260 AI What brass?

[astro]

Going to build new F-class rifle and looking at the 260 ai. Which would be the least amount of prep time. The 308 Lapua necked or the 243 Lapua necked up?

I read the article on the Accurate Shooter about the 243 Brass leaving a donut when necked up. Will the 308 brass do the same?

What about sizing the 243 brass to 7mm, then back down to 6.5 would I still have the donut problem?

 

[15Tango]

Save yourself the hassle and get .308 brass, the .243 brass necking up will give you a donut to deal with and you're looking for the least amount of prep time and donuts can be a hassle. If you're going with .308 Lapua also do yourself another favor and get the 308 Palma brass with the small rifle primer.

Necking up the .243 brass will create a donut no matter what because the shoulder material is becoming neck material when necking up, the shoulder's thicker than the neck, that's the donut. No way around it but to cut it out after.

Necking down, neck material becomes shoulder, no donut.

Get the Lapua 308 Palma brass.

Wayne

 

[prwhite]

Astro,
Go with what Wayne recommended... and when you get to fireforming, you'll want a HARD jam in the lands or you'll be blanking primers.
Pete

 

[BURL]

Save yourself the trouble and get norma brass -just dont max it out and it will do just dandy

 

[MarinePMI]

15 Tango,

Have you seen any issues with the base expanding as you neck down .308? I just got done with necking down .308 Prvi brass to 6.5 Creedmoor and have an interesting situation. The base of the brass appears to have swelled some, though is still within specs of the SAAMI measurements. That being said, the case does tend to drag a bit when chambered. Not a big deal with a bolt action, but wanted to ask it you noticed the same thing when going from .308 to .260 since the 6.5C and .260 share the same base diameter...

 

[15Tango]

Marine,

I have a 6.5CM and I've tried kicking down Winchester, Remington and Federal (though that was military 7.62) and Winchester didn't like the process at all, the body folded up, same with the Federal 7.62 Nato but Remington's worked quite well so far as far as forming, some formed almost perfect without need to fire form - they measured correctly at the body/neck diameter well.

That being said, I haven't had any issues with the bottom of the brass. Are you full length sizing with cam bump? I will say that all of my brass even when full length sized seems to have just a tad bit of drag on the body (at what specific portion I don't know) when chambering. I'm using Hornady dies, maybe they're a little large on the diameter? They're the ones that made the cartridge so I'm thinking that's how they designed it. They shoot well that way and it's giving it a bit of tight, almost custom die fit so I'm not complaining. Maybe it's just something the improved type cartridges do because they lack much body taper, the 6.5CM is only .008" after all.

Wayne

 

[usmc1986]

Get Win 7-08 brass, neck down one size no donuts. Or spend more time with brass prep on Rem .260 brass.

 

[MarinePMI]

15 Tango,

Thanks for the response. Yep, I tried virgin Win brass as well (.243) and no workee. Got the same results as you describe with Win .308. It worked great with Remington .243 (go figure), and formed well, with no excessive bulging anywhere. The Prvi .308 formed well, but left the necks about .0002" oversized, and required neck turning (not my favorite task in the world), but proved to be very good brass. Also, (I'm pretty sure) the Prvi brass is actually 7.62 MG brass, as the primer pockets are unchamfered, as if they were ready for a military crimp. Either way, I actually like how solid and straight the primer pockets are, and figure tighter is better.

BTW, I made this for chopping all those necks down.

http://www.homegunsmith.com/cgi-bin/ib3/ikonboard.cgi?s=7df7f92e2e166abf4c7e0f4f86773b04;act=ST;f=3;t=25256;hl=wildcat%

Makes for an easy case trim to clean up the cases when formed...

 

[DOGCAPPER]

Forget necking up or down..
Get Nosler 260 brass...comes sized, trimmed, beveled mouth in and out,uniform pockets..good as Lapua..also batch weighed.
Put a good heavy load in it ,jam and fire in practice....or use COW methid and save bullets, good powder and barrel...
LT

 

[MarinePMI]

DC,

I do have Hornady brass for the 6.5C, but (as many found) when there's a run on components, you have to have a back up plan. Necking up/down brass is an effort (IMHO) that should be explored before you get caught without needed components for a match or hunt.

Just my opinion, but the knowledge to form your own brass from other cases is one of those survival skills that may not be practical or often needed, but when you do need it, it's a Godsend.

As I was taught in the 'Corps, "Always have a backup plan, because no plan ever survives first contact"...


BTW 15 Tango,

I too am using Hornady dies, and they seem a bit generous around the base when compared to the SAAMI ammunition prints/specs. While the drag is annoying and not overly detrimental to functioning, I'm considering just turning a push through, small base sizing die on my small lathe. Maybe it's the anal retentive part of me coming out...

And yes, I'm FL sizing with cam over. I'm using an older Herter's "Super 3" C-style press, so I'm may switch over to a Lee cast iron "O" frame press and see if I'm getting some flex (though I seriously doubt it, as these old presses are built like tanks). On the body taper comment, I think you may have a point...I need to noodle on that one a bit...

 

[15Tango]

Marine,

It's interesting to hear you're having the same experiences as I am with the same brands of brass and dies. I'm using a RCBS Supreme and they're pretty rock solid and I'm still having the same drag on the body when FLS - the dies must be a bit on the tight side is all and I'm betting Hornady meant for it to be that way. It's never concerned me.

Wayne

 

[TX65]

I form from Lapua 308 Palma brass running through a 7-08 Die and then a 6.5-08 AI die before fire forming and neck turning. Lapua 308 brass is less expensive than 243 Winchester so thats the direction I go with.

As far as the least prep, start with 260 Remington brass, load and shoot to form it. That will give you the least chance of getting a donut.

 

[redrock]

Get Win 7-08 brass, neck down one size no donuts. Or spend more time with brass prep on Rem .260 brass.

Yep, the 7-08 brass is the ticket, for me anyway.