223Ackley IMP ?

[AWS]

So, I bought a 22 inch 223 AI nutted barrel from Urbanrifleman. Nice barrel, went on easy. I headspaced it with some Win White box ammo and I can size the fired brass with solid contact between a standard shellholder and the Lee FL die with just enough shoulder set-back for the bolt to close easily. All in all a great fit. Fire forming with the White box 45gr shot great.

Surprisingly 223 AI data is not that prevalent especially for 50gr bullets. I started with 50gr NBT(this is going to be a coyote killer) and 1gr over MAX for the standard 223 of Win 748 and loaded five each at 30gr, 30,5gr and 31gr. today at the range was windy, 20+mph and the first five rounds at 30gr went into a .351 group, with nicely rounded primer (Rem 7 1/2), easy bolt lift, the load seemed milder than the fireforming load. The 30.5gr load I pulled one out of the group but the four went into .451 and again seemed very mild primers still nicely rounded, easy bolt loft and no smears on the case head. So up we go to 31gr and it is just about a duplicate of the 30.5gr, pulled one and four in a .416 group and again seemed very mild with not a single sign of pressure. I'm 2gr over the highest max for a standard 223. How high can I go or am I in rarified air already but the case isn't telling me?

I discount the flyers as I'm 79 with arthritic hands.

 

[Mulligan]

So, I bought a 22 inch 223 AI nutted barrel from Urbanrifleman. Nice barrel, went on easy. I headspaced it with some Win White box ammo and I can size the fired brass with solid contact between a standard shellholder and the Lee FL die with just enough shoulder set-back for the bolt to close easily. All in all a great fit. Fire forming with the White box 45gr shot great.

Surprisingly 223 AI data is not that prevalent especially for 50gr bullets. I started with 50gr NBT(this is going to be a coyote killer) and 1gr over MAX for the standard 223 of Win 748 and loaded five each at 30gr, 30,5gr and 31gr. today at the range was windy, 20+mph and the first five rounds at 30gr went into a .351 group, with nicely rounded primer (Rem 7 1/2), easy bolt lift, the load seemed milder than the fireforming load. The 30.5gr load I pulled one out of the group but the four went into .451 and again seemed very mild primers still nicely rounded, easy bolt loft and no smears on the case head. So up we go to 31gr and it is just about a duplicate of the 30.5gr, pulled one and four in a .416 group and again seemed very mild with not a single sign of pressure. I'm 2gr over the highest max for a standard 223. How high can I go or am I in rarified air already but the case isn't telling me?

I discount the flyers as I'm 79 with arthritic hands.

The Sierra manual has 223AI load data.
I will go look

CW

https://sierrabullets.com/content/load-data/rifle/224/223-remington-ackley-improved.pdf

After looking at their published data, it appears the lawyers had a better day than the guy in the tunnel. Just saying,
CW

 

[urbanrifleman]

So, I bought a 22 inch 223 AI nutted barrel from Urbanrifleman. Nice barrel, went on easy. I headspaced it with some Win White box ammo and I can size the fired brass with solid contact between a standard shellholder and the Lee FL die with just enough shoulder set-back for the bolt to close easily. All in all a great fit. Fire forming with the White box 45gr shot great.

Surprisingly 223 AI data is not that prevalent especially for 50gr bullets. I started with 50gr NBT(this is going to be a coyote killer) and 1gr over MAX for the standard 223 of Win 748 and loaded five each at 30gr, 30,5gr and 31gr. today at the range was windy, 20+mph and the first five rounds at 30gr went into a .351 group, with nicely rounded primer (Rem 7 1/2), easy bolt lift, the load seemed milder than the fireforming load. The 30.5gr load I pulled one out of the group but the four went into .451 and again seemed very mild primers still nicely rounded, easy bolt loft and no smears on the case head. So up we go to 31gr and it is just about a duplicate of the 30.5gr, pulled one and four in a .416 group and again seemed very mild with not a single sign of pressure. I'm 2gr over the highest max for a standard 223. How high can I go or am I in rarified air already but the case isn't telling me?

I discount the flyers as I'm 79 with arthritic hands.

That seems pretty salty for 20 mph winds with a 50 grain bullet.

 

[alf]

A chronograph is a wonderful tool......

