Methods and Tips Loading for the 7mm RM

[Herd_Bull]

I’m a new hand loader and the cartridge I’m going to be working with is the 7mm RM for one rifle. I previously posted a thread on what components to use and got some great information. In this post I’d like to know any tips or suggestions in regards to reloading methods you guys have for this cartridge.

I’ve spent hours and hours reading information on the belted mags and why it’s better to headspace on the shoulder vs. the belt. And I’m still a little confused on how to do that exactly but understand that how easy or difficult that is will depend largely on the size of my chamber.

I’m only loading for hunting and recreational shooting purposes in one rifle out to maybe 600yds in a factory Rem SPS SS 700 bolt action with premium hunting bullet in the 150 to 175gr range.

I have already read load manual information. I don’t want to make this more complicated than it has to be and just want to establish a simple, efficient, and effective process to produce dependable, accurate hand loads. I’ll be starting out with purchased, once-fired brass that was not fired in my rifle. Thank you.

 

[nastynatesfish]

If your using new brass just load them and fire. If your using brass fired in a different rifle you'll need to full length resize then fire. If it's brass shot it that rifle you can just bump shoulder or neck size. 7 rem mag loads the same as any other cartridge. I've been loading for mine since 2009. It's a great round. Your rifle is a 1-9 or 1-9.25" twist so it'll shoot all the bullets from 140-175. I shot mostly the 154 interlocks when I first start and then moved to Bergers and amax.
A) you don't have to try to touch rifling to be accurate
B)make sure your press prep is consistent or you'll fight load developement
Need help. Feel free to pm me

 

[MrMajestic]

http://larrywillis.com/
Scroll down to the collet die.

 

[snert]

For years i was a neck size guy. then I got my Sendero 7RM and found it to shoot considerably better FL siizing. I use a Redding FL size die, a COMP seat die and run a hefty charge of 7828 behind a 150nosler BT, standard federal match primer. Honker just flat out shoots. My last deer was a called left eye hit at 331 yards off a bench. Yup, bad day for that deer.

 

[Herd_Bull]

Thanks guys. Does anybody use one of those Willis collet dies? Do you use it everytime you reload a case or only every few? And if I understand it correctly, you first resize with the FL die and then use the collet die correct?

 

[MrMajestic]

One end of the die is a gage. If the case doesn't fit you use the collet. Yes you have the correct order of operation. Very high quality piece of equipment.

 

[centerlineseal]

"I use a Redding FL size die, a COMP seat die and run a hefty charge of 7828 behind a 150nosler BT, standard federal match primer."

Hey Snert,

Care to share the powder charge on that? I exclusively use IMR4350 in my 7mmRemMag, but have a ton of IMR7828 for my 338 Lapua and am transitioning over to Reloader 33 for that round. Of course, loads need to be worked up from minimum book for each individual firearm.

10-Q

 

[MrMajestic]

From the IMR load data.

BULLET WEIGHT150 GR. NOS PART
ManufacturerIMR
PowderIMR 7828
Bullet Diameter.284"
C.O.L.3.270"
Starting Load
Grains62.0
Velocity (ft/s)2,792
Pressure51,700 PSI
Maximum Load
Grains66.2
Velocity (ft/s)2,952
Pressure58,500 PSI

 

['Freak]

I’m a new hand loader and the cartridge I’m going to be working with is the 7mm RM for one rifle. I previously posted a thread on what components to use and got some great information. In this post I’d like to know any tips or suggestions in regards to reloading methods you guys have for this cartridge.

I’ve spent hours and hours reading information on the belted mags and why it’s better to headspace on the shoulder vs. the belt. And I’m still a little confused on how to do that exactly but understand that how easy or difficult that is will depend largely on the size of my chamber.

I’m only loading for hunting and recreational shooting purposes in one rifle out to maybe 600yds in a factory Rem SPS SS 700 bolt action with premium hunting bullet in the 150 to 175gr range.

I have already read load manual information. I don’t want to make this more complicated than it has to be and just want to establish a simple, efficient, and effective process to produce dependable, accurate hand loads. I’ll be starting out with purchased, once-fired brass that was not fired in my rifle. Thank you.

When using any full length size die to size the case body, you’re also able to control the amount of case shoulder set back, or call it “bump”, by backing the die body a bit out the press for less bump or screw the die into the press a bit further to set back or bump the shoulder a bit more.

With a 1:14 thread pitch one full turn of the die body moves it .0714” either further into or backed out the press, depending, so that when the press ram is fully extended either more or less of the case body’s length gets shoved up into and is acted on by the die. Using a cheap calculator, you can quickly figger how far turning the die any fraction of a turn in or out will move the die body relative to the press ram while at the top of its stroke.

