6.5 284 vs 260 ai

[stick man]

Thinking about building my first full custom rifle in either 6.5 284 or 260 ai.

Going for a precision instrument with hopefully sub MOA groups, hoping for .25 to .35 if I can do my part.

I reload and currently have a 25 06 that fits the sub MOA bill. I have shot to 1100 yards with it and am happy with it except the BCs of the bullets. I have ran 117gn bergers, 120 Sierra match kings, and believe it or not my favorite bullet for it is the Sierra game king in 120. (Kinda wish someone was making some heavy for caliber bullets for the quarter bore, that was fairly available.)

A few questions for you guys about the 260 ai vs the 6.5 284 who know your stuff:
1: Which of the two cartridges has the most potential for sheer accuracy?
2: Which one would have the best potential barrel life (with reasonable working loads)?
3: Is there any benefit of AIing a 260, other than more powder and case life?
4: What length barrel for either?
5: This will be a hunter as well as a paper puncher, so heavier barrel but not too heavy, what contour would you recommend? ( looking to stay under 15 to 18 Pounds total gun weight)
6: Best twist rate recommendations for heavy bullets?


Thanks, Jesse

 

[CaptnC]

Tagging in...I think the experts will call it nearly a dead heat with the 6.5-284 having a slight edge.

I just screwed a 6.5-284 barrel on last weekend and hope to puts some lead down range this weekend. 260 AI looks good on paper...big plus is super cheap brass...308 fire forms easy from what I'm told.

 

[codyadams]

I have a .260 AI, and my cousin has a 6.5x284. I have a 29" krieger 4 groove barrel, standard palma contour (very similar but slightly heavier than a sendero or rem varming but a longer neck), with a modified Bell & Carlson Medalist stock, Harris bipod, Triad tactical stock pack, PTG Stealth bottom metal with a fully loaded Alpha 10 round mag that lets me load out to 2.975" OAL, and Vortex Viper 6.5-20 scope it weighs 14 lbs, and is built on a rem short action. As far as potential accuracy, they are both outstanding. For barrel life, the .260 AI will be slightly better. And YES, the is a benifit in a .260 AI, and that is the fact that I have 12 firings on my brass and have only trimmed once, and I have a significant performance gain. My rifle is a half MOA or less shooter with Berger 140's, which it sends at 3070 fps with cci br-2's, Lapua brass and 49.1 grains or Reloder 26.

 

[codyadams]

As far as performance a 6.5x284 SHOULD be better....but with Reloder 26 I got up to 3170 before I saw pressure signs, a safe load would be 3140 or less, and 3070 was where my node was. I see very few people get that performance out of a 6.5x284....but I think the alliant powder may have something to do with it. One other thing to consider is a .260 AI can be built on a short action, a 6.5x284 is pretty much a long action only cartridge with anything but varmint bullets.

 

[Clucknmoan]

I didn't see pressure till 3240 with my 6.5x284 with RL26 and 140 Bergers. Not finished by any means, but there's one heck of a flat spot in velocity at 3180. I think that's where it will end up wanting to shoot them.

 

[MudRunner2005]

Both have just as good a chance in accuracy, as accuracy has more to do with the rifle and barrel, than it does the cartridge it's chambered for. In all honesty, the 6.5x284 is going to have the velocity advantage, but barrel life is not going to be anywhere near as the .260 AI. Personally, I would go with a .260 AI. Cartridge design of the AI has many advantages, including a better designed shoulder, better wall taper, better pressure handling, a more efficient burn, and less case trimming/growth. As for barrel length, I prefer a 26" for each, with a 1:8 twist. As for barrel contour, I like the Rem Varmint/Sendero contour. Best twist rate for both will be a 1:8 twist.

Personally, I like the .260 AI, but to each, his own.

