What is a small base die

[wworker]

Most of the time, I can find an answer in this forum by searching, but for some reason, the search function is working this morning.


Here's my question:

Some dies for .223 are labeled as small base and some aren't.

What is the difference?

 

[Ol` Joe]

Small based dies size a touch farther down the case wall/body, nothing more. Neither small base nor regular dies size the solid web of the case.

 

[rodregier]

RCBS description:

"The Small-base die set full-length resizes the case to minimum dimensions for easier extraction in lever-action and semi-automatic rifles."

The downside is that a small-base die will tend to work the brass more, which can reduce it's life.

I'm using "normal" Redding full-length sizing dies with the carbide expander ball upgrade for all my rifle brass resizing, including for semi-auto and lever gun usage. Gives me a satisfactory dimensional result w/o chambering issues.

 

[DaveInFloweryBranchGA]

If you're sizing brass fired in your own rifle, you probably don't need a small base die. If you're firing brass fired in most AR15 chambers, you probably don't need a small base die

On the other hand, if you've just picked up a big batch of machine gun fired brass as surplus from the military or other clearing house, you probably need a small base die.

Hope this helps,

Dave

 

[steve4102]

Small based dies size a touch farther down the case wall/body, nothing more.

In most cases yes, but in some calibers it also sets the shoulder back a few thousands.

From RCBS:

Q. I see a Small Base Die Set listed for my caliber. Do I need these or should I buy a Full Length Die Set or Neck Die Set? How does each set differ?

A. The Small Base Die set is intended for use for ammunition to be used in auto, semi-auto, and lever action rifles so that the loaded round chambers and extracts easily. The Small Base Sizer Die sizes the case from the shoulder to the head of the case a couple of thousandths smaller than a Full Length Sizer Die. In certain calibers it also sets the shoulder of the case back a thousandth or two more than the Full Length Sizer Die. The Full Length Die Set or Neck Die Set is not normally recommended for ammo to be used in auto, semi-auto, or lever action rifles. The Full Length Die set is recommended for ammunition used in bolt action rifles, particularly for ammunition to be used for hunting. The Neck Die Set can also be used to produce ammunition for use in bolt action rifles. The Neck Sizer Die sizes only the neck of the case so it will hold the bullet firmly. It does not size the body of the case nor does it set the shoulder back. Neck sized cases will usually chamber for three or more firings, depending on the powder charge and chamber dimensions. However, over a period of time, a slight drag will be noticed when the bolt is locked. At this point, cases will need to be full length sized and the shoulder set back so they will chamber and extract easily

 

[wworker]

My primary rifle round to reload will be the .223 Remington.

I picked up brass from the range, so I don't know how the brass was used, in semi autos or bolt actions. Most likely the majority of the brass was from AR15's as that is what most of the guys at the range shoot.

That said, would it be beneficial to have both the small base die for the initial resizing of unknown origin brass and then use a full length resizing die for subsequent reloads on the brass?

 

[Slamfire]

All my .223's have commerical chambers and I use a small base die to size the base. Ensures better functionality between rifles.

I set my sizing die up using a Wilson type cartridge headspace gage. I size to gage minimum.

I talked with an RCBS rep about small base dies, he said their dies sized the case head .002" more than a standard die. In my experience they will also set the shoulder back more and need to be adjusted to fit with a case headspace gage.

As for overworking the brass, that is true if you set the case shoulder back more than .003 or so on sizing. And that is regardless of small base or standard die. My case life has not shown any lifetime reduction due to the use of a small base die. But most of my chambers are commerical. Military chambers are large enough to park blimps in them.

 

[Idano]

wworker,

I can't say you would never get into the situation where you would need a small base die but for the majority of the reloading you will do I wouldn't recommend one. Remember the more you work the brass the harder it gets, which will result in splits. My recommendation is get your self the standard RCBS X-die, then trim your brass initially to 1.740" before you every run them into the die and you will never have to trim them again. I have some brass with 10 -15 reload on them and they still don't show any sign of splitting. I usually end up either loosing them or eventually the primer pocket will loosen up over time.