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7mm Rem Mag help needed

Discussion in 'Handloading and Reloading' started by Pit4Brains, Jun 24, 2014.

  1. Pit4Brains

    Pit4Brains Well-Known Member

    I have never loaded belted brass before, just -06 and handgun. My question is weather or not to full-length size or just neck size the brass. It will be fired in the same rifle it was fire-sized in. I want to measure for a good c.o.l. so I'm kinda leaning towards neck sizing only. Thoughts?
  2. nastynatesfish

    nastynatesfish Well-Known Member

    You can neck since till it gets to tight to chamber. I never seen any benefits from neck to fl sizing. I set my die up to just bump the shoulder enough to close the bolt easy. I had 15+ loads on my brass in 3 barrels before I had my first separation. The brass I'm shooting now is Winchester and have 9 loads on it with no issues. I don't run blazing hot, I shoot 140 bergers with 64gr h4831 and 162amax with 63.5gr.
  3. tightgroup tiger

    tightgroup tiger Well-Known Member

    I wouldn't touch that shoulder unless I had to. See post 2. The better supported that case is the more accurate it can be when everything is right. I do this on 30-30s also with not bumping the shoulder as long as it will chamber easily in my lever actions or in my BLR Browning 30-06. If they will chamber I leave the shoulders along. Your belted magnum isn't that much different.
  4. Pit4Brains

    Pit4Brains Well-Known Member

    EDIT: Thanks for the advise. I guess I'll neck size and go from there like I normally do..
    I trimmed the brass to 2.490 IAW Hornady 8th Edition Handbook. I guess I'll have him chamber a few empties to check for fit before I go any further. If I have to FL size, I can always re-trim I guess. My Biggest concern was how belted brass headspaces at the belt instead of the shoulder. I'm still learning this headspace thing. Thanks for the help.
  5. witchhunter

    witchhunter Well-Known Member

    If this is your huntin rig, make sure you run em through the chamber before you take er huntin to make sure there are no surprises in the heat of the moment.
  6. oneounceload

    oneounceload member

    I have never done anything else but neck size for my 700BDL
  7. blarby

    blarby Well-Known Member

    Thats great advice right there.
  8. Pit4Brains

    Pit4Brains Well-Known Member

    These will be hunting rounds for my neighbor. I'm building them for his rifle so we'll fire a few groups of five one charge/c.o.l. at a time at the range looooong before he takes them to the field.
    I use RCBS and he brought me some LEE dies that he picked up. I'm not liking this collet-held sizer pin. It seemed harder to set this die than my RCBS. Maybe it's just my lack of experience with them.
  9. nastynatesfish

    nastynatesfish Well-Known Member

    They only headspace off the first new firing. Neck will work. I just quit using my neck die and only use my fl sizer
  10. gamestalker

    gamestalker member

    I get a few more reloads from the brass by necking. But do realize that even if you decide to neck, you'll still need to maintain the shoulders with a FL die.

    And another possible, which I've experienced with one of my tight chambered 7 mags. is the web will bulge out before the primer pockets or incipient head separation takes it's toll. I do load on the warm side though to, so I'm sure that has some bearing on this.

    At present, and head stamp depending, I average 10-12 reloads from my brass using a neck die. FL only, I get about some where between 7 - 10 loads form my brass.

    I am a proponent of using a neck die,both for accuracy and extended life of the brass.

  11. Pit4Brains

    Pit4Brains Well-Known Member

    Awesome. I have only necked my loads for my 25-06 break open and my 30-06 bolt and have had good success with each of them.
    Now I just hope he can find some powder and LRMP somewhere. Our shelves are empty around here.

    BTW, what is that third (die) that comes in a Lee set? Is that a collet bullet puller? Like I said before I'm pretty much RCBS equipped and I use a kinetic puller if needed.
    Last edited: Jun 25, 2014
  12. gamestalker

    gamestalker member

    I've never used Lee bottle neck dies before, so I couldn't say. But from what I hear around here, they make a pretty decent rifle die.

