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.308 accuracy revisited

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A few weeks ago I posted a thread concerning the dreadful accuracy my newly converted S-308 was exhibiting. I could not get this thing to shoot anything less than 3-6 in. groups at 100 meters. I deduced the three variables at play could be manipulated in order to figure out the offending culprit. The variables; rifle, optical device and ammunition. The rifle is a newly converted S-308, done by Red Jacket. The scope, an ATN 2-6x40mm with bdc. The ammo Monarch and So. African 7.62x51mm. The gun was $1000.00+ so, this kind of accuracy is TOTALLY unacceptable, the scope also, very pricey. So I focused on the ammo first. Although not match quality it could not be that lousy. Some of you said it was but I rejected that hypothesis. I then looked at the optics. Some said the mount is loose, again no-go, I have been benchrest shooting for 20 years + and I can assure the optics were locked down. I then theorized that this scope has a T-type reticle with a dot. This dot covers 3.5in. at 100m. therefore, theoretically a 0-1 moa capable rifle could at best only produce 3.5in groups. I was getting 3-6in. groups, this translates to 15-30in at 500m. Unacceptable, that is a clean miss and of no use to me, I might as well have had a slingshot. I put on a PSOP 8x42D PRO with a mil-dot reticle and lined up the iron sights with the reticle. This is easily accomplished with these scopes since they are offset to the left and the reticle is in the primary focal plane i.e. visually moves with adjustment. The results: the first three shots were a 1 in. horizontal group 1 in. left of dead center at 50m. At 100m the gun produced 1.5-3 in. groups, this was all with the Monarch ammo. I did get a 3 round 1 in. group at 100m with the SA ammo, 2 out of the 3 impacts were 0.5 in. I was not only impressed but satisfied. Conclusion: I was able to return the ATN scope for refund and due to the optical physics involved got the results I was expecting with the PSOP and this rifle. It is not feasible to expect better than this because this is the upper limits of the weapon's capability. You know, tolerances and all. Maybe better with match handloads. One member did report this kind of accuracy with his handloads. My VEPRS consistantly get 0.5-1.5 moa, so I new I could get close. The aim point was much more refined. I have the same scope on my Valmet M-78 and it will consistantly impact a 3 in. by 4 in. steel plate at 350m. Thanks for all your input

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That sounds more like it. Mine does pretty well with the SA stuff, haven't tried much commercial yet but I would expect good hunting or handloads to do better.

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Nice post, great thoughts.

 

I initially started with a belurus-made high mount and a Tasco 3-9x40. Poor results, of course.

The Tasco was a cheap piece of crap and the high mount left nothing for cheek weld.

 

I've just switched to a low-rise mount and a Nikon 3-9x40. Much better.

I've also found British L2A2 to be superior to South African in terms of accuracy. I'm almost through all that though, and getting more will be tough.

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The results: the first three shots were a 1 in. horizontal group 1 in. left of dead center at 50m. At 100m the gun produced 1.5-3 in. groups, this was all with the Monarch ammo. I did get a 3 round 1 in. group at 100m with the SA ammo, 2 out of the 3 impacts were 0.5 in. I was not only impressed but satisfied.

 

So you just ignored the ammo suggestion and then found it out to be true? :haha:

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The results: the first three shots were a 1 in. horizontal group 1 in. left of dead center at 50m. At 100m the gun produced 1.5-3 in. groups, this was all with the Monarch ammo. I did get a 3 round 1 in. group at 100m with the SA ammo, 2 out of the 3 impacts were 0.5 in. I was not only impressed but satisfied.

 

So you just ignored the ammo suggestion and then found it out to be true? :haha:

No, the ammo performed as it should. If by true meaning Monarch will do no better than 3-6moa, even the poorest ammo will usually beat that so that variable was rejected. Even with the most accurate ammo available you could not overcome the limitations of the optics. That is why most red dot scopes are 5moa or greater for shotguns, has nothing to do with shotgun ammo being accurate, you are still going to get a much larger spread than 5moa and precision is not the game there.

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The results: the first three shots were a 1 in. horizontal group 1 in. left of dead center at 50m. At 100m the gun produced 1.5-3 in. groups, this was all with the Monarch ammo. I did get a 3 round 1 in. group at 100m with the SA ammo, 2 out of the 3 impacts were 0.5 in. I was not only impressed but satisfied.

 

So you just ignored the ammo suggestion and then found it out to be true? :haha:

No, the ammo performed as it should. If by true meaning Monarch will do no better than 3-6moa, even the poorest ammo will usually beat that so that variable was rejected. Even with the most accurate ammo available you could not overcome the limitations of the optics. That is why most red dot scopes are 5moa or greater for shotguns, has nothing to do with shotgun ammo being accurate, you are still going to get a much larger spread than 5moa and precision is not the game there.