 

[AWS]

Yes, it is but it only tells you how fast you're going not if you're ready to destroy things.

our range, wide open and windswept. but nice solid benches

 

[alf]

Don't you have any data with your 22-204 with 50's & 748, they have about the same capacity.

Otherwise, when dealing with an unknown, I load one round at each increment, & keep going till I find pressure, & of course over a chronograph. Then I go back & shoot in 3 shot increments, not 5. If you're lucky, small groups & low extreme spreads coincide, which you can only see over the chrono. Only then do I shoot five shot groups to confirm & test at distance.

 

[Hal]

Aws

Great looking shooting bench.
Very well thought out.
Looks very stable and movable.

Hal

 

[Gary in MD]

I agree, you need a chronograph.
You should be able to beat the standard 223 velocities by 150 fps or so. Some guys beat it by more than that, depends on barrel length and how hard you are willing to lean on the powder measure.
I don’t use 748 in mine, so my loads and velocities won’t do you any good.
Good luck

 

[kelbro]

I have read that the 'Ackleying' of the .223 case can/will mask overpressure signs.

I had great luck with the 50ish gr bullets just over standard 223 book maxes but the 1:8 Shilen barrel really performed best with the heavier bullets.

My 243AI was scary how far it would go velocity-wise before I saw any signs of pressure.

 

[urbanrifleman]

I think I would call 30 grains a win. I think 28.5 is the standard max load for the 223.

 

[AWS]

I'm thinking the same thing, but it is scary how there is NO pressure sign a full grain over it. I usually load to pressure sign and back down to a safe load that gives long brass life.

As for the 22-204 I built it 20 years ago for one purpose, pelt hunting coyotes and developed one load around the 40gr NBT. Other than a brief dabble with a NBT Lead Free it has fired the same load for the whole time and does a wonderful job of killing coyotes, dropping them like a deflated balloon with one tiny hole, sometimes a bit of jacket will make it through the far side but never an exit. So no data for reference. The load is 30gr of 2230 under the 40gr NBT, 4000+fps from a rechambered Savage 223 barrel. It is still the rifle I pull out when when I get in a slump, it is so reliable, it wears a Sightron ll 1.5-6x40.

I'll load up 20 rounds at 30gr and stretch out the distance. I might try 31.5 and see if there is any signs there.

I do have a chrono from when I was doing some original wildcatting, but is was to let me know what I accomplished not to developed a load.

Brad the barrel is great. I think a 20P might be in the future.

 

[Homerange]

In the small case of even a 223 AI you would be wise NOT to increase loads in 0.5gr jumps.
0.2gr would be safer....just saying.....

 

[ELR LVR]

So, I bought a 22 inch 223 AI nutted barrel from Urbanrifleman. Nice barrel, went on easy. I headspaced it with some Win White box ammo and I can size the fired brass with solid contact between a standard shellholder and the Lee FL die with just enough shoulder set-back for the bolt to close easily. All in all a great fit. Fire forming with the White box 45gr shot great.

Surprisingly 223 AI data is not that prevalent especially for 50gr bullets. I started with 50gr NBT(this is going to be a coyote killer) and 1gr over MAX for the standard 223 of Win 748 and loaded five each at 30gr, 30,5gr and 31gr. today at the range was windy, 20+mph and the first five rounds at 30gr went into a .351 group, with nicely rounded primer (Rem 7 1/2), easy bolt lift, the load seemed milder than the fireforming load. The 30.5gr load I pulled one out of the group but the four went into .451 and again seemed very mild primers still nicely rounded, easy bolt loft and no smears on the case head. So up we go to 31gr and it is just about a duplicate of the 30.5gr, pulled one and four in a .416 group and again seemed very mild with not a single sign of pressure. I'm 2gr over the highest max for a standard 223. How high can I go or am I in rarified air already but the case isn't telling me?

I discount the flyers as I'm 79 with arthritic hands.

I think 28.0 grns of W-748 is the highest I ever took a straight .223
That was a worn barrel though that gave me 3500 fps with 50 grainers.
I will double check but I also believe I am using 27.0 W-748 with a .222 Rem
Depends on your bore condition, brass capacity, etc I would say.
---
That 30.0 gr 748 load looks really nice at the bottom there
Read the pressure signs - (Ejector marks and shiny swipes on the rim face_