    Just resize them as if they didn't have a belt. In other words, don't push the shoulders back more than is absolutely necessary for chamber fit, or you'll experience case head separations right away. Tightgroup Tiger said it very well, don't touch the shoulders unless it's necessary, and then only enough to obtain chamber fit.

  13. Skyshot

    Skyshot Well-Known Member

    I only neck size my 7mmRM and as was said by gamestalker, keep a close eye for web seperation. You can make a feeler gauge for this with a large paper clip. Straighten the clip out and turn one end up at 90 degrees. You can then insert that end into the case and scrape it against the inside wall and you can actually feel a dip when the web starts to separate. Use a new case for reference if your not sure about how it should feel. You can get good case life by sticking to medium velocity loads.
  14. Pit4Brains

    Pit4Brains Well-Known Member

    We finally got some primers and powder shipped in. I am using CCI 250 primers and IMR4064 under a 160 gr nosler. Before I load these round with these hard to find primers, I was wondering if I can get away with large rifle primers instead of the magnums. LR primers are on the shelf here. I'm starting the loads at 49 gr and working up to 53 one grain at a time. With a load density between 67% and 72%, It seems to me that a standard primer should do the trick. Thoughts??..
  15. gamestalker

    gamestalker member

    If it's been fired through the same rifle your going to shoot it from, then you can certainly just neck size until it needs bumping, which it eventually will. I recommend chamber checking each piece after necking it, and prior to going forward with priming, charging, and seating though, just in case you get an odd ball piece that may have already been tight from the get go, I run into that now and then, in fact I just did about an hour ago. But I also have a very tight chamber, which I'm sure has some bearing on this.

    I get 2-3 more cycles off my brass by necking my 7 mag. brass, which is to say 10-12 loads by necking it v.s. 8-10-ish only FL sizing. But because I load on the rather warm side, I run into problems with the web getting pushed out before my primer pockets get loose or incipient head separation presents. This is something I'm going to address with a Innovative Technology collet die in the very near future.

    As for primers, the powders and data I load with are published with magnum primers, so that's what I've always used. In other words, stick to the published recommendation in this respect and you'll be fine.

    Last edited: Jul 10, 2014
  16. Pit4Brains

    Pit4Brains Well-Known Member

  17. nastynatesfish

    nastynatesfish Well-Known Member

    I use standard primers in my 7mag. I use h 4831sc. Never tried 4064 in mine. It may just be easier to set up your fired brass in the press. Adjust the die depth until the sized brass chambers easily. I only bump shoulders. I don't neck size or fl size anymore. I haven't since 2009.
  18. gamestalker

    gamestalker member

    Belted cases only head space of the belt the first time they are fired. After the initial firing you definitely want to work off the shoulder, other wise, you'll very quickly start experiencing case head separations, just like with any bottle neck cartridge.:eek:

    Is it possible that a chamber may so tight as to head space off the belt and shoulder at the same time, maybe? But to avoid any issues as described above, always seek to head space off the shoulder.

  19. ironworkerwill

    ironworkerwill Well-Known Member

    Very true.

    OP, you will have to get a FL die if you want to keep using the brass. Or at least a body die.
    Last edited: Jul 10, 2014
  20. ArchAngelCD

    ArchAngelCD Well-Known Member

    Magnum primers are only needed for hard to ignite powders and for heavy charge weights of 70gr or higher. IMR4064 is not a hard powder to ignite and your charge weights are not heavy. Unless you are going to be shooting this ammo in -30 degrees standard LR primers are just fine...

    BUT, how did you make your powder choice? It's my opinion that powder is way too fast for the 7mm Rem Mag. I would have bought 4350, 4831 or Hybrid 100 instead. (especially with a 160gr bullet) I feel the slower powders will produce better accuracy considering the fill the case better.

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