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Posted: 6/18/2009 7:32:25 AM EDT
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Rifle:
WOA 6.8 SPC (spec I), 18" SS, midlength gas, badger stabilizer forend, swarovski 4-16x50 in a LaRue SPR mount. Ammo: SSA 110-grain Nosler AccuBond S&B 110-grain PTS I bought two boxes of the S&B ammo back in the fall, when CTD was still selling it for somewhere around $16-$17 per box. I haven't had time (or inclination) to test it until recently. This ammo was purchased in October 2008; I do not know the lot #. I also recently purchased some SSA 6.8 SPC ammo (the 110 grain Nosler load; no lot number, but the box is marked May 19 2009) and a couple of different SSA 5.56 loads. I hope to test the 5.56 ammo in the next few days, or weeks. Yesterday evening I set my chronograph up at 11' from the muzzle and erected a 100-yard target for my 6.8. Conditions: 85 degrees high humidity bright evening sun I loaded 10 rounds of the Nosler Accubond load into a CP magazine, and fired 10 shots at 100 yards with the following results: 2577 2570 2563 2568 2550 2581 2554 2564 2563 2572 Average: 2566.2 Extreme Spread: 31 SD : 9.56 Group size at 100.2 yards : 2.2 inches. Sorry; I didn't bring the target with me to calculate mean radius. 
I then loaded 10 rounds of the Sellier & Bellott 110-grain 'PTS' load, which looks much like a Hornady V-Max bullet. I fired 10 shots, with the following results: 2685 2721 2703 2694 2706 2685 2672 2683 2688 2724 Avereage: 2696.1 ES : 52 SD: 17.03 Group size at 100.2 yards: 2.8 inches. I was SHOCKED at how hot this ammo was, but a little disappointed at group size. (If this load had grouped better, I might have withheld the range report until I had scrounged up a few dozen boxes of it...  )
I grabbed my laptop, guesstimated a ballistic coefficient for the S&B bullet (my guess was a tad high, I think), calculated a hold for my 363-yard steel 16"x9" sillhouette target, and fired 5 rounds, producing a 7" group on the steel target 363 yards away. While inexact and not statistically meaningful, this was roughly what I expected (or better) with that load at that distance. For what it's worth, at that range, the 6.8 smacking the steel target is noticeably louder than any 5.56 load I've shot. 
Summary: The SSA Nosler load shot acceptably well enough. I need to measure mean radius on that group - it would show the ammo in a better light as the 10-shot group was weighted towards the center a bit more than it's raw size would indicate. In other words, one or two shots went slightly wider than the rest of the group. I'm curious to try this load on deer, however, I have questions about how much expansion this bonded bullet will exhibit at lower (250 - 300 yard) velocities. At this point in time, I'm still a fan of the hornady v-max load, which I know to expand well at low velocity; the hornady load also groups great in this rifle. At any rate, though, this load shoots to the same POI as the hornady load, and I'm glad I bought a couple hundred rounds of it. It's good ammo. Group size depends on so many things that I can't condemn the ammo for a 2.2" group. What I CAN do is point out that a SD of ~9.5 FPS is very, very good for factory ammo of any sort, and the velocity (2566 out of an 18" barrel) is right where it should be (18" barrels having little advantage over 16" with the 6.8). The S&B load isn't accurate enough to make me want to buy any more of it (unless I find it again at pre-election prices), but I am IMPRESSED with the velocity. As an aside, primers with this (hot) laod showed no signs of flattening. Ejector and extractor marks on the cases were very light. Extractor marks may not be pressure signs, anyway - I recently upgraded the extractor on this rifle (I was on a roll and did so with all my ARs) and it's still tight. Ejector marks, however, were not as bright or pronounced as other ammo I've shot before. S&B got the velocity on this load RIGHT. I know now why nobody has reported on the S&B ammo here - they're hoarding it all! 
(ok, maybe not...) 
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Quoted:
Nice report. I'm thinking that the accuracy or lack there of with the S&B may be due to the Hornady V-Max bullet. I've yet to see some one that can get these things to shoot when loaded to magazine length. Hornady's factory V-max load will shoot 1.25 MOA out of this rifle. When dealing with 10-shot groups fired by real people in real life (not just on the internet....), I'll take 1.25MOA all day long. Further, the V-Max is an EXCELLENT terminal performer on deer.
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arowneragain, saw your Page 4 re-direct here from "THE STATE OF THE 6.8" thread in the variant forum. Note to self to check the Ammunition forum more often. Chronoheads are few and far between, probably only about 20% of gun owners have them.
Interesting that the S&B 6.8 was 5% faster than the SSA. I just checked the S&B web site and they don't list it under the metric or standard calibers they describe there. Did you shoot both boxes of the S&B? If not, can you measure 5 rounds for an average loaded length and also pull a bullet to inform if it's flat based or boat tailed, and is the powder round flake or extruded cylinder? Also, was there a shooting break between groups? Or was the S&B fired thru the barrel pre-warmed by the Accubond rounds? Good looking rifle and thanks for posting the info. |
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