sizing once fired brass with bushings

[Fellas]

hi guys how are you , i just go a new 308 rifle and i bought as well some once fired brass . these are not fired from my rifle and i like to use the redding type s with bushing. some necks have dent wich i need to straighten up. how do i determine the correct bushing size? do i have first size the cases with normal FL die and shoot them so i can get the size of my chamber and then choose the bushings, or just get them trough the K&M expander then with bushing dies.

as these are not fired from my rifle and i dont neck turn the cases how do i choose the correct bushing . The OD of the cases is very good measured with a caliper they vary from 0.341.5 to 0.0343

thanks very much for your appreciated help

 

[Martin52]

Size with care...first concern is that you have a new rifle and cases that have been fired in a different rifle.

I suggest full length sizing a few of these cases in a standard FLS die, if the expander is left in place it should correct any dings in the case necks. if it's removed, then after sizing, run the necks through your K&M expander to remove any dings. Check the case length (for .308, 2.005 inches is OK,) Then chamfer the necks inside and out.

Check the empty unprimed resized cases will chamber in your new rifle, the "other rifle" might have a longer chamber, also your FLS die may not have sufficiently resized "fat" cases from a sloppy chamber etc.

The correct bushing size depends on how much neck tension you want, as a start, deduct 0.002 from the diameter of a loaded round that will chamber in your new rifle (tested with the firing pin removed as you probably know, just to be safe !)

Once these reloaded cases have been fired in your new rifle, measure the diameter of the case necks, deduct 0.001 and that will roughly approximate to your chamber neck diameter.

Martin

 

[Erik Cortina]

For correct bushing, measure the neck diameter of a loaded round and deduct .002"

Try to chamber brass in your gun, if it chambers then just neck size and run expander through brass to fix dings.

If it doesn't chamber, run brass through F/L sizing die first. Turn die down until it touches the shell holder and back it off one full turn. Size a piece of brass and try to chamber in your gun. If too tight, turn die down slightly and try again. Do this until bolt handle closes with very little resistance on your brass, then run expander through brass and you are good to go.

 

[timeout]

The gentlemen above have given you good advice. From what information you have given us to work with, it sounds like if you can find an experienced mentor to guide you through the process, it would be invaluable. I have found that the once fired brass thing can be a very poor way to go - and a waste of hard earned dollars. The brass is not always as advertised. With someone at your current experience level, you may want to consider buying some new brass. That way you can properly prep it and once you have fired it in your rifle, you can setup your die to "bump" the shoulder back .001" or .002". Also, when you say that you have a new .308, we are making the assumption that it is not a custom made rifle with a tight neck chamber. One thing that I do when checking resistance to the bolt closing is first remove the firing pin. With the firing pin left in, it is possible to get a false feel for the amount of resistance to chamber the cartridge. Hope that I have not created confusion. If you only take one piece of non professional advice that I have offered, start with new brass. Happy Shooting!

 

[Erik Cortina]

The gentlemen above have given you good advice. From what information you have given us to work with, it sounds like if you can find an experienced mentor to guide you through the process, it would be invaluable. I have found that the once fired brass thing can be a very poor way to go - and a waste of hard earned dollars. The brass is not always as advertised. With someone at your current experience level, you may want to consider buying some new brass. That way you can properly prep it and once you have fired it in your rifle, you can setup your die to "bump" the shoulder back .001" or .002". Also, when you say that you have a new .308, we are making the assumption that it is not a custom made rifle with a tight neck chamber. One thing that I do when checking resistance to the bolt closing is first remove the firing pin. With the firing pin left in, it is possible to get a false feel for the amount of resistance to chamber the cartridge. Hope that I have not created confusion. If you only take one piece of non professional advice that I have offered, start with new brass. Happy Shooting!

Yes, remove firing pin.
+1 on new brass.

 

[Fellas]

hi guys thanks for the comments i think we are not understanding each other. what i need to know is please how to determine the proper neck tension for once fired brass that has not been fired from my rifle ex

i have these once fire brass which the OD measures from .341.5 to .343
so i want to find the proper neck tension using the bushing dies. As these are once fired cases and not been fired in my rifle

1) do i have to size using a normal FL sizing die then fire from my rifle and choose the bushing from there when i have the size of the chamber

or

2) can i run the brass trough the K&M expander to straighten the neck as some of them have dents and not perfect round then start experimenting with bushing

thanks
for your all comments for me sure they are more than welcome to learn from all of you

2)

 

[Shynloco]

Fellas,
All great advice ahead of my post. The thing with "Once Fired Brass" simply creates too many variables and issues, especially in a new chamber. I'd definitely echo what the others have said about using NEW BRASS in a new rifle. And I'm going to assume this "new rifle" is a general production rifle and not a custom rig with a dedicated chamber. That would create a whole sets of serious concerns especially trying to use "once Fired" brass in that chamber. But good luck and have fun with that new rig.

Alex

P.S. Just saw your newest post. Personally, if I had to choose from your two ideas, I'd choose "1" as you need to find out what the brass does AFTER it's been fired in your chamber. But again, I'd be using at least a few new pieces of brass in a new chamber and then work on the neck sizing and neck tension after getting your basic sizes AFTER firing them in your new chamber.

