358 Win from 30-06

[Hannibal]

I'm new to reforming brass, so pardon me if my terminology/methodology isn't quite right. I have a .358 BLR and a chamber cast has shown me that the neck was cut .060" deeper than the SAAMI max length spec. I'm thinking of using this to my advantage by reforming 30-06 brass into long-neck .358. Having never attempted this, I am wondering if a Redding form/trim die is going to be helpful, or perhaps necessary?
I understand that annealing/neck turning/reaming are going to be required finishing steps. Just not sure about how the trimming/reforming needs to happen?
Any and all constructive input would be appreciated.

[waksupi]

I would just form from .308 brass, and not worry about it.

[Duckiller]

+1 What Waksupi said. Let the brass grow a bit before you trim it and then don't trim too short.

[dragon813gt]

I would just form from .308 brass, and not worry about it.

Neck comes up short when you do this. If you have a 358 full length sizer try running to 30-06 brass through it. It may work or you might have to trim the brass some first. I've never done it but I'd try that before buying forming dies.

[MarkP]

Take the expander out of the die and run a lubed 30-06 into the die, you will end up with a case that looks similar to the picture. Next take measurements on the location of the mouth. Trim and expand the mouth accordingly. You will most likely need to ream the necks, the easiest I have found is to use a spiral fluted chucking reamer. Measure the O.D.'s and I.D.'s of fired brass and resized brass to determine an approximate average thickness. I form and ream cartridges without the expander plug in place. The reason being is the walls are tapered in this location, I like to push the taper to the inside (as much as possible) and let the reamer clean it up, making the ID & OD parallel. On some cartridges I will ream while the case is in the forming die. You can order the chucking reamers from McMaster Carr, MSG,133085

[Hannibal]

Thank you dragon813 and MarkP, this is what I needed to know. Thanks very much!

[GRUMPA]

http://castboolits.gunloads.com/showthread.php?266585-358Win-from-308-brass

I don't have any problems using 308 brass, they aren't undersized when done either..

[EDG]

I think you would like the RCBS trim die the best for your project.
I understand that you know you chamber is .060 longer than SAAMI for the chamber or for the cartridge?

The next question is have you measured the diameter of your neck. It is easy to do. Form a .308 case to .358.
Then use a long tapered punch like a large center punch to expand the neck over size. Keep expanding until it drags going into the chamber. Then expand a little more so that the empty expander case has to be forced into the chamber. This will squeeze the trumpet end of the case down to fit the chamber. Then extract the case and measure the mouth that was dragging on the neck. You can compare this to a dummy loaded round using your .30-06 brass. If the loaded round is .003 smaller than the chamber you are good. NO neck turning baloney is needed if your neck if found to be smaller than the chamber.

The RCBS trim die leaves the ID of the neck about .010 larger than a loaded round. Once you have cut off the brass the large ID allows the case to slip over your FL die expander button.

You can skip the RCBS trim die and just use your FL sizer but the necks will be to small for the button to pass over so you will need to expand with an M die or just ram the case over the expander button. I have done it all 3 ways and maybe a few others.

I have 2 .358 Win sizer dies and the neck ID measures RCBS at .374 ID and Pacific at .376 ID.
I do not have a .358 trim die but I have a .357 Automag trim die and it measures .385 at the neck. The shoulder angle and shoulder diameter are the same as the .358 Win so I use it for my .358 BLR.

I have never measured the neck length of my BLR. If it is as long as yours I may form some brass to fit the length and sell or trade the expensive .358 brass that I have.

And back to your brass. It will need to be annealed either after you form it or after it is shot the first time. I doubt that your necks will need turning.

[MarkP]

If you are using 30-06 brass the 358 neck will be in the location where the 30-06 shoulder and body where located and this region will have a tapered wall section.

[Hannibal]

If you are using 30-06 brass the 358 neck will be in the location where the 30-06 shoulder and body where located and this region will have a tapered wall section.

