260 Rem, Lapua Brass, neck up or down?

[AKDaddy]

Hey all,

I just ordered a 260 Rem Match reamer with a .294 neck for a new build. I'd like to give Lapua brass a try, and was wondering whether it would be better to neck up Lapua 243 brass or neck down 308 brass?

I'd really like to use 308 brass, for two reasons. First of all, I was thinking I'd like to experiment with the new 308 Palma brass (small primer pocket) when it comes out, to see if it will work for a 260 Rem using small rifle magnum primers and RL 17 or H4350. Second, after forming the brass to 260 Rem, I plan on turning the necks just enough to even them out. My thought was that necking down would provide a little thicker neck wall to work with.

However, since I'll be necking down using Redding bushing dies I am worried about having to deal with a bad donut of brass right above the shoulder when I'm done.

On the other hand, if I neck up from 243 brass I wouldn't have a donut to deal with but the neck wall would be thinner, thus leaving me less to work with for neck turning.

Anybody have any thoughts or experience with this? Would it help eliminate a donut if I neck down in two or three steps, then run the brass over an expander mandrel before neck turning?

Thanks!

 

[2506]

I myself would neck up from 243. My buddy hand one of the first Rem. 700's to come along. We had to make our own cases and find our own load data at the time. We found that 308 neck down made the case a little bit short but the 243 neck up gave you good case length. Like you said with necking up you don't have donut problems. If you are not going to have a tight neck chamber and just want to clean up the necks you should not have any problem with the 243 neck up. Just my two cents worth.

 

[BHarvey]

I had better results with necking down 308. The do-nut did not appear until around firing 15.

With necking up, it is almost instant do-nut time, AND you had to check and recut every other firing, or at least I did.

Necking down, you WILL have to turn necks on Lapua brass as a loaded round would have a neck dimension of .297" or so.

Necking up the neck the dimension would be .293", so you might have to turn anyway depending on your chamber dimension.

This is for either necking up 243 Lapua, or necking down 308 Lapua.

 

[AKDaddy]

Dang! One of each. I was hoping for a simple answer! Thank you fro your replies, and I'm still listening. Anyone else have experience with this?

 

[deucedog]

I've had better luck necking up the .243 brass. As stated, the .308 ends a little short and necks too thick for my chamber. Takes a lot of turning to get them down. The donut on .243 is manageable with an inside neck pilot cutter (K&M or similar). I turn all my necks to clean up regardless, so the neck turning to clean up the shoulder and remove the donut is not a factor for me.

 

[savageboy]

I neck down the .308 for my .260AI/ Works great, no donuts. I do clean up the necks though

 

[MattPeetz]

Just get Rem 260 brass and be done with it. I necked down 308 and got tired of all the steps and neck turning.

I didn't notice any differance between the Lapua and Rem brass.

But if you want to do it go ahead but i would neck down instead of up.

 

[Raptor]

I agree with BHarvey. I am on my 4th 260 barrel and I had one of the first 260s to come out. I did not like the early Remington brass so I necked down 308 Lapua brass and turned down the necks by neck turning the brass. I have never had any problems doing it this way.

When my brass started wearing out, the Lapua was getting hard to find and more expensive, so I decieded to try Winchester 7mm-08 brass and this worked great!!!! Its easy to form and shot as well as my Lapua brass.

The only problem I had was trying to find enough brass that weighed the same. I found some of it to be 10+grs heavier or lighter. I am sure I won't get the number of reloadings that I get from my Lapua but it is a great alternative and shoots great for a reasonable price.

 

[Tcon260]

My wife and I have been through eight 260 barrels. I started out necking up from 243 Lapua.. No question that this will give you donuts. If it is throated long enough, maybe that doesn't matter....not sure.

I now use 260 Rem brass. If I was to make the brass, I would probably use 7-08 brass.

I still have several hundred new Lapua 243 cases I will sell you if you want to go that way.

Ted

 

[Laurie]

started out necking up from 243 Lapua.. No question that this will give you donuts. If it is throated long enough, maybe that doesn't matter....not sure.

+ 1 on that! My .260 was deliberately throated long. so 140s are seated with the bearing area just above the doughnut, so I don't worry about it unduly.

.243W brass does have the advantage of being specified a little longer than the .308W version, so you don't end up with an overly short .260 case.

Laurie,
York, England

 

[CJ6]

Neck down 308. Plus if you use the Lapua you will now have the choice of SM or LR primer pockets ;D

 

[louielouie]

I had my Rem 600 rebarreled w/Shilen using a match chamber. Since I don't have the luxury of a long throat I've been necking down Winchester & Remington 7-08 (260 was sold out at the time). The Winchester brass is lighter & the primer pockets don't need as much clean-up as the Remington brass but the p-pockets get loose very quickly - and that's with 'safe' loads using 140 Nosler comps & H4831sc.