 

I decided to take my Saiga 308-1 to the range today and try some of my reloads to see how much difference there was between it and the milsurp stuff. I get anywhere from 2-6 MOA with milsurp.

 

My reloads are Remington brass, Hornady 165 gr Interlock soft points with 45 grains of Varget powder. I shot a 10 shot group. The first two shots were low and right, the next 8 were a nice 1.75" group.

 

DSC02412.jpg

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I think that the greatest culprit in most s308 accuracy experiences are lousy scope mounts or big dots on scopes. Once you get those variables cleaned up, then you need only to figure out if you want to sight in "cold" or "hot".

 

Cold will almost always produce a tighter group than hot, but you need to be very patient and have lots of trips to the range to try different rounds and combinations. I settled on hornady 165 soft points and 42.6 grains of accurage 2460 as a good sub 2 inch cold bbl (first three shots) load. The first two shots of the three are almost always within 1 inch so I feel like the saiga is a decent gun in the sense that it's accurate for starters then can stay within 4 in groups under a lot of heat. Only after about 20 rounds will it open up to the 5 in range, but that could be just me after that many rounds. Glad you got yours dialed in. I know how frustrating it can be to build up a promising gun only to think that it's a loser. Enough experimentation usually solves the problem.

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I think that the greatest culprit in most s308 accuracy experiences are lousy scope mounts or big dots on scopes. Once you get those variables cleaned up, then you need only to figure out if you want to sight in "cold" or "hot".

 

Cold will almost always produce a tighter group than hot, but you need to be very patient and have lots of trips to the range to try different rounds and combinations. I settled on hornady 165 soft points and 42.6 grains of accurage 2460 as a good sub 2 inch cold bbl (first three shots) load. The first two shots of the three are almost always within 1 inch so I feel like the saiga is a decent gun in the sense that it's accurate for starters then can stay within 4 in groups under a lot of heat. Only after about 20 rounds will it open up to the 5 in range, but that could be just me after that many rounds. Glad you got yours dialed in. I know how frustrating it can be to build up a promising gun only to think that it's a loser. Enough experimentation usually solves the problem.

 

I have been thinking about a 308. What is the effective range with a good scope compared to just a converted 7.62? I wanted a little bit more of a sniper scope.

Edited by Revelation

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I have been thinking about a 308. What is the effective range with a good scope compared to just a converted 7.62? I wanted a little bit more of a sniper scope.

You can easily hit with good kill probability a deer sized target at 300 meters. If you can shoot well enough i.e. benchrested, with match ammo 500 meters is not unrealistic. I say that in regards to making 1.5- 3 moa shots at 100m.

It can be done. I think the best optics especially in light of cost are the Russian PSOP series. They ARE made for these rifles, are easily zeroed and have range finders and BDCs. An added plus is that you do not have to remove them to clean your weapon, although any good quality scope will do.

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Montana - thanks for your excellent write-up. Its good to see real numbers for someones load and honest ten shot groups. Three shot groups mean little. One question though - what length barrel are you using?

Edited by dasu

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Montana - thanks for your excellent write-up. Its good to see real numbers for someones load and honest ten shot groups. Three shot groups mean little. One question though - what length barrel are you using?

 

Denada amego. 21.5 " barrel.

 

Considering cutting it down though...hmm..tough choice because I love shooting the 400 yard and 500 steel targets and I've had many a debate with knowlegeable folks about whether cutting the barrel down to 18"ish length would really change the effectiveness on a man-sized target at those ranges. I'd love to hear what folks here have to say as well.

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Montana - thanks for your excellent write-up. Its good to see real numbers for someones load and honest ten shot groups. Three shot groups mean little. One question though - what length barrel are you using?

 

Denada amego. 21.5 " barrel.

 

Considering cutting it down though...hmm..tough choice because I love shooting the 400 yard and 500 steel targets and I've had many a debate with knowlegeable folks about whether cutting the barrel down to 18"ish length would really change the effectiveness on a man-sized target at those ranges. I'd love to hear what folks here have to say as well.

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yeah me too buddy. I was wondering if you had any knowledge of how even a 16" barrel would have an effect at 500-600 yards compared to a 21.5 barrel. From my understanding and a link at remington a .308 bullet only loses 200fps max going from 21.5 to 16 inch barrel and I would think if you had a good optic the length should not make much of a diffence on terminal ballistics. Thanks

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