So if I follow you correctly, necks on reformed cases will most likely need inside reaming/outside turning, correct?

[GRUMPA]

So if I follow you correctly, necks on reformed cases will most likely need inside reaming/outside turning, correct?

That's almost always the case but here's how to find out. Form them without the expander in the die and measure the outside of the case. Now put the expander back in the die and run it through the case and measure the outside of the neck. Chances are your going to find a hefty amount of taper when the expander is run through the case, that I'm almost certain of. When I make the 358 from 308 I can't use just any head stamp, some just aren't going to make the grade without reaming.

[EDG]

There is nothing on the current SAAMI drawings that forbids a tapered thickness in the case neck. The .358 SAAMI cartridge drawing shows a maximum neck diameter of the loaded round to be .388 +.000 -.008. The loaded round can vary anywhere between those numbers and still work in every .358 Win chamber.

The .358 Win chamber neck is dimensioned to be .391 at the shoulder junction and .389 at the case mouth. The tolerances are +.002 -.000. Notice this makes the chamber neck slightly tapered at nominal. Also notice that the degree of taper is the same as the tolerance. This prevents the neck from being acceptable to the drawing with a reverse taper - which would lock the case in the chamber after it is fired.

You will notice that with a minimum chamber neck at .389, the maximum neck diameter cartridge still has .001 clearance.

The neck wall thickness of the case by the definition of ASME 14.5M Geometric Dimensioning and Tolerancing is allowed to vary the full amount permitted by the drawing. This produces no problem as long as there is adequate clearance. You can also survey SAAMI cartridge and chamber drawings and you will find there are some of both that are designed with a taper. For example the 7X57 Mauser has .0036 taper designed into the chamber and .0036 into the cartridge neck. To produce a perfect cartridge at maximum dimensions would require the case neck to be tapered.

If the .358 Win chamber neck is tapered there is little you can do to produce a matching taper on the brass unless you set up a neck turning tool or a lathe to cut that taper. I have played with this using a Pindell neck turning tool but I do not consider it very practical.

If the .358 chamber neck is straight then you can turn brass to match it easily. If the cartridge neck is already smaller than the chamber neck, you will be only be uniforming the brass to a fit with more clearance. If the brass is uniform and it clears the chamber I would not bother turning it.

I base this on forming hundreds of SL-54 .30-06 brass into 7.65X53 Argentine Mauser and 8X57 Mauser. I have never turned a single case one of these cases. This GI brass is a good bit thicker than commercial brass and yet it has plenty of room.


If you are using 30-06 brass the 358 neck will be in the location where the 30-06 shoulder and body where located and this region will have a tapered wall section.

[GRUMPA]

Another thing to give some thought too. If you were to hold a 06 case next to a 308 case and pay close attention to the extractor groove you'll notice the 06 case is narrower. If you go through with the conversion, make sure your extractor isn't banging against the body from the narrower extraction groove.

[MarkP]

