First time loading lead for 7mm Rem Mag

[MediumCore358]

I've loaded Many lead boolits for straight walled pistol calibers over the last few years, but soon I am going to attempt it in 7mm Remington Mag. I have a load in mind from the Lyman Cast Book, but I was wondering since you flare certain cases to ease bullet insertion how does it work on a rifle case? Do I have to worry about shaving lead while seating boolit? Tips please and thank you.

[jcren]

I load cast in a 3006, and yes you need to flare the case mouth. I have used a taper punch inserted and tap the case/punch to make a slight flare, but now use t the lee universal taper die. If the mouth is flared enough for the bullet to start slightly it shouldn't shave, but might swedge or squeeze the bullet smaller as it goes on in. Just depends on your size requirements and the neck tension of your brass. If you need larger case necks, layman m-series dies are made for the purpose, or if neck sizing Lee can make a custom mandrel for their premium collet dies.

[Echo]

Best solution is to buy a Lyman M-die in 30 caliber - expands the neck further than the spud on the sizer spindle, and gives a little extra flare making seating lead boolits much more satisfying. And other inserts are available for the M-die, allowing it to be used for other calibers.
Or. Use a set of needle nose pliers, to do a quick bell job. Practice and experience will teach you just how many spins, what pressure, &cetera...

[MediumCore358]

Great information so far guys, whatever means I end up flaring the case is that taken up or the flare closed /flattened by the seating die?

[GabbyM]

In a perfect world. Your neck expander plug would be .001” under your bullet diameter. Brass spring back would leave your neck close to .002” under boolit diameter. Consistency in bullet tension is more important than actual tension pressure. Thus after you start thinking in tenths. (.0001”) you are in bench rest area. But don’t be so silly as to think you can push a bullet .003” under neck diameter then get anything but junk ammo. Just because a few tenths are not significant does not mean one thousandths is not.

RCBS makes expander plugs in .001" increments. I've several Lyman M dies that were all in tolerance and load good ammo.

[jcren]

The flare is straightened out at the crimping stage. Whether you have a 2 or 3 die set, you can set the crimp to just take the bell out without crimping.

[sundog]

MC358, been there and done that, and actually found an accurate load. However, I will say this. Some cartridges are best served with good quality jacketed bullets. This cartridge has a very short neck and a very large boiler room, neither of which serve the best interests of shooting cast, but it can be done. Patience, friend. And a lot of trial and error. My best load was using RCBS 168 SP loobed with FWFL and IMR 3031.

Keep us posted on your progress.

[GabbyM]

Not loaded for a 7mm Mag yet. Although in both 243 A.I. and 270 Win. Which are also quite overbore. I found a charge of shotgun powder to get them up around 1,900 fps worked as well or better than much more rifle powder. Unique is what I am using. I shoot a 122 grain Loverine over 14.0 grains of Unique in the 270. With the 150 gain bullet I use 5744 and have used Rx7 with success at around 1,900 fps. In the 243 A.I. with a Lyman 245496of 84 grains. I shoot 11.0 grains. It's a medium weight varmint with 24X scope and will bench shoot just under one MOA all day long at 100 yards with this load.

[MediumCore358]

Thanks for the tips and information gentleman, I'm thinking about using the Lee universal flare die although the Lyman M series dies sound nice. In a pinch or if I get antsy waiting for the mail to arrive I may just try the needle nose or punch die flaring technique. I really like the term "boiler room" for case capacity lol I'll remember that for a long time, 7mm Remington Mag probably isn't the ideal cartridge for cast but why not? Ya know.

[Wally]

I use the RCBS 168-SP-GC bullet, a Lyman "M" die, & a C & H Taper Crimp die made for the 7mm Rem Magnum. Have used 15 ~ 17.5 grains of Unique as well as 15.0 grains of Red Dot. I also make my own aluminum GCs and use standard primers.

Be sure to place charged cases on a loading block and do a flashlight test to be sure you don't double charge.

[Baryngyl]

Before I got my LEE universal expander would just use a smaller bottle neck case flipped over and tapped, I think I used a 270 or 25-06 case to expand my 30-30 and 30-06, just use one that is no longer going to be reloaded and used, not sure if it changed the shoulders any but I was taking no chances and kept the couple cases I used for that marked and separate.



Michael Grace