Home Forums Reloading Big Game Rifles Converting a long magnum case into a short magnum

I am wondering if it is possible to use a full-length sizing die and convert a long magnum cartridge into a sort magnum. Specifically, I would like to know if I can produce Lazzeroni 7.82 Patriot cases (short action) out of Lazzeroni 8.72 Warbird cases (long action). The two cartridges are identical except that the Partiot is one inch shorter than the Warbird. I was thinking that it should be possible to push the shoulder down in successive steps (say, each time 0.25") to cover a long cartrige into a short one with identical body. Is this practical?



Warbird:



Patriot:

You will have to go in steps to reduce the shoulder DIAMETER. If the shoulder is say .500" you will need to take it down to maybe .450" then .400" then .350" and so forth till you get it the right length for your job.

Very easy to do. RCBS probably has the dies and reamer to handle this. You'll have to size the case down with one die. That die will take care of the step down in one operation. Then you'll have to cut the surplus brass past the new neck. Easily done in a variety of ways. After that you'll have to get the neck down to an even workable thickness. That is best done with a reamer in one of the dies you can get from RCBS.

I did this with Jamison line of cartridges using one of the old Jeffreys cases. That was before the RUM cases now domestically available. It's really an easy operation and the die set was not particularly expensive. You have to have a whole bunch of the long Lazzeroni cases to make it worthwhile though. As someone else posted, use plenty of lube. I used Imperial Wax.

Hi Bob (and Ringman and dye),

Is a full-length sizing die for the short caliber what I need or it requires an specially made die? Are you sure this can be done in just one operation??! That would be cool.

As you mentioned, this is only economical if I convert many cases. I have a rifle in 8.59 Titan Lazeroni. I have cases for both 8.59 Titan and 7.82 Warbird (which I use to create Titan cases). These are long-magnum cartridges. I saw a rifle in 7.82 Patriot and I want to know if I can make cases for it. Lazzeroni doesn't seem to make cases or cartridges for this caliber any more.

My dies are packed from a recent relocation, and it's been a few years since I had to make those cases, so I can't check and tell you exactly what I have. When the RUM came out, those are the same cases and they were easier (and cheaper!) to make. Too much time has passed for my memory.

From memory, the die set I got from RCBS had only 3 dies and a reamer. Paid between $100 and $200 for it in the early 90's. The initial reamer die had nothing at the top. You ran the Jeffrey case in there, and used a hacksaw to cut it off at the top of the die. You then ran the reamer in there to bring the walls of the neck down to consistency and proper thickness. The process was finished with trimming to even out the rough hacksaw cut and get near the correct case length. You finished with a trimmer. Then you were ready to go.

There was a later problem that popped up after you fired the case a few times. As the brass stretched, the junction of the old main body/shoulder, and the neck, stretched into the neck. That could pinch and hold a bullet when chambered and fired. If the base of the bullet didn't get down that far, or you used boattails, it didn't matter. Flat bases that seat down that far in the neck, could be pinched. That raises pressures and affects accuracy. It can be dangerous. I had to run the reamer into the the die every two or three reloads to insure this didn't happen.

Why don't you call RCBS and talk to them? They were wonderful and knowledgeable people to deal with. I would guess that what you are attempting to do isn't a common thing. If they don't have the dies you might be talking about considerable expense for a custom set. I'm sure they'd do it, but at what price?

You do have an alternative that might cost you a few cases. If you have a seating die for the short case, pull the stem and the seater out. Measure and cut off a case of the long cartridge, run it into the seating die, don't cut off any more than you have to, then run it into the sizing die. With a bit of experimentation you might be able to shorten the cases that way. Then run it into the FL die. That would then mean you have to turn the necks of the new case to get the neck walls even, and then you'd have to do it again after you fire it two or three times. You'll still get the thick part of the body stretching up into the neck at the junction of the shoulder/neck, which means you'll have to turn the neck on the outside at the neck/shoulder junction every few reloads.

Try it using the seating die to get the right length. That might be the best and most economical approach. If money is no object, RCBS can help you out with a proper die set. Good luck!

Hi Bob,

Thank you very much for the detailed and helpful notes. From your comments I gather that it is possible to shorten a long magnum case but you did not explicitly mention that you did it using a standard full-length die (for the short cartridge). Also, by the "reamer" I suppose you mean the standard stem that comes with both neck-sizing dies and full-length sizing dies?

My idea was to do it in several steps using the FL die (for the short case) as shown in the diagram below. In several steps, the shoulder is pushed back and the brass flows into the neck area. After a few steps, the case can be shortened by 1 inch as desired. At the end, the extra brass at the neck is cut and the neck with be the proper length.

