Snake wrote: Now the issue becomes 284 win or 308 for 1000yard AND silhouette......

ppkny wrote:Yes, The Tikka looks like it might be a hard find. I'm also considering a Savage Model 10 Pred Htr in 260. It has a 8 twist fluted barrel.
ppkny

DanDeMan wrote:Ladies and Gents,

Iffen I was to have a purely F-Class Open rifle built ( 800, 900 & 1,000 yards,) it would be an 8-twist 7-08, YES, you got that right, a 7-08. I've long ago gone through the design process for an F-Class, 7-08 chamber optimized for the 180-gr, long-range bullets. With the proper powder and chamber design it is possible to launch the 180-gr bullets to over 2,800 fps, plenty to compete at the top of the heap. And, barrel life will be significantly better than when shooting a 284 or 6.5 x 284, both of which I have/had that were built back in the late 90's. I toyed with an Ackley Improved 7-08, but decided that barrel wear from fire-forming the cases as well as no perceived need for a bit more case capacity put the kibosh on that idea. The design focused on not having to fire-form cases before load development, one design parameter I've developed and used for years in HP and BPCR chambers, when using off-the-shelf FL dies. Both of these large-case-capacity cartridges are capable of fine accuracy, but the barrels go right quick, especially the 6.5 x 284.

Recently I designed an Ackley Improved 260 reamer for a customer that was designed to use the most excellent 260 Lapua brass and Redding 260 AI dies. The design process uses a Cerrosafe cast of the FL die to design the chamber reamer along with the designated bullet and seating depth. This design has only the boattail below the shoulder-neck junction for max powder capacity and max bullet-to-case alignment. The bullet-shank of the 140 A-Max completely fills the case's neck for enhanced bullet-to-case alignment. Serious testing has shown, especially for cases with short necks like the 260, that best cartridge concentricity is had when said short necks hold nothing but full-diameter bullet shank. It was designed to use the Hornady 140 A-Max, to be launched at 3,000 fps. I'll keep all ya'll in the loop as the feedback filters this way. I talked to the top-quality gunsmith, Mike Lewis, doing the work, today. He is just finishing the chambering. Mike Lewis has built a lot of my rifles over the years. He is a graduate of the Trinidad gunsmithing school and has done nothing but top-quality work for me and everyone I've recommended him to. Based on experience and computer simulations, the 260 AI should be accurate to at least 1,400 yards.

Trent wrote:.... What is the gain of going with your .260 AII (Ackley Improved Improved) design versus the ole' 6.5-284? More efficient?

Yes, more efficient as well as cheaper brass and a bit longer barrel life. Lapua 6.5x284 brass is going for $135/100, 260 Lapua for $109. I've been running my 6.5-284 at 3,085 fps with 50.0 grains of H4350 under the 140 A-Max using a 30", 8-twist Krieger barrel. I'd like to run it slower, but accuracy of the current load is excellent from 100 to 1,000 yards, well below 1/4 MOA during load development. From a 30" tube, the 260 AI should be able to do the same with about 45 grains of powder.

I'm using 6.5 Creedmoor and it's doing very well (140's at 2800). I've also had my butt handed to me by a couple guys shooting 6br and 6brx rifles. I'm starting to consider the 6brx for my next barrel.

I think the 6.5 Creedmoor and 6.5 x 47 are two excellent choices for F-Class and should be mild to shoot and have extended barrel life compared to the 6.5-284. I did some preliminary design work with the 6.5 x 47 optimized for the 140 A-Max seated so just the boattail would be below the neck-shoulder junction. With the measured powder capacity, from that exercise, the round should be good for MV's a bit above 2,900 fps. Me likes little cases that can do BIG jobs. I tried to get the guy I designed the 260 AI for interested in the 6.5 x 47 but he wanted more case capacity so he could launch the bullets, with excellent stability, well past 1,000 yards. He's a cattle rancher from CO that likes to bust rocks and ground vermin with his buddies, way, way out yonder.

I too have seen some fine long-range shooting by shooters using the 6BR and its variants. I've got a 6-twist, 6.5 BR that is throated for the 115's. It shoots them into little bitty groups. The rifle has only been shot out to 600 yards, so don't have any basis of comparison with regards to the 6.5 x 284 at 1,000-yds.

Where are you shooting F-Class other than the River Bend range at reduced distances? I can't think of any 1,000-yd ranges in your neck of the woods, YET!!! Get ready to rumble. Dirt is being moved in Alabama for a 1,000-yd range as I type. There is also a 1,000-yd range in the planning phase to be built in the Jackson, MS area. My LA, MS, AL and GA buddies are salivating big time.