 

[dennisinaz]

I have a 260 with a .294 neck and i have to neck turn both 308 and 243 Lapua cases to use them. I have better luck with 243 myself. If I use 308 brass, I neck turn it while 308 to get rid of most of the extra- this pushed the thinner brass beyond the neck/shoulder junction and makes things nicer.

To remove donuts, I chuck my K&M case holder in my 3-jaw and use a .250 chucking reamer on a slight angle. I use my thumb as side pressure and it skives the donut right off.

 

[techshooter]

I tried the necking down of Lapua 243 for my 260 AI, and got donuts big-time. I ended up using Remington 260 brass, and culled the ones with non-uniform neck wall thickness. There is an article on this here:

http://www.6mmbr.com/260AIforming.html

The Remington brass has been excellent so far. My next choice would be to neck down 308 Lapua, but I hate turning necks on brass.

Cheers,

 

[AKDaddy]

Here's an update. I had 49 pieces of Winchester 7-08 brass lying around, so I decided to see how that would work out. I first experiemented with two or three pieces, and when things seemed like they might work out I did all 49. Here's what I found.

First of all, I only had neck bushings in .305 and .289. I first necked down from full diameter to .305, and then I had quite a big jump necking down from .305 to .289. As might be expected, the big jump gave me pretty odd necks, meaning they were not straight at all, and flared quite a bit near the mouth. However, I expanded them with a .263 expander mandrel and necked them back down using the .289 neck bushing, and after repeating that process twice the case necks looked pretty normal again. I expanded one last time to get them to fit the turning mandrel and neck turned them until they were even thickness all the way around.

The bug in the system is that many of the case mouths turned out to be very far from square, and that by the time I trimmed the case necks enough to square them up the length of the cases was 2.018, which pretty much ruined any advantage in neck length gained by using the longer 7-08 cases to start with. (SAAMI specs for 7-08 case length is 2.0457). Of course if I had used .308 brass to start with (2.015 SAAMI spec length) I might have ended up with *really* short necks/cases.

Since Winchester 7-08 brass is pretty cheap I'm going to try again once I get some intermediate neck bushings to avoid the big jumps when necking down. Hopefully this will keep the necks a little more even in length, and result in less trimming to square them up, and hence somewhat longer necks. Not that my first batch of brass is ruined. I expect it to shoot very well. I'd just like to see if it's possible to lose less neck length when necking down.

Anybody else have similar experiences?

 

[nhm16]

Have you tried just running the 7-08 brass through a 260 Rem full length sizing die to get it started? And then use a mandrel and your preferred 260 bushing? Or just using a Lee collet die?

 

[AKDaddy]

I don't have a Lee collet die (should I?) but I just got in a plain-jane RCBS full length die that I intend to try. Still, that would be necking the whole thing down in one big step, which seems even worse than two smaller steps using bushings. I would expect that to give even less uniform/more deformed necks, or am I missing something?

I got the RCBS FL die just to have one regular FL die to size the entire neck before neck turning, since the bushing dies all leave a small portion near the shoulder unsized.

 

[nhm16]

From what I've read, it's not a big deal going from 7mm to 6.5mm... now if you were going from .30 cal down to 6.5, it might be a different story. But since the bushings will never size the whole neck anyways, I think you're better off starting with using at full-length sizer or the collet die for the first pass to make 260 brass, then later using the bushings to neck size. Also, try the collet die instead of the bushings, generally. Gives very low runout.

 

[Adam Morris]

I have had very good results necking down 308 brass to 6.5-08 using a FL 7-08 die in an intermediate step. I start by FL sizing 308 brass and end by FL size in 6.5-08 die. If the neck I.D. is too tight, I'll run my neck turning expander through once and resize the necks in a NK. sizing die w/bushings. As I have a .292 neck I either use Winchester brass as is or neck turn the thicker stuff while in virginal 308 form with very good results, similar to Dennisinaz reported. Not only have I had the pleasure of an immediate donut w/.243 brass, but have had pressure issues as well. These pressure issues may be traced to a relative tight neck that does not allow much brass expansion. As an aside, I throughly enjoy the performance and brass life the 6.5-08 brings to the table.

 

[AKDaddy]

That's the plan then: neck turn .308 brass down a bit, resize to 6.5 mm in two or three steps, expand and neck turn again.

I'm still going to experiment a bit with some new Winchester 7-08 brass that ought to arrive in my mailbox in a day or two. I want to see how using the FL die to neck 7-08 brass down to 260 in one step works, and I'll also try it in two steps of about .01 using neck bushings, then one FL resizing before neck turning. I'll write up my results here. Could be a week or more before I can get to it, since I'm working all day and taking three hour classes after work for the next two weeks. Not to mention that I have orders for several bowstrings, in addition to finding quality time with my wonderful wife and two young boys. Maybe 'cause it's winter up here in Alaska, and by the time the days get longer I'll be ready!