I did NOT do it using ANY full length die. The die provided with the RCBS set I used was a trim die they called a 'reamer die', already set to be the correct case length. The long neck extrudes through the top, then you can cut off the excess at the top of the die in one operation. Best I recall, I tried to cut the top off right at the top of the die for the exact OAL. I didn't like that the saw blade marked up and wore the top of that reamer die. I cut a bit above, ran the reamer into the neck to uniform the neck walls, then trimmed the case to size on a separate trimmer. I initially used the 404 Jeffery cases (@ $2. each!) but when the RUM's came out which were based on the 404 Jeffery case, I started using them. The walls of the RUM cases were much thinner and therefore easier to uniform. I made a big supply of the brass and haven't had to make any more in probably 20 years. I still have the gun which was the one I used for my very last elk before I retired from elk hunting. A one shot 'bang/flop' @ 340 yards.

You certainly can accomplish forming the way you're suggesting. You'll likely have to do it in multiple steps, but it sure can be done. You likely cannot run the case very far into the die before it hits the top threaded portion, but of course it depends on the die you have. You will have to use an expander when done, and then turn the irregularity of the neck walls from the outside. There are multiple ways to approach it as you can see. Give it a shot and alter as needed as you go along. Don't overlook the 'donut' you'll regularly have at the base of the neck as you reload the cases.

I tried forming the cases the way you intend, and hated it. I avoided it because I absolutely detest neck turning. I've gone a bit too far into the shoulder when turning and I've had cases come apart at the juncture with the shoulder. Obviously operator error but the requirements were just a bit more demanding of me than I cared for which is why I went for uniforming from the inside. Faster and better in my opinion since the outside is supported by the walls of the die as you ream, and there's no flex or bounce back during the cutting. Be sure to run the expander through the neck before you turn in order for the irregularities of the shoulder to be pushed to the outside where you will be uniforming and turning. And remain aware of the donut you will have as you reload and fire the cases. Good luck!

Forgot to explain re your question. I thought I covered it earlier. The dies from RCBS included a reamer die, the reamer goes into the top of the die and is machined to ream the irregularities of the neck where it had been the body of the longer cartridge. They are matched so that as you run the reamer in the die those irregularities are cut. The walls of the die prevent flex and in my mind give more uniform neck walls that when you turn the outside where the inside of the neck isn't supported as the cutter goes over the outside. Probably minutiae, but much of reloading is the confidence you have in your own work. There is no stem in a reamer die, and the die is shorter than a regular sizer or seater as it's also made to enable cutting the neck to near the correct length. In the others you have the threading for stems and expanders that aren't necessary on a trim die.

Looking for images I just found pictures of the dies, die sets and cases I was working with. This may help to clarify your questions. Note the reamer die is shorter than the FL die.

FL die and reamer die w/reamer.



Also, among the many die sets I have, I believe I have a Lazzeroni set but it was for a 30 caliber gun used for thousand yard shooting. Don't know which Lazzeroni cartridge that was. I was loading for someone else and don't even recall who the guy was, but he was somewhere in the midwest as I recall. You triggered memories!

Thank you very for the clarification Bob. Your experience is very helpful. As I said, I am contemplating byeing a Lazzeroni short-action rifle and knowing that it is possible to convert existing brass for it is very important factor. Lazzeroni cartridges have slightly different dimension that the RUM family and I think I read somewhere that they the head and body dimensions are close to 416 Rigby.


8.59 Titan (left) next to 270 Win and 243 (dummy):




8.59 Titan loaded by myself (Lapua Naturalis bullet, 231 grain)

Here is a very old short fat seven beside a .223. The fat one is a .378 shortened to 2 1/4" and necked to 7mm. The case capacity matches a .300 Weatherby. I am 72 now and came up with this when I was in my late thirties. It was fantastically accurate with the original Barnes "X". I used a couple sizing dies to get to this length and diameter.

Another idea that has come to my mind: Is it possible to make Lazzeroni cases from 378 Weatherby (after belt removed) or 338 Lapua? The head dimensions look very close. What are the typical tolerances for fitting the case head to the bolt face?


378 Weatherby head dimention:



338 Lapua head dimention:


8.58 Lazzeroni Titan dimentions:

Why? I would rather spend my time shooting rather than forming brass!! But if you like it, I am all for it.. Let us know how it turns out..

I think I read somewhere, at about the time I was loading for the Lazzeroni, that 'someone' had successfully made and fired Lazzeroni cases after turning the belt off the 378 Weatherby.

There is no reason I can see that it wouldn't work, but I hate to think of all the effort. At that time I purchased a mini lathe thinking that need might arise for me in the future for 'something'. I was think of using domestic brass as opposed to the RWS and other foreign stuff for which I had to pay $2 a case. That never came to be and I still have the lathe. It's been quite useful for some things.

From comparing dimensions, I also can't see any reason you couldn't use the Lapua case, unless sizing down will somehow distort the head, especially the primer pocket and flash hole. Those two things could be correct, with the primer pocket being the most difficult if it does distort as the brass is compressed. You could inexpensively try it with one case and see. The body of the brass compressing a bit shouldn't make that much difference. After all, you're just slightly returning it to one of the stages from where it came from a blob of brass when it was started to be formed. Doesn't hurt to try!

Why is the OP doing this? Because Lazzeroni brass is no longer available, and he has some expensive firearms which are just cheap pieces of metal without ammo. I suppose he could rebarrel to another cartridge but overcoming the challeges is part of the fun of all this.