I've been working on a 30 caliber wild cat for my 336 for several months now. The gun smith informed me that he is almost complete with the work and I should receive it in a week or so. The new cartridge is based on a 308 shell casing with the shoulder set back .1" with an AI body and shoulder profile. I've never sized a new cartridge case from an existing commercial case. Should I be able to run an unmodified 308 case into the wild cat sizing die or do I need to size the new casing incrementally?
You should be able to use the new custom die, but the neck will have to be cut back, as it will extend a bit. After shooting , you case should be perfect for the rifle. You need to watch for neck expansion and cut it back once in a while.
In the perfect world, when forming, new cases are used.
About your wildcat, you are necking up a 308 to 338, this will shorten the neck, the advantage is the .100 shoulder set back, most wildcats are formed when fired, setting the shoulder back .100 thousands will form most of the shoulder.
Necking a case down causes most of the failures to form as in folds and wrinkles in the shoulder, when forming the 338 there is less shoulder to form making it easy for the brass to make the turn if a good lube is used.
And as has been said check the length of the case and trim as required.
'incrementally' there are times when as many as 3 dies are used to form a case, if you have one die I would suggest raising and lowering the ram to check progress, I do not have a forming die shorter than the 308 W, after using the forming die cases are required to be sized in the sizer die of the final caliber. If you only have the full length sizer die you have no choice.
Sounds like an interesting project and based on what you described, you will be able to run new 308 cases into your custom sizing die, which will push the shoulder back. Just lube the cases as you normally would and it might take a little more elbow-grease to operate the lever on the press, but probably not enough that you'll even notice.
I'm not sure that it will form the angle of the shoulder perfectly but the first firing will do so, either way. As for trimming the neck shorter, I don't think that will be necessary, particularly if the chamber was not cut for a shortened case. I would confirm the trim-to length with your gunsmith before trimming any cases.
What is this particular 'cat called? I have to admit, it seems a bit odd to me, creating a rimless wildcat specifically for a lever-action gun, but that's what is so cool about the shooting world: If you've got the money, you can build just about anything you can imagine!
Maybe I missed something...but, where does he say he's necking this up to shoot a .338 bullet? He's using a 336 action, but from what I read, still shooting .308 bullets. Basically a 308 AI?
yes, that is what I thought, he is setting back the shoulder and will need to then, shorten the neck a bit. I try to figure out the goal or reason for the change; here it seems he might be wanting to get the 308 to fit in his Marlin. I use the regular 358 and have no problems with 200 grain bullets, but a bit with the 220. I guess I could have done what he is doing to get around the problem?
No excuses, I filled in some blanks that were not there, I take nothing and put something together, the ideal of taking something and making it into something else never occurs to me.
I would suggest purchasing a cheap used 308 W die and have someone remove .095 thousands from the base of the die, my opinion the best method for shortening the die would be butt grinding, the modified die would allow for moving the shoulder back without the 40 degree shoulder, the modified die would serve as a forming die before final sizing.
And we all know the shoulder is not moved back, part of the case body becomes part of the shoulder and part of the shoulder becomes part of the neck.
The first thing I would do is lightly lube my 308 Winchester case from the point of the shoulder down toward the base and then run it through your size die. This should work without lube dents on the shoulder.
I am posting the drawing or your case. I believe this picture is approximately the one you settled on. If so, you are only pushing the point of the shoulder back .1198”, but the bottom of the neck is pushed back .2052” which is a substantial amount to push it back without a form die. Also the shoulder angle is steepened up quite a bit and there is a possibility of lightly collapsing the neck at the shoulder junction or bulging the case just below the point of the shoulder.
If one of the above happens pull the stem from you bullet seater and run your lubed case up into the seater die. You may have to back the die off the shell holder ⅛” or so and maybe half that distance.
The Marlin 336 action will not take full power loads with the 307 Winchester case.
I have always felt the Improved case shape would solve the problem.
This wildcat will be able to se its full case capacity with the pointed Hornady bullets and due to the Improved case should avoid extraction problems with higher pressure loads.
I see my drawing did not attach for some reason.
I think this is a very interesting cartridge and that it should bring to Marlin 336 performance up to the 307 Winchester.
Slim's explanations for the cartridge are correct. I've spent a lot of time experimenting with the 307W cartridge in the 336 and the first limiting factor in the 336 action is the bolt thrust. Slim designed the cartridge and Regan Nonneman is building the rifle. I'm calling it the "30 lever maximum" which might be a presumptive name. Time will tell.
