April 29th, 2008

Tilley's 260 Ackley Improved

Forum member Ron Tilley finished fourth overall at the recent NBRSA 600-Yard Nationals. This was an impressive performance for a relative newcomer to the 600-yard game without “local knowledge” of the Sacramento range. The top 3 finishers, Jerry Tierney, Peter White, and Craig St. Claire, all have extensive experience shooting at Sacramento.

While many of the top shooters were using a 6mm in Light Gun (such as a 6 Dasher or 6-6.5×47), Ron campaigned a 260 Ackley Improved. This is based on a 260 Rem case, with the shoulder blown forward to 40 degrees. Improving the 260 Rem case adds just enough extra capacity to get the 140gr-class bullets into the 2900+ fps velocity window where they seem to perform best.

Ron starts with Lapua 243 cases, necked up to 6.5 mm. He was shooting 140gr Berger VLD bullets, pushed by Hodgdon H4831sc powder and Russian primers. Ron says this combination has been “very accurate right out of the gate.” Ron’s 2920 fps load delivers 5-shot groups in the high teens and low twos, with very low ES and SD. In the video interview below, Ron explains the merits of the 260 AI cartridge, and offers tips on case prep and loading for accuracy.


Ron was shooting an eye-catching rifle. It featured a carbon fiber and wood Terry Leonard stock, BAT Action, and Nightforce scope. With all-premium components, Terry’s 260AI is a beautiful rig that shoots as good as it looks.

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