Fireforming 308 to 358 winchester

[Lever-man]

​I have a new BLR on the way in 358 Win. Birthday present to myself. I remember reading somewhere about taking 308 military ammo and firing them in the 358 to make the brass, but I can't find the article. Does anyone here know about this? I have 40 rounds of 7.62x51 NATO FMJ. I don't want to ruin a new gun

[KLR]

Do you have reloading dies in .358 winchester? I just lube the cases well and run them in the sizing die.

[Lever-man]

I have the dies on the way too, as well as some once fired brass. Just wondering what to do with these loaded rounds?

[EDG]

Do not fire form. Just make sure your expander is tapered enough to expand the case mouths.
I have RCBS dies and they come from the factory set up for expanding .308 cases.

[Outpost75]

The NATO Ball ammo is worth $0.60 per pop. Sell it and use the money to buy decent brass.

[frkelly74]

If you pull the bullets and dump out ( and possibly save ) the powder you may be able to fire form the brass using a small charge of unique type powder and a dose of cream of wheat cereal to fill up the rest of the case, use a small pc of toilet paper to keep the C O W in the case and keep things neat. You can probably trade off the bullets if they aren't damaged and discard or reuse the original powder as your confidence/ comfort level with doing that dictates.

Or wait till your dies come and expand the necks that way.

[Lever-man]

The dies that are coming will be Lee dies. I will check on the taper of the expander before using them. I also have the Lee universal expander that I can use to flare the case mouth some before running through the re-sizing dies. I guess I will have to fire the loaded ammo in a gun chambered for 308 before re-sizing them to 358. I was thinking of eliminating a step by firing the loaded ammo in the BLR, but don't want to damage the barrel.

[Lever-man]

I hadn't thought of selling the ammo. That would be the best solution, or maybe trade it for some 308 brass?

[frkelly74]

If that is gas operated auto I would not use the method that I just recommended. Cream of wheat in the gas system does not sound like a good idea.

[Lever-man]

It's not an auto....... It's the Browning BLR Lever action

[Lever-man]

I think I like Outpost75's idea of selling the loaded rounds, or maybe see if anyone would be interested in trading for some brass.

[MostlyLeverGuns]

I have fired several hundred LC military tracers and other surplus boxer primed military into snow-covered hillsides in a pre-81 Browning BLR .358 and Savage 99 .358 without harm or incident. That was before the value of 7.62x51 spiked. 1980's and 90's. NO damage to rifles. Browning still shoots under 1.5 MOA, the Savage about the same. I have had Winchester brand .358 Win brass that was to short from shoulder to head cause misfires. Hornady .358 Win has been OK. All have been checked in a Wilson .358 Win headspace guage and using the Hornady headspace guage on a caliper. In the 80's there was little .358 Win brass or cartridges to be found. You can resize and trim 8x57, 30-06 and others. If I were to use .308 brass, I would fireform using any LP or LR primer, 8-10 grains of some fast-burning powder (Unique, HP38, HS6) fill the case with Cream or Wheat, top with a paper or wax wad, lubricate the case and fire. This provides the 'optimal fit' . With the current powder/primer shortage neck expansion is the second best option.

[jonas302]

Why not just pull the bullets won't get as much but you can sell those easier, for me the cost of shipping 40 rounds would be to high and to much hassle

[No_1]

I have Redding dies. Lube inside as well as outside the case eased forming of the cases. First firing finalized the job.

[williamwaco]

+1 on sell the ammo and buy new brass.

[Lever-man]

Mostlyleverguns nice to know that someone has tried firing 308 loaded ammo in the 358 win. I don't know if I can bring myself to do it in a brand new gun though. I have 270, and 243 brass on hand as well as some once fired 308 brass that should be here next week with the dies. Will probably just wait it out and use the dies to re-size some brass to load. Don't know about taking the 243 up to 358 seems to me that the neck would be a little thin after re-sizing.

[waksupi]

The NATO Ball ammo is worth $0.60 per pop. Sell it and use the money to buy decent brass.

Do this.

[KLR]

Mostlyleverguns Don't know about taking the 243 up to 358 seems to me that the neck would be a little thin after re-sizing.

I formed some 243 to 358. I sized it to 308 first and then to 358. Neck thickness is .010 at the minimum.

But I'd sell the ammo. I'll bet someone here would trade you 100 pieces of once fired brass. Cost $5.80 for a small flat rate box shipping.

[Lever-man]

That seems to be the opinion (sell the 308 ammo) of most everyone that has replied, and I want to thank everyone for their comments on the subject. It has been very helpful. I will probably put it up for trade on here and see what happens.