338/375 ruger finished

[WildRose]

Not at all. It's about as far as a person wants to go in one step, but works fine. Never crushed a shoulder or ruined a case otherwise. Just one pass with 375 Ruger brass in my 338-375R FL sizer die and I'm ready to load.

Thanks, I'm trying to figure out a good way to get from .375-..300-.280 or so in two steps without crushing a bunch of them.

If I can get to 7mm they'll feed through my 6.5LRM die fine I'm sure.

 

[LeddSlinger]

Thanks, I'm trying to figure out a good way to get from .375-..300-.280 or so in two steps without crushing a bunch of them.

If I can get to 7mm they'll feed through my 6.5LRM die fine I'm sure.

Whew! Thats a long ways to neck down... No way to do that in 2 steps. Just too far. 3 minimum, but I would probably go with 4 steps: 375-338, 338-308, 308-277 or 284, then the final step to 264. I bet those necks end up super THICK. Would definitely need to turn a lot of brass off the necks then anneal the cases

Have you ever looked into the 6.5 RCM? Will give you similar performance, but easier to neck down from 300 RCM brass. These days, I try to avoid wildcats that take more than 2 steps for forming. I've done some pretty crazy widlcats in the past and they are just so much work. Not always worth it to me.

 

[yorke-1]

Thanks, I'm trying to figure out a good way to get from .375-..300-.280 or so in two steps without crushing a bunch of them.

If I can get to 7mm they'll feed through my 6.5LRM die fine I'm sure.

I go from 375-338, 338-308 then 308-270 with no issues as long as I don't try to use a bushing die. You can just use 338 RCM, then 300 RCM and finally 6.5 PRC dies to get down to 6.5. For the 270 I'm using a 300 RCM then a 270 WSM to go down to 270, followed by a 6.5 PRC bushing die with a .301" bushing to finish.

 

[LeddSlinger]

When starting at 375, you won't make it from 308 to 264 in one step. The neck walls are becoming so thick and compressed at that point it's just too much to go 264 from 308. Like I said, 308 to 277 will probably work, 308 to 284 will work for sure. But 308 to 264 is asking for trouble.

You can get 40 thou jumps pretty easy to start, but the more you neck down and the thicker those walls become, the less you are able to jump in one step without getting folds in the neck.

Whatever you do, don't dare use an expander ball when necking down that far. You'll probably be fine with an expander ball from 375 to 338, but after that it can become extremely difficult or even near impossible to remove without damaging the decapping rod or brass.

I was recently necking down Lapua 423 Dakota brass to 300 Norma Magnum. It had been a few years since I necked down that far. I had a brain fart and forgot I left my 30 cal expander ball on the decapping rod when making the final jump to 308. It took a TON of force to get the brass free from the die. If I wouldn't have had the big thick rim inherent to the 416 Rigby parent case, I don't think I would have been able to remove it. Smaller thinner rims would have ripped from the shell holder like they do when a case gets stuck in the die

 

[Wild Monkey]

.

 

[Pdvdh]

95% outside turn the case necks after downsizing the necks that much, and then anneal the shoulder/neck before the first firing.
After first fire forming, then final finish outside neck turn. I think that's how I'd proceed.
My 25-300 RUM is over bore monster. This one would not be too underdone or terribly overdone. Just right.

 

[yorke-1]

95% outside turn the case necks after downsizing the necks that much, and then anneal the shoulder/neck before the first firing.
After first fire forming, then final finish outside neck turn. I think that's how I'd proceed.
My 25-300 RUM is over bore monster. This one would not be too underdone or terribly overdone. Just right.

That's what I do with the 6.5 Badger (6.5x338 RUM), size down in 3 steps, turn necks, anneal then fire form.

 

[WildRose]

When starting at 375, you won't make it from 308 to 264 in one step. The neck walls are becoming so thick and compressed at that point it's just too much to go 264 from 308. Like I said, 308 to 277 will probably work, 308 to 284 will work for sure. But 308 to 264 is asking for trouble.

You can get 40 thou jumps pretty easy to start, but the more you neck down and the thicker those walls become, the less you are able to jump in one step without getting folds in the neck.

Whatever you do, don't dare use an expander ball when necking down that far. You'll probably be fine with an expander ball from 375 to 338, but after that it can become extremely difficult or even near impossible to remove without damaging the decapping rod or brass.

I was recently necking down Lapua 423 Dakota brass to 300 Norma Magnum. It had been a few years since I necked down that far. I had a brain fart and forgot I left my 30 cal expander ball on the decapping rod when making the final jump to 308. It took a TON of force to get the brass free from the die. If I wouldn't have had the big thick rim inherent to the 416 Rigby parent case, I don't think I would have been able to remove it. Smaller thinner rims would have ripped from the shell holder like they do when a case gets stuck in the die

DD, I just need to get to 7mm. I can run 7LRM brass in my 6.5LRM die with no problem.