 

[Erik Cortina]

Fellas, read my reply above, I told you how to measure for correct bushing size.

 

[Fellas]

i read it mr eric but even with the OD of another chamber still remains the same

thanks

Fellas, read my reply above, I told you how to measure for correct bushing size.

 

[rox]

Fleshing-out what has already been said: to get the bushing size just size a round (doesn’t matter whether FL or Neck, as long as the bullet doesn't slide in with no resistance), then seat a bullet (don't bother to prime or charge), and measure the OD of the case neck, taking an average of several measurements at different points around the neck (make sure you measure where the bullet is in contact). Subtract 0.001 (current Redding advice) or 0.002 (as recommended by others here) and you have your bushing size.

The chamber dimensions aren't relevant to this, nor are the fired dimensions of the case. You just want to achieve a sized case neck ID that is 0.001 or 0.002 less than your bullet size. This method achieves that, accounting for the brass thickness. But, note that if you need to reduce the neck diameter by more than about 0.005 it is usually recommended to do so in multiple steps of up to 0.005.

..

 

[Fellas]

thanks to everyone for all your help

thnks

 

[Shynloco]

The chamber dimensions aren't relevant to this, nor are the fired dimensions of the case. ..

REALLY???? They are if the "Once Fired Brass" won't fit in the chamber after being resized!

 

[rox]

REALLY???? They are if the "Once Fired Brass" won't fit in the chamber after being resized!

Sorry, I don't follow at all. I descibed how to find the bushing size, not how to size rounds in preparation for loading. Choosing a bushing isn't going to determine whether the rounds chamber. Sizing method and setup will determine that.

..

 

[Barlow]

You might full length resize them, fire them, and if they are accurate, forget bushings. Barlow

 

[CatShooter]

People often tell to pick a bushing that is 0.002" smaller than the loaded neck size - that works with tight, or no turn necks, but if you have a standard SAAMI neck, you can wind up with a very undersized neck - so the automatic recommendation of -0.002" is not valid for these chambers - you might need a bushing LARGER than the neck, to get a finished neck that is ~2 thou smaller that loaded neck size.

 

[timeout]

Not saying my way is the correct - or only way - but, I prefer to measure neck thickness and take that dimension times two, add bullet diameter, and subtract .003" to determine bushing size.

 

[GSPV]

Cat, could you elaborate? I just don't see it.

 

[GSPV]

Not saying my way is the correct - or only way - but, I prefer to measure neck thickness and take that dimension times two, add bullet diameter, and subtract .003" to determine bushing size.

Which, if you accurately measure both the neck thickness and the bullet diameter, gives you the same thing as a loaded round minus 3 thou.

We all tend to say "3 thou neck tension", but that's just a stand in for it. The real neck tension is that minus the springback. As we all know, springback changes as the neck work hardens. Till it is annealed, that is. Provided that it is correctly annealed

 

[rox]

Cat, could you elaborate? I just don't see it.

I think it's the same point I made about reducing the neck in multiple steps. When you take the neck down by more than 0.005" or so in one hit, you tend to 'overshoot' and reduce it by more than you would expect.

..

 

[CatShooter]

Cat, could you elaborate? I just don't see it.

I ran into this about 12 or 15 years ago, and I spoke with Patrick Ryan at Redding, to some length - I had (and still have) a very fine 300 WM 1,000 yard rifle that had a tight body, but a fairly loose neck.

I did the 0.002" thing and my necks were way too small - so small that when I put he bushing loosely on the neck, it rattled and fell off.

Pat Ryan didn't believe me at first, but back then, pretty much all users of bushing dies were BR shooters with tight necks. So he tried it on a large neck and called me back the next day, and said, "I'll be damned!!".

Here is what Redding now puts in their catalogue now about it.

— Tech Talk —
Bushing Selection and Use

The easiest way to determine the proper diameter bushing,
is to measure the neck diameter of several loaded
or dummy cartridges with an accurate micrometer.
Subtract .001”–.002” from the smallest average neck
diameter and this diameter bushing will generally size
case necks to create the proper press fit for the bullet.
Note: If the neck wall thickness of your cases is on the
thin side of the SAAMI tolerance, your fired case necks
will measure considerably larger (.006-.010” larger)
than your loaded cartridges. Under these circumstances,
our tests have shown that a bushing .001“ larger may
give the desired results.
Another method is to measure the neck thickness with a
ball micrometer. Double the neck wall thickness and
add this number to the bullet diameter. The result is the
neck diameter of a loaded cartridge, and bushing size
can be determined as above.
After loading several cases, it’s a good idea to test the
neck’s grip on the bullet. The simplest method is to push
the bullet in a loaded cartridge against the edge of your
reloading bench with moderate hand pressure. The bullet
should not move easily in the case neck. If the bullet
pushes deeper in the case, select the next smaller bushing
and start again.
When using your bushing die, we have found that lubricating
case necks and installing the bushing numbers
down may improve results. Many reloaders like to
adjust the die to size 1/2 to 3/4 of the case neck. This
has been shown to improve accuracy in some instances.