260AI vs 6.5x284

[skeetlee]

How does the barrel life and accuracy of the 260AI compare to that of the 6.5x284. Does the 260AI gain that much over the standard 260rem? Just thinking about some different ideas for the f-class rifle i am gearing up to do. Thanks Lee

 

[fivering]

When comparing these two cartridges, you have the same bullet being propelled by two different quantities of hot gas working on the throat of the bbl under similar pressure conditions.
The one with the larger amount of gas,direct function of powder charge) is going to erode the throat faster.

 

[skeetlee]

Very true I guess the question is how much faster, or how much longer will the 260AI shoot before needing work compared to the 6.5x284?

 

[jthyttin]

If we're talking about using the same bullet at the same speed:

- with 6.5-284 you have the option to use slower/cooler powder and/or single base powder instead of double base

- with 260AI you might attain better fill ratio, and bring down ES/SD while using less powder

If bullet or speed is changed between the cartridges, all bets are off. I'd say you need to pin down what you want to do before getting reasonable answers. After all, most of the time it's not just about the inherent accuracy in F-Class, it seems...

 

[JHardy]

You might want to look at the 6.5x55 AI. Lapua or RWS brass, long case neck,a good thing), and well proven at 1000 yards. A great round.

Jim Hardy

 

[habu]

I REALLY LIKE AND SHOOT THE 6.5 X 08 A BUNCH [142 SMK]
THE THROAT WENT OUT AT 2250 RDS. [.058][TRUFIGHT BBL] THROATED OUT TO .075 [FROM CHAMBERING], MOVED BULLET TO LANDS [WHERE IT SHOT BEFORE], GROUP OPENED FROM .025-.030 TO .040 WITH SAME LOAD.

IS STILL SHOOTABLE IF NESSARY.

I'M GOING TO BE TRYING A 6.5 HABU - [30 DEG. SHOULDER] BIT MORE CASE CAP. AMOUNG OTHER THINGS

WILL LET YOU KNOW LATER THIS SUMMER.

RON

 

[Rust]

What I've seen is that the few guys I know running a .260 AI are running pretty close to the same load I am in a 6.5 X 284, with a target velocity of right at 2950 fps. The case fill ratio is better on the .260 AI than the 6.5 X 284 although from the accuracy and ES/SD there isn't really any difference at that velocity. The 6.5 X 284 does offer a little more flexibility in loading with the heavier bullets, several powders will work fairly well although everyone seems to have standardized on either H4831 SC or H4350,seems to work better in shorter barrels).

I got about 1,300 rounds of match accuacy out of my first two barels in 6.5 X 284 which is to be expected with 20+ round strings. I suspect a .260 AI with a simliar firing rate would fare little better.

IMO longer necks do help a little with erosion, and they can certainly help keep the bearing surface of the bullet above the neck shoulder junction.

Two likely prospects would be a 6.5 X 55 Swede AI, and another would be the 6.5 X 57 AI. Lapua brass is available for the Swede, and occasionally RWS,may actually be better than Lapua) brass can be found for the 6.5 X 57. Failing that, 6.5 X 57 is easily formed from 6mm Rem, 257 Roberts, 7 X 57. Periodically Norma 7 X 57 is available too.

 

[larryt]

I have built several 260AI rifles. Most have over 2500 rounds through the barrels with no drop in accuracy. Have been shooting 140gr Berger VLD's at 2850 - 2870 fps. The guns have been used for f class, 560 yd clay bird shoots, 1000 paper shoots, and 1000 yd steel plate matches.

The best accuracy has come from using full loads of either RL19 or MRP.