Home Forums Hunting & Shooting Hunting Rifles Forming .358 from .308?

Anyone making their .358 Win brass from .308? If so, are you using dies or simply fireforming with .308 cases?

I use a Hornady 338 to open .030" and my RCBS 358 dies to complete the process.

Piece of cake. Get a little lube inside those case mouths, make sure you have a good compound leverage press securely mounted to a really heavy or permanently mounted table and run 'em through your .358 die with no other steps needed. Requires a little muscle at first but I have not lost a single case this way and have loaded many this way. No need for fireforming, cases formed this way are ready to go and hunt with right out of the gate when made this way.

Go thou forth and slay the beasts of the field with ammo so made.

Have made a ton of 35Wh from old '06 cases. Single pass through RCBS dies with their tapered expander. Occasional split neck, crumpled shoulder, crooked mouth.
Should work about the same for 358 Win from 308. My brother shoots an old M88 in 358Win, 200gr bullets at 2400+. Think he hoards any 358 brass he can get his hands on.

Tell him that with R-19 he can get 225gr TTSX's to go 2500! I am shooting a model 88 as well, albeit with an aftermarket stock and PacNor 22 inch 358WIN Barrel.

Mark,

I think your post is slightly misleading... Not all .358 dies come with the tapered expander. If one's die is not so equipped, I see no way to neck up the brass from .308 to .358.(At least up to my standards...)

Tapered expander assy's from RCBS are only $10 or $15 or so... The last I bought from Redding I think were only about $14. They makes the process much easier. As you said, a bit of inside lube and it's an easy process. Without the tapered expander, lopsided necks are often the result, in my experience.

I ran .308 brass exclusively in my .358's until I came upon a respectable supply of factory .358 brass. At the moment I have four rifles so chambered. A Browning BLR, a Remington M-Seven MS, a Ruger #3, and a Mauser Mk-X w/26" bbl. The BLR and M-7 have 20" bbls, and the #3 has a 22". I keep thinking I need a 22" bolt gun to kind of round them out.

Grasshopper

P.S: Best to use new, unprimed brass for best results...

Hornady 35 caliber necksizing die + graphite powder for lube. One pass and they're ready to size. I've done a couple hundred and haven't lost a single case. Takes a few minutes to set up is all.

Same die works for 30-06 to 35 whelen too.

Bonus: it also necksizes fired brass for all your 35 caliber reloads from whelen to 35rem including 350 rem mag. Don't know about the Norma.

It's a right handy tool.

'Nother way to make 'em, is fire forming the 308 cases in the 358 chamber. Prime the case, add a small charge of pistol powder, (I used 6 grains of W-W 231) and fill the case with cornmeal. you can top the case with vasoline to keep from spilling the cornmeal, or just keep the case pointed up while loading and firing. Have used this method for forming 30-06 to 35 Whelen. Makes a perfectly formed case. I got this information from Ken Howell.
Virgil B.

The Redding 358 dies come with the tapered expander already installed.

Most good dies come with tapered expander's today, if you really want em win 358 brass is an annual run, and they are not that expensive. I want some nickel cases so i will have to run 308 cases through the redding dies, and imperial sizing die wax.

I've always been able to buy a supply of 358 brass, like it lot better than resizing 308. 308 Headstamp just leaves to much room for error.
Now I do resize 308 brass to fit my 338-08 with one pass through my RCBS dies with out any problem. I do color the base of the brass with red permanent marker though.

I have been fooling with the 35 Whelen and the 358 for many years. The headstamp being room for error makes no sense as you can't chamber a 358 round in a 308. I also have never used any special die parts to neck up my brass. As to Winchester 358 brass I have on two different bags of factory brass had problems with thin neck material, never had this problem with necking up 308 brass. However lubing the inside of the case neck is very important and I use Armorall Protectant wipes for this. Tear a piece of it off big enough to wrap around a cleaning brush ( an old one as you will start doing this with all your long necked cartridges to ease the expander buttons trip back out of the neck) and wipe the inside of the case neck with it. Doesn't take a lot but it seems to be a miracle lubricant and it does not need to be removed. Also heavily chamfer the inside of the case neck before you run it thru the size die.

True a .358 isn't going in a .308, but I have several .308's along with one .358. Haven't poked one in or checked, but I'm assuming a .308 will fit into a .358. I stick to the .358 brass for that reason and haven't had trouble finding it.

JCM

Jason280,

I do it all the time.

Start with new brass, or else the necks will be much more likely to split. I suppose annealing used .308 brass might cure that... have not tried it though.

I use Winchester brass and a Hornady "New Dimension" .358 die. The neck lube is key. That "Royal" stuff is supposed to work. I couldn't find any, and I was in a hurry at the time, so I tried several things and found something that works really well. It is... drum roll.. boot dressing from Obenhauf! It's got lanolin and beeswax in it and it just works great. I put a little inside each neck with a Q-tip.

I size from .308 to .358 in one pass. It takes some leverage; but my RCBS press does fine. The brass lasts a long time and neck splits are not an issue, but, I am running a custom barrel with a tight chamber so YMMV in that regard.

I think I have some old die that doesn't have a tapered expander so I have been using a 338 expander first, then my 358 die. I really should buy a new 358 die set but somehow I just never get to it.

Marc,

I have two Redding .358 dies, One has the tapered Expander and the other does not. I think I have another set, I just can't find them...

I just bought a new Redding set because it came with the tapered expander. I became "rich" with 308 brass a couple of months ago.

Try the Armorall Protectant. I suppose you could get the spray bottle and spray it on a Q tip to wipe inside the case necks. I also reccomend new or once fired brass for necking up. As to not noticing the difference between 308 and 358 diameter bullets I think you ought to get your glasses replaced.

RCBS dies do now, too.

Jason, I have formed a lot of 358 Win out of 308 brass over the past 25 or so years. My experience has been the same as the other posters. No need to fireform, just full-length size and go! Haven't had a dozen split necks in all that time.

Ted

Thanks for the info. I have a pretty good stash of .308 brass, and have a set of Redding dies en route. I am not sure if they have the tapered expander or not, but I should know in a few days.

I think I am going to start with a few 1x fired cases, and anneal the necks prior to resizing. I've formed a bit of 7mm TCU from .223, and hope the .358 forming goes as easily. I would occasionally get split necks, but was never too big of an issue as .223 brass is cheap and plentiful.

I've also formed around 75 or so cases of .260 out of .243, and I am not too concerned about getting them mixed up. I went ahead and dremeled the "43" off the portion of .243 on the case head, which lets me know they're .260 cases. I'll likely do the same with the .308 cases.