Recipe for .223 65gr Sierra GK in a 5.56 chamber and at 5.56 pressures?

[WillaminaOR]

I got some dies, powder (BL-C(2)), primers, and 65 gr Sierra GameKings. I've found reloading data that applies but it is all for .223 Rem chambers and pressures. Has anybody here tried a load for the higher 5.56 pressure rating? Might be able to get a few more FPS out of my fairly short AR.

Bryan

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[deadshot2]

What is 5.56 pressure? There's no SAAMI pressure spec for it, just .223. It calls for a max pressure of 58,500 PSI.

The "so called" 5.56 standard as outlined in TM43-0001-27, Small Arms Ammuntion Manual (US) states 52,000 PSI for the M-193 (55 gr) and 55,000 PSI for the M855 (62 gr w/penetrator).

You aren't going to get any faster ammo by searching out 5.56 pressures as the round is one and the same. The confusion over 5.56 and .223 has only to do with chamber shapes and the problem one can have with pressure spikes when a 5.56mm NATO round is loaded into .223 chamber with a shorter throat.

If you want higher speeds, you will need a longer barrel. You'll be better off by just using the suggested loads for AR-15's rather than pushing pressure limits. All you will end up doing for a few fps (very few at that) is to beat the firearm to death. If you do decide to go to the limit, just be sure to carry an extra bolt carrier group with you or at the very least a spare cam pin.

I would suggest that you just use the suggested load data for the .223 chambers, preferably as spec'd for AR-15's, not bolt guns. Then if you want speed, save up and buy a complete upper with a 20" bbl.

 

[Darkker]

Dead is exactly correct.
The pressures, if measured in the same place, in the same mannor; are the the same. The leade, or throat is the difference. NATO does not conform to SAAMI. The difference in pressure testing location, and often mis-quoted exceptions; is why people think that the pressures are different. The "individual round pressures" are allowed to be 60,000 psi on NATO ammo, the average working pressure is the same however. So is the brass, and the rest.

The problem with "data" that is for bolt guns is the port pressures. You can use bolt data for AR's, as the USUALLY longer throat will lower the working pressures. HOWEVER, if the port pressure is too high; then the action/BCG gets pounded, and wears substantially faster.

The velocity is a function of the barrel length.

 

[Varmit]

In the 49th Edition of the Lyman manual, there are some loads with heavier bullets as tested in a colt ar15 20" barrel. Also note that all their 223 loads are much hotter than any of the powder or bullet manufactures that I have seen lately. I have been using their loads with Varget and H335 in my Mini-14 and have seen no signs "excessive" pressure. I do get considerable flattening of primers when approaching the max loads, so be careful if you plan to do that, particularly if you use Lapua cases. I use LC cases.

 

[the4thshake]

I have tried and achieved 5.56 pressure loads.

You must use a primer with a thicker cup. I use Wolf or CCI 450. Normal primers will pierce at 5.56 pressures.

Work your way up slowly from 223 loads!

Use a chronograph.

 

[Darkker]

I have tried and achieved 5.56 pressure loads.

Unless you are using a Pressure Trace, or an Oehler. You have no clue what "pressure" you have achieved. Given that Cartridge Brass is spec'd at 85,000psi tensile strength. If you have been popping primers, or seperating case heads you are WELL beyond 60,000psi.

Not sure what you are calling "Normal" primers.... CCI 200's have a thicker cup than the 450's or "mil-spec" 41's. The difference (between the 41's & 450's) is in the length of the anvil. Having a shorter anvil(41's) provides less sensitivity.

Here is your homework assignment for the weekend:
Primers And Pressure

 

[Blitzkrieg]

Also the brass you use is vital.. is it military 5.56 or commercial .223?

 

[Darkker]

No more vital than any one individual component change

 

[deadshot2]

Unless you are using a Pressure Trace, or an Oehler. You have no clue what "pressure" you have achieved. Given that Cartridge Brass is spec'd at 85,000psi tensile strength. If you have been popping primers, or seperating case heads you are WELL beyond 60,000psi.

Not only that but how does one achieve 5.56 pressure loads, implying there is a standard that exists for such thing (it doesn't)

Perhaps this was a "mis-think" and the poster meant "speeds" but then again, there is no "standard" unless you want to accept the TM spec of 3025fps for an m885 (62 gr) load. BTW, that's measured 78 feet from the muzzle so the actual muzzle speed is higher.

One of he most misunderstood rounds is the 5.56/.223 as people don't realize that they are for all practical purposes one in the same. Not like the .308/7.62X51 NATO relationship that causes much knotted underwear.

 

[Blitzkrieg]

View attachment 45415

No more vital than any one individual component change

True but he only failed to mention the brass he is using

 

[WillaminaOR]

Well I didn't mean to go and abandon my own thread. Been keeping up but to busy to post back.

I didn't do much of any research before posting so I didn't know that there was no official pressure spec for the nato rounds, at least not one that can be directly compared to .223. I do still have to come to the conclusion that the nato rounds are loaded more powerfully than "plain ol'" .223 rem. The reason I figure this must be true is that they can achieve dangerously high pressures in .223 chambers and they just feel most powerful, in my rifle, even with the same bullet weight. How would one explain that if the nato is not loaded hotter than the .223? It stands to reason then if I am firing the rounds in a nato chamber that I could load my 65 gr GameKings to that more powerful spec, what ever it may be.

