ar-15 5.56 and .223

Pistollero1050

I reload for a ar-15 in 5.56. My question is, Is it better to size to .223 or 5.56 using small base dies? I currently us .223 SB dies and some can be a little tight. I have never seen dies in 5.56. Any info would be great, thanx.

Mobuck

You won't find any "5.56 dies". Check previous topics on GB about the .223 vs 5.56 comparisons. Most if not all reloading data is geared toward the .223 but there are some manuals which list service rifle data for fast twist 5.56 chambered barrels. I load for 1/2 dozen AR's and 4-5 bolt actions using range brass and don't use SB dies. I've worn out a couple of LEE 223 sizer dies but haven't had a problem with chambering on any of the rifles. I use the bolt rifle with the tightest chamber to check fit when I start a sizing run and I do run a LOT of 223 brass. Right now I have 5 gallon of ready to load brass and another 5 gallon of sized brass and at least that much dirty brass waiting.

dcs shooters

Don't take a chance with just full lenth sizers for a AR. Get a small base die. The Lee mobuck uses might be a small base. He just doesn't know it, if it doesn't say it on the die.

243winxb

223 Rem dies are used for both. You are using SB dies. Your sized/loaded rounds should not be tight. Are you loading pick up/range brass? The web area near the head is not always sized fully, this leaves a fat case, larger in diameter. If your die is not screwed in fully, the shoulder may not be getting pushed back enough on Full Length Sizing. To correct this, screw you die in deeper in to the press, making hard contact with the shell holder/plate. Buy a Wilson case gage to check for correct sizing of the cartridge headspacing. quote: Lee Full Length die adjustment

When using our full length sizing dies for rifle cartridges, the die should be turned in to touch the shell holder and then enough more that there is no daylight between the top of the shell holder and the bottom of the die during the sizing process. This is the preferred method because the act of sizing sometimes results in flex that prevents the shell holder from touching the bottom of the die.

Lee dies are designed so that the shoulder of the case is not sized until the very top of the die has been reached. This is done for two reasons; first, we do not want the die to overwork your brass and second and more importantly, we do not want to invite headspace problems. Pushing the shoulder back too soon can create a situation that can eventually cause case separation and a dangerous situation.

If you notice that your Lee Die does not appear to push the shoulder of your case back, ensure that you are adjusting the die so that there is no daylight between the top of the shell holder and the bottom of the die during the sizing process. If you see daylight at the top of the stroke, readjust the die downward and repeat sizing until it disappears. If your case is still difficult to chamber, you can send the die back to us with a sized case and we can modify the die to minimum SAAMI specifications.

Lee Precision, Inc.
4275 Highway U
Hartford, WI 53027

Pistollero1050

thanx for the info. 243winxb you maybe correct, I have it set to just touch the shell plate but not take up the slack in the linkage of the press and it is mostly range brass of mixed headstamps. When I say tight sometimes it's hard to eject by hand.

243winxb

quote:When I say tight sometimes it's hard to eject by hand. If you chamber a round, then try to remove it without firing it? Then i would look at your seating die. There is a crimper in most. If you over crimp the case, the neck or shoulder will bulge. Turn you seating die out some, so its not crimping. No crimp is needed.

Pistollero1050

I use a Lee Factory crimp but also I will look to see if I'm bulging the neck on some even though I do case length trim. P.S. They work fine in my Mini-14.

cpermd

I reload and shoot about 12,000 5.56 each year.
Never have used a small base die.
I use a Sinclair case gage on about every 100th rd.

YMMV

CP

243winxb

Thats all the ideas i have, seating die bulging the shoulder. Maybe the shell plate is keeping you from pushing the shoulder back far enough for the AR, if the AR has a tighter chamber then the Mini. See Photos here on how to measure a Dillon Shell plate. http://forums.accuratereloading.com/eve/forums/a/tpc/f/2511043/m/4261005841

Pistollero1050

I do use a Dillon and the shell plate measures .116 just like in your link. So if its to thin I need to back off on the seater die?

243winxb

quote:Originally posted by Pistollero1050
I do use a Dillon and the shell plate measures .116 just like in your link. So if its to thin I need to back off on the seater die?
Maybe. And maybe back off on the sizing die also. Your small base die with that shell plate is possibly pushing the shoulder back to far. This will cause the brass to stretch. http://www.brownells.com/.aspx/lid=12897/GunTechdetail/Gauging_Success___Minimum_Headspace_and_Maximum_COL

Pistollero1050

Thanx guy's I give a try next time I reload.

FrancF

Your good to go- its the other way around that can lead to problems with 5.56 mill brass being thicker.

11 years ago I replaced my Colt Flat top 5.56 HB with a DPMS 20" .223 SSHB and no matter what I do, 5.56 brass will not cycle worth a darn.