223 AR15

[Ian]

Agreed it's tough to get those .22s hard when quenching because of their low mass. Mine heat treat in an oven/cold quench to 27 bhn after they age about a week if used straight. Water-quenching must be done very briskly from a very hot mould to have any significant effect, which you can get if you cast in a really big hurry and keep that mould hot.

I wouldn't add more than 25% Lino, if even that much. I think Fiver uses a home mix similar to Taracorp Magnum (92/6/4) in his .22s. I just use straight clippy weights and heat treat and have had decent results with the RCBS 55-grain mould, but I'm not pushing them as hard as a lot of folks due to not needing to cycle an action. My COWW get also come out harder than "web sources" as well as published sources, I think due to calcium content of "modern" weights. Air cooled straight come out about 13-14 bhn.

 

[fiver]

4% tin and 6% antimony.

there's a few way's to get there.
cut lino in half and add tin back.
buy some commercial bullets [not Lazer-cast] and add more tin.
or get close-nuff by cutting ww's 3 to 1 with lino and add more Tin.

I tried straight Lino-type at the first go round [I have 12 pigs of Lino and our local paper has buckets of Lino still kicking around [small towns are nice]
but since I had been using the 4/6 alloy for some other things I decided to give it a go.
it immediately produced smaller groups for me, at the higher velocity's.

terra-corp's magnum alloy is 2/6/92 and is pretty much the commercial casters alloy of choice, it just happens to be lino-type cut in half with pure lead.
back in the day it was easier to order what was being made in quantity then modify it, than try to order something custom made.
and once it was being used for commercial casting it become the standard for everyone else wanting to get into the business.

 

[Phil]

fiver,
I'll see if I can come up with something close to the 4/6/90 and give it a go. Maybe it will get rid of the 20% fliers.

I have also been wondering if maybe the fliers are shedding their GCs.

 

[fiver]

could be the G/C's but I'd bet it's weight anomalies.
the little guy's will fling outside the group with a weight variation as small as .2

 

[Phil]

could be the G/C's but I'd bet it's weight anomalies.
the little guy's will fling outside the group with a weight variation as small as .2

My notes indicate that when I first cast the little critters I did weigh them with about 90% showing < 0.1 gr deviation and others < 0.2. I have not weighted later castings.

I'll try the suggested alloy and weight the critters.

Thanks for the suggestions.

 

[300BLK]

Does anyone have any updates on their results, and particularly in the AR?

 

[fiver]

I'm still getting the same results as I was getting back then.

 

[300BLK]

I just cast some from an RCBS mould. The mould was on top of the Lyman 20# as it heated up and only the first cast was dumped into the sprue box. I made about 30 casts and had to take a nature break so put the mould back on the Lyman (with bullets in cavities), and then returned and resumed. I fluxed a couple of times and added in a couple of 1/2#, preheated ingots. The thermometer never varied more than 20*, and I was pressure casting with an old Lyman ladle. The total number cast was 166.
I weighed 83 (half), and no effort was made to segregate by cavity.

57.6gr (7)
57.7gr (21)
57.8gr (35)
57.9gr (17)

I think it a remarkably small spread considering, and particulary since there was no thermocouple or PID used. I quit weighing bullets years ago after seeing similar or better results in longer casting sessions with 350gr+ bullets, so tend to just give them a visual before sizing.

 

[fiver]

that's a bit heavier [1.2gr average] than I get from my rcbs mold.
probably a factor of the higher tin/antimony alloy I use.
if I try pressure pouring mine I get fins of alloy in the vent lines of the mold.

 

[300BLK]

Mine drop .225-almost .226" depending upon the cavity and where they are measured. I L&S in a .227" die as my throat will take a full .227" and it appears that I could seat the bullet to crimp into the middle band. That would be OK if just the lube ahead of the GC is adequate.

 

[fiver]

I seat so the lube groove is just barely covered.
most 22 cal rifles will accept a 227 diameter but I find in the AR type rifles sizing just a bit smaller helps them feed better.
your gonna jump across a throat gap anyway so a little more won't really matter.
the jump and the nose in front of the drive band taking the brunt of that jump is why I stepped up the alloy.

