Annealing when forming belted magnums

[LeadHead72]

As a total newbie in forming one caliber from another, some time back I decided to see what would happen if I tried to form some .350 Rem Mag cases from some 7mm Rem Mag brass simply by using the 350 Mag sizer. I ended up with some wrinkles in the shoulder/neck due to the moving of a LOT of brass. Would annealing previous to the resizing process alleviate this, or is there another step required? It seems like it should be a relatively simple procedure since both calibers use the same parent brass.

[tygar]

I use various Lee tapered expanders to gradually neck up brass. Unless brass has several firings I usually don't anneal unless I see splits. That said, I usually use new brass to expand & anneal after fire forming. On the larger cals, I usually just fire form with 12-15gr of Unique & only expand up if it doesn't work good.

I form a number of different calibers 223-30, 25-6.5, 30-338, 30-375, 338-375, 375 & 416-450 Watts. Think there are a couple more but can't remember what.

[EDG]

If you minimize the amount of brass moved by each pass using multiple dies you can eliminate those problems.
The goal really is to get good brass. If your goal becomes forming brass with no investment often you pay by ruining a lot of brass.
So a few extra dies are often a good investment and they can be used for multiple projects.
You can try using a short die with a large bore to form many cases. For your project a .375 H&H die could be cut off to provide an intermediate die.

To get away from stretching the neck so much you might experiment with .300 Win Mag brass since the shoulder is further forward. I have used it to make .416 Taylor brass. It would work even better for .350 Rem Mag.

As far as annealing goes you can try annealing before forming. Even if you succeed you will still need to anneal after forming.

[LeadHead72]

You guys make some good points. Stretching doesn't seem to be the problem, however. Since a 350 Mag case is way shorter than a 7mm Mag you end up sizing the body down to form the neck and shoulder rather than stretching the neck to accommodate a larger bullet. As a result, there's more brass than there should be in the neck particularly, causing wrinkles from the excess brass.

[MarkP]

Take the expander out of your die; size the lubed 7 mm in your 350 Rem Mag die, Trim the 7 mm neck off of the case, (I use a fine toothed hack saw) you will most likely need to ream the necks of your formed cases. I need to ream even when loading 0.358" jackets bullets.
As the walls in shoulder portion of the case are tapered.
I have made several 350 RM cartridges from 7 mm RM.
I made a file type trim die to get the cartridges within about 0.005" of desired length. Square up and trim to final length with trimmer and deburr OD & ID. After forming and reaming anneal the necks.

[LeadHead72]

Thank you, MarkP. Do you not get wrinkles from the excess brass being sized down from the diameter of the body to the neck diameter? At this point that has been my only complaint.

[MarkP]

You can buy chucking reamers from McMater Carr in 0.0005" increments. You will need to experiment a little to determine the correct diameter of reamer to use.
Remember to take the expander out this will make the OD of the mouth parallel with the CL of the cartridge and push the taper inward allowing it to be removed by the reamer, this will make the walls straight (outside and inside parallel) I ream some cartridges while they are in the size die. My long (9/16") necked 416 Wildcat made from 300 WSM brass. Sometimes you will get some dialation due to the feed pressure when cutting / removing mat'l. The mouth will spring open and the desired amount of material is not removed.

[EDG]

With your low post count I have no idea how much case forming you have done. Most of the time the wrinkles are caused by excessive lube.
It takes very little lube to be excessive lube. As the case is pushed up into the shoulder of the die lube gets trapped in the gap between the shoulder of the case and the die and piles up. If You make a long stroke even with a little lube it can dent the shoulder and cause wrinkles. I know I have killed hundreds of cases trying to form a case with one pass.
Instead barely lube your case and size about 1/4" of it. Then remove the case and redistribute the lube by wiping it off of the neck. Then size another 1/4". Keep doing this until you develop a process.
The problem with stretching the neck is the brass gets thinner and weaker. I prefer to neck down thicker brass since I can turn it thinner if required. I cannot make thin brass thicker if the neck is to thin.
I have a set of dies used to form 45-70 brass to .33 Win. The .45-70 brass is about the same diameter as H&H belted magnum brass. The brass is taken down in 2 steps and then a trim die is used. After that a trim die is used and then the .33 Win FL die. These dies work flawlessly.
By comparison I also used the same brass to form .40-65 Win brass with no intermediate die. It is a real PIA to form without getting wrinkles. I eventually found a shorter .40-60 form die and now I can make cases .40-65 without a bit of wrinkling.

