Selecting a Neck Size Bushing with once-fired brass

[peaceatwar]

Greetings all,

I'm pretty new to reloading. I have been reading a lot and trying to get a grasp of things, and I have used the search function just haven't gotten the answer to this question.

I have been shooting all FGMM and I hear federal brass isn't the #1 choice so I bought some once-fired winchester brass from a mile high demo shoot. I would like to purchase a Neck Size Die(Getting a redding S one) but I don't know what bushing to get? I'm assuming I can't just measure the current cases as they haven't been fired in my rifle (GAP Customer Templar .308) and then order something that is .001 & .002 under that correct?

So I will need to FL resize, prep, load, fire and then measure? Or will I need to do some prep to that fired from my rifle case and then measure in order to find the right neck bushing?

Thanks for your help.

 

[ChrisGarrett]

I've got a batch of 50 Winchester cases, from some of their hunting ammo, that requires a .331" bushing for .001"-.002" of constriction.

I have bagged component cases from Winchester that I use a .334" bushing on, for .002"ish constriction.


I have nine different bushings I use on my 308 handloads, so my bases are covered. Measure a fired case and see what it mics at, as you could also need to use a 'step down' bushing in an intermediate step, if your throat blows out your necks, so you're not sizing a great amount all in one pass.

If I had to guess, I'd say buy a .334" for a bolt gun and a .333" for a gas gun.

You probably don't have a ball mic, but if you do, you can measure the neck walls at various places, get an average from a bunch of measurements and then double that number and get an idea of what exactly you need.

Chris

 

[milo 2.0]

If you have a loaded FGMM, measure the case mouth, subtract .002", that should be your bushing for the Federal brass.

 

[sab9259]

.002-.003 less than fired measurement

 

[FLIGHT762]

For Federal GMM brass, I use a .337" bushing for .001" tension. Recent Federal brass has been very consistant in neck thickness. If you want to be safe, get a .336" bushing. For Winchester brass, most of my brass has thin necks and I use a .331" bushing for .001" tension, this brass usually weighs in at 158-163 grains,however, I've found some Winchester brass that weighs in at 170 + grains and has slightly thicker necks and require a .333"-.335" bushing. I weigh the brass with a primer inserted so add 5 or subtract grains for the primer.

I use a variety of brass and have on hand 5 bushings that will cover most any brass. I have .329",.331",.333", .335" and .337". Those sizes get me by.

I used the method of measuring the O/D of the neck of a loaded round and subtracted .001". You can subtract .002" and be good also, most people do. I load for bolt guns and autoloaders so I need the variety of bushings so I can tighten up / loosen my neck tension when needed.

 

[JGorski]

For Lapua brass I had to go with a .334 bushing, 336 gave no tension whatsoever, Rem & fed get the same 334, Win 331 work best, but it's a bit more than .001 tension, I believe. My 308s seem to shoot best with .002" neck tension.

 

[peaceatwar]

Definitely using winchester brass for my operation, I guess one question I'm still unclear of is:

Do I need to measure after its been fired in my chamber? or can I measure it even though it wasn't fired in my chamber?

It looks as though I'm going to need a few anyway, just want to save the hassle and wait if I that's what is best.

 

[JGorski]

Definitely using winchester brass for my operation, I guess one question I'm still unclear of is:

Do I need to measure after its been fired in my chamber? or can I measure it even though it wasn't fired in my chamber?

It looks as though I'm going to need a few anyway, just want to save the hassle and wait if I that's what is best.

All that will tell you is the size of your chamber neck.

 

[FLIGHT762]

Do I need to measure after its been fired in my chamber? or can I measure it even though it wasn't fired in my chamber?

No it doesn't have to been fired in your chamber. Just measure the O/D of the neck of a loaded round.

 

[peaceatwar]

All that will tell you is the size of your chamber neck.

No it doesn't have to been fired in your chamber. Just measure the O/D of the neck of a loaded round.

Thank you.

 

[TRTAC]

You need to measure a loaded case neck then subtract .001 from that. That will get you in the ballpark. go .002 smaller if you want more tension. Dont size the entire neck either. Leave a little portion of the neck unsized to better help with case/bullet alignment. Good luck!

 

[hondo1312]

No it doesn't have to been fired in your chamber. Just measure the O/D of the neck of a loaded round.

Any loaded round or a round using the same brass you plan to reload?

 

[ChrisGarrett]

Any loaded round or a round using the same brass you plan to reload?

It should be the brass you're going to load. Brass neck thickness can vary from headstamp to headstamp and even within a particular headstamp, as in my example above, regarding Winchester brass from their hunting ammo and from their component batches.

Chris

 

[hondo1312]

[MENTION=10962]ChrisGarrett[/MENTION]

That's what I thought. I've been trying to get the right bushings as well, and without the clarification of measuring the loaded ammo with the brass you are going to use, it didn't make any sense because I knew that different brass had different neck thickness. I ended up ordering bushings in .292, .291, and .290 for SSA brass and 6.5mm bullets. I measured 10-15 pieces of unfired ammo and the brass was all between 0.014 and 0.015 thick.

 

[ChrisGarrett]

[MENTION=10962]ChrisGarrett[/MENTION]

That's what I thought. I've been trying to get the right bushings as well, and without the clarification of measuring the loaded ammo with the brass you are going to use, it didn't make any sense because I knew that different brass had different neck thickness. I ended up ordering bushings in .292, .291, and .290 for SSA brass and 6.5mm bullets. I measured 10-15 pieces of unfired ammo and the brass was all between 0.014 and 0.015 thick.

Most factory new brass in .308 mics around .014"-.015", whereas a lot of .223 Rem brass falls between .0105" and .0130", from my experience.

I usually use a ball mic and measure a piece at 12:00, 4:00 and 8:00 and get an average, then I'll measure a few pieces and confirm the first piece's measurement, for an overall average for that batch.

I don't turn my necks, so things vary a bit, but that's how I handle neck wall thickness when using/choosing bushings.

Chris

 

[former naval person]

Save your money. Get a body die and a Lee collet neck die, less cost than a bunch of bushings. Better ammo and less brass working. You'll have to (probably) full length size the fired brass in order to get it to fit your new chamber. Neck size them with the Lee collet die, then body size and shoulder bump with the body die. Bump just enough (size and try) until the sized case just allows bolt closure with minimal "touch". Lee collet neck size after that until you get noticeable closing force, then body size again to bump the shoulder. Usually 4 to 5 firings. See the recent post on "Two step case sizing" in this forum.