reloading belted magnums

[atr]

this is a general question about belted cases
I have a friend who has a 7mm Mag....belted mangum and he would like me to help him reload for this cartridge.
I personally have not reloaded for any type of belted case, so I am asking if there is anything different or special about case preparation for belted magnums ?

thanks
and Happy Holidays to all
atr

[Ickisrulz]

After time cases can buldge. This collet die is supposed to help:

http://www.larrywillis.com/

[Stampede]

I reload the .300Win Mag for over 20 years now, in my opinion it is not that much different from regular/other calibers. At least I never-ever encountered any problems what so ever.

When you regularly reload the cases, just check them for the correct dimensions and weak spots.

Peter (Stampede)

[MBTcustom]

I reload 300WinMag and I only neck size the cases, other than the investment in brass, I cant tell any difference between it and 30-06 or any other rifle cartidge. Now if you are asking about casting boolits and shooting them through a magnum rifle, I have yet to go there, although I have thought about it quite a lot. If I ever do start loading lead in the win mag, I can tell you several things that are going to happen right off the bat.
First I am going to get a realy heavy boolit mold, anything I can do to slow it down.
second, I am going to spend quite a while making sure there is no copper left in my barrel.....at all!
Third I will be using White Label Lubes 2900 lube.

[winelover]

Belted Magnums by nature tend to stretch faster than the non-magnums. I found that the RCBS X- dies does a good job controlling this condition.

Winelover

[freedom475]

After fireing forming the first shots in the rifle, your case will stretch to fill the chamber.... When you size it is important for case life NOT to knock the shoulder back with a full length resizeing... this will help the brass to headspace on the shoulder (barely, to tight here and it will be difficult or impossible to close your bolt)....if you full length size and knock the shoulder back every time you load the case will head space off of the belt and your belt will blow off in just a few loadings

I think RCBS makes a special micrometer die to asist in setting the sizing die to fit your chamber perfectly.

[Lloyd Smale]

Ive loaded about ever belted mag made at one time or another and never treated them any differnt then something like an o6

[roysha]

Ive loaded about ever belted mag made at one time or another and never treated them any differnt then something like an o6

Yup! What he said.

[nicholst55]

Brass life can be very short with belted mags, because of the way a lot of people size them and the way their chambers are cut. Since they headspace on the belt, many chambers are very generous (read sloppy) in the belt-to-shoulder dimension.

What I do is adjust the sizing die to allow the case to headspace on the shoulder, assuming that we're talking about a conventional bottleneck cartridge here. That way you aren't bumping the shoulder back excessively each time you size, then forcing the case to stretch to fill the chamber again when you fire. This will increase your brass life a few more firings. I've never tried the Willis die mentioned above.

[leadman]

I agree that to ignore the belt on the case and headspace off the shoulder is how it should be sized to prolong case life. I have and Encore 7mm Rem mag barrel with max dimensions. This along with the fact that most 7mm RM brass I have found new is short from the belt to the shoulder and case life is really short if you full length size.
I go so far as to load Unique in the case and fill the rest with Cream of Wheat, then a wax plug in the case mouth to hold everything in the case. This fireforms the brass to the chamber without thinning the brass in front of the shoulder. The amount of Unique will have to be adjusted to get the case to fireform well. Start at 15grs.

[Pigslayer]

I have had a 7MM Rem. Mag. for about 10 years. I load for it & it shoots well But it's not something that I take to the range to plink with. That guy is serious artillery and not easy on the shoulder so that being said, I don't shoot it a lot. Therefore I have always full length resized due that my frequency of shooting it dictated that I not worry about case life. But now that I have read this thread I'm considering a neck sizing die "and" I would like to cast for it. I just read a thread on this site having to do with Lyman #1 which involves using copper and due that higher achieved velocities. Hmmmmm.:?:

[1hole]

"I agree that to ignore the belt on the case and headspace off the shoulder is how it should be sized to prolong case life."

Ditto.

[DCM]

"I agree that to ignore the belt on the case and headspace off the shoulder is how it should be sized to prolong case life."

Ditto.

double ditto. I load my 300WM off the shoulder not the belt.