 

[300BLK]

By crimping into the middle band I can avoid "jumping a throat gap". I'll have to try it both ways and see what the rifle likes.

 

[Ian]

If you're shooting an AR having a little gap to jump may be inevitable. The SR primers have enough pop in that little case to breech-seat the bullet anyway, and using that to my advantage is part of what helped me learn to make them shoot straight. I found neck tension to be pretty important, particularly the uniformity of it, and honing out the resizing die neck to give me a .222-.223" neck ID before cleaning them up and belling with a .224" RCBS cast bullet expanding/flare die keeps necks concentric to the case body which is a critical step. If you use the factory FL die and crunch the necks down to .216", then drag the expander ball back through them to make them .220" or so, then ram a belling expander down in there for your cast bullets, you'll fubar the necks every time. With a .22 cal, it seems like every detail of fit is an order of magnitude more important because of the reduction of scale.

You may find that culling or at least sorting brass by felt resistance to the drag of the expanding/belling die spud will help your groups.

 

[Pistolero]

The Star top punch is 27 threads per inch. They sure wanted you to buy them from them! No lathe that I know will
turn a 27 tpi thread - although I imagine some sort of weird special end gear setup could be made to get it to work.

Bill

 

[KeithB]

Bill, I found this laying in a drawer in one of my machine cabinets. At one time I was working on making an adapter to allow a Star to utilize Lyman/RCBS style top punches. The item shown is 7/8" long, has been drilled and reamed to .265" ID, and is threaded externally to 1/2-27. I had planned to cut a slot across the face for a screwdriver blade. It was designed for my top punches, which had an O-ring on the shank to make them self retaining. Regular punches would need to be glued in or held in place with thick grease.

I only found this one piece, but I'm sure there is a small bucket of them somewhere in the shop. If you want this one I will be glad to send it to you, just hit me back with a street address or box #.

If I find the rest of them I will offer them to the members here.

 

[Kevin Stenberg]

Ian would the Lee collet sizing die be a good alternative to the standard sizing die squeeze and expand?
I wish I had an alignment gauge to check my loads.

 

[KeithB]

I have zero experience threading with lathes that require physical gear changing. But my Clausing Colchester 15" has 27 tpi threading. The first batch of adapters was run on my manual lathe, then on my CNC lathe.

CNC of course gives you virtually any pitch you want.

 

[Brad]

I sent Bill a copy of a chart I got off the Hobby Machinist site. It lists gear and gearbox settings that work on many lathes. Worked great on mine and I can turn 27 TPI any time I want.
My lathe lists some threads on the cover but many of the possible settings are listed. Probably a case of not enough room for that large a chart and likely little demand for some thread pitches.

 

[fiver]

Kevin.
the LEE neck collet is exactly what I use.
.0015 neck tension works for my AR's just [barely] fine.


this has the be the only place that has threads with 2 and sometimes 3 different conversations going on in them and nobody gets all bent out of shape about it.
usually half the participants are involved with both conversations.

 

[Ian]

Kevin, I have grown away from using the Lee collet neck sizing die but admit to never using one for .223. I prefer full and straight support so there's no chance an off-center flash hole will force the collet die to swage a neck crooked. I also like to just bump the shoulder (.002-3") and "kiss" the case body back for a clean drop-in fit in a dirty chamber, so I end up using a modified FL die anyway. All that matters is that your brass will fit your gun in a good way and hold the bullet straight, centered, and held with even tension, it doesn't matter what tools you use to get there. You don't need a high-dollar tool to check neck bullet or neck run-out. Just roll the brass or cartridges on a perfectly flat, clean surface (Granite counter top or scrap thereof procured from local installer works great) and your Mk-1 Eyeball can detect as small as half a thousandth discrepancy as the cartridge rolls.

Brad, Bill, Keith etc. I don't see why 27 NPT would be so difficult, it's the pitch of 1/8" national pipe threads. Might even be the same major diameter minus taper. Incidentally, 1/8 X 27 NPT is the threading Lee uses for their decapping pin lock nuts, though you can bet they use a pipe-thread tap to cut their resizing dies and farm out the tapered, split locking plugs to a high-production specialty outfit rather than cut the odd and tapered pitch on a lathe.