On my computer I use a program to find the Balistic Coff. and powder loads for various bullets and calibers. It has listed for the .264 Magnum a 155 grain Sierra HP BT with a BC of 0.615 and a stock number of 9570. But I cannot find it in any of Sierra's listings. Anyone know anything about this bullet?

Sierra 155 gr matchking

www.sierrabullets.com/index.cfm?section=bullets&page=bullets&displayAll=18brandID=1

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Ok, I guess the link isn't going to work. When you get to the Sierra mainpage, click on Matchking under the "Bullets by brand" header. It will be about half way down. By the way, they list a BC of .570 for speeds of 2800+ FPS -not even close to .615

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Last time I talked to Sierra - was informed they no longer produce the 155 Matchking. Don't know why it is still on the web site. Either I was lied to - or they haven't updated site.

I have the latest Sierra poster and it isn't listed on it. And the BC for the one I mentioned, bullet # 9570, is 0.615. The 140 grain is 0.545. The Hornaday Vmax is 0.618. But will call Sierra today about it and clear it up.

Published ballistic coefficients for bullets are a lot like the published eye relief and field of view for scopes, or published muzzle velocities for factory ammunition; that is, they are closer to what the manufacturer believes will help sell the products than they are perhaps to the product's actual performance.

Ballistic coefficients do vary with velocity (and with atmospheric conditions). The only way to dependably compare the ballistic coefficient of two similar bullets is to actually shoot them under controlled conditions and compare their trajectories (and this is not as easy as it sounds).

Anecdotal evidence from the field indicates that the polymer-tipped bullets (Ballistic Tips, Blitzkings, etc.) have even less wind resistance than calculated, and that hollow points tend not to be quite as "slick" as the published figures indicate. But your "mileage" can, and assuredly will, vary. The differences we're talking about are only inch-fractions at several hundred yards, anyway.

I called Seirra and asked about the 155 for the .260 and he said they quit making it. They were real nice and gave me a lot of info on usin gthe 120 grain bullet in the .260 for better stablization. All their tests showed it as being better. Yeah we are talking about minute changes in some cases. But Sierra was real helpful.