Starting COAL 223

[jLorenzo]

Just got a WOA 18" 223 wylde barrel, have Hornady 75s and Varget. With my old barrel 23.8 seemed to be the sweet spot accuracy wise. I was going to load 5 of each at 23.6, 23.8, 24 to get started. What COAL should I be starting at? I am still without a base to ogive measuring tool, just have calipers at the moment. I know COAL can be inconsistent. Will be looking to pick one up as well as a OAL length gauge. Which is best? Considering the curved Hornady but not too sure yet.
*I should mention I will be using Pmags, so is it 2.25 or 2.26 only anyways?

 

[spife7980]

Start at mag length.

 

[918v]

Make a slit case and use it to find the lands

 

[jLorenzo]

Make a slit case and use it to find the lands

Ive tried that with my .308 and it didnt really work out. Also feels weird thinking about chambering a case with the neck cut, potentially marring the chamber wall. Im going to buy a gauge I just need to figure out which one. Also as of now I am limited by mag length. Legacy Sports mag on the .308 and Pmags on the .223. Will be buying a Tikka Varmint in .223 to put in a Bravo and run AICS mags if thats the best mag option. Assuming those will allow longer COAL than Pmags.

 

[jLorenzo]

For now I am just going to throw a factory round of Hornady 75gr match in the seating die to set the seating depth.

 

[918v]

Ive tried that with my .308 and it didnt really work out. Also feels weird thinking about chambering a case with the neck cut, potentially marring the chamber wall. Im going to buy a gauge I just need to figure out which one. Also as of now I am limited by mag length. Legacy Sports mag on the .308 and Pmags on the .223. Will be buying a Tikka Varmint in .223 to put in a Bravo and run AICS mags if thats the best mag option. Assuming those will allow longer COAL than Pmags.

Marring the chamber wall with a brass case?

 

[jLorenzo]

Marring the chamber wall with a brass case?

You could easily scratch steel with a sharp brass edge

 

[spife7980]

You could easily scratch steel with a sharp brass edge

You won’t scratch your chamber with a slit neck.
Get your calipers out, measure the mag, seat the bullet to fit.

 

[918v]

You could easily scratch steel with a sharp brass edge

So how do you not scratch it with a trimmed case neck? You can’t. Stop being a pussy and do it.

 

[db2000]

Get a gauge if you can’t do it the OG way. They are finicky too so...
Also get a bullet comparator for your caliper and start measuring BTO and not COAL, which is inconsistent with OTM bullets.

 

[SporterII]

Seat a bullet mag length plus xxx
If it fits, run some mag length. Limited by mag length with that bullet limits this exercise. You will find that you need it all.

 

[308pirate]

Just got a WOA 18" 223 wylde barrel, have Hornady 75s and Varget. With my old barrel 23.8 seemed to be the sweet spot accuracy wise. I was going to load 5 of each at 23.6, 23.8, 24 to get started. What COAL should I be starting at? I am still without a base to ogive measuring tool, just have calipers at the moment. I know COAL can be inconsistent. Will be looking to pick one up as well as a OAL length gauge. Which is best? Considering the curved Hornady but not too sure yet.
*I should mention I will be using Pmags, so is it 2.25 or 2.26 only anyways?

Whatever will fit in the mag. Don't bother with distance to the lands. Don't bother with OAL gauges. You're way overthinking this.

This isn't benchrest

ETA: you do need a set of calipers. Even cheapos from Harbor Freight will do.

 

[308pirate]

You could easily scratch steel with a sharp brass edge

Maybe if the steel is annealed dead soft. And if your barrel is that soft you have bigger problems to worry about.

 

[308pirate]

Get a gauge if you can’t do it the OG way. They are finicky too so...
Also get a bullet comparator for your caliper and start measuring BTO and not COAL, which is inconsistent with OTM bullets.

He needs to fit the magazine. He doesn't need any of that shit. As long as the tips clear the front of the magazine interior, he's GTG

Holy fuck why does nobody read the OP in detail?

 

[308pirate]

For now I am just going to throw a factory round of Hornady 75gr match in the seating die to set the seating depth.

You don't have a set of calipers?

Reloading manuals all have SAAMI OAL for every cartridge they list, so why are you asking where to start?

WAIT......you DO have a reloading manual, right?

WTF..........ay madre de Dios!

 

[jLorenzo]

I do have calipers and said so in my posts.

 

[jLorenzo]

So other than backing off overall length from mag length and powder charge weight/type there isnt much else I can do to tune the load?

 

[oldiephrt]

That is a lot right there. 'less you single feed.

 

[308pirate]

I do have calipers and said so in my posts.

How about a reloading manual?

 

[Halfnutz]

So other than backing off overall length from mag length and powder charge weight/type there isnt much else I can do to tune the load?

No. Not really.

 

[Scttschnd]

I did a seating depth test when I was running the H75HPBT match in my WOP Kreiger service rifle uppers with wylde chambers
I found as I seated the 75 shorter from 2.25-2.245-2.240-2.35 in LC or PSD brass and 23.2 8208 the groups became smaller and more round to where a dime covered a five shot group
Fired from prone with sling position

Of course your barrel timing or node may be different but the Nosler 77 CC reacts the same while the SMK77 and Lapua 77 doesn’t care.
20” service rifle barrels

 

[spife7980]

So other than backing off overall length from mag length and powder charge weight/type there isnt much else I can do to tune the load?