There is nothing on the current SAAMI drawings that forbids a tapered thickness in the case neck. The .358 SAAMI cartridge drawing shows a maximum neck diameter of the loaded round to be .388 +.000 -.008. The loaded round can vary anywhere between those numbers and still work in every .358 Win chamber.The .358 Win chamber neck is dimensioned to be .391 at the shoulder junction and .389 at the case mouth. The tolerances are +.002 -.000. Notice this makes the chamber neck slightly tapered at nominal. Also notice that the degree of taper is the same as the tolerance. This prevents the neck from being acceptable to the drawing with a reverse taper - which would lock the case in the chamber after it is fired. You will notice that with a minimum chamber neck at .389, the maximum neck diameter cartridge still has .001 clearance. The neck wall thickness of the case by the definition of ASME 14.5M Geometric Dimensioning and Tolerancing is allowed to vary the full amount permitted by the drawing. This produces no problem as long as there is adequate clearance. You can also survey SAAMI cartridge and chamber drawings and you will find there are some of both that are designed with a taper. For example the 7X57 Mauser has .0036 taper designed into the chamber and .0036 into the cartridge neck. To produce a perfect cartridge at maximum dimensions would require the case neck to be tapered. If the .358 Win chamber neck is tapered there is little you can do to produce a matching taper on the brass unless you set up a neck turning tool or a lathe to cut that taper. I have played with this using a Pindell neck turning tool but I do not consider it very practical. If the .358 chamber neck is straight then you can turn brass to match it easily. If the cartridge neck is already smaller than the chamber neck, you will be only be uniforming the brass to a fit with more clearance. If the brass is uniform and it clears the chamber I would not bother turning it. I base this on forming hundreds of SL-54 .30-06 brass into 7.65X53 Argentine Mauser and 8X57 Mauser. I have never turned a single case one of these cases. This GI brass is a good bit thicker than commercial brass and yet it has plenty of room.The final draw punch is tapered in this section thus making the walls tapered, in the mouth region the punch is cylindrical and larger in diameter to create thinner walls. Just ahead of the mouth section on a draw punch there is a reduction in diameter, as the brass passes through the draw die the material is not drawn and is therefore thicker and springs back to create larger OD to allow the brass case to be stripped off of the draw punch. The 358 mouth will be in the shoulder / body region of the parent 30-06 case. In addition when reducing the body dia down to the 358 neck diameter the walls will thicken (constant area / volume....... OD1^2- ID1^2 = OD2^2 - ID2^2) Now add boolits that are .360" into the case and they will not chamber. Final draw punches are different within a family of cartridges such as 308 family 243, 260, 7-08, 308, 338 Fed, 358 same for the 30-06 and belted cartridges. There are some sharing possibilities such a 280 Rem and 270 but usually there is a specific punch per cartridge. The smaller the neck the thinner the brass is on the final draw. I will post a few pictures of a draw punches to clarify.

[EDG]

You can discuss this based on theory but it is better to measure the actual brass and the actual chamber if you want to know if the rounds will fit the rifle.
You are forgetting that the mouth of the .358 is larger than the mouth of a .30 cal round and does not thicken as much because it is not squeezed down as much.
Second all your calculations are on the case side but you don't know what thickness of brass a shooter is starting with. Fore example US GI brass will be thicker than WW.
Third you also don't know what his chamber neck measures.

Like I said I have made many, many 7.65x53 Mauser and 8X57 Mauser cases out of SL 54 GI 30-06. I bought 2000 when they were a penny a piece - nearly 2 (5 gallon) buckets full. In addition I have made a few out of range pickup .270 and .30-06. The .270 are actually easier since you do not have to size the entire .270 neck when forming the case.

