.223 reloading dies

Small Base Die--
The part of the die that sizes the body of the case
is slightly smaller in diameter
Used when the chamber of the gun is smaller than usual
( you have difficulty chambering a rounds )
( not normally used )

223 Die --
Is the caliber of the Die or Die set
Can be small base, full length, neck sizing or competition Die

Full length Die --
A normal sizing die is a full length die, it sizes all of
the case ( body, shoulder and neck )

Neck sizing Die --
Sizes only the neck of the case
normally only used in a bolt action rifle, NOT A semi automatic
Cases can be neck sized 3 to 5 times, then they need
to be full length sized
( old way of loading, with measuring tools available now
you can measure a case and set your sizing Die to an exact
measurement usually 2 to 3 thou smaller than your chamber,
making neck sizing obsolete )

Competition Die --
Die is made to closer tolerances than normal Dies
The sized case will be to exact specs. of that caliber
Competition Seating Die usually has a micrometer Dial to
seat the bullet to an exact length
 
Small base is used for range brass from what i see online. Never needed one loading brass fired in my 223 and 5.56 guns. RCBS make a small base set that taper crimps. I never crimped.
 
A small base die is also a full-length resizing die, just one that squeezes the lower part of the case just a little narrower than normal. I've never personally needed a small base set for any of my ARs but as was said sometimes range brass that was fired in a generous chamber might need it (at least the first sizing) to properly fit yours.
 
The part of the die that sizes the body of the case
is slightly smaller in diameter
Used when the chamber of the gun is smaller than usual

OR

Small base is used for range brass from what i see online.

Yes when the firearm that originally fired them had a larger then usual chamber . I get my brass from my local club that allows the Navy , coast guard and some local law enforcement train there . I had to by a small base die for a 500ct lot of LC-14 308 brass I bought . It appears the chamber these were fired from was quite generous and my standard die did not size them back down enough . Actually it did but just barely . The cases had a snug fit . Kinda felt like I had neck sized them but I'm kinda anal about FL sizing my cases to an exact .002 shoulder bump .I had never needed a small base die before so It took me awhile to figure out where the hang up was .
 
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In most cases a Small Base die is not needed. It does full length size the brass. If you used it every time your brass would give out sooner. It only needs to be used one time if you are not going to be firing it out of a machine gun every time. If that is the case your cases should be tossed after 3 reloads. Paper clip test on the ones that a range member fires showed head separation at 3 loads there was the tell tale ring about a quarter inch up the case.
 
I use 'Small Base' dies particularly on AR chambered brass.
All semi-auto chambers are pretty sloppy,
And AR-15s/clones are unsupported just before the bolt face, so the bottom of the case tends to bloat a little more than bolt rifle fired brass.

In most cases, 'Small Base' dies reach down the brass a little farther to control that bloat and push most of it back where it belongs, more or less...

Brass fired through a high rate machine gun (think belt fed) will most certainly need a 'Small Base' die to get the case back to some semblance of SAAMI case specification.
Machine guns have HUGE chambers and the brass gets blown out appropriately.

Sometimes you will run into a batch of brass that needs 'Rolled',
Nothing wrong with using two precisely located steel plates that roll the entire case sides back where they belong, between the plates.
Kills ALL of that bottom case bloat, then you can use about any SAAMI (more or less) dies to form up the brass tops...
 
Small base dies are also needed with early generation glock pistol brass as the rear of the case is unsupported..
Especially in the 40 s&w

As for my guns, I have never needed a small base die and I have 2 AK's, 3 AR's, and several semi auto pistols. Anymore most modern guns except belt fed machine guns won't need their brass small base sized.
 
Depends entirely on the chambers,
The current crop of AR clones with 'China' (who knows where) made barrels are a ballistics/brass nightmare for someone with a tight chambered rifle.

When you can buy 'Carbine' length AR barrels in bulk for under $30 each, you can't really expect much, and you don't get much...

