best 123gr bullet powder??

[bbqncigars]

Initial load testing last Saturday showed my 20" BCA upper really liked around 30.0 grains of CFE223 behind a 123gr Nosler CC. COAL was limited by the mags. The five rounds of that load were all touching in a nice cluster at 200yds. My scope (first gen LRS-1) crapped out on the next loads (30.3gr). AAARGH! I'll load some more up and try later this week with a backup scope. I'm hoping some slight tweaking of the charge might reduce the group size, but 1/2MOA is ok with me. ;-)

[GeauxTide]

In my Alexander Arms, 123SST shot 5 in .3" under 30.0 of CFE223.

[LRRPF52]

One thing I've noticed is that if you don't have the compound throat, accuracy can be very temperamental depending on what powder, bullet, and seating depth combo you're using.

With the compound throat of a SAAMI chamber and a well-made barrel mated to the receiver tightly, it almost doesn't matter.

The compound throat allows you to pick a load and go shoot in most cases.

The downside is that if you get a barrel that was reamed on the end of a reamer's life that should have been replaced, you'll have early land engagement unless the chamber gets finish-reamed.

All my personal SAAMI Grendel chambers with the compound throat are fine, but I've had to finish-ream a few for others with my Manson reamer.

Some of the throats out there are so long, my dummy cartridge with a 140gr A-MAX loaded well past 2.400" (longer than the inside of the AR15 magazine well, way beyond mag restrictions at about 2.280-2.300" in most cases) still doesn't touch the lands, which is just stupid jump.

If you're experiencing finicky accuracy, I always look first at:

* Barrel quality (concentric, quality steel, concentric chamber, concentric threads, correct mate to the extension)
* Barrel assembly method and fit to the upper (loose goose, don't expect much beyond 1.5 MOA consistently)
* Trigger (heavy triggers will promote muscle tension to translate into unnecessary momentum from your finger into the rifle, throwing the shot)

With my very lightweight barreled 17.6" Lilja, I've literally rapid-fired sub-MOA 6rd groups at 1000yds, and it cuts ragged holes with 10rd groups at 100yds with CFE223.

It has a SAAMI chamber with compound throat that Bill A. cut for me personally for free. No matter what factory or hand load I've shot through the rifle, it has just shot out of the gate, consistently over the past 6 years.

All other compound throat, higher-end barrels have been the same way.

When I have tested parallel throat barrels with all the same assembly methods, the window for accuracy narrows considerably in most cases. I can still find a load, but it takes much more effort with loading or vetting different factory ammo.

[FW Conch]

^Question^... How long, in round count, can the compound throat be expected to last ? In general, on average.

[Lowell Higley]

I have been reading about the loads on here. I may be in error, but some of them seem hot. Pressure? I have been reading about pressure problems. I was reading that spherical powers, Winchester Ball popped into my mind, were more subject to pressure change due to temperature change than would the extruded Powder. H 4895 was mentioned.
Just a question.

[LRRPF52]

^Question^... How long, in round count, can the compound throat be expected to last ? In general, on average.

At 52,000psi and under chamber pressures, a long, long time.

Once you push over the 55,000-58,000 psi chamber pressure, depending on the steel, overbore, case volume, and shoot schedule, that's when you start to see more erosion kick in.

With Grendel, we have:

* Lower chamber pressure
* Not overbore
* Low case volume

With a Melonite barrel, you'll get more throat life on top of that.

The various stainless barrels from known sources tend to span the hardness spectrum as well, with some being really soft, and others very hard (Bartlein, Krieger).

4140 and higher Chromoly steels are a lot harder, which also makes them more difficult to drill a straight hole through when boring before the rifling process.

Throat life hasn't been an issue for me yet, and I doubt it ever really will be.

Les Baer had a Grendel with over 22,000 rounds through the pipe, still cutting 1/2 MOA groups like it was easy. Not sure if there was a velocity loss though, which is a better indicator of throat erosion's real effects before the bore is toast.

You end up with better throat life than in a .308 Winchester, primarily because of pressure and case volume.

[caleb90]

got 50 round loaded up with h335 in 3/10 incronments. just havnt had time to test em

[FW Conch]

Thanks "52", very informative.