Slim, I should receive both the rifle and the dies within a week or so. Regan had trouble modifying the dies and had to buy another set. He received them about a week ago and is working on making some brass to test the rifle. I grew a little concerned because it sounded as though he was having trouble forming the cartridge so I posed the question above.
I am pretty exited about this cartridge. I believe you have a better idea than I did. I have crunched the numbers quite a bit and I believe your plan is better than mine.
This should make a very fine rifle and I want to urge to you to write this up for a “Readers Research” submission to handloader. I believe this cartridge is going to a better solution to the pressure – power balance problem of the Marlin 336 action than the 7mm STE.
If it is any help I fully understand about troubles modifying dies. Back when the 300 Whisper was “proprietary” my Dad made dies for his TC barrels. We heated the dies to anneal them and he recut them. This proved to be a challenging task and we should have bought die blanks. You just can’t believe all the little difficulties you encounter.
Again, sizing and forming is not the same, if it was easy RCBS would not be selling special forming die sets for $300.00, in the first post the shoulder is to be moved back 100 thousands, when forming a shoulder by establishing it .100 back through a die with a 40 degree shoulder the person operating the press shoulder expect the case at the shoulder/neck juncture to wad up as it makes the turn, something like making a high speed turn on a flat track, I would expect a do-nut that would require a reamer, then I would wonder if the case neck was going to stay on during firing, and again, I would take a a 308 W (or a 307 die) sizer die and grind the die in my in-line/butt/angle grinder and remove .095 thousands. forming the shoulder in a die with a 20 degree shoulder is more practical than trying to get the shoulder formed with a 40 degree shoulder AND the extra effort required when sizing compresses the case.
Forming cases with a sizer ball installed, if the do-nut appears, expect the neck sizer ball/stem Assembly to brake off inside the case.
After forming a few cases with the modified die and it is found the cases require too much effort when sized, the modified die can be shorten again,
Many moons ago, I had a Rem 722 in 300 sav.. I wondered about first, redoing it to 308 Win., second, to 30-284, and lastly, to have the neck cut in the chamber extended, and reform 308's into 300 Savage, but with a longer neck. RCBS dies in 300 Sav. would give the extended necks as is, and 300 Savage ammo would still function. But it wasn't worth the expense. I just made do with what I already had. I stuck to reloading 180 gr. bullets. You will run into a wall with a different case mouth length, as you have to crimp your bullets, to use them in the tube magazine rifle. The 30-30 has a 53mm Length case vs. the 51mm length of the 308. I was thinking of going the other way with the box magazine 300 Sav.. When you are up and running, will you get back to this thread and advise which bullets work?? One reloading manual says to use regular 30-30 bullets in a 307BB reload. I don't know if you can score the real 180 gr. 307BB bullets, as components. Note that I had a twenty four inch bbl. on the old Remmie.
Yes, he based it on the 308 Winchester case because the Marlin handles rimless cases so well and he could get high quality brass from a variety of vendors to add to the accuracy trials.
With 20º to 35º shoulders you can push them back quite easily. As the shoulder becomes steeper it becomes slightly more difficult. There are a few tricks which make it easier. Often a simple anneal of the case neck and shoulder will make the job easier.
I don’t anticipate a doughnut at the bottom of the neck as he is not reducing neck diameter. If a small bump is formed it is an easy matter to ream it out. I form 308 Marlin 307 and 356 Winchester cases along with 25-35 and 25-35AI and ream all of them.
You are right in that the easiest way to form cases is to shorten a size die to set the shoulder back and then fire form them to shape, with or without a bullet. This is not a very exotic wildcat case and the initial case forming is not anything to be concerned about.
Eric,
I would start off with Hodgdon or IMR 4895. I’ll send you some thoughts on starting loads.
Regarding neck reaming: Is there any real benefit of neck reaming over neck turning? I have a Sinclair neck turner that does a great job and it seems to me if I allow it to carve into the shoulder slightly, I should be able to eliminate a donut should one form. I have reamer but have never used it.
Regarding crimping: I was planing on grinding the bottom of a Lee factory crimp die until it crimps at the correct neck mouth opening length. I've looked inside my 308 LFCs and they don't appear to be closely fit to the 308 case body.
I'm going to experiment some to find the best case length. The distance from the bolt face to the rifling is supposed to be about .20050 so I thought I'd shorten the neck until I have adequate clearance but still can position the bullet shoulder close to the rifling.