[BD]

I reload for the .270 WBY mag. I do not own a single case that has ever been full length sized. I'm using a bushing style neck die that Redding made for me. I get about 10 reloads out of them before they start to show signs of wanting to be full length sized. Then I chuck them. My thinking is that when I'm messing about at 65,000 psi, case life is not my primary concern. This is not a rifle I download, or shoot cast in.
BD

[o6Patient]

Ive loaded about ever belted mag made at one time or another and never treated them any differnt then something like an o6

Ditto: Just head space off the shoulder as if it were an 06 unless your caliber design
prohibits this such as 300 H&H etc.. Do not over size(set shoulder back to much) and
treat it like any other bottle neck cartridge. brass won't last as long due to the nature
of the beast but modest loading pressures will help and I'm convinced that the Larry
Willis collet die will help greatly even though I've not used mine yet.

[r6487]

on the larry willis site concerning the belted magnum resizing collet--notice the first customer to purchase was the secret service--they had already discovered the belted cases can expand just above the belt and can't be resized completely with a normal FL resizing die. I bought one of these dies. You can drop a belted case in upside down from the top. if is does not drop in all the way to the belt, it needs sizing with the collet (acts as a built in gauge). I went through 1100 300 weatherby brass. Had about 60 or so that had to be sized with the collet. Collet die was $90.00 Just depends on how much you shoot and whether or not you don't mind throwing out belted brass once it has expanded. Have discussed this with a few other belted shooters who reload. They weren't aware but admitted having brass that would stick after a few reloadings and didn't understand why and would finally just toss that brass and go on.

[o6Patient]

on the larry willis site concerning the belted magnum resizing collet--notice the first customer to purchase was the secret service--they had already discovered the belted cases can expand just above the belt and can't be resized completely with a normal FL resizing die. I bought one of these dies. You can drop a belted case in upside down from the top. if is does not drop in all the way to the belt, it needs sizing with the collet (acts as a built in gauge). I went through 1100 300 weatherby brass. Had about 60 or so that had to be sized with the collet. Collet die was $90.00 Just depends on how much you shoot and whether or not you don't mind throwing out belted brass once it has expanded. Have discussed this with a few other belted shooters who reload. They weren't aware but admitted having brass that would stick after a few reloading and didn't understand why and would finally just toss that brass and go on.
That's why I went to the 300 mag years ago over the 30-338 I had at the time(yeah yeah yeah
I bought into the "neck's too short" argument on the 300win originally back when I knew it all too.)
To compound matters I was pushing the 30/338 a little hotter trying to get the same performance
that a 300 gives. That collet die should be just the ticket for the mags.

[Freischütz]

Don't trust the belt to produce the correct headspace. Pretend you're using a standard rimless cartridge and headspace on the shoulder.

[Lloyd Smale]

Just had to toss a batch of 300 win mag ww brass i had used for load developement. It had been fired 7 times, all stout loads and full lenght sized each time. the primer pockets were opening up and primers didnt stay in anymore or it would have still been servicealble brass. Id bet if it would have backed off a grain of powder in each of those loadings it would have lasted just as long as ANY brass ive used. Ive seen my weatherby brass become unuseable after only 2 or 3 firings but again my own fault for running loads to the point that primer pockets open up. I think this is where the thoughts come from that mag brass doesnt last as long. Typicaly when loading a mag rifle your looking for velocity. It you werent you sure dont need to fool with a mag rifle. I think about 99 percent of mag rifle shooters look for those last 10 fps and thats what makes brass life shorter. For me anyway when i load for something typical like an 06 or 308 I rarely push it to the absoulute max. I dont see the point as if i need that extra i can grab a 300. back off a grain or two and mag brass will last just as long as any brass and id bet in some cases its actually made stouter and would outlast most brass.

[o6Patient]

Here goes, I know I'll probably catch some flack here.
I am an advocate of head spacing off the shoulder and do
so for my mag calibers...with that said head spacing too tightly
off the shoulder increases the case head expansion ( in my
humble opinion) if the rifle chamber has longish dimensions
to start with. A chamber that just allows the go gauge is much
better than a looser one that is technically within specs.
As said: keeping the pressure off mx will greatly help the life
of the brass also.