5.56 vs 223 Difference?

[Dixie Dude]

I was reloading some what I though was .233 brass last night and when I put the bullets in, the brass cartridge crimped on several that were military brass.  Is the 5.56 a little longer than the .223?  I was using .223 full length Lee dies.  I sized and decapped, cleaned them, primed, loaded the powder, then when placing the bullets, some crimped, and they were brass military rounds.  What gives? 

[yooper77]

OK, I don't see any where that you said you checked the trim length.

The military brass could be longer than the factory brass if you didn't trim.

If you have the die set where it doesn't crimp the shorter case, but when you insert a long case it crimps.

Check your brass trim length and trim all to the exact same length.

yooper77

[Dixie Dude]

I didn't realise that trimming would be that sensitive.  It is crimping right at and below the shoulder at the body of the cartridge.  The bullet is actually seating properly in the neck. 

[yooper77]

The die doesn't crimp the case at the shoulder, only at the neck.

It sounds like to me that the die is crushing the case?

Improper or no trimming can also cause high pressures to occur.

yooper77

[Dixie Dude]

I will check my case lengths.  Thanks

[Badnews Bob]

Milatary brass is also thicker that may be causeing some of your problem.

You say its crimping it? do you mean crushing the case some at the shoulder?

[Dixie Dude]

Actually right at where the shoulder meets the body of the case.  The actual shoulder and neck stay in place.  Bullet seats properly. 

[Badnews Bob]

sounds like your die isn't adjusted properly for those cases, You are crushing the case with the die, Back the die out a little and readjust the seater.

You may want to segragate the milatary brass from the civilian stuff and load seprately.

 The mil stuff will generate higher pressures with the same load as civ stuff so be careful.

[wncchester]

"Actually right at where the shoulder meets the body of the case."

I'm puzzled. 

Crimping is at the mouth of the case, pushing the case tightly against the bullet.  What is happening to your cases at the shoulder-to-body junction?

For a reloader, there is no difference between the GI 5.56 and .223 other than the GI brass is usually a tad thicker than most civilian cases so pressures may be a tad higher in mil cases with the same loads.  Not enough to matter much unless you are really pushing the limits.  We reload both cases with the same dies.

[Dixie Dude]

I didn't get to make the picture due some family sickness.  I will as soon as I can.  Like I said, it is not the neck or shoulder crimping, but the body right below the shoulder.  I did measure some of the remaining cases, some were a little too long.  That might be the problem.  Will try later.  I am not loading to max, The min is 23, the max 28 for this load, I am loading 24.6 with a dipper.  Should be ok, military was up the shoulder a little, standard was right at the base of the shoulder.  I am reloading 55gr fmj ammo.  If I were reloading hunting ammo, I would be more precise.  I adjusted my dies using a standard factory round.  Reloaded 50, 9 crimped.  Was a mix of military and factory, most was military. 

[yooper77]

I am sure case trimming and/or seating die adjustment is the problem.

Sounds like:
-the neck is crimping before the bullet is done seating.
-then when the bullet is still trying to seat the case is collapsing from the force of seating a crimped bullet.

yooper77

[Dixie Dude]

The neck and the shoulder look fine, bullet seats in neck to proper depth.  Just crimping the body of the case.  Never seen that happen.  I've seen necks and shoulders crimp from not being adjusted properly, but not the case body.  I am going to trim the cases to get the right length on the ones I have found to be stretched longer.  OAL is supposed to be 1.760".  I have them running over 1.77+.  It may be just enough to seat the bullet then press the entire bullet, neck and shoulder into the body causing the crimping.  Found about 1/3 of my brass to be too long.  I measured the rest of the case on some and was ok, just OAL of case. 

[wncchester]

"It may be just enough to seat the bullet then press the entire bullet, neck and shoulder into the body causing the crimping."

You should have NO buckles/bulges on the case body, at all!  A buckled or bulged case body is not a crimp.  Attempting to crimp cases that are too long can cause such buckling.   

Standard die crimping rings are quite demanding for a consistant case length, within narrow limits. So, try a new approach.  First, trim your cases to near the same length, within maybe 6-10 thousanths spread at the most. 

Back the seater die out a half turn and seat a bullet deep enough so the case mouth stops just about even, or a little less, with the outer edge of the bullet's crimp ring. Back the seater stem out a couple of turns and then turn the die body down until you get a visible crimp at the mouth, with no body distortion.  Then, leaving the ram fully raised, turn the seater stem down until it's in firm contact with the bullet.  That should do it.   

Then try to seat and crimp another round and see if it doesn't do right.  If not, tweak the die body or seater stem to make it right.

[yooper77]

Dixie Dude, i got a question?

What type of firearm is this being used in?

yooper77

[Dixie Dude]

AR-15.  If I had a bolt gun I might could squeeze these rounds in to fire.  Picked up about 500 rounds of brass at the range.  I was going to reload them.  I didn't think about trimming to resize. 

[yooper77]

OK, so you need to crimp the bullets for the AR-15.

If the cases are too long, and you forced it into the chamber it will spike pressures into a unsafe level, plus don't ever force anything.

Not trimming to re-size, you size then trim.  The case grows during the re-sizing process.

Are you also removing the primer crimps, before you re-prime?

yooper77

[Dixie Dude]

I ran them through the sizing die, decapped, trimed out the primer hole, put them in the tumbler to clean.  I didn't measure them before starting to reload.  I will trim to proper length, then try to reload again.  When it crimped at the channelure of the bullet, I think that is when it pushed down and crimped the body because the neck was a little too long. 

[yooper77]

You got it.

Good luck.

yooper77

[Lloyd Smale]

dont really know the answer but i know the same company will sell you both a .223 reamer or a 5.56 so they must be slightly different. I also know that bushmaster will sell you a gun in either the .223 or 5.56. I allways kind of guessed that it was a matter of the 5.56 having a slightly longer throat but im not sure.