5.56 NATO pressure for varmint loads

[Jake L]

I must warn you that I am not a reloader, yet. (someday). Through a search, I could not find an adequate answer. I am asking the questions about reloading simply for my education, and to complement the answers to my practical question. So here goes... skip to end for most important question.

For those folks reloading .223 ammo for use in 5.56 chambered rifles, is it common to load to pressures beyond SAAMI spec (~55,000 psi) and into pressures similar to NATO spec (61,000+ psi)? Would these loads exceed the max loads listed in the various manuals?

To be more specific, I have an AR-15 with a 16" midlength barrel and 5.56 chamber. I've noticed that true 5.56 ammo is often listed at velocities significantly higher than 223. Also, my rifle functions better with full-pressure ammo such as xm193 than is does with low pressure loads like PMC bronze. If I reloaded could I safely push vmax bullets downrange using NATO pressures instead of SAAMI?

And my final and most practical question. Are there any commercial 5.56 NATO pressure loadings with varmint bullets?

thanks all

 

[cfullgraf]

I don't reload to the listed maximums for 223 Remington data, somewhere below.

I cannot speak for others.

I do not buy much factory ammunition so I am no help there.

 

[rcmodel]

Pressure isn't what you need to look at.

NATO measures 5.56 chamber pressure different then SAAMI measures .223 Rem.
So the PSI difference is not comparable.

Powder selection is more important then Max chamber pressure anyway.

Hodgdon data lists several powders that will get you 3,300+ FPS at less then 50,000 PSI out of a 24" barrel.

Of course you can't get that in a 16" barrel, but you can't get that with 5.56 NATO ammo either.

Running balls to the wall reloads in used brass through an AR-15 is not a good idea.
Your best accuracy will usually be found at a safer & saner grain or two below Max anyway.

rc

 

[cmbrown]

i shoot alot of .223 ammo out of a ruger no.1 and a savage bolt gun. i mostly shoot at 200 meters(about 220yards) and have never had to go over safe pressures, my no.1 shoots on average about 1.25in and my savage shoots about the same. i am not telling you what to do but for me i worry about what's accurate at the distance i shoot. i also shoot a ruger sr556(piston driven ar-15) that has a nato chamber and have found that my gun shoots better with 50 grain bullets a little below max load specs. why beat your gun up if don't have too?

 

[45lcshooter]

I do not reload for pressure nor reload at the hot end of the table. I like to keep my brass on the reloading cans, not in the scrap cans. And to me running high pressures in weapons just seems not ideal.

Call me what you want but not late for dinner. I know what my rifles can handle, i dont go on the high end of the powder table because who knows where range brass has been. I used to have loooong range guns, but got rid of them so i dont focus on pressures, just looking as cases after fireing.

For my AR for varmint rounds, it slings 40gr bullets pretty good and fast.

 

[Hondo 60]

My AR is rated for 5.46 ammo, but I don't load above SAAMI 223 Rem pressures.
There just is no reason as far as I'm concerned.

My standard load is 26.0 gr of Varget with a 55gr fmj bullet.
(Max is 27.5 which is compressed)

 

[Jake L]

You all have made good points. It's nice to get a more practical view. A related question: I've heard of guys purchasing military ball like xm193, and pulling the fmj and adding a 55 gr vmax or something. Now this sounds super dangerous to me, but I thought I'd just ask you guys. Dangerous? Stupidly insane dangerous? Or just be smart about the way it's done and you're a-ok?

Personally it sounds like the most expensive way to make ammo... And it might not deliver accurate results... But how's the safety aspect?

 

[rcmodel]

Possibly dangerous if the NATO load is already on the top end of the pressure range.

The flat base V-Max bullet is shaped differently then the military FMJ-BT bullet.

55 grain FMJ-BT

55 grain V-Max

Although the weight is the same, the bearing surface & bore friction isn't.

rc

 

[MEHavey]

Probably more important, the resulting increased seating/shank depth required of the V-Max to meet magazine length restrictions raises pressures from NATO max of 62,400** to 68,000psi.





**
(depending on whose side you are on in the is-this-real-NATO/CIP-measured-pressure argument)

 

[mdi]

Even for varmit hunting, good results/bullet preformance is achieved well below max. pressures/velocities.

 

[moxie]

When you start reloading, start with loads that are in the mid-range. Then, once you become more familiar with the process, say after a few years or a few thousand rounds, get a chrono and dial in your loads to the velocity you want, using published data. You'll be safe.

The v-max in 193 rounds thing is, I can't say it here.

 

[ArchAngelCD]

.223 Remington max pressure = 55,000 psi.
5.56X45mm NATO max pressure = 62,366 psi.

BUT, that Varmint you're looking to shoot in the head will not know the difference between the two if you do your job so why would you want to load so hot?

 

[R.W.Dale]

.223 Remington max pressure = 55,000 psi.
5.56X45mm NATO max pressure = 62,366 psi.

BUT, that Varmint you're looking to shoot in the head will not know the difference between the two if you do your job so why would you want to load so hot?

The military uses a copper crusher to determine pressure (I believe its a guess compared to transducers) they're just lazily and erroneously referr to the resulting numbers as "psi" in the world of commercial ammunition testing that same number would be listed as CUP and therefore couldn't be directly compared to psi.




posted via that mobile app with the sig lines everyone complaints about

 

[ArchAngelCD]

From what I've read the military uses the number of 430 MPa as the pressure guideline limit which is why the translation is 62,366 psi. It's a strange number because the real number is 430 MPa. (It's not my fault the military likes Pascal lol)
(what I mean by strange is it's rare to see 62,366 instead of 62,000 or 62,300)

 

[MEHavey]

(It's not my fault the military likes Pascal )

It's not the US military that's enamored w/ Pascals. It's Europe/NATO.

More to the point, the European pressure methods/piezo sensors AND measurement location in the chamber yield different pressure numbers for the same cartridge.

The result is that instead of a two-body problem (SAAMI CUP and SAAMI psi), we now have a 3-body problem with the introduction of European measurement systems/numbers. This leads to blogosphere chaos.

I'd recommend people stick w/ SAAMI's 55,000psi.

 

[steve4102]

For those folks reloading .223 ammo for use in 5.56 chambered rifles, is it common to load to pressures beyond SAAMI spec (~55,000 psi) and into pressures similar to NATO spec (61,000+ psi)? Would these loads exceed the max loads listed in the various manuals?

Common? Not really. There is load data available for loading your 5.56 chamber to 62K psi. Following this data would get you safely into NATO pressure ranges.
http://www.ramshot.com/wp-content/uploads/2010/09/ramshot_handgun_rifle.pdf

http://www.accuratepowder.com/wp-content/uploads/2011/01/accurate_load_data_3.5.pdf

Following most all other load data will keep you in the 223 or 55K psi range.

If I reloaded could I safely push vmax bullets downrange using NATO pressures instead of SAAMI?

Yes, as long as you followed published data and didn't wing it.

 

[Jake L]

Thanks for all the responses. I've gathered the info I was looking for. I have no intent of loading vmax into 193. I was just curious about it. It looks like it is doable to load to 5.56 pressure, but often not practical or even beneficial. When I do get around to reloading, I'll stick to manuals. For now though, I just pay for my boxed ammo with arms and legs then save the brass for someday...

Cheers.