I'm thinking of a couple of tapered dies going from .375 down to about 7.5-7.775 and another going from there to right at or maybe just under 7mm.

From there I should be able to work them into the 6.5LRM die without any problem or at least that's what I'm hoping for.

It would cost me about 400.00 to buy custom brass from the manufacturer which seems like a waste when I have so much brass laying around and of course better options for even higher quality .375Ru brass.

 

[yorke-1]

DD, I just need to get to 7mm. I can run 7LRM brass in my 6.5LRM die with no problem.

I'm thinking of a couple of tapered dies going from .375 down to about 7.5-7.775 and another going from there to right at or maybe just under 7mm.

From there I should be able to work them into the 6.5LRM die without any problem or at least that's what I'm hoping for.

It would cost me about 400.00 to buy custom brass from the manufacturer which seems like a waste when I have so much brass laying around and of course better options for even higher quality .375Ru brass.

Here's how I'd do it using dies that I have on hand. Remove the expander ball and decapping assembly from all of the dies.

1) Adjust a 338 RCM die so that it will just touch the shoulder on a piece of 7 LRM brass and tighten the lock ring on the die. Now back the die off a couple turns.
2) Take a piece of 375 Ruger brass and very lightly lube the case with a lanolin based case lube and run it into the 338 RCM die so that it sizes the entire neck down and just kisses the shoulder at the top of the press stroke. The die will be threaded out of the press by a few turns.
3) Turn the die in 1/4-1/2 turn into the press and rotate the case 180° in the shell holder and run the case all the way into the die.
4) Repeat this until you've pushed the shoulder back to the appropriate position for the 7 LRM chamber. Now you have a 338 LRM.
5) Run the 338 LRM case into a 300 RCM die adjusted to just touch the shoulder.
6) Run the 300 LRM case into a 7mm WSM, SAUM or any other 7mm die you have around.
7) Make one final pass into the 6.5 LRM die.

From there I'd try and a run a 6.5 mm expander mandrel like a Sinclair or K&M into the case to even out the inside of the necks. Now outside neck turn and anneal and you should be good to load and shoot. I' probably try going from 300 down to 6.5 just to save a step. I've done it many times forming 260 brass from 308, but those necks were a lot thinner.

 

[WildRose]

Here's how I'd do it using dies that I have on hand. Remove the expander ball and decapping assembly from all of the dies.

1) Adjust a 338 RCM die so that it will just touch the shoulder on a piece of 7 LRM brass and tighten the lock ring on the die. Now back the die off a couple turns.
2) Take a piece of 375 Ruger brass and very lightly lube the case with a lanolin based case lube and run it into the 338 RCM die so that it sizes the entire neck down and just kisses the shoulder at the top of the press stroke. The die will be threaded out of the press by a few turns.
3) Turn the die in 1/4-1/2 turn into the press and rotate the case 180° in the shell holder and run the case all the way into the die.
4) Repeat this until you've pushed the shoulder back to the appropriate position for the 7 LRM chamber. Now you have a 338 LRM.
5) Run the 338 LRM case into a 300 RCM die adjusted to just touch the shoulder.
6) Run the 300 LRM case into a 7mm WSM, SAUM or any other 7mm die you have around.
7) Make one final pass into the 6.5 LRM die.

From there I'd try and a run a 6.5 mm expander mandrel like a Sinclair or K&M into the case to even out the inside of the necks. Now outside neck turn and anneal and you should be good to load and shoot. I' probably try going from 300 down to 6.5 just to save a step. I've done it many times forming 260 brass from 308, but those necks were a lot thinner.

Thanks. Unfortunately I skip from .300 wm and Rum to .375 in my caliber selections.

You ave however given me a definite idea to try. I should be able to pickup a .325 or .338 short cased necking die for the first step down and from there be able to get down to .300 without a problem.

I have both full length and neck dies for all of the cartridges I load for so this might be the easiest way to get where I want to be.

 

[Wild Monkey]

.

 

[WildRose]

When 300 PRC Brass gets on the Shelves this will make your Cartridge an easier accomplishment. Then Your necks won't be so darn Thick. Otherwise you're going to need a small Lathe to turn all that Brass off. I am looking forward to some 300 PRC Brass as I'm leaning towards the 7mm now.

I don't see how the PRC brass could help me at all, it's based on a different, much shorter case unless I've misread something somewhere.

I've never been one to turn necks but if it would save me 400.00 or more on building up an adequate brass supply it would be worth it.

Again I appreciate the help.

 

[gregsjt]

I don't see how the PRC brass could help me at all, it's based on a different, much shorter case unless I've misread something somewhere.

I've never been one to turn necks but if it would save me 400.00 or more on building up an adequate brass supply it would be worth it.

Again I appreciate the help.

You're right about the 6.5 PRC, but the 300 PRC is a 375 Ruger necked down to 30 caliber. It's still 2.580" in length

 

[Wild Monkey]

.