Mag length becomes your max. That’s where I would start. But if you want to mag feed you have no choice but to start there and work shorter to tighten up groups with seating depth.
Maybe other mags will give you more space.

The 75 stuffed in for a normal plastic mag length is gonna be stuffed way in there deep. I have a wylde I use the 75 eldm in but in an aics mag bolt rifle seated .025 off the lands and I’m seated to 2.4xx” coal, waaaaaay beyond ar mag lengths.

 

[308pirate]

The Hornady 75 HPBT was designed to work just fine inside a SAAMI spec magazine. I shot thousands and thousands of them seated at mag length in the years I competed in Service Rifle and they provided stellar accuracy all the way to 600 yards

 

[spife7980]

The Hornady 75 HPBT was designed to work just fine inside a SAAMI spec magazine. I shot thousands and thousands of them seated at mag length in the years I competed in Service Rifle and they provided stellar accuracy all the way to 600 yards

Oh shit, I forgot about their non tipped offerings. That’ll fit much nicer than the eld my mind defaulted to.

 

[jLorenzo]

How about a reloading manual?

I have the Hornady one.

 

[jLorenzo]

I did a seating depth test when I was running the H75HPBT match in my WOP Kreiger service rifle uppers with wylde chambers
I found as I seated the 75 shorter from 2.25-2.245-2.240-2.35 in LC or PSD brass and 23.2 8208 the groups became smaller and more round to where a dime covered a five shot group
Fired from prone with sling position

Of course your barrel timing or node may be different but the Nosler 77 CC reacts the same while the SMK77 and Lapua 77 doesn’t care.
20” service rifle barrels

Thanks, this is the kind of info I'm looking for. If you were working up a load with 75s for a Wylde chamber where would you start with seating depth? I understand that they are all individuals. I'm right at 2.25 with my load developement rounds. Is it bad to run a already seated bullet back through the seating die to bring the coal back?

 

[pabrousseau]

Won't hurt anything to push the bullets in further.

 

[Molon]

Reloading For The AR-15: Hornady 75 Grain BTHP

Hornady produces three different versions of their 75 grain open-tip-match bullet in 22 caliber (0.224”). For this article, we’ll be looking at the projectile that is colloquially referred to as the “T1”.

The T1 is available as a reloading component, with a product number of #2279 for the 100 count boxes. It’s also available in 600 and 4000 count boxes.

I use the Hornady 75 grain BTHP bullet to load match-grade hand-loads for my semi-automatic AR-15s chambered in 5.56mm/223 Remington. According to Ballistic Performance of Rifle Bullets by Bryan Litz, the Hornady 75 grain BTHP has an average G1 ballistic coefficient of 0.356 and an average G7 ballistic coefficient of 0.183.

The lot of T1 projectiles used for this article have a nominal length of 0.988” and I load them to a nominal COAL of 2.245”. When fired from a Colt SOCOM barrel with a 5.56mm NATO chamber, this COAL will create a jump to the lands of 178 thousandths of an inch. When fired from a Larue Stealth barrel with a 223 Wylde chamber, this COAL will create a jump to the lands of 115 thousandths of an inch and when fired from a Krieger barrel with a 223 Remington chamber, this COAL will create a jump to the lands of 78 thousandths of an inch.

The jump to the lands figures stated above where obtained using a Sinclair bullet seating depth gauge and a Forster 223 Remington 1.4636” head-space gauge. These figures are contingent upon a variety of variables, such as the particular chamber reamer that was used for your barrel, the number of rounds that have been fired through your barrel when the measurement is obtained, the particular lot of bullets used and whether you use a virgin case, a fired case, a resized case or a head-space gauge to obtain this measurement.

WARNING!
Reloading is an inherently dangerous activity. The information provided here is for educational purposes only. It is not intended to be used for the actual loading of ammunition by the reader. No warranty, guarantee or assurance that these loads are safe is stated, suggested or implied nor should any be inferred. Usage of this information for the actual loading of ammunition may result in malfunctions, damage and destruction of property and grave injury or death to beings human in nature or otherwise. Don't even view this information in the presence of children or small animals.




For this hand-load of the Hornady 75 grain BTHP bullet, I use virgin Lake City brass that has been weight-sorted, match-prepped and neck-sized. The cases are primed with Federal GM205M primers and charged with VihtaVuori N140 powder and as mentioned above, the T1 projectile is seated to a COAL of 2.245”. This process is conducted in a semi-progressive manner on a Dillon XL-650 press using a Pact Digital electronic powder dispenser and scale to dispense a powder charge of 24.1 grains of the VihtaVuori N140.

When chronographed from a 20” Colt A2 barrel, a 10-shot string of this hand-load fired over an Oehler 35P produced a muzzle velocity of 2638 FPS with a standard deviation of 4 FPS and a coefficient of variation of 0.15%. (The muzzle velocity was calculated from the instrumental velocity using Oehler Ballistic Explorer.) A 10-shot group fired from one of my Krieger barreled AR-15s, at distance of 100 yards using my bench-rest set-up, had an extreme spread of 0.526 MOA.

No canines were harmed during the testing of this ammunition.

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