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Forming 350 Rem Mag Brass

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02 December 2020, 20:43
257 Roberts
Forming 350 Rem Mag Brass
I was lucky enough to stumble into a T/C Encore Custom Shop barrel in this cartridge. Been wanting to try one for years and I jumped at the chance.

Now brass isn't easy to find, especially these days. A few stray lots around on Gunbroker and such, I am watching those of course. I do have reloading & form dies and bullets on order, just waiting on shipping.

I have read that forming brass is possible from any of the belted mags, 264WM, 7RM, 300WM, 338WM even the 375H&H. Is there a preferred size that works best? I've read that maybe 338 or 375 is the best to start with, as they require less total brass movement? I am concerned about neck thickness, as I don't own any large size neck turning tools.

I've also read that forming from 358 Norma works good, and maybe even as simple as a shoulder bump and trim to length. Anybody ever done this?

If anybody has any 350 Remington Magnum or 358 Norma Magnum brass, I'd be interested in discussing further.

Thank you for
02 December 2020, 21:19
Dale
I have formed quite a bit of brass for my .350 Rem. I bought a CH4 trim die, but I think other companies make them also. Just run belted magnum brass all the way into the trim die, cut it off with a hacksaw, and file it down. Then I trim it to the recommended length in a case trimmer. Fire form and you have good usable brass. I can not tell that one caliber works better than another. I once formed 20 cases, and then loaded and fired them 12 times. Lost only one case, a split neck after 11 finings. Good luck.
03 December 2020, 02:35
358WCF
quote:
Originally posted by 257 Roberts:
I was lucky enough to stumble into a T/C Encore Custom Shop barrel in this cartridge. Been wanting to try one for years and I jumped at the chance.

Now brass isn't easy to find, especially these days. A few stray lots around on Gunbroker and such, I am watching those of course. I do have reloading & form dies and bullets on order, just waiting on shipping.

I have read that forming brass is possible from any of the belted mags, 264WM, 7RM, 300WM, 338WM even the 375H&H. Is there a preferred size that works best? I've read that maybe 338 or 375 is the best to start with, as they require less total brass movement? I am concerned about neck thickness, as I don't own any large size neck turning tools.

I've also read that forming from 358 Norma works good, and maybe even as simple as a shoulder bump and trim to length. Anybody ever done this?

If anybody has any 350 Remington Magnum or 358 Norma Magnum brass, I'd be interested in discussing further.

Thank you for


Best to use the correct brass if you can get it. Keep an eye out on the classified section here & other places. There has been 350 RemMag brass for sale regularly here & there at a reasonable price. With the cost of 358 Norma brass (about $2 each these days if you can find any), I make my 358 Norma brass from Prvi 300 WinMag brass @ $28/50 last time I bought it. It works just fine. If all else fails & you must form the cases, look at cartridge drawings. The 350 Rem case ends about where the neck/shoulder junction is on the 358 NM case. That's more than a shoulder bump. You will need a stout press attached to a sturdy bench for forming. Like Dale said above, 338WinMag, etc. will all work & neck diameter of the parent case has damned little to do with what you'll be ending up with. Keep an eye on loaded neck diameter if forming the neck from shoulder & body of a longer case too. Not all brass is the same dimensionally on the inside.
03 December 2020, 03:50
dpcd
It is very easy on a standard Rockchucker. I make it from 338 and 7mm mag brass and trim on my lathe.
However, it all depends on the ID of your chamber neck; some will take it as is, some require either neck turning, or easier, neck reaming. You will know if your ammo won't chamber.
You are making necks from shoulder meat and that is thicker. No matter what brass you use.
I have talked to every major brass maker and they all say; not enough demand to make 350 brass. I offered to buy the first K, but to them, one thousand is literally nothing.
I have 4 350 rifles. I like the caliber. Works best on long actions.
03 December 2020, 12:45
xausa
I have a .358 Norma Magnum on a Ruger 77, which I had rebored and rechambered from 7mm Remington Magnum some time ago. I have never bought a round of .358 Norma ammunition or brass.

Once fired 7mm Remington Brass is very reasonable from a number of dealers and refurming it to .358 Norma Magnum is simply a question of neck expanding, which I do in one pass with an RCBS neck expanding die. Annealing the case necks beforehand will extend the case life and make reforming easier.
03 December 2020, 18:48
Dale
I should have mentioned I like Imperial Sizing Die Wax for case forming. You may have to form your cases in 2 or 3 steps, removing the case and adding a little lube each step. I have never had to turn case necks but it is worth checking to be sure they are not too thick. My rifle is a Rem. 700 Classic from the 1980s.
03 December 2020, 18:54
Stonecreek
Forming .350 RM from something like 7mm RMag is pretty analogous to forming .300 Blackout from .223. Pretty simple if you approach it right.

