Reloading the 7mm rem mag, got any tips?

**Trucker76** · January 10th, 2014, 08:57 AM

So today I pick up my 7mm, and snow be damned I'm taking it to the range. I'm looking forward to loading some brass for this gun. I remember reading somewhere that there are some issues reloading belted magnums. Is there anything I should look out for? Also this will be my first time reloading brass with a shoulder. Up to now I've only loaded straight walled handgun brass.

**dk99358** · January 10th, 2014, 12:17 PM

Start by adjusting your dies as per the directions. Cases should chamber easily. Then try adjusting them so that it takes a slight bit of effort to chamber and close the bolt. For hunting rounds, where you want easy feeding, readjust slightly so they close normally.

What you are trying to do is minimize the stretching that they can do. Rimmed magnums headspace on the rim, but that sometimes leads to shorter shoulders which then expand a lot on firing. All that leads to shorter case life.

Don't forget to LUBE them before running them into the die. I'd start with a slow powder (something like one of the 4831's) and a magnum primer.

Dale

**Trucker76** · January 10th, 2014, 12:48 PM

Originally Posted by dk99358

Start by adjusting your dies as per the directions. Cases should chamber easily. Then try adjusting them so that it takes a slight bit of effort to chamber and close the bolt. For hunting rounds, where you want easy feeding, readjust slightly so they close normally.

What you are trying to do is minimize the stretching that they can do. Rimmed magnums headspace on the rim, but that sometimes leads to shorter shoulders which then expand a lot on firing. All that leads to shorter case life.

Don't forget to LUBE them before running them into the die. I'd start with a slow powder (something like one of the 4831's) and a magnum primer.

Dale

By rimmed do you mean belted? Rimmed to me is like a 38spl which has a rim vs a .45 auto which doesn't. I know the 7mm headspaces on the belt.

Yep I have a lube pad and whole bottle of lube unused thanks to carbide pistol dies. I'm guessing this will be a good time to buy a set of calipers and a case trimmer, maybe a powder trickler too.

Now all I need to do is find some brass.

**mikal90** · January 10th, 2014, 03:27 PM

I load 7 mag. Unless your trying for some kind of super match grade ammo, you won't need a case trimmer right away. I use H-4831, CCI magnum primers. You will need a powder trickler. Pick a powder, primer, bullet and load small and work it up. Check the loading info from the bullet company and cross match with the powder company. When I work up a load for accuracy I start at the published min. powder charge and load 3 or 4 rounds. Then I move up a grain or 1 1/2 grains and load 3 or 4 more rounds. I keep doing this until I have around 4 or 5 different grain charges and then I head to the range. I never load max charges. Also the max charge might be different between the bullet co. data and the powder co. data. To keep track of the different loads I put each 3, 4 rd. batch in a ziplock bag with a note on the powder charge. I shoot those for groups, checking the brass for stress and then back in the same bag for home. If you don't like what you see from the loads after that. then change powder. Say 63gr. and 64 gr. are grouping 1" or less you can try a 63 1/2 gr load to see if its better. Before the snipers start about 1" groups suck. I load hunting ammo. I also weigh every charge. H-4831 meters poorly.

**Trucker76** · January 11th, 2014, 02:24 AM

Originally Posted by mikal90

I load 7 mag. Unless your trying for some kind of super match grade ammo, you won't need a case trimmer right away. I use H-4831, CCI magnum primers. You will need a powder trickler. Pick a powder, primer, bullet and load small and work it up. Check the loading info from the bullet company and cross match with the powder company. When I work up a load for accuracy I start at the published min. powder charge and load 3 or 4 rounds. Then I move up a grain or 1 1/2 grains and load 3 or 4 more rounds. I keep doing this until I have around 4 or 5 different grain charges and then I head to the range. I never load max charges. Also the max charge might be different between the bullet co. data and the powder co. data. To keep track of the different loads I put each 3, 4 rd. batch in a ziplock bag with a note on the powder charge. I shoot those for groups, checking the brass for stress and then back in the same bag for home. If you don't like what you see from the loads after that. then change powder. Say 63gr. and 64 gr. are grouping 1" or less you can try a 63 1/2 gr load to see if its better. Before the snipers start about 1" groups suck. I load hunting ammo. I also weigh every charge. H-4831 meters poorly.

