243 to 260, necking turning results

[Zak Smith]

In my current 260 Remington project, quality 260 brass is an issue. The R-P stuff just isn't working for me. It's too soft and the primer pockets are soft enough to allow gas seepage.

I have gone to using Lapua 243 Win brass, and necking it up to 6.5mm.

First, I use a K&M expander mandrel to neck it up. This turns part of the shoulder into the new neck, so the bottom of the new neck is thicker than it should be. To fix this, I neck turn with a K&M tool (with reamer pilot). Finally, I full-size to provide proper neck tension, and load.

[ link to LARGER image ]

L to R

1. new Lapua 243 Win case
2. necked up to 6.5mm
3. neck turned
4. full-sized, then loaded with a 139 Scenar

Switching to the Lapua brass reduced my velocity S.D.'s by about 30-40%, and improved accuracy, besides fixing the issues with soft brass and gas seepage.

 

[Ol` Joe]

The R-P stuff just isn't working for me. It's too soft and the primer pockets are soft enough to allow gas seepage.

Never had a lick of trouble with Remington brass in my 260. The only stuff I`ve used since ~`97, except for a couple 708s I necked down before factory brass was available. They were Remington too.

I would take a look at your load. Gas seepage is usually a good sign of a load that is too hot.
JMO...........

 

[michael_aos]

Granted, I'm a newbie, but I my perception is the R-P brass is "good enough" also.

I could probably take some of that R-P 260 brass if your hands if you're not happy with it.



Mike

 

[Zak Smith]

It is possible I have a batch with loose primer pockets. Seating primers on the R-P cases that I have is much easier than seating LR primers in any other brass I've used (ie, Federal, Win, Black Hills, Lapua).

The neck tension on the R-P cases is also pretty variable, while it's always the same with the Lapua brass.

 

[Jim Watson]

Guys over on the Long Range board have little good to say about Remington .260 brass. One said you have the choice between necking Lapua up or down from .243 or .308 or rigorously sorting Remington and getting maybe 70% good cases.

Zak, why not neck down .308s which would give you more meat in the neck for turning to match your .260 chamber?

 

[Zak Smith]

It's partly technical, and partly logistical. My machinist buddies advise me that it's easier to stretch metal than to compress it, and I would just as soon remove less metal during the turning step. On the logistical side, it's easier to sort brass if all my "260" says 243 on the head, instead of all my 308 and 260 saying 308 on the head. I did try to neck some of my existing Lapua 308 down to 6.5, and it was extremely difficult (ie, mucho force required on the press) even using the sizing wax.

Another option is using Winchester 7-08 brass.

I am looking into a source for Lapua-type-quality 260 brass, but I won't have details for a little bit.

ETA-- I did try sorting the R-P brass by weight (within 1gr) and would have not used about 33% of it.

 

[USSR]

Zak,

In MHO, the lack of quality brass is what has kept the .260 from being a truly popular and successful cartridge. That's why I elected to go with the 6.5x55 for my F Class rifle.

Don

 

[ball3006]

Been reloading for 40 years and....

I have never had a problem with RP brass reloaded multiple times. I believe you are having pressure issues that you better think about..........chris3

 

[Zak Smith]

I would normally agree. Outside of having a pressure barrel, there are a number of places to look for physical evidence of overpressure, case-head expansion being probably the most reliable. It did not indicate overpressure. For example, there were "seeping" loads in the R-P brass which showed 0 and 3/10,000ths expansion, which is not indicative of overpressure. Secondary and tertiary indicators were primer condition and velocity (same or less than factory loads using suitably slow powders).

 

[michael_aos]

I've got some R-P 260 brass I've fired 5-times.

123gr Scenar @ ~3000fps from a 24" bbl.

No issues that I can see. I just kind of figured 5 times was enough.

Mike

 

[rbernie]

other than the loose pocket issue, what signs led you to conclude that the primer pockets were seeping? Were you actually seeing carbon ringing the primer pocket?

 

[Zak Smith]

Exactly. Soot around the primer ring.

When I tried some tighter primers, the problem went away, but I could not get the accuracy and low SD's I wanted with that combination of primers & powder.

-z

 

[michael_aos]

I've been using the Federal 210M almost exclusively.

Mike

 

[Ol` Joe]

What is the load you`re haveing trouble with?
I toss all my (including 260 Remington brand) brass at 10-12 loads, whether they appear OK or not. I`ve never seen any sign of weakness in them at that point yet. Case web stretching, neck cracks from over working, ect, aren`t a case fault. They are normally avoidable with proper sizeing ect. Leaky primers are usually a sign of damaged pockets, brittle primer cups, overloads, or stretched primer pockets. If you are not excessive in your load (0.0003 is concidered "normal" from what I`ve READ) then too much pressure is not the problem, something else must be. Primers are meant to expand and seal the pocket. If they leak something is either stopping the expansion or defeating it.

 

[Gewehr98]

Something isn't right if you're that close to blowing primers.

Especially for the .260 Remington.

Granted, I've been a big fan of Lapua brass since the mid 1990's, because it's incredibly consistent. That, and I scored several thousand pieces of 7.62x51 headstamped Lapua brass back around 1994.

Zak, did those ringed primers feel loose or take little effort to seat? Outside neck turning should be a last resort, especially when necking up a round, even with a slight moving of the shoulder. Necking down a .308 to .260 Rem would be a given.

Neck turning is a benchrester's technique to comply with tight (minimal) throats reamed in their custom BR barrels. Likewise, it keeps chamber pressures down, reducing neck tension when resizing larger caliber brass down to something smaller diameter. But cutting expensive Lapua .243 brass for long-range tactical toys, even a .260 Reminton, doesn't sound like a lot of fun. Did you try to fireform some of the necked-up Lapua without turning them?