There are a number of ways to go about it, but my recommendation is to first trim the neck entirely off of the longer case down to the juncture of the shoulder -- this will leave it just a tad longer than the finished length of the shorter round. The quick and simple way to do this is grind it off on a common grinding wheel (be sure to wear gloves!) This is not only easy and requires no special tooling, but has the effect of annealing the area which will end up being the case mouth with the heat of the grinding process.

Next, run it through your FL .350 RM sizer (but set the sizer so that you more accurately headspace on the shoulder and not the belt).

Now you are ready to trim to finished length in a normal case trimmer, then chamfer the mouth inside and out.

Whalla! All done.
03 December 2020, 20:30
dpcd
One other thing; do not fall for the scam of a forming die; those are entirely unnecessary and accomplish zero that a FL die won't.
I trim after forming; here is why; when you size with a neck that you are going to cut off anyway, you run no risk of a bad case mouth, which you can get wen you trim them first. Allows you to be more careless.
And also yes the 358 Norma is a no brainer as far as case forming goes; I have used 338 mag. I think I built a few some time ago.
03 December 2020, 21:13
jeffeosso
458 win seems that best starting point.. if you can find that


opinions vary band of bubbas and STC hunting Club

Information on Ammoguide about the416AR, 458AR, 470AR, 500AR
Order AR/AccRel Brass
What is an AR round? Case Drawings 416-458-470AR and 500AR.
476AR,
http://www.weaponsmith.com
04 December 2020, 00:28
Atkinson
I prefer to expand the necks as they don't seem to need outside neck trimming as a rule..squeezeing them down thickens necks, again as a rule..350s should be easy with a 338 trim die, but Ive never done that one! but it can't be too much trouble to make 350 rem mag brass out of any belted case, just pick the one that has the least metal to change..


Ray Atkinson
Atkinson Hunting Adventures
10 Ward Lane,
Filer, Idaho, 83328
208-731-4120

rayatkinsonhunting@gmail.com
04 December 2020, 01:47
jeffeosso
you have a point, ray .. most of my 358 win started life as 308 brass


opinions vary band of bubbas and STC hunting Club

Information on Ammoguide about the416AR, 458AR, 470AR, 500AR
Order AR/AccRel Brass
What is an AR round? Case Drawings 416-458-470AR and 500AR.
476AR,
http://www.weaponsmith.com
07 December 2020, 01:49
Atkinson
Jeffe,
I had a SAvage 99F 358 and all my loads were 308 cases ran through the 358 die and a file trim die or a rotary die, but few actually needed it as the tended to be a tad short anyway, just tried to keep them the same length.


Ray Atkinson
Atkinson Hunting Adventures
10 Ward Lane,
Filer, Idaho, 83328
208-731-4120

rayatkinsonhunting@gmail.com
09 December 2020, 04:28
USAF-ATC
Here is a good video from youtube that explains the process.
https://www.youtube.com/watch?v=Tx_DzlVwuyE&t=406s

This is the die you will need. You may have to contact Redding directly. There are hard to find

https://www.amazon.com/gp/prod...04_s00?ie=UTF8&psc=1


USAF RETIRED
NRA LIFE MEMBER
RMEF LIFE MEMBER
09 December 2020, 04:38
dpcd
You do NOT need a form die for the 350; that is a waste of money. Trim die? Ok, that die in the ad will work for doing that.
And there is no mag brass that will just require necking up for a 350; ALL require sizing down the shoulder area and making the 350 neck. Using a 338; same; I've done lots of them.
Not sure why this is hard to grasp.
Making a 350 Norma is an easier way to go, but the 350 is cool. And if you insist on a short action, well, you know.
09 December 2020, 21:06
Atkinson
Wouldn't a Rem 7 mag, 264, or 338 require sizing UP? Or am I missing something, and a 458 would require down sizing to make 350 rem mag brass??

Im thinking thats why its hard to grasp??


Ray Atkinson
Atkinson Hunting Adventures
10 Ward Lane,
Filer, Idaho, 83328
208-731-4120

rayatkinsonhunting@gmail.com
09 December 2020, 21:20
dpcd
Nope.
The 350 is shorter than the base to shoulder/neck junction length of any of those so the necks of the parent cases get cut off no matter what they started out to be. Sure, if you use a 338 or 7mm mag for example, and run it into a 350 Fl die, you will expand the original neck to 350. And then cut it completely off, using none of the original neck as a neck. All the new 350 neck will be made from the shoulder and body of the parent case. Which is why you might have to ream it,, or might not. depending on your chamber and brass.
Only on a 358 Norma would its be as you say. .
10 December 2020, 00:44
crbutler
The only sizing up would be 6.5 rem mag, which is if anything rarer than the .350.

