.223 Heavy Bullets.

[markm87]

What I meant by margin, was how close the line on the bullet that transitions from bearing diameter to ogive will stick out of the case neck when loaded to mag length.

Gotcha. If I trimmed my brass back to factory and the cases didn't have that pretty deep Giraud chamfer in them, there'd be no negative inset at all. I think there's a very tiny gap at the mouth due to chamfer on the case neck, but my eyes are getting older.

I run a Lee Factory crimp die set pretty light, but yes... a taper could cover this.

I am running the ammo as is in mag fed ARs with no issues.

Bottom line, mag length (2.25") is totally doable.

 

[jelenko]

What velocity are you seeing with the 85's?
What is the barrel length?

With the reduced amount of powder, I'm wondering what gain there is in ballistics.

 

[markm87]

What velocity are you seeing with the 85's?
What is the barrel length?

With the reduced amount of powder, I'm wondering what gain there is in ballistics.

I'm still working on a load, but we're at 2604 FPS out of a 23.75 Bolt gun (Tikka). We're seeing MOA accuracy.

I'm running VV N135. (I don't have my charge weight handy here at work)

The 85 RDF is really cool and a fun project, but honestly the extra weight and case capacity limitation about has it a wash compared to a mag length hot load with 77gr SMK or TMK.

Not relevant to the original AR question.... BUT I did load 5 RDFs to 2.335" with 23.5 gr of Varget, Wolf SRMs. Those shot 2705 fps and shot MOA too.

(groups all shot at 200 yard paper instead of our usual 100 yards to get a truer sense of accuracy potential)

 

[markm87]

Now when you go 85 RDF vs 85 Barnes Match Burner at 1000 yards?

The RDFs smoke the Match Burners in hit predictability and consistency. I love Match Burners, but they're best at 750 yards and in.

 

[markm87]

Found another load that's mag length

85 gr Match Burner.

22.3 TAC with Fed AR Match primer. 4 shot group (would have had 5 shots, but I shot the first round with the scope dialed for distance)