Necking down 416 to 375?

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regulate34

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I am looking to see what’s involved in necking down a 416 ruger case to a 375ruger.

375 Ruger brass is hard to find at the moment.
i have some load developing I plan to do over the winter.
I can find 416ruger

I feel like running it trough a 375ruger die is probably too big of a jump in one pass?
Do I need a in between die?
I’ve never done this yet.

What do you guys recommend to neck down 416 to 375?

Too much hassle to be worth it ?
 
Well I lubed it up and ran it trough a FL 375 ruger die.
It worked. Just needs a fire form to get the shoulder right

Should I anneal the brass?
Before or after necking down?

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Normally you anneal before necking up or down. I figured it would work without annealing. Firing them will finish forming the case. I assume it chambers in your rifle. I usually back the die out and size and try chambering. Keep turning the sizing die in 1/4 turns until the case chambers. You don’t want the shoulder pushed too far back.
 
I didn’t measure the shoulder but visually it looks further back than one of my fired cases.

My die is set to bump
The shoulder .002” on my fired brass.

Maybe ill try annealing one and see how it
Turns out
 
regulate34 said:
I didn’t measure the shoulder but visually it looks further back than one of my fired cases.

My die is set to bump
The shoulder .002” on my fired brass.

Maybe ill try annealing one and see how it
Turns out
Click to expand...

For a rimless case, not sure how it would be possible to push that shoulder forward when resizing - unless you created a "false shoulder" somehow? I think when the firing pin strikes, it is going to push that unfired case as far forward as it can go - meaning there will likely be an air gap between bolt face and rear of the cartridge? So the firing of that case will cause the case walls to grab tightly to the chamber walls nearest to the neck - meaning that case head will go backwards to meet the bolt face - that often results in excess stretch within the case walls - but perhaps that brass lets you do that. With a "false shoulder", the firing pin can not push the case body forward very much - so that case tends to blow out and fill out the shoulders, with the case head snug or near snug to the bolt face - is what you were trying to do when you set your die to do a .002" bump from being fired. If you did that once - should be able to do again? I think I would do as advised in Post #5 - repeatedly try sizing and turn down the die a bit at a time - know that you are starting too long - until the false shoulder just barely allows the bolt to close - then that one is ready to fire form. Reset your die later, to restore your .002" bump.
 
Size the case just enough so it won’t chamber. Turn your die by small amounts and resize. Try chambering after each adjustment. I like the bolt to close a little tight when case forming. Once your die is set for your first case try a couple more. See if they chamber. I always load 5 to 10 cases and test their fit in the chamber before I load a bunch up. After to have them fired then you can resize normally. A lot of times I resize with the die just touching the shoulder, your 2 thou shoulder bump. It’s better to have the case a little tight than too loose. You can also seat a bullet out to touch the rifling which will make sure the case head is pushed back against the bolt, minimizes headspace.
 
So I measured the shoulder on the 416 brass that I necked down. It was pushed too far back.
So I did another one. Kept adjusting till the bolt will just close snug.

I get what you are saying about having to be tight to the bolt face.

Now what do you recommend for a fire forming load?

I have some cast 375 bullets I hope to use.
I also have trail boss.
 
With cast rifle loads the two powders I use are IMR 4198 and 2400. Others can be used. I always use a starting load or just above book minimum. I don’t have anything listed for trailboss in my book, Lyman 50th. They list 250gr and 335 gr cast. Starting loads of IMR 4198 33.5 -38(250gr) and 34-38 grs (335 gr)cast loads.
 
Snider shooter said:
With cast rifle loads the two powders I use are IMR 4198 and 2400. Others can be used. I always use a starting load or just above book minimum. I don’t have anything listed for trailboss in my book, Lyman 50th. They list 250gr and 335 gr cast. Starting loads of IMR 4198 33.5 -38(250gr) and 34-38 grs (335 gr)cast loads.
Click to expand...
Perfect. I have a few lbs of IMR4198
Now I can’t seam to find my cast bullets. Maybe I shot them?
 
Snider shooter said:
Size the case just enough so it won’t chamber. Turn your die by small amounts and resize. Try chambering after each adjustment. I like the bolt to close a little tight when case forming. Once your die is set for your first case try a couple more. See if they chamber. I always load 5 to 10 cases and test their fit in the chamber before I load a bunch up. After to have them fired then you can resize normally. A lot of times I resize with the die just touching the shoulder, your 2 thou shoulder bump. It’s better to have the case a little tight than too loose. You can also seat a bullet out to touch the rifling which will make sure the case head is pushed back against the bolt, minimizes headspace.
Click to expand...

I would disagree a bit with your last two sentences. My shooting was mostly as hunting - so I prefer really slick chambering without commotion - I have missed enough to need second or third shot - so I want them to go in slick - not to be tight - but I think I can see that from a shooting bench on sandbags that snug fit is not a bad thing at a target range. Unless you meant to be a bit tight for that initial fire-forming, in which case, I agree with you.

As far as seating bullets out long - about two issues - at least one rifle here, with the bullets of interest - bullet is all the way out of the case before it reaches the lands - not sure if rifle was made that way or if it has worn that much. As well, I am not so sure that a bullet into the lands will actually hold the case against the firing pin strike - I have read others to say they did so - just strikes me that I would prefer a "false shoulder" on the case, as opposed to relying on the neck tension to hold that case in place?

As I think we agree - is as if OP's parent cases were made with shoulder slightly short for his rifle's chamber - not sure that I understand how reducing neck size could also push back the shoulder, unless the die was not set with that in mind?
 
Seating the bullets out to touch the rifling is only for the first fire forming round. Basically to make sure the case forms to the chamber without having excessive headspace. Method is used to make sure the case head is held against the bolt face allowing the shoulder to be formed in the proper place. One time deal only. When loads are worked up the bullet shouldn’t be touching the rifling.
 
Neilm said:
I would just do a regular and fire it. I have done this often but not with the 375 Ruger. That is just me.
Click to expand...

Seeing as I can’t find my cast loads. I might just do that. Got a bunch of bullets sitting around. Got to do something with them.
 
Once you have the case reformed so the bolt just barely closes on it, a crush fit, you have a perfect fit to that chamber. There is no need to fireform the new case with reduced loads of any kind. Just load with any sensible load and go to the range.

The fired cases will be perfectly formed to the chamber in that particular rifle. I have even hunted with 9.3X62 cases loaded with full power loads that had not been previously fired. Long story, but suffice it to say there was only a few minutes to make some ammo before leaving. 😊

Ted
 
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