Reloading 260AI where to start

ceriksson

ceriksson

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What are my options for forming brass for 260AI?

I have one on the go and an contemplating my options to make brass for it since none is available off the bat.

now I want to be using more precision based casings such as Lapua, Norma, etc so I was thinking of loading 260 and fire forming it.

What are some other options? Possible to size it down from a .308 or 260?

ideas, advice? especially from any of you 260AI shooters.

thanks in advance
 
is it the type of improved round that can safely fire a standard .260 round ?

if it was my gun , i'd use brass from a cartrige i didn't have a rifle for to avoid mixing up loaded rounds later .

i'd use something like 7mm-08 and just neck it down enough so it just barely chambers .
throw a primer and some pistol powder in , no bullet , and go somewhere out of the way and form some new brass ( make sure your pointing the rifle up to avoid losing the powder )

308 brass would work , but you might end up with a fair amount of trimming.

260 brass , i might be tempted to neck it up to .270 or 7mm , then partially neck it back down , just so there was something that was holding the cartridge from going into the chamber deeper that might cause stretching in the brass near the head .
 
Easiest way is to just fire factory 260 in it. The design of the Ackley Improved is set up 0.004" shorter in headspace then the factory cartridge for this reason. If you wish to use other brass, then you are neck sizing and fireforming, and possible (depending on which case you choose) neck turning/reaming. - dan
 
I use Winchester 308 because Winchester cases have more power capacity than Lapua. I fire form using match Sierra 142 bullets with 4350 powder. I shoot this in the short rnage leg of matches (300 to 600 yards) because it groups very, very well but is 200 fps slower than a blown case full of H1000.
 
I`ve done it two ways, necking up Lapua .243 brass and necking down Lapua .308 brass. If you are necking down then do it in two stages if you can, 7mm then .264. I found that I got more consistancy in the necks that way.

I fireform using a charge of 15gr Unique, cream of wheat to the shoulder and capped with either vegtable shortening or tissue paper. I worked up from a charge of 12gr and found that 15 gave the sharpest shoulders. You should work up as well.
 
I just neck up .243 Lapua brass, fireform with cheap 6.5 bullets, a modest charge and be done with it. Lapua brass is head and shoulders above the rest and will last a long time in a .260 AI if you aren't maxing out.
If you need some load data let me know, it can be very hard to find on the net and I've spent alot of time searching so I have compiled a small library in addition to my own loads and testing.
If you plan to use RL 17 I can help with that too.
Ivo
 
ivo said:
I just neck up .243 Lapua brass, fireform with cheap 6.5 bullets, a modest charge and be done with it. Lapua brass is head and shoulders above the rest and will last a long time in a .260 AI if you aren't maxing out.
If you need some load data let me know, it can be very hard to find on the net and I've spent alot of time searching so I have compiled a small library in addition to my own loads and testing.
If you plan to use RL 17 I can help with that too.
Ivo
Click to expand...

Thanks everyone, some great ideas

I have access to .243 dies so that will likely be my avenue. I also have the ability to neck down in stages from .308 as well, but from what I can see wouldn't be as easy or practical.

Ivo any recipes would be awesome thanks.
 
Be careful using 243 brass as you may end up with an unwanted donut at the base of the neck.

Better to start with 7-08 or 308 (my choice).

I run Win 308 brass through a 7BR sizer to form a second shoulder so that the case is held against the bolt face when fireformed. lapua would not be my choice to do this forming.

I use a light charge of pistol powder behind Cornmeal to do the actual forming.

Then brass prep and first smokeless powder load. It will be slightly lower then your best load. My final forming is about 1/4 min less accurate then my normal load so great for practise.

I have found CCI BR2 or Wolf primer, H4831SC, 139gr Lapua or 140gr Berger VLD perfect for this cartridge.

If you looking for a suitable body die, let me know. I have some from Redding on order.

Jerry
 
Yea I'm familiar with the donut, but I did order some new 243 brass so I'll do some experimenting and see how it turns out.

I happened to have already ordered a full redding comp set for the rifle, But I will be looking to you for some Bergers.

What about powder? what is the go to powder for 260AI anyway? I use varget primarily for my .308 but also load blc2 and RL15 for it as well. So that is what I have on hand at the moment.
 
