Case length for 223

[74shovel]

I’m am currently loading a large quantity of 223. I am using once fired 5.56 military brass with varying head stamps that I picked up off a range back in 94 or so.

The brass measures 1.758 to 1.768 after full length sizing. My Lyman book calls for a max length of 1.760. I have been trimming this brass but have been thinking is it really necessary. This ammo will be used in a AR15.

What do ya’ll think? Is it really needed for this weapon system?

Also what is the max case length for the 5.56 round verses the Rem 223?

Thanks

 

[NuJudge]

Danger, Will Robinson!

You could have a gunsmith do a chamber cast and find out how much case neck your chamber will tollerate. A lot of chambers are cut to tollerate much more neck length than the books say they will. You could even measure it yourself with a material called cerrosafe, which is available from Midway and others:
http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=462291

If you're not willing to do that, play it safe and trim shorter than maximum. If you have a neck that lengthens overall case length more than your chamber will tollerate, I would fear slamfires and pressure excursions.

CDD

 

[Walkalong]

Trim to 1.750, after sizing of course.

 

[SSN Vet]

My one and only failure to feed that locked up a reloaded cartridge in my AR happened because I did exactly what you're describing.

I got lazy and didn't want to trim. So I measured them and only trimmed the ones that were over 1.760".

I didn't measure every single one, however, as only the Federal head stamps were even close to the limit. Or so I thought.

Why risk jamming up your rifle? Or worse yet, accidently chambering another round on top of the stuck one?

I have repented and hereby resolve to trim all mixed brass.

 

[Birdhunter1]

I trim all my brass to 1.752 and seat my bullet as long as I can that will still fit in my AR mags and I do not remember what that length is off the top of my head.

 

[Historian]

Birdhunter, OAL for an AR is 2.250" which is just a little under what will fit in the magazine. Some recipes say 2.20" but I have never had a propblem with the 2.250" length. Just remember if it won't fit in the magazine, it's too long.

Historian

 

[74shovel]

Thanks everyone I knew what ya’ll were going to say but I just had to ask. Will continue to trim. My trim length is 1.752. I hate trimming except when building match loads for the other rifles.

 

[kelbro]

Get a Sinclair chamber length gauge (plug) for about $6 and you will know. Many factory chambers are very generous.

 

[Walkalong]

Buy an RCBS X die. I am told they work great. I must get one myself.

 

[Uncle Chan]

I trim to 1.75 and load to 2.10 (to fit in my Mini-14 mags).

 

[Kernel]

Winchester News and Press Releases:.223 Rem VS 5.56mm
http://www.winchester.com/lawenforcement/news/newsview.aspx?storyid=11

I trim to 1.750" and check every case with a Lyman E-ZEE case-length-gage.

 

[Clark]

74shovel

I’m am currently loading a large quantity of 223. I am using once fired 5.56 military brass with varying head stamps that I picked up off a range back in 94 or so.

The brass measures 1.758 to 1.768 after full length sizing. My Lyman book calls for a max length of 1.760. I have been trimming this brass but have been thinking is it really necessary. This ammo will be used in a AR15.

What do ya’ll think? Is it really needed for this weapon system?

Also what is the max case length for the 5.56 round verses the Rem 223?

Thanks

Interesting you asked that.
I was up late last night with the same situation.

Do .223 cases really need to be trimmed from 1.76" to 1.75" ?

Headspace guage + (2) layers of .0015" shim = .003"
a)Ruger #1V will close, but it is tight = .003"
b) Colt will close on .005", but it is tight = .005"
c) Wilson will close on 0.0065", but it is tight = .0065"
d) Bushmaster will close on 0.008", but it is tight = .008"
e) Turk Mauser will close on 0.008", but it is tight = .008"

a) Ruger #1V chamber neck length from breech = 1.791"
b) Colt chamber neck length from breech = 1.789"
c) Wilson chamber neck length from breech = 1.789"
d) Bushmaster chamber neck length from breech = 1.786"
e) Turk Mauser chamber neck length from breech = 1.789"

taking the difference of neck space minus extra headspace:
a) Ruger #1V 1.791" - .003" = 1.788" useable neck space
b) Colt 1.789" - .005" = 1.784"
c) Wilson 1.789" - .0065" = 1.7825"
d) Bushmaster 1.786" - .008" = 1.778"
e) Turk Mauser 1.789" - .008" = 1.781"

Measuring a sample of my 8,000 rounds of sized but not trimmed .223 brass:
10% less than 1.760" and therefor need no trim per the book.
80% between 1.76" and 1.77" and there for need a trim per the book, but not per my measurements and calcualtions
10% are over 1.77"

What does it all mean?
I could potentially sort my brass and only trim 10% or only use 90%

I should add that I made a neck space gauge from a .223 case and a piece of free machining steel .248" in diameter. I turned down most of the rod to .224".
When I chambered the two, the rod is pushing into the case.
I eject and measure the length of the two.

The reason I subtract off the excess headspace is that is the distance that the case might be pushed forward by the firing pin.

My useable neck space may be from 1.778" to 1.788", but yours may vary.
I got an extra .018" of case length I don't have to trim.
YMMV.

 

[Clark]

I did more testing

CAUTION: The following post includes loading data beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The High Road, nor the staff of THR assume any liability for any damage or injury resulting from use of this information.


I sorted through ~ 50 of my 8,000 sized cases, and picked the longest one:
LC 01
1.771"
I loaded, fired in Ruger #1 V, and resized [should be .001" shoulder push back per Ruger #1] 13 times with .246" bushing in S die and loading with 25 gr Surplus bulk IMR4895 and 60 gr TAP moly bullet 2.26" [H322 like] ~ 66kpsi

After 12 firings, it was 1.786" long and some resistance closing on loaded cartridge but no resistance closing on resized case.

I fired it a 13th time, still resistance on the cartridge but not the case.
I took the case's picture.

What does it all mean?
The case is .011" too long.
I fire it 13 times with 11k psi pressure over SAAMI max average pressure.
It gets to be 1.786" long [0.026" too long] and starts to resist chambering.
That is close to where I calculated there would be trouble, but not the trouble I calculated.

The case looks good with all that over pressure, no trimming, no tumble cleaning, and full length sizing, huh?
I think so, I thought only neck sizing could have done this.