Bryan

 

[Darkker]

THERE IS NO SPOON!!!

The reason that "They CAN achieve high pressure" has ABSOLUTELY NOTHING to do with the Powder, OR Pressure-loaded to! PERIOD!! It has to do with a "standard pressure" load, but jamming the bullet into the lands....

The Original Spec, as delivered to SAAMI AND the military by Remington, was the same. During the development they found out that...ooooppppsssss! we can't get the quoted velocity with these powders and that heavier bullet. Fast forward about 3 years and they had a "re-do" where suddenly Remington claimed the military "Mis-read" the print, although they never said anything until getting called-out for not meeting requirements, then did the first of many twist changes....

The Throat, or the Leade is longer on the NATO chamber. UNLESS you have a horribly, horribly short throat(honestly probably under SAAMI spec) no STANDARD ball ammo(M855, or the M193) will Jam the lands. The other REASON that the leade is longer, is to be able to use sabot loadings and tracers, which are much longer.



If using Surplus ammo: The larger question is WHY did the ammo get surplus'd in the first place? If the ammo is up to snuff, would they be selling it? Not right now they wouldn't.

Please, do some reading that HAS pressure testing equiptment:
5.56 vs .223 – What You Know May Be Wrong - LuckyGunner.com Labs

For your history on the reality of the 5.56/223 and it's platform:

The Gun Zone -- A 5.56 X 45mm "Timeline" Prologue

 

[WillaminaOR]

I read the first link you provided, did you? In it, he states that the 5.56 round is often loaded to higher pressures than SAAMI specs would allow to satisfy what ever military ordered the ammo. Seems the article is more about the effects of chamber size and if you should be really worried about firing 5.56 in a .223 chamber.

Bryan

 

[Darkker]

No, READ the article, don't pick-out certain words. What he stated is: "Still, it is generally agreed upon that 5.56mm ammunition MAY be loaded to higher pressures."

The word is MAY, not IS, and NOT OFTEN.
And if you read it all he does pressure testing, where we see.......The same pressure!!

 

[deadshot2]

No, READ the article, don't pick-out certain words. What he stated is: "Still, it is generally agreed upon that 5.56mm ammunition MAY be loaded to higher pressures."

The word is MAY, not IS, and NOT OFTEN.
And if you read it all he does pressure testing, where we see.......The same pressure!!

Darkker, just remember the words of Dale Carnegie, "Those who are convinced against their will are of the same opinion still".

(actually a paraphrase of an earlier person:

""He that complies against his will,
Is of the same opinion still."

by the earlier Samuel Butler (1612-1660)"

People WANT to believe that 5.56mm Nato Ammo just has to be more powerful and therefore more pressure than good old .223 and can't accept the fact that their short barrels will always be short barrels. You can only get so much speed from a short barrel. I don't write the rules, that's just the way it is.

Situations like this is why the word phrase "Whatever" was coined. Just shorthand for "whatever you want to believe".

 

[the4thshake]

Unless you are using a Pressure Trace, or an Oehler. You have no clue what "pressure" you have achieved. Given that Cartridge Brass is spec'd at 85,000psi tensile strength. If you have been popping primers, or seperating case heads you are WELL beyond 60,000psi.

Not sure what you are calling "Normal" primers.... CCI 200's have a thicker cup than the 450's or "mil-spec" 41's. The difference (between the 41's & 450's) is in the length of the anvil. Having a shorter anvil(41's) provides less sensitivity.



Here is your homework assignment for the weekend:
Primers And Pressure

I used the term pressure because that is what the OP used. Velocity would have been a better term.

CCI 200's are indeed thicker than 450's......but just how are you gonna squeeze a large rifle primer in a small primer pocket?

 

[WillaminaOR]

The graphs on that linked page clearly show that the 5.56 rounds he tested (Federal M855), using his methods, in his bbls, with his equipment, are about 5,000 PSI more than several different .223 Rem loads in the same bbls, same equipment. That's not "MAY be loaded to higher pressures", that is 5,000 PSI more pressure than any of the .223 loads he tested. That is only one representative loading, are you inferring he randomly picked a HOT one? Or that those graphs don't show 5K more pressure for the nato loading he chose? I read all the text (article), and read the graphs too.

Bryan

 

[bballer182]

The problem I have with that article is the the loads used were 5.56 M855 vs. .223 REM 55gr. Anyone who reload know that you are going to see higher pressures with a heavier projectile.

IMHO the best way to have gone about that test would have been to use either M193 vs. commercial 55gr OR M855 vs. commercial 62gr. Its pretty much like comparing apples to oranges...

 

[WillaminaOR]

Anyone who reloads knows you'd see higher pressure with a heavier projectile seated over the same amount of powder. That's why charge weights are reduced, the heavier the bullet, so maximum allowable pressures are not exceeded.

Bryan

 

[bballer182]

Anyone who reloads knows you'd see higher pressure with a heavier projectile seated over the same amount of powder. That's why charge weights are reduced, the heavier the bullet, so maximum allowable pressures are not exceeded.

Bryan

I don't know why you are apparently taking offense to my post about a "study" or article that you didn't publish. I merely said I didn't like the way the experiment was conducted. It sounds like you are a very accomplished reloader and therefore don't need anyone's advice and pretty much know everything already thus nullifying the need for this thread. So why don't you just lock this thread and load 223/5.56 which ever way you want to and don't tell us what happens.