 6.5 level, but respectable for a 30 cal, 168 grain bullet. I also boosted the charge weight to 41.5 grains of H4895. I new from previous load testing that this charge weight worked well with this bullet. The result was an additional 100 fps.

This extra push seems to put the bullet over the top, so to speak. I was able to hit 1000 yards repeatedly in a mild wind. Once the wind picked up, I pulled back to 700 yards where there loading seemed to be dead on.

As much as I love the rifle, I'm feeling it has real limitations when compared to both the Remington 700 6.5 CM and Ruger M77 Hawkeye 6.5 PRC.

The 6.5 PRC shoots these Hornady 140 gr. ELD Match bullets over 3000 fps. The superior BC cuts through the wind and dominates the 1000 yard game.