Sounds like you load the same way I load my pistol ammo. I usually do 5 round batches since the rows in a 50 round are 5x10. One trick that may make your life easier is to get a pack of colored sharpies. I mark the primers of each batch a different color and write down the load info for each color in my journal. much easier to keep track.

I'm shooting 1" groups at 100 yards now with factory ammo (winchester) but was dismayed to see how inconsistent the rounds were. Bullets were seated all over the place. I would generally get 2 shots in the same hole then a flier. But all 3 were always in the 10 ring. I only had 20 shells and had to use some to sight the scope in as it wasn't even hitting the paper at 50 yards when I got it. I know when I open it up to 200 and 300 yards factory ammo is not gonna cut it for me.

**SteveWag** · January 11th, 2014, 01:41 PM

The 7mm Rem., and all belted mags, were designed to headspace off the belt. You, as a reloader, can correct this design flaw. As mentioned earlier, DO NOT set the FL die against the shell holder. Set the die about 2 turns above the holder, size a lubed case, and look at the neck. You should see that it is only sized about halfway down. Lower the die about a quarter turn down, and repeat, until the sizing line just touches the shoulder. The idea is to size only the neck and allow the expanded case to headspace off the shoulder. Another idea is to buy a neck sizing die.
Steve

**dk99358** · January 11th, 2014, 03:26 PM

Originally Posted by Trucker76

By rimmed do you mean belted?

Yeah, I did. Brain fart on my part.

You'll need the case trimmer, I trim my 270 Win cases about every other load. Calipers too, I measure every time I load them.

Look for the SC (short cut) version of H4831, it meters much better than the regular H4831. Data is the same for both powders. IMR 4831 is different. 2 other powder options are Ramshot Magnum or IMR7828SSC.

I too use the baggie method for separating different loads. I use Avery stick on labels on the bag, and reuse the bags by simply sticking a new label on for different loads.

I consult several load sources, decide what is a viable max charge for my bullet and then load 3 rounds at 90%, 92%, 94%, 96% and 98% of that max. Off to the range, shoot them off, and measure groups. I'll load 6 of the best again. I also split the difference between the best charge and the ones above and below and load 6 of each of those. For example, if the first test run was 48, 50, and 52, and the best was 50 grains, my second run is 49, 50, and 51. If I don't have the accuracy or velocity I want, I try another powder.

For hunting rounds, I seat the bullet to the max overall length listed in the data. Once I have determined the powder type and charge, then I try a few rounds with the bullet seated deeper and a few seated longer (if the magazine allows). I want absolute feeding reliability.

For big game ammo, I am perfectly happy with 1 inch groups at 100 yds.

Dale

**cephas** · January 11th, 2014, 04:06 PM

Originally Posted by SteveWag

The 7mm Rem., and all belted mags, were designed to headspace off the belt. You, as a reloader, can correct this design flaw. As mentioned earlier, DO NOT set the FL die against the shell holder. Set the die about 2 turns above the holder, size a lubed case, and look at the neck. You should see that it is only sized about halfway down. Lower the die about a quarter turn down, and repeat, until the sizing line just touches the shoulder. The idea is to size only the neck and allow the expanded case to headspace off the shoulder. Another idea is to buy a neck sizing die.
Steve

This^^ Would also advise a micrometer and measure the belt when using this method. You may find a full resize is needed every so often, depending on your loads, chamber and so on. My experience is with the H&H mags that have a gentle taper to the neck and seem to rely more on the belt for headspacing. However split necks have been more of a problem than anything after several full house loadings. Anybody care to talk about annealing?

**jonsue** · January 12th, 2014, 01:49 PM

I have found that I have had the best groups with 63.2 grains IMR 4350 Fed 215 primers with a sierra 140 boat tails. That load works good in all 3 of my 7 mags. Normally after 3 or 4 loading the brass develops a shoulder by the belt causing them not to chamber. If you want to get more loadings out of your cases try this:

www.larrywillis.com/index.html
Look at the Belted Magnum Collet Resizing Die

I got one of these and it works great.