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As I was in my LGS today trying to find something that I just could not do without, I found nothing. That's sort of a sad state of affairs for an old gun nut I have been revisiting my old friend the .308 Winchester, and have been running a lot of ladders for different powders. I already had my Varget loads pretty well finalized, but I tried CFE223, IMR4064, and BL-C(2), To my surprise, all of the best loads came within 20 f/s of each other. Varget and IMR4064 had the best groups over a range of loads, but all the best loads were very close with sd's of 4-10. I think I will stick with the Varget because I use it for other rounds and the temp stability. I looked through the factory ammo with 168 grain projectiles. Most of the factory loads were running very close in the low 2600's like mine, then I ran up on the Hornady 168 ELD-M Superformance Match bullet #H80963. It was listed at over 2800 f/s. I came home and Googled it and found their literature stating that they had a powder that was low pressure producing higher velocities and accuracy. Since all the loads that I am using are running from 50-60,000 psi, can someone help to expand on their claims. Also, is this a good accuracy velocity? I haven't run any .308 Winchester at that speed. Just another old man filling in retirement time with trivial thoughts.
 

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I don't put much stock in manufacturer advertised velocities simply because the speed of the projectile is affected by many firearm specific subtleties. Barrel subtleties include the degree a barrel is polished versus not and number of rounds through the barrel. My experience with my factory 700P 308 was that with 175SMK 43.2gr IRM 4064, I was getting average of 2685fps. After about 4300 rounds round count on the barrel the same load and bullets, I was getting 2711. Not a big increase but enough to get you off target at 1000yds.

Also there are fast barrels and slow barrels from the same manufacturers. I've spoken to some knowledgeable gun guys and what that differences are due to is not universally known. At least not to a degree of scientific certainty.

Then there is barrel length. Generally a 20" will yield a lower speed than a 26" barrel in a 308Win most other factors being equal..

As far as precision and accuracy, tuning your loads to your rifle IMHO is most likely going to be the best way to go. I was able to get great results with a Lee Hand Loader out of that 308 and getting into loading... at least initially was relatively inexpensive. I load for my bolt guns and I buy factory for my AR's. Finding what the AR's like for me is simply a trial and error exercise.

Claims from manufacturers and just that CLAIMS. If you look at the ballistics reference book put out by Bryan Litz's company Applied Ballistics, there often are differences in the ADVERTISED BC of a bullet and that tested by he and his engineering staff. I'd chalk it up to sales talk an the part of the sellers of ammo. I use his G7 BC's for the rounds I use and I find that I do not have to adjust my ballistics AP at all for calculated vs actual bullet drops at distance. Usually when I miss it, my elevation is spot on and my goof-up is my wind call..
 
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