.223 / 5.56 OAL

[11wideglide]

My Hornady book says set the OAL of .223's at 2.200 w/ trim length at 1.750 (55gr), while my Lyman book says 2.250 (same trim length), and all commercial ammo is around 2.245-2.255 with a case length of 1.760-1.770. Just curious for 55gr FMJ loads what is everyone setting their OAL and case lengths at for AR platforms? Thank you!

 

[BradMacc82]

For the AR, I normally trimmed to 1.750" (can normally get a firing or two before needing to trim again). And for 55gr FMJ-BT, I'd set the COL right around 2.245".

 

[dist1646]

2.25" OAL is pretty much standard. I just measured one each, LC 55gr ball and it is 2.247" OAL, LC 62gr is 2.253" OAL.

 

[outrider58]

Depends on the bullet and powder. I load my 55gn precision rounds out to 2.260. Brass to 1.760(max)
Hornadys 55gns run from 2.200 to 2.250. It all depends on individual bullet design and materials.

 

[DaemonAssassin]

Use the bullet manufacturers OAL data.

 

[Doco Overboard]

Some bullets will get good groups when they just touch the rifling. Reduce the load a few grains while allowing the gas to expand against the bullet before it moves. The lighter load will still allow the same velocity without excessive pressure. This is how I load for my ar with 55 gr bullets. This also restores some accuracy in vintage stuff with some throat erosion by selecting a longer bullet and then reducing charges of course. 2.252 with 23 gr of 335 is what works for me if I remember correctly My rifle has a 223 chamber. This is about as soon as the cannelure passes the case mouth with a Hornady 55g fmj with my set up.

 

[11wideglide]

Thank you all for the replies, sorry for the delay!

 

[Sharpeneddark]

Well, yes, the trim length should be 1.750 ish...unless you're Winchester. If Winchester made their brass any longer, they'd have to start putting rifling on the cases.

Pic of once fired Winchester brand .223 Rem.

 

[atblis]

The min case length per the SAAMI draing is 1.730"

I've found 2.26" to be too long for some magazines (pmags maybe). 2.25" and no problems.

 

[StickShaker]

Well, yes, the trim length should be 1.750 ish...unless you're Winchester. If Winchester made their brass any longer, they'd have to start putting rifling on the cases.

Pic of once fired Winchester brand .223 Rem.

Is that the measurement before resizing? 20 to 25 thousands growth is what I see from pretty much any brass fired with a semi-auto.

 

[Sharpeneddark]

Is that the measurement before resizing? 20 to 25 thousands growth is what I see from pretty much any brass fired with a semi-auto.

Really? That's interesting. I usually only see 1-3 thousandths of an inch growth from resizing. However, to answer your question, that was after resizing. Next time I get some once fired Winchester, I'll measure. Of that Winchester lot, though, most of it was hanging right around 1.760, this one piece was an outlier.

 

[StickShaker]

Really? That's interesting. I usually only see 1-3 thousandths of an inch growth from resizing. However, to answer your question, that was after resizing. Next time I get some once fired Winchester, I'll measure. Of that Winchester lot, though, most of it was hanging right around 1.760, this one piece was an outlier.

Sorry, I often use too few words. What I meant was, If I measure a fired case before resizing it's often .020~.025 longer than it should be. Since the one in your post was about that length I was wondering if it had not been resized yet.