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Forming .260 Rem Brass- .243, 7-08, or .308- Help needed

Discussion in 'Handloading and Reloading' started by FTSESQ, Apr 4, 2010.


    FTSESQ New Member

    Hi all. I am seriously thinking about buying an AR10 in .260 Rem (ok, so i'm 90%). But form what I've been reading, .260 commercially available brass is of spotty quality, and it seams that most serious shooters are forming their own brass from .243, 7-08, or 308 brass.

    My "reloading" skills are pretty basic. I reload .45ACP, 38spl/ 357mag and 6.5 Grendel, but I'm really just reloading, not doing anything fancy.

    So, What is the best starting point; .243, 7-08, or .308. I don't have any guns in those calibers, so mixing up brass is not a concern... yet :D. Is one better or easier than any of the others? .308 brass is a lot cheaper than the others, but it seems that most folks form their .260 from .243. Any reason? Also, is this something that I can do if I pay close attention and am careful, or is this an "advanced" maneuver, that I should not attempt until I get some instruction from an experienced reloader?

    Anything that I may have missed or should know?

    Thanks in advance
  2. evan price

    evan price Active Member

    The .260 Rem is more or less a .308 case necked to fit a 6.5mm bullet. It's a great combo. I'm doing a Mauser bolt gun in .260 this year.

    You can run any of those cases into your .260 Rem sizing die and trim as needed, but given the scarcity of 7mm-08 brass and the number of shooters that want .243 brass, I would say start with .308 Win brass and trade off the 7mm-08 and .243 for more .308.

    Make sure you get a little lube on the inside of the case neck to aid the resizer.
  3. alfack

    alfack New Member

  4. Zak Smith

    Zak Smith Moderator Staff Member

    I recommend trying Remington brass first. It works for many people.

    If that fails and you have the budget, consider the Nosler brass.

    Otherwise, the next easiest thing to do is use .243 brass. Winchester .243WIN is your best/cheapest bet. I recommend using sizing wax and a neck-up sizing mandrel for this operation. Make sure the resulting neck is not tight in your chamber with a bullet seated. If it is, you might have to outside neck turn a little bit near the rear of the neck.
  5. Offfhand

    Offfhand Active Member

    For top quality .260 loads I use Lapua .243 brass necked up to 6.5. It's a simple operation with a Sinclair neck expanding mandrel.
  6. GW Staar

    GW Staar Active Member

    One thing that happens when you neck down, is the the material in the necks gets thicker. When I used to get my .243 brass by necking down NATO Lake City stuff, I bought an inside neck reamer for my Forster trimmer, to ream it.

    When necking up from .243, you don't have that problem, but the neck gets thinner.

    I, for one, would rather ream...than have thinner neck walls. Not to mention that military brass has been cheap and plentiful in the past.

    If you use decide to use military .308, resize first with a .308 die, then with the .260 die. Stepping it down a little at a time is easier on the brass.

    Forster reamer
    Last edited: Apr 6, 2010
  7. JimKirk

    JimKirk Active Member

    Do you mind measuring the end of the reamer that goes in the tool shaft?

    I'm wondering if it would fit my RCBS trimmer. If the shaft size is the same or close enough to fit, it should work.

    Jimmy K
  8. EddieNFL

    EddieNFL member

    I use W-W 7/08 and turn the necks. I've checked lots of R-P brass and it tends to have inconsistent wall thickness. Not always, but more often than others.
  9. Afy

    Afy New Member

    I have had good luck with RP .260 brass.
    Have tried the .243 Neck up with the Lapua brass, and doghnut removal etc.. but didnt actually see a difference.
  10. GW Staar

    GW Staar Active Member

    Forster uses pilots and reamers with a .185" shaft. I know that Hornady and Redding Pilots are interchangeable, but I'm betting you're out of luck with the RCBS. At least the "Original Forster Trimmer" is not that expensive. I may buy another just for reaming and outside reaming.
  11. GW Staar

    GW Staar Active Member

    I probably should elaborate on the Forster reamer, lest anyone misunderstands. (my memory did)

    The reamer is made to ream the neck BEFORE sizing. That means you fire-form your .308 case-made .260's. Then the first step on the next reload of the case is to ream before you size.

    There is the possibility that the 1st reload,with too thick a neck, might not chamber in a really tight chamber. I haven't seen that, but if that's the case one would need to ream (before fire-forming) with an outside neck reamer.
    See Forster Reamer Instructions.
    Outside Neck Trimmer
    This URL is a review of the Forster trimmer used as a reamer.
    Last edited: Apr 6, 2010
  12. JimKirk

    JimKirk Active Member

    Thanks GW

    RCBS shafts are .150, so yes out of luck unless I turn them down.

    Jimmy K

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