I have also made several hundred .30 Herrett from R-P, WW, and FC factory brass. When you shove the shoulder back and expand a .30 Herret case you can see that the last 1/8" of the Herrett neck is a little thicker at the shadow of the original shoulder. But .30-30 brass is thin to begin with so when it gets thicker it does not get thicker very fast or very much. The result is you can fire the cases as is because they still have a lot of clearance in the factory chambers. (See my earlier remarks about tapered chamber necks designed into some calibers.) I have several case turning tools and I also have a .30 Herrett reamer die and reamer. I have played around with these on Herrett brass but I don't think they are necessary. You can use the tools to thin the necks if you want but it does nothing except make the case fit sloppier.
When .010" thick RP .30-30 brass is formed to .30 Herrett the resulting case mouth is about .0105 to about .011 thick.
The last (bottom) .125 of the neck thickens to .013 to .0135. Nothing out of the ordinary with that. They shoot fine. I got these numbers about 5 minutes ago from a lot of Herrett brass that I stored while it was in process. There are raw cases, formed cases, formed and trimmed and FL sized and trimmed brass in that lot. All the brass is RP bought from an indoor range.
Another similar adventure for which I have significant notes is the 6.5X53R Dutch Mannlicher. I have used Federal, WW, Hornady Frontier and Remington to form brass for these rifles. I will not bother to repeat the case neck thicknesses because of one significant number with these rifles. The bullet is .264. The chamber necks in 4 barrels all measure .300".
When I formed the first cases for my carbine I used a 6.5X54R trim die. I had NO loading dies. The neck of RCBS trim dies are .010 larger than a FL sizer die neck. Even the .010 over necks chambered easily. If you subtract the bullet diameter from the chamber neck diameter .300 -.264 =.036. Divide that by 2 and you get a maximum case neck thickness of .018 before there is interference. There is no way you will ever get close to .018 with the brass I am using. The Frontier brass that I am using measures .013 to .014 after the first firing.
In closing whenever you get a product made of brass a commercial venture is going to attempt to give you the product with the brass at the lowest total weight/volume. The stuff is expensive so they will try to keep the brass on the thin side.
I know I used to see the aluminum sheet used in a large factory was always received rolled to close to the minimim thickness. Keep your eyes open it is always possible to get thicker material - maybe from RWS, DWM, old Speer brass or military specification. Most of the time you will never see a case mouth too thick to chamber safely. It can happen. When you neck .405 Win Hornady brass down to .303 Brit the resulting cases will not chamber due to neck interference. When you neck .444 Marlin down to .303 they chamber fine.
The real rule is not that the brass gets too thick. The rule should be the brass gets thicker. Know what will fit in your chamber. To make a very bad pun, in most cases there is not likely to be any interference. There could be but most of the time you are not even close.



The final draw punch is tapered in this section thus making the walls tapered, in the mouth region the punch is cylindrical and larger in diameter to create thinner walls. Just ahead of the mouth section on a draw punch there is a reduction in diameter, as the brass passes through the draw die the material is not drawn and is therefore thicker and springs back to create larger OD to allow the brass case to be stripped off of the draw punch. The 358 mouth will be in the shoulder / body region of the parent 30-06 case. In addition when reducing the body dia down to the 358 neck diameter the walls will thicken (constant area / volume....... OD1^2- ID1^2 = OD2^2 - ID2^2) Now add boolits that are .360" into the case and they will not chamber. Final draw punches are different within a family of cartridges such as 308 family 243, 260, 7-08, 308, 338 Fed, 358 same for the 30-06 and belted cartridges. There are some sharing possibilities such a 280 Rem and 270 but usually there is a specific punch per cartridge. The smaller the neck the thinner the brass is on the final draw. I will post a few pictures of a draw punches to clarify.

[MarkP]

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Shown in picture are 308 family cases after the following operations; 3rd draw, sectioned headed case, headed un-trimmed case. I could not find a 308 family cup to show, the neck thickness is controlled during the last drawing operation.

In the sample draw punch picture; The (2) left most highlighted dimensions change depending on final cartridge; such as 243 Win, 260 Rem, 7-08 Rem, 308 Win, 338 Federal, 358 Win. The smaller the neck the larger the draw punch is to create a thinner draw. The recessed area terminates the drawing operation and creates a thicker wall with a knob or bulge at the top of the draw. This is to allow it to be stripped off of the draw punch. If not the wall of a final draw rifle case is very thin and the stripper will not strip or would damage the top portion. The bulge is trimmed off before the heading operation.

As the case is formed in the tapering operation the neck's wall will thicken. Also note the third dimension to the right, it is smaller in diameter, this is in the shoulder body area. This is the bulge that causes the cartridge to not chamber in an in specification SAAMI chamber. Wildcats can be designed around this by creating a larger neck diameter.

The difference between prime and scrap C260 is less than most would think. Material is not saved in the neck. There is quite a bit of scrap during the trimming operations between drawing and heading operations

[Tonto]

And this is how these forums are supposed to work, thanks to all of you for the education.