Exactly a quarter turn of the die body moves the die .018” nearer to or further from the shellholder; (1/14) / 4 = .0179”. An eighth of a turn moves the die .009”; (1/14) / 8 = .0089”. Backing the die out the press exactly one sixteenth of a full turn moves the die body .0045” further from the shellholder of a fully extended ram so that .0045” less of the case’s length will enter and be acted on by the die. If you want exactly one thousandth more shoulder bump then you’ll need to turn the die further into the press so nearer the shellholder by exactly 1/71 of a turn, (1/14) / 71 = .001006...”.

It’s very much difficult to figger how much die body rotation constitutes exactly 1/71 of a full turn just from eyeballing the thang and without some sort of reference. So, you can make do real close by placing two tiny dots, one on the 7/8”-14 die threads and the other on the press next to the first. The value of Pi times the die’s 7/8” major thread diameter figgers its circumference of 2.74889...”. Circumference divided by 71 (for the 1/71 of a turn = .001” further in or out the press thang) and you get .0387…” or how far the dot on the die threads needs to be moved along its circumference away from the dot placed on the press in order to move the die .001” either nearer to or away from the press ram/shellholder; (Pi (7/8)) / 71 = .0387…”. I use the tenths/hundredths scale on a 16R steel rule and shoot for best I can a fraction of a bitty hair under .040”.

 

[Herd_Bull]

Freak - Great response... thank you. I'm assuming you did well with math in school

My new brass just got here today, so I'll be loading this weekend. How far can I "bump" the shoulder of case fired in my rifle back and still have it headspace on the shoulder and not the belt? I know it varies, but let's say a .001 to .002 or maybe even a .003 would still headspace on the shoulder and not the belt?

 

[284driver]

When using any full length size die to size the case body, you’re also able to control the amount of case shoulder set back, or call it “bump”, by backing the die body a bit out the press for less bump or screw the die into the press a bit further to set back or bump the shoulder a bit more.

With a 1:14 thread pitch one full turn of the die body moves it .0714” either further into or backed out the press, depending, so that when the press ram is fully extended either more or less of the case body’s length gets shoved up into and is acted on by the die. Using a cheap calculator, you can quickly figger how far turning the die any fraction of a turn in or out will move the die body relative to the press ram while at the top of its stroke.

Exactly a quarter turn of the die body moves the die .018” nearer to or further from the shellholder; (1/14) / 4 = .0179”. An eighth of a turn moves the die .009”; (1/14) / 8 = .0089”. Backing the die out the press exactly one sixteenth of a full turn moves the die body .0045” further from the shellholder of a fully extended ram so that .0045” less of the case’s length will enter and be acted on by the die. If you want exactly one thousandth more shoulder bump then you’ll need to turn the die further into the press so nearer the shellholder by exactly 1/71 of a turn, (1/14) / 71 = .001006...”.

It’s very much difficult to figger how much die body rotation constitutes exactly 1/71 of a full turn just from eyeballing the thang and without some sort of reference. So, you can make do real close by placing two tiny dots, one on the 7/8”-14 die threads and the other on the press next to the first. The value of Pi times the die’s 7/8” major thread diameter figgers its circumference of 2.74889...”. Circumference divided by 71 (for the 1/71 of a turn = .001” further in or out the press thang) and you get .0387…” or how far the dot on the die threads needs to be moved along its circumference away from the dot placed on the press in order to move the die .001” either nearer to or away from the press ram/shellholder; (Pi (7/8)) / 71 = .0387…”. I use the tenths/hundredths scale on a 16R steel rule and shoot for best I can a fraction of a bitty hair under .040”.

Or, you could use this.
http://www.pmatool.com/pma-micro-die-adjuster-w-thumb-screw-upgrade/

 

[MrMajestic]

Remove the firing pin and set the bump so you can close the bolt with minimal effort. Remember if you are not using the collet die the case just forward of the belt will not get sized and can drag also. With a factory chamber you most likely will not be close to the belt after fire forming. Are you jamming the bullet to fire form?

 

[Herd_Bull]

I am not jamming the bullet to fire form.

 

[wapiti25]

I have been loading the 7mm mag for over 30 yrs and 4 rifles. I shot out the original barrel in a 700 rem (lots of rounds). You may not need the Willis collet die, I have never needed one. Set the full length sizer to bump the shoulder until the brass just feels good on closing about .002" to .003". Do not set the die to touch the shell holder as RCBS would have you do. IMR 4350 works good for bullets to 160, IMR 7828 works great with the Nosler 150 BT. I hunt now with the Berger 168 hunting VLD using H1000. I have killed mule deer, elk, moose, and antelope with my rifles. An inline seating die is recommended, I use the Redding comp seater. I like Winchester brass but Rem is ok, I did get my hands on some RWS which should be close in quality to Lapua but have not shot it yet. I have some bullets that I will be selling, mostly Nosler some Hornady and Sierra contact me and I will look see what I need to sell if you are interested.

 

[MrMajestic]

I am not jamming the bullet to fire form.

It may then take several firings to reach full expansion. Try chambering w/o sizing after the first firing.