 

[Greyfox]

IMO, they are very close in performance and barrel life given comparable conditions. For sheer accuracy, I'd probably give the edge to the 6.5x284 as I've been spoiled with my three rifles(factory, semi-custom, and custom) shooting sub .25MOA with single digit ES. I'm partial to the 6.5x284 case having felt that the 308 parent cases were rather weak in the case head, with a tendency to develop loose primer pockets prematurely, particularly when pushing loads. One box(100) of Lapua 6.5x284 brass is good for 1000+ rounds with no fuss.
For hunting/casual targets I like a 1:8, 26" tapered barrel with a muzzle OD in the .73"-.83"(3.5-4.5 pound) range. I find this size/weight range manageable for carry, but still providing a very stable shooting platform for the longer shots. Add(approx); 2.5 pounds of scope/rings, 2 pounds of action, and 3 pounds of stock, you end up with an 11-12 pound rifle.
I put this together s few years ago using a Bartlien/Sendaro taper. Weight 12 pounds.

 

[just country]

morning, MUD is right. I just me like the 260AI.
GBOT TUM

 

[Mike Dunaway]

I am not sure how fast you can push a 260AI but probably would be my choice.

 

[dmoon]

I'd consider the length of the action/bullet/bottom metal and decide from there. If that doesn't work just flip a coin, either cartridge would be awesome.

 

[tbrice23]

I have a .260 AI, and my cousin has a 6.5x284. I have a 29" krieger 4 groove barrel, standard palma contour (very similar but slightly heavier than a sendero it weighs 14 lbs, My rifle is a half MOA or less shooter with Berger 140's, which it sends at 3070 fps with cci br-2's, Lapua brass and 49.1 grains or Reloder 26. View attachment 89180 View attachment 89181

Sweet rig.
I bet recoil is next to nothing!
My vote is 260ai. I've had two 6.5-284 barrels, wasn't impressed. I'm positive however my next build will be 260ai. I've always wanted one .

 

[MudRunner2005]

I'd consider the length of the action/bullet/bottom metal and decide from there. If that doesn't work just flip a coin, either cartridge would be awesome.

I think both would be better in a long action, but of the 2, the .260 AI is shorter, so would fit better in the short action.

 

[nkyshooter]

Pretty much all the arguments are here in the thread above ...

6.5-284 likely to push the pills a little bit faster than the 260 AI ...

BUT

260 AI wins for me due to:
- Better brass life
- Better barrel life
- Short action vs Long (this does in fact have a true potential accuracy advantage)
- Brass options and availability (if you HAVE to you can form off 308 which is EVERYwhere)

My 260AI is built on a savage 10 with a 27" 1:8 tw barrel (.675 at muzzle) from Jim Walters (he uses Green Mountain barrel blanks ... not high end stuff) all in a B&C m40 stock with a heavy SWFA 5-20 on top. Guessing in the 12.5lbs range but is just an educated guess.

What is NOT a guess is the results I get ... I'm getting honest 5 shot groups well under .5 MOA and typically in the .3's. I'm using Berger Hunting VLD's and using my load of H414 (don't laugh - it meters PERfectly ) I get 2925 fps at 70F and 650' altitude. While I know I could get more velocity if I went to another powder, I've taken an approach of using enough cartridge that I don't have to push for maximum potential velocity but rather find excellent accuracy and know that at whatever velocity it turns out to be, it will be more than enough for anything I'm planning to do with it.

My 260AI is the #1 favorite at the 1000 yard range when a group of family/friends all go together and try out different rifles, etc at different ranges. The #2 and #3 are my 6BR and then my Savage Ashbury in 6.5 Creedmoor.

If I had a 6.5-284 though - I suspect it would be in the short list of the favorites

Last thought is this ... while it won't push them as fast as the 260AI or the 6.5-284, the 6.5 Creedmoor is still PLENTY capable at 1000 yards as is a straight/standard 260. I like the AI for the increase in brass/barrel life and as long as you like to reload is a great choice. If you have need to rely on factory ammo, the 6.5 Creed begins to take over as the better 'tradeoff' ...

Post some pics when you're all done with it so we can all "lurst" after it a bit ...

Cheers
Tim

 

[stick man]

Thanks for all the input guys! I have decided on the 260AI.

Now the fun begins piecing all the stuff together. Should have it built in 18 to 24 months, when it's done I'll post up some pics.