You guys make some good points. Stretching doesn't seem to be the problem, however. Since a 350 Mag case is way shorter than a 7mm Mag you end up sizing the body down to form the neck and shoulder rather than stretching the neck to accommodate a larger bullet. As a result, there's more brass than there should be in the neck particularly, causing wrinkles from the excess brass.

[MarkP]

Thank you, MarkP. Do you not get wrinkles from the excess brass being sized down from the diameter of the body to the neck diameter? At this point that has been my only complaint.

No wrinkles; the cases look kind of like a blank round; basically just pushing the shoulder back and the 7 mm neck is still there.

[MarkP]

I prefer spiral fluted reamers as compared to straight fluted when I ream necks.

[LeadHead72]

With your low post count I have no idea how much case forming you have done. Most of the time the wrinkles are caused by excessive lube.
It takes very little lube to be excessive lube. As the case is pushed up into the shoulder of the die lube gets trapped in the gap between the shoulder of the case and the die and piles up. If You make a long stroke even with a little lube it can dent the shoulder and cause wrinkles. I know I have killed hundreds of cases trying to form a case with one pass.
Instead barely lube your case and size about 1/4" of it. Then remove the case and redistribute the lube by wiping it off of the neck. Then size another 1/4". Keep doing this until you develop a process.
The problem with stretching the neck is the brass gets thinner and weaker. I prefer to neck down thicker brass since I can turn it thinner if required. I cannot make thin brass thicker if the neck is to thin.
I have a set of dies used to form 45-70 brass to .33 Win. The .45-70 brass is about the same diameter as H&H belted magnum brass. The brass is taken down in 2 steps and then a trim die is used. After that a trim die is used and then the .33 Win FL die. These dies work flawlessly.
By comparison I also used the same brass to form .40-65 Win brass with no intermediate die. It is a real PIA to form without getting wrinkles. I eventually found a shorter .40-60 form die and now I can make cases .40-65 without a bit of wrinkling.

I'm not new to reloading, just new to case-forming and am familiar with the problem of excess lube. While trying this project (it's been a few months ago) I didn't THINK there was too much lube but you could be right. Also, I was taking it in much shorter increments than 1/4", sort of "nibbling" at the brass by adjusting the die maybe a turn at a time (without the expander installed), keeping the Rock Chucker in its range of greatest mechanical advantage. Is that a bad idea?

[EDG]

Keeping the Rock Chucker at the point of greatest mechanical is what most of us do by habit.
Even when nibbling the lube can accumulate in the die and on the case. Even with absolute minimum lube you can still get artifacts on the surface of the brass that look like worm trails when forming .40-65 from .45-70 when forming with the FL die.

I'm not new to reloading, just new to case-forming and am familiar with the problem of excess lube. While trying this project (it's been a few months ago) I didn't THINK there was too much lube but you could be right. Also, I was taking it in much shorter increments than 1/4", sort of "nibbling" at the brass by adjusting the die maybe a turn at a time (without the expander installed), keeping the Rock Chucker in its range of greatest mechanical advantage. Is that a bad idea?

[LeadHead72]

Thanks for that info. This has been nagging at my mind for quite some time wondering what I needed to do differently. I do appreciate your time and sharing your knowledge.

[kycrawler]

I have found that when forming 375 whelen from 30-06. And 338 win from 7 mag I have to pull the stem and clean the he die out about every 100 rounds.

[JSH]

Lead head how did your 350 magnum brass turn out.
I picked up a model 7 custom in 350 Rem magnum. I finally got a set of dies,Lee, not my first choice. The blasted things have a vent hole right at the shoulder body junction. The leave a very unsightly gouge in virgin brass and a bit worse when trying to form some from belted cases. At $2+ per case for virgin brass, it grinds my gears to say the least. I have emailed Lee and will see what they have to say.
I have been down this road of case scratching before with them before. No it probably will not shorten case life, but let me put a door ding in a fellows brand new car, it won't effect the way it drives but explain that to the owner.

I also have a low post count be some standards, I just don't comment if I don't see the need and all questions asked or answered seemed to have helped the OP. Been reloading a while 25+ years and have from what my notes reflect,mfoed with at least two dozen wildcats and reformed a lot of hard to find cases of various shapes,forms and calibers.
Jeff

[LeadHead72]

I haven't tried forming any more since then, JSH. I found a great deal on a large quantity of brand new 350 brass and stocked up enough that I'll likely never shoot them all, even once.
I understand your feelings about scratched brass. When I was attempting to form the brass mentioned in the original post, I had a set of old Bair dies. After finding a used set of RCBS dies (my first choice) the Bair dies got sold before I realized the RCBS die was scratching my brass--badly. Gotta make that phone call to RCBS and explain; they're always happy to help, though.