When you form the 243 brass to standard 260R dimensions, you will have to push the shoulder BACK so part of your neck is where the orig shoulder was. This brass is way thicker and voila, a donut is formed.

The only way around this is to form a 6.5-243AI. you have a shorter neck but no shoulder movement. You also have larger case.

For the lighter bullets, Varget and Re15 are possible but for the heavies (still too fast in my opinion), H4831SC is ideal. I have tried H4350 and Re17 and they were both too fast for my tastes.

With H4831SC and 140gr Berger or 139gr Lapua seated out long, you are in the 47.5 to 49gr range with your best load likely somewhere in the 48 to 48.6gr range (as usual, always work up cause you will be at elevated pressures when done).

My first smokeless load is a few tenths below my final accuracy load.

Jerry
 
What Jerry said.....I did run into the donut issue when going up from .243. I favour H4350, but only because my barrel is only 24" which isn't quite long enough to utilize H4831 to it's full potential.
 
yea I have a 28" bbl

so i'll be on the lookout for H4831 then.

as for the .243 like I said, the order button has already been pressed so I plan to try some of it for resizing otherwise i'll just sell the remaining unfired brass and try the other recommended method.

260AI seems to be gaining in popularity, would be nice if one of the casing makers would jump on the bandwagon.
 
Norma, Nosler and Rem have 260Rm brass.

Manf don't like making improved cases because it is apparently difficult to form at the speeds they run at.

personally, I WANT to start with Win 308W brass. I get the shoulder where I want cause the chamber isn't always cut to spec. I get a slightly thicker neck which lets me neck turn to the thickness I want. 308W brass is made is such quantity that quality is usually excellent and it is very strong - still haven't lost a case and I have gone through quite a few barrels.

The 260AI or 6.5 Mystic is an ideal case volume with a long barrel for the 140/139's. Like the 6BR, it produces velocity and accuracy much great then the case would suggest. it is dead easy to tune and you can dial out vertical dispersion.

With a 100% load density, you don't have some of the tuning issues of the larger 6.5-284. You will not go as fast but the difference of less then 100fps is offset by the almost 50% better barrel life and super easy set up.

It is also about all the recoil my busted shoulder can handle these days - no 7mm's in my future me thinks.

It took decades for the 6BR to gain traction and now it is so popular, it is a standard reference point.

The 260R also languished despite being an excellent cartridge and it is really F class that is bringing attention to the improved cousin.

I set up my 6.5 Mystic as a middle ground between better LR ballistics compared to the 6BR but less recoil vs the 7's. I took a guess at what the velocity would be and it was bang on. The extra tuning benefits were a very pleasant surprise.

I have corresponded with other shooters of similar wildcats and they also use similar data so the chambering is not finicky at all.

I think as more shooters compete at the 600 to 900yds ranges, the 6.5's will continue to grow in popularity and the 6.5 Mystic/260AI will become an ideal case volume.

The 6.5 Swede reg and improved are also excellent options and should easily meet the 6.5-284. But barrel wear will likely creep close enough to not make either as attractive.

Jerry
 
I'm rapidly becoming another 260AI fan. Just finished putting together this rifle with parts purchased from Rick at ATRS (AICS stock) and Jerry (barrel and scope).

SavageAICS_1.jpg


I used Jerry's method to form cases, but opted to just use new R-P 260 brass instead of downsizing 308 cases. 7g of Titegroup under a caseful of cornmeal got the brass to about 95%. I did zero case prep....and I mean zero when I loaded my first actual rounds. The newly formed cases dropped into my chamber, so I just necksized with a Lee Collet, loaded with 48g H4831SC, topped with a 139g Scenar and went shooting. I figured they would still shrink a bit when they got fired, so I'd do the brass prep/sorting afterwards.

I took 10 shots to get my scope dialed at 50 and then 100, and fired the following 2 groups, one week apart.

260Group_1.jpg
260Group_2.jpg


The first group was off a really lousy bench where I could see the wobble in my crosshairs. Second group was off a good bench, but breezy 20kmh winds. As you can see, vertical stringing is almost nil, and I haven't even started working on tweaking the load.

Overall, I'm liking the rifle and cartridge a lot. Thanks for the help putting this together Jerry and Rick.
 
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