.223REM / 75gn ELD-M

[CameronWilson]

Hi Guys,

I'm looking to try some Hornady 75gn ELD-M in my 223REM/5.56NATO rifle.

The Hornady Max load for N140 is 23.6gn (2,600fps), whilst the Vihtavuori Max load for N140 is 26.2gn (2,917fps)

Hornady is a 20" barrel, whilst Vhit is a 25"

Strikes me as being quite a large discrepancy between those loads?

[Richiew]

I’ve gone all the way to 25 grain and that’s a full case in a tikka t3 varmint 20” barrel. 2.3” case overall length. Worked it up from 23 grain and using magnum primers. 

[Laurie]

The Viht N140 data include the compressed load notation. Id say it is - and how! I doubt if you'd get 26.2gn in a Lapua case with the 75 ELD-M at 2.260" COAL!

 There are two issues here. The first is a generic one over chamber form, specifically freebore and throat angle. US loading manuals (with the exception of Sierra's 'AR-15 Loads Data' invariably use the findings from industry-spec test barrels and and chambered to the very restrictive SAAMI specs with a mere 25 thou' freebore and a steep (short) leade. This creates way higher pressures than most people's factory rifle barrels, and even more so commonly found Wylde, 5.56 and even longer freebore chambers.

Have a look in here:

https://www.luckygunner.com/labs/5-56-vs-223/  

As well as being an interesting read in itself, read the section on chambers specifically. Note in particular the author's words:

.223 Remington ammunition is pressure tested in what is called a “SAAMI Minimum Spec” chamber – that is, a “worst case scenario” chamber in this regard, made to the smallest dimensions, which would result in the highest pressures with any given ammunition. In reality, the likelihood of encountering such a chamber outside a testing lab is incredibly small. Many .223 Remington chambers will see maximum chamber pressures which are several thousand pounds per square inch (PSI) lower than those seen in SAAMI test barrels.

 

Hornady will undoubtedly use exactly such a SAAMI barrel and chamber. Viht as a CIP member will use that organisation's specs and the CIP pressure measuring method and ceilings which aren't directly comparable. (US companies are working to 55,000 psi MAP measured on the case-body mid point and CIP 62,366 psi on the case-neck (same methodology and pressure ceiling as NATO uses for the 5.56X45mm).

So, there's a bit of apples and pears here.

Case-fill levels aside, some of Viht's recent additions have been to my mind and experience 'dubious' to put it euphemistically.

See:

http://www.targetshooter.co.uk/?p=3856

 

with the 77gn SMK in Lapua brass (same as the Viht data). BUT note that my rifle uses a non-custom chamber with a very much longer freebore allowing a 2.400" 77gn SMK COAL (2.500-inch plus with the longer-nose ELD and its acetyl tip). Using QuickLOAD to model loads, it allows near 1gn higher charges than a standard SAAMI COAL and chamber. So my max 25.0gn N140 would be closer to 24.0gn in a standard barrel/chamber. QuickLOAD was right on the money with its predicted MV for my rifle's set-up and its 30-inch barrel at 2,996 fps predicted vs 3,007 fps actual from the 25gn N140, but says it produces ~59,000 psi in achieving it.

 

Viht's 25.5gn for the Sierra 77gn TMK and 26.2gn N140 for the ELD therefore look 'dodgy' to put it mildly. However, I reckon handloaders are pretty safe as I don't believe you'd manage to get those weights of powder into the case anyway, and certainly not seat a bullet to magazine length in most rifles.    

[Richiew]

From viht web go down to N135 and use less powder for similar high 2800s speed  . N 135 works fine with a Berger 73 bthp sub half moa .

[Scrumbag]

Also might be worth checking if Hornady is 5.56 / CIP commercial or SAAMI .223 Rem.

Looking at Hornady's app, the 5.56 load for N140 and the 75gr ELD-M is 24.8

[Laurie]

10 hours ago, Richiew said:

From viht web go down to N135 and use less powder for similar high 2800s speed

 

Again, I can't see how Viht gets its load in Lapua brass and the quoted 2.26" COAL with the 75 ELD-M. N135 is a lower density powder than N140. QuickLOAD (which is pretty accurate on fill-ratios) calculates 100% case-fill at just over 21gn in my Lapua cases (30.5gn water capacity fireformed). Using a reasonable length small-bore drop tube, you can pack around another 1gn into the case, but I just don't see how you'd ever achieve the quoted maximum of 24.4gn. The 75gn ELD-M is a long bullet with 0.55" inside the case when seated to that overall length. That sees 0.35" of bullet intruding into the powder space below the neck on this small and already constrained case.

I loaded the cartridge up to 24.0gn N135 with the 77gn SMK (BUT that seated right out at 2.400-inch for the custom long-freebore chamber). That was both a heavily compressed and HOT load that gave over 3,000 fps in the 30-inch barrel. QuickLOAD calculated PMax of a hair under 60,000 psi to achieve the velocity I got with 24gn of this powder. I wouldn't load up to this level in my rifle despite the extra freebore never mind Viht's still higher figure. 

[Richiew]

What about N540 24 grain with the 75 eldms this is another of my favourite loads . 

[Mat]

Yeah, don't believe the viht data, beyond about 22gr of N135 and you have serious powder compression at 2.260"

I've run up to 24.4gr but loaded at 2.394", chrono'd at about 2950fps but SD was rubbish at all 0.2 increments up to there so I gave up.

I hit the jackpot with 21.4gr / 2.260" with good SD and accuracy out to 600y albeit modest mv averaging 2659fps (20" barrel)

[Richiew]

On left 73 gr eldm , on right 75 gr eldm , both at 1.894” case base to ogive  . Case overall length is 2.3315” and 2.4295” respectively 

•  

[Richiew]

Richiew

Posted June 5, 2022

Latest info 

loaded some 73g bergers to 2.26” and 25 grain of n540, this was a good load earlier this year with no pressure signs  . 

[Richiew]

What’s your favourite 223 fox bullet .
try this thread on this forum lots of good info 

[Laurie]

47 minutes ago, Richiew said:

loaded some 73g bergers to 2.26” and 25 grain of n540, this was a good load earlier this year with no pressure signs  .

See how 25.0gn N540 performed for me in my F-Class rig with the 77gn Sierra MK

http://www.targetshooter.co.uk/?p=3856

[Durham Shooter]

I am still using up my 80 grain A Max, Vhit N140, 22.0 grains, C.O.L. 2.5 inches from a 1 in 7 twist barrel, ok for paper targets up to 600 yards.

[One on top of two]

On 3/20/2023 at 4:24 PM, Durham Shooter said:

I am still using up my 80 grain A Max, Vhit N140, 22.0 grains, C.O.L. 2.5 inches from a 1 in 7 twist barrel, ok for paper targets up to 600 yards.

What MV are you getting with that ? 

[Durham Shooter]

Never had chance to chrono yet, barrel stamped 5.56, using 5.56 cases Hornady service rifle data in edition 11 has them going at 2500.

[Richiew]

On 3/16/2023 at 11:40 PM, Laurie said:

See how 25.0gn N540 performed for me in my F-Class rig with the 77gn Sierra MK

http://www.targetshooter.co.uk/?p=3856

Hi there 

can confirm this was a good load and have read your articles on the mouse cartridge etc . Tikka 223 shoots 53 Amax , 55,60 ,70vld ,73 Berger and 77 lapua bullets very well with n135 , n140/540  . It’s just a matter of finding suppliers with actual stock. 
Thanks for the articles on powders .