The brass out of my chambers will usually fit right into most other AR chambers without resizing,
But I can't use any of the other brass without at least full length resizing, most times with small base dies...
And a bunch of 'Once Fired' brass I have to roll before it will fit my chambers...
I cut my chambers longer (more support) and tighter, closer to SAAMI specification, so blown out brass simply don't fit!

I know my early Glock .45 Brass had to be rolled before it could be used in my 1911 pistols, REALLY blown out at the base...
Good thing brass is easily shaped or I would have had to scrap a bunch of brass!

The rule is, if it chambers & fires easily, then run what you are doing,
If you have issues chambering what most others are doing, the. Its time for a little more work...

With me, its an accuracy issue.
If I can't hide a 10 round group under a dime @100 yards with my AR builds, then I blow them apart and start over looking for the problem...
Most guys won't worry about groups that tight, and they probably sleep better for it!
 
Your basic sizing die is the easiest, most basic, simple way to resize brass to fit back in most chambers.
Don't confuse a simple die resize with the brass being SAAMI specification, or the brass being back to factory specifications, because its simply not.

If a simple sizing die returned the brass to SAAMI specs, then there wouldn't be things like case rollers, ect to return the brass closer to SAAMI specification.

Its your basic starting point...
The next step is usually getting a press that will form the brass consistantly without stretching, deflecting, ect.
When a press/die take on a brass, either can win that show of force, the press usually wins, but not always...

The general rule amongst home reloaders is:
If the ammo fits/fires with little or no issues in your chosen firearm, then you don't worry about going any farther.
Kind of like finding your lost keys, you don't keep looking for them once you find them, so they are always the last place you look...

With some shooters/reloaders, they are looking for hyper accuracy, so no stone goes unturned...
The cases get the works, primer pockets, flash holes, necks trued, cases rolled, ect...
Not all of it works to add accuracy, but you never know what will add accuracy unless you try everything.
 
Rolling and small base dies

In reference to Jeephammer,
Rolling and small base sizing does not INCREASE accuracy, it just allows you to essentially "repair" cases that have been fire formed in a chamber with loose tolerances like belt fed machine guns or the older glocks... so loose that area near the head cannot be sized and they will not work in your gun. With my bolt action guns I neck size after the first firing which does in fact help enhance accuracy as the case doesn't have to swell as much.
 
Small base resizing dies are the only dies I use for all the different calibers I shoot. There are advantages in there use and negatives also. One negative. A Small base resizing die repetitive use will shorten case life and in some situations as in short necked brass case's. Increase their chance for neck separation. There benefit. Never a harsh cycling of cartridge into its chamber will their firearm and user experience.
The reason for there invention. To accommodate the fast cycling rate of Full & semi auto firearms.
 
Mine sized the base diameter down an extra .001 to .0015 on the cases that need it . Sometimes it may be .002 . I just know I was surprised how little it actually was and that it worked .
 
Accuracy comes with consistancy, starting with a brass that fits the chamber is your basic starting point...
Doesn't matter if the brass is exactly SAAMI or not as long as it fits the chamber.

On the other hand, if you have two or more rifles in the same caliber,
Or if you intend to reload for others (NOT RECOMMENDED!)
The idea is to produce SAAMI specification ammunition so its NOT UNSAFE when used in any/all of your firearms...

Since I shoot 'Service Rifles' I tend to stick with military calibers when I buy firearms, lots of available brass/loaded ammo, reasonable prices, just as fun as everything else to shoot...
Even more fun since premim rounds run me 25 to 45 cents a round, where pulling the trigger on something 'Exotic' can run $5 a round.

Since I have a rack full of .223 rifles, I generally try to restore cases to .223 SAAMI specifications, same with .308, ect.

Since I only have ONE .45-120 Sharps, those rounds can fit one chamber, and can be further off SAAMI specification.
 
Small base dies were designed for sizing cases from fully automatic guns, such as the SAW and M60. Fully auto weapons tend to have very generous chambers so there are no stoppages - at least to jammed ammo.
 
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