What Dies for AR 15 5.56 Nato

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Dillon carbide! If you are going for match ammo, I would look at bushing dies.

Dillon carbide dies are for high volume loaders, those loaders who load enough to wear out a steel sizer die in short order.
 
I have upgraded to all Dillon dies for hand gun and for .223. They just run smoother on my 550b press. Carbide may be overkill, but I bet you won't wear them out!
Bushing dies are amazing! If you check the concitricty on fired rifle brass, resize and recheck, you should find they are not as true as before. As you pull the carbide button out of the neck, it can pull the case out of alignment. I have tried spray lube, polishing the button, ect.
Bushing dies avoid that. They may actually help true the brass up. They also have less resistance when sizing (at least on the up stroke). You can also change the neck tension by using different size bushings.
 
I have a set of "normal" RCBS full length .223 dies and I have never needed anything else. If you buy quality dies and adjust them correctly you won't need gimmick, ummm, I mean small base dies. (IMO of course)

There are enough different "standard" 223 Remington chambers in AR-15s out there that you can get into an accumulation of tolerances where a standard resizing die will not size a case fired in one rifle enough to fit a different rifle.

It does not happen very often, but I have such a combination of dies and AR-15 rifles.

The resizing die in question is a quality, standard, in spec RCBS 223 Remington sizing die. I do not have the same issues with a Redding standard sizing die.

So that I do not have to segregate cases by rifles, I small base resize all my 223 Remington cases and avoid the issue.
 
Bushing dies without expanders do make straighter case necks resizing brass than standard dies with expanders. Just don't be hyped into the marketing ploy makers of bushing dies claim. RCBS and Reddijng bushing dies size most of the fired case neck, but stop several thousanths short of sizing all the way to the shoulder. That unsized part of the case neck is claimed to better center the round in the chamber; an untrue statement. It does help centering before the bolt's closed on it, but the round's not fired with the bolt open.

Bottleneck cases headspacing on their shoulder perfectly center their front end in the chamber when something pushes them there to fire it, it's always the firing pin and sometimes an inline ejector pushing the case forward against the chamber shoulder when loaded. The case shoulder perfectly centers in the chamber shoulder; doesn't matter how much clearance there is between the case neck and chamber neck. The case neck floats clear of any contact with the chamber neck when the round's fired. Any amount of off center case necks will also off center the bullet relative to the bore.

Full length bushing dies don't center the sized case neck quite as perfect on the case shoulder as standard full length dies with their necks opened up to a couple thousandths smaller than a loaded round's neck diameter. The difference is small and typically isn't noticed until the rifle shoots ammo into sub 1/4 MOA groups at 100 yards.
 
Glad you added that. I like Lee stuff, and am about to get them to reload for an AR. Call me a cheapskate, (Well I do spring for the deluxe carbide versions) but Lee stuff has always done me right.

Russellc
 
Bushing dies without expanders do make straighter case necks resizing brass than standard dies with expanders. Just don't be hyped into the marketing ploy makers of bushing dies claim. RCBS and Reddijng bushing dies size most of the fired case neck, but stop several thousanths short of sizing all the way to the shoulder. That unsized part of the case neck is claimed to better center the round in the chamber; an untrue statement. It does help centering before the bolt's closed on it, but the round's not fired with the bolt open.

Bottleneck cases headspacing on their shoulder perfectly center their front end in the chamber when something pushes them there to fire it, it's always the firing pin and sometimes an inline ejector pushing the case forward against the chamber shoulder when loaded. The case shoulder perfectly centers in the chamber shoulder; doesn't matter how much clearance there is between the case neck and chamber neck. The case neck floats clear of any contact with the chamber neck when the round's fired. Any amount of off center case necks will also off center the bullet relative to the bore.

Full length bushing dies don't center the sized case neck quite as perfect on the case shoulder as standard full length dies with their necks opened up to a couple thousandths smaller than a loaded round's neck diameter. The difference is small and typically isn't noticed until the rifle shoots ammo into sub 1/4 MOA groups at 100 yards.

The partially sized neck can indeed help center a round in a static state, but the problem is the rear of the case. It doesn't matter if the front is centered if the rear is hanging down in a sloppy chamber.

Does the firing pint center the shoulder in the chamber? Sounds feasible, and why FL sized or new ammo can shoot so well, but I do not know this for fact.

My question would be can it center the rear by centering the shoulder, or will drag from the firing pin stop the case head from sliding to center, which should (Hopefully) be a short journey. I do not know the answer to this either.

I do know BR guns shoot well below 1/4 MOA, and I do know many of the top competitors used FL bushing dies cut with reamers with the bushing adjusted to size only part of the neck. This is how I sized my cases. This is on top of using tight necked chambers with the round barely clearing in the neck area and fairly tight in the rest of the chamber, all of which help center a round. If the firing pin pushing the round forward also tends to center the round, this has to be a good thing, as the less the round needs to move towards center, especially at the rear, the better the chance of the firing pin centering the round.

Thoughts?
 
For me it's the confidence factor. I have a lot more confidence in a loaded round with a runout of less than .002" then I would if it was .007" or greater. Even though I have measured many Factory rounds that were much worse than .007".

The price of a decent set of dies you only have to buy once, verses that flier that you are not sure if it was you or your reload...
 
I don't have small base dies & have reloaded 1,000s of rounds for my AR.

Not saying small base dies are worthless, just that I wouldn't bother unless I were having problems.
 
All of my 223 brass is unknown. I pick it up at the range. It's a private club. The police use our range for training so a lot of my brass was shot out of their AR's on auto. I size with a standard Lee FL sizing die and have never had any issues. I don't see the need for a SB die.
 
"...for .223. They just run smoother on my 550b press. Carbide may be overkill, but I bet you won't wear them out!"

I bet you're right. I also bet you won't wear out a steel die. Since carbide bottle neck dies require lubing same as steel, if your carbide dies actually "run smoother" than steel there's something more in play than just a very costly carbide sizer.

Adjusting "neck tension" with bushings isn't as simplistic or beneficial as some hopeful guys have been led to believe. There's a lot more to bullet grip than the outside diameter of the necks - or even the inside diameter for that matter.

Not a lot of experienced reloaders know how to properly use bushing dies and no noobs at all - not a slam, just a fact. Bushing dies incorrectly used - and from what I read on the 'net, many are - can leave case necks 'bent' about as badly as any others; straight necks just aren't as easy to obtain as saying "buy a bushing die" makes it sound. And saying it to a new guy suggests a significant lack of experience.
 
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"And saying it to a new guy suggests a significant lack of experience."

Was this intended as a slam? If so, let me say I am still learning but have been reloading for 35 years. Handgun, shotgun, and rifle. I use bushings for two calibers. 6.5 Grendel in an Ar-15 and .308 Rem.
I do use Lapua brass in both. The instructions that came with the dies explained how to figure out what size bushings to use. Have had no issues with them.
Would I use bushing dies to size cheap multi manufactured brass? I don't think so.

Stopping here.
 
Not a lot of experienced reloaders know how to properly use bushing dies and no noobs at all - not a slam, just a fact. Bushing dies incorrectly used - and from what I read on the 'net, many are - can leave case necks 'bent' about as badly as any others; straight necks just aren't as easy to obtain as saying "buy a bushing die" makes it sound. And saying it to a new guy suggests a significant lack of experience.
While I do not, and have not, ever advised anyone to use a bushing die for AR 15 reloading, bushing dies are are reasonably easy to use. Not rocket science, that's for sure. :)
 
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