260 AI barreled up, any ideas on load would be appreciated....

[Dewey7271]

Hi all;
Just barreled up in 260 AI (Apache made barrel) and fireformed 50 pieces of brass. Accuracy was good with the fireforming loads (a midrange load of 4350 jammed up) like it seems most fireforming loads turn out for me.:o
Anyone shooting this cartridge.
Stuck it in a long action and it's a 26" barrel. 1-8 twist.
Thanks in advance!

[stomp442]

Mine loves 42 grains of H4350 and a 140 Berger. This load gives me 2940fps.

[Dewey7271]

Thanks Stomp!

[LongRange]

Try some RL-17 as well...also try the 142g SMKs...i havent had a barrel yet they didnt shoot out of in a plan jane 260.

[stomp442]

If the bullets in the green box don't shoot, you got a problem.

I keep going back to RL-17 because it gives me some incredible groups at 100 yards but it never holds up for me as range increases. At least that is the case in a couple of my 6.5s. My 6.5-284 when I had it would group in the low .2s at 100 but would struggle to hold MOA past 300 yards and I have experienced similar results in my .260AI. My .22-250 with 69 grainers and my .250 savages with 115s love the stuff though.

[hcpyro13]

Norma MRP Or H4831 and a 139 Lapua scenar. Can find starting points for load development in the manuals for a standard 260. I had a 28" barrel on my ack and found the 4350 a hair too fast burning. The 4831 or MRP with a case stuffed full enough to make ol' Scope Eye proud finally settled down my ES and SD to where I was happy.

[LongRange]

If the bullets in the green box don't shoot, you got a problem.

I keep going back to RL-17 because it gives me some incredible groups at 100 yards but it never holds up for me as range increases. At least that is the case in a couple of my 6.5s. My 6.5-284 when I had it would group in the low .2s at 100 but would struggle to hold MOA past 300 yards and I have experienced similar results in my .260AI. My .22-250 with 69 grainers and my .250 savages with 115s love the stuff though.

Ive had good results with the RL-17 but have a large stock of H4350 for a reason.


Norma MRP Or H4831 and a 139 Lapua scenar. Can find starting points for load development in the manuals for a standard 260. I had a 28" barrel on my ack and found the 4350 a hair too fast burning. The 4831 or MRP with a case stuffed full enough to make ol' Scope Eye proud finally settled down my ES and SD to where I was happy.

Ive played with just about every powder you can run in a 260...in a short free bore barrel RL-17 RL-19 H100v and H4350 are top of the pack...in a long free bore barrel RL-19 RL-22 RL-25 and as you said MRP are top for velocity vs pressure....ive never gotten the velocities i want before hitting pressure issues with H4831sc or IMR 7828ssc and IMR 4831 is very accurate but falls way short on velocity.H4350 is the most used powder in a lot of cartrages because its simple to make accurate but even with a 30" barrel a 45g charge in a 260 is only burning 98%.... I was playing with numbers on quick load last night and from 45deg to 85deg H4350 showed a 57fps difference...100V showed a 47fps difference and RL-17 showed 33fps difference. I know quick load is not the end all do all of loading but its been VERY accurate for me...im working up loads in one of my 260s with all 3 of these powders and will keep track of summer velocities and compare them this winter.

[eddiesindian]

Mine did well 41.5gr IMR 4350. Hornady 140 gr. 020 from the lands.
130gr vld berger did well 40.5 imr 4350 .003 from the lands

[alphapygmy]

I have a 260AI Criterion I'm running on my 600 yard league gun. It has the long freebored match chamber. Mine shot better with H4831SC than H4350. I'm running 46.0 with Sierra 142's and a .020" jump, and 46.5 with 140 Berger LR-BT jammed .010". Mild loads but it shoots in the mid .3's at 100 and I'm currently in the lead in my class at 600. I also tried RL17 and had great speed and very low SD but couldn't get it consistently accurate. Just my opinion but it seems like H4831 is right on the borderline of being too slow for the case volume in 260 and 260AI. With the improved case and a long freebore I can make it run excellent but I've never been able to cram enough in a regular 260 to get any velocity out of it. I'm using Lapua brass so that might be part of the issue. I've seen people say they're using around 48-49 grains but my cases were starting to compress powder at 47.7. I'd like to do more work with RL17 but the barrel is shooting so good with H4831SC I want to finish league in August before I start tinkering and burn the barrel out.

[Dewey7271]

Man, you guys are great!
Thanks!

[LongRange]

The guys getting 48 to 50gs in a case are using remington or winchester brass....i shoot lapua brass too...most Hodgdon powders kernels are larger than other powders so they take up more case capacity....when i look at powders i look at velocity vs pressure and burn rate...then try the powders that are high velocity low pressure and 99 to 100% burn rate first and if they wont shoot ill move to other powders.

And if the H4831 is shooting that well in your rifle i wouldnt change it either...ive used it and like it but it just wouldnt do want i wanted it to.

[Dewey7271]

Thanks very much for the suggestions.
Here's some fireforming loads from a benched backpack as a support. No seating adjustments or tinkering just fireforming at the lands. RL15 (38 gr) to play with.
http://i1279.photobucket.com/albums/y540/dewey7271/Mobile%20Uploads/image_zpsfjz6btok.jpg

The pulls are strictly my fault. Seemed to have the whoopsies yesterday and we had a pretty stout wind but with darn near constant rain, saw a gap in showers and ran out and shot.

[stomp442]

Looks like it will be a shooter.

[Dewey7271]

Yes, I was pleased considering the yoyo pulling the trigger.:cool:
Jim makes good barrels.

[Dewey7271]

Quick update.
Fooled around with some RL17 in a couple loads.
I think there's room to go and can tighten these a little but with a sporter contour not too bad
Two different seating depths but not much difference.
Yes, I know the windage was off a click.:p
http://i1279.photobucket.com/albums/y540/dewey7271/Mobile%20Uploads/image_zpskz2rgnyr.jpg
http://i1279.photobucket.com/albums/y540/dewey7271/Mobile%20Uploads/image_zpstq44qshz.jpg

[alphapygmy]

I tried RL17 and got super velocities and exrtemely low ES and SD but couldn't get the same accuracy as my H4831SC load. It looked good at a 100 but fell apart at 600. I wanted to do more work with the powder but my current combo is shooting so well I'm currently in 1st place for my 600 league and want to save the barrel for next year too.

[Dewey7271]

I like the 4831 SC, just wanted to play with RL17 and see what it had.
I'll stretch it out a little next weekend and see if the 17 falls apart. Good information, thank you!

[alphapygmy]

To be fair I didn't do a full work up on the RL17. Everything came together with H4831 and my league gun and I started shooting perfect scores the last few outings so I'm doing everything to prolong it's barrel life in case I don't get another barrel for next year. I think I was in the middle of a scatter node because I was in a time crunch and didn't work it up like I normally do. I thought about switching to a Dasher next year but the 260AI has really grown on me. If it keeps shooting this well I may just get another barrel and work up the RL17 to potential. It's nice beating the 6BR and Dasher guys with a 260AI! I've got 3 more weeks to shoot before scoring ends so I'll see what happens.

[Dewey7271]

Yessir, that's good stuff.
Hope the 260 AI continues for you.
FWIW, I really like this cartridge. Seems pretty flexible.