I'm going to experiment some to find the best case length. The distance from the bolt face to the rifling is supposed to be about .20050 so I thought I'd shorten the neck until I have adequate clearance but still can position the bullet shoulder close to the rifling.
I was taking a look at your wildcat today. We are looking at the same drawing, 1.4598” to the point of the shoulder and .4550” diameter at the point of the shoulder?
I am attaching 4 pictures of the 308 Marlin Express and the 308 Winchester cases. The cases rolled as I attempted to take the pictures while holding the caliper. What I am trying to show is how close the point of you shoulder is compared to the 308 Marlin Express. I believe you should be able to run your 308 Winchester cases into a 308 Marlin Express full length size die and then into your full length size die and you will have a case ready for fire forming. You will need to adjust your size die so the Marlin lever just trips the safety under the lever and allows the action to close. You know how long you need to trim your cases so you don’t need to make a chamber cast for measuring.
I would then put a heavy chamfer on the case mouth and seat a bulk 150- or 170-grain bullet a touch long and let the closing of the action seat the bullet with it in the origin of the rifling. With a moderate charge of IMR or Hodgdon 4895 you should have an accurate fire forming load.
Of course there is no reason you could not fire form with 6.0 to 8.0 grains of Alliant Bullseye and the remainder of the case filled with cornmeal and closed with a dab of Alox or soft candle wax. With the full length size die adjusted so as to just allow the lever safety to trip, the case will not move forward and cause stretching problems.
I was going to make sure you had seen the two threads linked below on making 308 Marlin Express brass from 30-06, 308 Winchester and 444 Marlin cases and the similar thread on making 307 and 356 Winchester brass. I reviewed them and realized I did not go into very much detail on the actual case forming; I was more interested in the shooting. I will add more case forming detail the next time I post a similar thread.
It does look like 308 Marlin Express data for 4895 will be a good starting point.
That's a good idea to use the 308 ME forming die. My chamber is very close to the same dimensions. Of course I really won't know the actual size until I get the rifle back. I was thinking of grinding down one of my old 308 dies to help form the the case. This should be fun. It has been a long wait.
Do you suppose I should post the data on the wild cat forum or resurrect the old 307 thread?
I think a new thread on the wildcat forum. I anticipate you will be posting on both threads.
Edit] Eric, good day for shooting, we were out with the 327 Federal. Lousy day for picture taking due to low light. If I had a reflector handy I might have taken a good picture.
I ran a 308 Winchester through the 308 Marlin Express size die. I lubed the inside of the case neck with Lee size die wax and the outside from the point of the shoulder downward with Imperial size die wax. I ran the case through the size die and formed it into a long necked 308 Marlin Express.
The 308 Marlin Express has a neck approximately .300” long. The R-P 308 Winchester case came out of the die with a neck approximately .400” long. This would make an interesting cast bullet cartridge.
The approximate neck length on your case is .2858” long.
I cannot seem to get a good picture of a cartridge line so I tried making a drawing but they all seem to be of a different scale when I paste them together. The line at least gives you an idea of what I am seeing.
Since you have a 308 Marlin Express in your future I would just buy a die set and use it as the intermediate form die.
It might pay to have Lee make a custom case trimmer for your cartridge. These used to be about $14.00 and speed case trimming chores. If you have a good movie to watch it’s not so bad using a crank trimmer for a 100 or so cases.
I got curious so I gound down a 308W full length sizing die and ran some old brass though it. I noticed that the brass wrinkes at the intersection between the neck and the shoulder. Is this normal? Do the wrinkles shoot out when I shoot it the first time? There were also a couple of large wrinkles at the case shoulder edges.
Trimming wasn't the ordeal I thought it would be. I havea couple of different timmers and they all worked well on the case.
I had no wrinkles when I formed the cases in the previous thread and when I ran the 308 Winchester case through the 308 Marlin size die I had no wrinkles.
If the wrinkles are not too bad they will shoot out.
You might try backing the die off the shell holder 1/8". Size the case and then run the die down to touch the shell holder and size again.
I wonder if it because I used old brass. I'll try some new stuff or aneal some old.
Edit: I tried new brass. No wrinkles. The old stuff must have been too brittle. Would anealing new cases at the shoulder be worth trying too?
Edit 2: It turns out that the wrinkles were caused by the lubricating medium. As the die pushes the shoulder back, some of the lubrication get into the shoulder area and causes dents. If I unscrew the die and clean it a couple of times the dents disappear.
Unfortunately, that’s about as good as it gets on the forum for attached photos. I have dial-up so no photo sharing for me.
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