Should I buy small base dies when reloading .223 for an AR-15? I see MidwayUSA has them on sale this month, and I need to buy dies for my M&P15.

Tried do do a search, but I never seem to have luck using search on this board.

Small base dies are a must for semi / full auto rifles .

No. Small base dies overwork your brass and they are not needed at all for ARs.

I don't use small base dies.

This has been my experience. As long as you adjust your dies to properly bump the shoulder, I find my normal 223 dies work just fine for the AR's (many) I load for.

I have a set of small base dies on my shelf that I have never used.

I was wondering about overworking the brass. Thanks for the help!

Unless your chamber is oversize or your loads are too hot, you won't need them.

I’ve never used the sb dies in the 223 either. I used to have to use them for an m1 Garand that was extremely picky.

If you load full house loads & heavy bullets for your ar you won’t have to worry about over working the brass. The primer pockets will start giving out after the 3rd loading.

Likewise. i have found no need for small base dies in loading for ARs......or any other autoloader or pump. SB dies appear to be the solution to a problem that doesn't exist, but I can imagine that once upon a time there were some standard dies that were on the large side of tolerances that someone tried to use to load for an autoloader with a chamber on the tight end of tolerances and a problem occurred. A rare occurrence in my experience.

Not so for my brass. I have a batch going on 7x firings with no issues.

7x, what load/bullet are you using?

To the posters that are not using small base dies, are you using RCBS dies?

Excuse my lack of knowledge, but what are small base dies? I've reloaded plenty of .223/5.56 rounds using regular Hornady dies.

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'Merica!

RCBS Small Base 2-Die Set 223 Remington - MidwayUSA

They just squeeze the case a little tighter. That link says it applies a roll crimp too, which seems odd?

I have Lee and RCBS (standard) 223 dies and they don't leave a roll crimp. I just give the case a little kiss with the Lee FCD for usual blasting ammo anyway.

I've used the Dillon .223 dies and they work fine too.

Quoted from the Midway link above:
From what some old guys told me,...what RCBS means by this is that their small base dies do this as compared to THEIR regular full length sizer dies. Their regular dies are made for bolt, single shot and lever actions that can be forced more by the shooter and they do not size the cases down, or back, as much as other brands of dies because of this. If you buy other brands of dies you shouldn't need a small base die.

The roll crimp isn't odd as they are made for autos, semi autos, pumps et. el. and some people like to crimp their bullets in a cannelure.

Incorrect. I use a regular RCBS 223 die and it sizes plenty for both of my ARs. In fact, I don't screw it all the way down and do a minimal full length resize. Rounds drop right into both of the chambers in my guns.

Small base dies are a solution to a problem which 99% of people don't have.

I use the cheapo Lee .223 die set and never had any problems, and I load quite a bit of steel cases too. I have loaded some brass cases ten times before I stopped counting. I won't push my luck with steel cases, but they can usually be loaded at least three times.

I find that loading for the AR-15 platform is very easy and trouble free. Same with the AK-47. But loading .308 for the various semiautos has been a real nightmare and I have all kinds of sizing issues, even when using small base dies. I can't quite figure it out.

Dave Sinko

Now you are incorrect. The "old guys" worked at RCBS. Just because you don't have the problem doesn't mean the problem doesn't exist, it just doesn't exist in your case. Also, the AR 15 isn't the only semi auto rifle in use.

If you look at RCBS's die list, they don't list small base dies for 7.62X39 because their regular dies for this caliber are already small base. They consider it as an "auto" caliber and don't make a die for specifically for bolt actions.

If every AR 15 is able to use regular RCBS dies with no problems, especially with headspacing, then it might be a good idea to use them instead of their small base or any other brands of regular dies.

I am not using RCBS. After I determined my Lyman die would not provide an adequate shoulder bump unless I shortened the shell holder, I picked up a set of Redding dies. They are REALLY nice. I use a Lyman cartridge gauge to set my die for the shoulder bump.

The Lyman die I had worked fine for bolt action, but left the brass about the same dimension as a "field" AR headspace gauge. So I was having problems with the bolt not closing on some rounds.

My cheapy Lee dies work just fine in my Colt Match Target H-Bar

Almost all bullet seating dies can be set to crimp the bullet in the case, depending on the caliber it can be a roll or taper crimp. Some people prefer to crimp in a separate operation. i.e the Lee FCD. If you use the bullet seating die to crimp, trim length of the case is critical, as if you adjust too much you can crush the case, especially if it is a roll crimp. To crimp with the bullet seating die screw the die down to where it is touching the case mouth, on a empty case.(ram all the way up) Then insert a bullet, and adjust bullet seating depth. Now back out the seating stem about 4 turns, and bring the case back into the die, all the way up, and start tuning your die alittle at a time(about 1/8 turn at time) until you get a crimp, adjust to your needs or wants, heavy or light. Once you get it where you want it tighten the lock ring, now run your case back into the die(all the way up) and adjust your seating stem until it stops turning on the bullet. You're all set up up to seat and crimp in one step.

I bought RCBS small base dies back in the mid-70s when I got my first AR because that was the conventional wisdom. I used them once. They actually swage down the web area of the case. I didn't like the look of that. It seems to me to be a poor place for a cartridge case to be greatly undersized. I then tried the standard die I already had. It worked fine and always has worked fine since in many different rifles. I reload for other semi-autos in 30-06, 270, 308, 7.62x39, etc. Standard dies work fine. That small base die set was a waste of money and messed the brass up.

The justification for small base sizing dies that I have heard that may have some validity is that people were using surplus brass fired in machine guns with sloppy chambers. Brass springs back a certain percentage when withdrawn from the sizer die. Oversized brass may spring back enough that a standard die doesn't size down enough.

Just because Bubba who "worked for RCBS" told you something doesn't make it true. And we are talking about ARs here, not other semiauto rifles.

I need some help. Several weeks ago while running down the items I need to start reloading for .223 servicw rifle, I ran across a set of dies that were mixed from redding and Dillon. Sizing was the Dillon carbide, seating was a match Redding die, and I'm not sure who made the cromping die. I can not for the life of me find them again. Can anybody point me in the right direction. I know I'm cheap and don't want to buy things I will just put away. I already have a big pile of unused stuff and need not add to it :>)
Mike

I use a regular two die set from RCBS. No problems with my AR.

I use Redding dies for my AR and have had no problem. Also I got a shoulder bump gage from Sinclair International that is used with their bullet comparator body which attaches to your calipers. You use it to measure several of your fired brass from your AR with the primers removed to get an accurate reading of clean brass but not sized. This gage fits the shoulder angle of your brass. You then size your brass .003 to .005 less than the reading you got in the first place. You use the shoulder gage setup to check the brass as you set you full length sizing die until you have that .003 to .005 less than the origional measurement and you're good to go. I would also steel wool the shoulders on the brass to remove any carbon to get a truer reading. A pretty simple process really. Of course if you change guns then your readings will probibly be slightly different, but probibly close enough to work. Hope this helps!
Jim

I use RCBS regular base dies when loading for 4 AR-15 rifles, one M1A, and a half dozen Garands. Small base dies are not needed for military chambered rifles.

I use small base RCBS, loading for a mini-14. Never had any problems, some brass has been loaded 8x. A friend claims he uses the SB dies to avoid issues when the gun gets dirty after long sessions. I've never noticed a problem like that, although 150-250 is a normal run for me.

when full sizing for a few different ar15 5.56X.45 uppers or .223 rifles...