Found this article on gear scout. It goes into great detail about the 2 calibers. An article every shooter should read to gain some more knowledge.
Great link. Thanx for posting.
Interesting read. 5.56 vs .223 – What You Know May Be Wrong
That is the best article I’ve yet to seen on the subject. What I found interesting is that it contains no surprises.
Thank you for the link
Happy to share and be of help.
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Thanks for the link, that was a great article. It’s always nice to be able to cite fact, against speculation when you hear it.
Kudos for the link and kudos for the guy taking his time doing the tests
Really informative link, thanks. Gonna spread this one about on a couple of the other forums I frequent.
Nope no difference at all? I guess this picture is incorrect then - but I though pictures don’t lie!:rolleyes: Pay close attention to CASE OAL. Do you see the difference? Same bullets -55gr FMJ’s .
Threads merged due to exact same content.
I hope the tester continues testing several other .223 chambered rifles including both bolt action and semi-auto ARs. Having a test sample of only one .223 chambered rifle is a start but is it conclusive? Of course not but some people will interpret it as such. I know it would be a lot of time consuming work to sample more but I think testing a Ruger, Remington, Savage, Browning would give a better picture on what the pressures could be in common .223 chambered rifles. The pressures could be a little lower or the same or maybe a lot higher than the already max. + 10% pressure of the one test sample. It would have interested me to see the pressure curves of the various tested .223 ammo fired in the .223 chambered rifle to have a comparison. Like I said, hopefully this will be a work in progress.
ETA: Now finding people who would volunteer their rifles to be subjected to a possible destructive test procedure might be a very hard sell!
Andrew T did a great job on the article. He has more data, and is organizing it now.
Also thanks to Lucky Gunner for financially subsidizing his research.
I’m looking forward to his folow-up articles on the secondary pressure spikes. This will be interesting to say the least.
I know one thing – I’ll never fire Tula or Silver Bear ammo. Not in my gun, not in anyone else’s.
Since the secondary spikes are most prominent on the steel case ammo (the Tula and Silver Bear), my first thought was it might have to do with the case obturation qualities of steel vs brass.
Can you expound on why you feel that way?
The graphs of the data. These spikes indicate something is way wrong. Not sure if it’s the case material, a improper powder selection by the mfg’s or an improper primer selection. But these spikes shouldn’t occur.
Also consider running a carbine length gas system. We often assume pressure drop off is gradual and by the time the bullet passes the port, pressure is “x”. Well these graphs indicate that after so many microseconds, secondary spikes are occurring. Not sure how the elapsed time lines up with the bullet passing the gas port, but I’m assuming that with Tula and Silver Bear, your gas port sees a lot more pressure than a better load that features the steady, gradual drop off of pressure as time ellapses and the bullet transits the bore. Maybe it takes several milliseconds for the bullet to transit the bore (and one millisecond is 1,000 microseconds), so maybe it’s not a huge deal given this data. But I don’t like seeing secondary pressure spikes that nearly match max pressure.
Compare these secondary spikes to what was measured with the 855 loads. those are much more representative of a proper load as the pressure spikes early (as expected), and then dissipates steadily as time elapses and the bullet transits the bore.
The Tula/Silver Bear suggest an effect like SEE. When we see posts of AR kabooms, it’s more than just a slight overcharge, I’ve always contended that it’s secondary pressure spikes causing these effects. With a true case of SEE, the secondary spikes get huge, much higher than proof rounds. These Tula/Silver Bear loads look like they are partly on their way to generating these types of effects. At least that’s my takeaway of the data.
That could be attributed to a slight difference in the brass forming dies used by different manufacturers. It does not automatically mean that 223 Remington is physically different than 5.56 NATO.
The article did not say 223 and 5.56 load specs were the same.
The differences in the linked photo are simply difference in seating depth. Bullets seated out too far can cause pressure spikes, something every shooter should know and be aware of.
Before anyone starts jumping to conclusions on either side of the 5.56/223 argument, study what the article says and do some research to find out what it means.
Find out what affect chambers that are tight, nominal or a bit loose actually has on pressure. Find out how throat dimensions affect pressure. There’s some half-baked conjecture going on in this thread that is being passed as fact
From article one can get impression that 5.56mm NATO cartridge is not standardized:
While .223 Remington chamber dimensions and maximum pressures have been standardized by SAAMI, 5.56mm NATO dimensions and pressures have not.
It is true, considering SAAMI only. But 5.56mm NATO is standardized per CIP. Actually CIP uses same chamber sizing and proof pressure both 5.56mm and .223rem (CIP max pressure for .223 is little lower than max pressure for 5.56, but test pressure is same). However CIP pressure measurements procedure is different from SAAMI, so values can not be directly compared.
If barrel is CIP proofed or made to CIP specification it is safe to shoot 5.56 from barrel designated as .223. I even have military surplus ammo (Spanish Santa Barbara 62gr FMJ) that was reclassified from 5.56 to .223rem designation under CIP guidances (case base says 5.56 and NATO sign, case wall has printed ‘.223rem’ and boxes have markings “CIP .223rem”. Reason to do that, is because some European countries does not allow to sell 5.56 ammo to civilians, so it must formally be reclassified into “civilian” .223rem.
great read, learn something new every day.