I have both, but so far 500 pieces each seems to be a more than a lifetime supply...
10 December 2020, 22:13
257 Roberts
Got my dies, tried some initial forming this morning. Just experimenting mainly to see what I can get. Not too bad actually! I was expecting worse.

Starting with a few range pick up Federal 300WM, fully cleaned.
1. Lubed case swaged into the trim die.
2. Hack sawed the old neck off.
3. File trim to die length.
4. Deburr & Chamfer
5. 350RM FL Size with sizer button installed.
6. Trim to 2.165" length.
7. Deburr & Chamfer

Overall looks good, I am pretty happing with the result. Here is where the questions start...

The formed brass doesn't easily "fall" all the way into the chamber. It does easily until the base of the belt, and then stops. I have no doubt, closing the TC action would [sea]t the brass into the chamber, but I question getting it back out...

I have one loaded round I picked up back in the early 2000s. It literally falls in and out of the barrel chamber easily. Loaded round is Ø 0.382" at the neck, and Ø 0.525" at the belt.

My formed case is Ø 0.387" at the neck and Ø 0.530" at the belt. Using a ball mic my neck thickness is right near 0.017". Calculating backwards, that's about Ø 0.353", or about 0.005" neck tension, which seems like a lot. What neck tension do typical sizer buttons use?

All that said, dimensions look spot on, so I am not sure why the brass doesn't fully chamber easier...thoughts?

Checking the SAAMI chamber dimensions, I see the neck area being tapered from Ø 0.389-0.390", so my 0.387" seems to be ok...for now...but I worry that once the bullet is loaded its going to push it out too much. I am not sure its even worth seating a dummy round, as I suspect it will be too big. Calculating the other way, .358 bullet + .017 neck wall x 2 = 0.392 [Or put other way, .002-.003" too big].

I need to seat a dummy round, but at least this FC brass appears to require neck turning.
10 December 2020, 22:43
257 Roberts
I just tried the same process with a Frontier brand 300WM case and the neck diameter comes out at Ø 0.389-0.390, with neck walls in the upper 0.017s

Again seems like not enough room for neck expansion.

Maybe I should take this one factory live cartridge and fire it to figure out my chamber dimensions.
10 December 2020, 23:17
dpcd
Yes, 017 neck wall thickness is too much for most chambers. You need to neck ream, or turn. Reaming is easier.
Doing a chamber cast of YOUR chamber is the only way to tell. Firing a cartridge will not tell you that. I have 4 350s and they are all different. It's not the bullet tension that you need to be concerned about; it is, will the brass release the bullet and not be compressed by the chamber. In a TC, you don't have to worry about that either, having zero camming power.
Neck ream, or turn, is the only solution.
Or open up your chamber. another good option, if that brass is all that you will use.
Now, if your brass does not easily chamber before you seat a bullet, then it is base to shoulder length; remember that you have just formed a new shoulder from very thick brass; it needs to be sized to the shortest possible length due to spring back. I milk each case into the die, 4 or 5 times, and make the shell holder butts against the die so there is considerable cam over. If that does not work for your chamber you can either shorten the die, or lengthen the chamber. Make sure you are sizing them as much as possible as I described.
They will never make this brass again; I have personally talked to all the brass makers; no demand. Wait for the estate sales of the hoarders, is my plan.
11 December 2020, 01:43
Mike McGuire
quote:
Originally posted by 257 Roberts:
I just tried the same process with a Frontier brand 300WM case and the neck diameter comes out at Ø 0.389-0.390, with neck walls in the upper 0.017s

Again seems like not enough room for neck expansion.

Maybe I should take this one factory live cartridge and fire it to figure out my chamber dimensions.


You might be better stat=rting with 7mm Rem as being shorter you won't be as far down the body.

Might be worth trying 270 Wby or 7mm Wby brass as Wby brass is thin in the case walls.
11 December 2020, 06:55
dpcd
I've used plenty of 7 and 338; same issue.
If you find a lot of brass that is thin in the upper body, like the Wby suggested, that would be great.
19 December 2020, 22:49
Dale
Load one of your cases with a fairly light load with a .357 pistol bullet and fire it. If a .358 rifle bullet will easily slide in the fired case (before resizing), your necks are thin enough. I have never had a problem with any of my reformed cases, but maybe I have a larger chamber.
20 December 2020, 01:34
theback40
I'll put your name on the stash of 350 brass I have Tom, for when I kick off. Smiler
23 December 2020, 03:57
Palladin8
I used 300 Win Mag brass that I had laying around. Took me 6 months to find actual 350 Rem Mag brass.

I had to inside ream because I couldn't turn the necks down close enough to the shoulder junction where it wouldn't cause a problem once they had been fired more than once. It was a lot of work but like I said I waited six months to find head stamped brass and i've never waited that long to shoot any gun I have bought.