 

[Zak Smith]

Ol'Joe. Yes, I also concluded that something else besides pressure was the problem--- the brass. The load that was seeping in the R-P brass was 41.5gr H4350, 139gr Scenar, with 210M's or BR2's (this is 1/2gr below Hodgdon's max).

As I said, it was much easier to seat primers in the R-P brass than other types I have tried. I think we can rule out work hardening and sizing issues because these were all with new R-P brass, which was only full sized in a Forster die to set the neck tension.

Gewehr98,

It's not clear that the R-P brass loads are "close to blowing primers", since there is no case head expansion and other normal pressure indicators were not present.

To be clear, the reason I am neck-turning the Lapua 243 brass and not just shooting it is because part of the shoulder of the 243 brass gets turned into 6.5mm neck when it's sized up, and this rear part of the new neck is thicker than the neck ought to be. When a bullet is seated, this "donut" is pushed to the outside and the round will not chamber. The solution is to remove the extra material at the base of the neck to return it to the normal thickness. You cannot use fireforming to solve this problem.

Neck turning is also the way to remove the donut that forms near the base of the neck in high pressure cartridges, even in "native" brass. By removing more material in my initial step, I delay the onset of this donut formation due brass migration. Tubb talks about this in his second book.

 

[Gewehr98]

I know about the secondary "donut" that appears later.

If I find donuts formed by the initial resizing of brass, I'd leave them on my reformed 6.5-06 brass, without cutting them, regardless of what Zedicker/Tubb says. My theory is that the brass is going to flow the most towards the case mouth on the first firing after case forming, and that contributes to the longer OAL, which then gets trimmed. I do that for 6.5-06 from 7x64 Brenneke (RWS) brass, and also when I make 7.62x45 Czech from 6.5x54 Mannlicher Schonauer (Norma) parent cases (big move of shoulder, minimal donut). to the appropriate thickness, and if I have too strong of a bullet pull afterwards, I would inside ream where I thought the secondary donut was causing excessive neck tension.

Don't get me wrong, if you're having problems chambering a newly resized piece of brass because of the donut, then by all means fix it. I just get squeamish about turning and cutting into a new piece of brass before it's even fireformed, when maybe an extra fraction of a turn or so on the sizing die will let it chamber without causing too high of a bullet pull situation. I guess it also depends on how close the dimensions of the sizing die are to those of your chamber and/or chambering reamer.

I do, as a matter of practice, always anneal the shoulders and lower neck of all my resized brass, be it 6.5-06, .236 Super (aka 6mm-.270), .32 Remington, or 7.62x45 Czech. Once I do that, I find that the newly-resized brass retains dimensional stability considerably longer in the critical shoulder/neck areas, and neck splits are postponed almost indefinitely.

 

[Zak Smith]

Believe me, I tried all combinations of adjusting the sizing die before resorting to this extreme step, since adding an extra evening per 100 cases of case prep is not my idea of fun.

Actually, chambering the empty necked-up cases worked fine, because that extra material at the bottom of the neck was pushed to the inside. And even then 30% of the loaded rounds would still chamber.

With regard to the donut.. I have seen sectioned 338 Lapua cases which definitely had the donut, and their owner said you could feel the bullet go over it while seating. These had several firings with a hot 300gr load.

-z

 

[michael_aos]

That's another advantage of sizing down from 308. The shoulder is down a little further at 1.712" -vs- 1.804" on the 243.

I've also been using the 123gr (shorter) bullets and seating them as long as my magazines will allow.

I haven't encountered any doughnut issues I'm aware of.

Mike

 

[Gewehr98]

Neck tension can indeed be a problem with those 6.5mm bullets.

They have such a long bore-rider section that when seated, they grab all of the case neck. I've loaded 6.5x55 Swedish rounds, using 139-160gr bullets, and they were almost impossible to pull using a kinetic bullet puller. Upon examination, there was no donut in the neck, just that much neck tension and surface area on those long bullets. A larger expander ball would probably do the trick, assuming the case neck would still chamber smoothly. The other option is the Redding bushing neck dies, where one selects the proper neck bushing to best match their rifle's chamber. Once I get completely relocated to my new digs here in Wisconsin, I will start in earnest on a .260 Remington project I've had on the back burner for a while. (Along with a 6.5-284 and .45-70 AK-47 project) I just hope I won't have to do the neck-turning that Zak's running into.

I'm not too far from the 1000 yard range at Lodi, so I can see some fun weekends coming up in the not-too-distant-future. A buddy in Sacramento used a Remington 700 Varmint variation at the Ione 1000 yard matches to very good effect, my 6.5-06 worked fine but almost seemed overkill.

 

[USSR]

I've loaded 6.5x55 Swedish rounds, using 139-160gr bullets, and they were almost impossible to pull using a kinetic bullet puller. Upon examination, there was no donut in the neck, just that much neck tension and surface area on those long bullets. A larger expander ball would probably do the trick, assuming the case neck would still chamber smoothly. The other option is the Redding bushing neck dies, where one selects the proper neck bushing to best match their rifle's chamber.

I use the Redding Competition Dies with bushings exclusively. You pick the bushing to select the amount of neck tension you want, not to match your chamber. I have found that minimal neck tension results in lower ES and SD numbers.

Don

 

[michael_aos]

I use a Redding titanium nitride neck sizer bushing.

.290" for R-P 260 brass. .293" for resized Lake City 308.

Mike

 

[michael_aos]

Oops. Turns out I am getting gas-seepage with my R-P 260 brass.

I just didn't know what I was looking at until Zak pointed it out to me.

Mike