223 to 300blk

[ducatilover]

Got my dies and plenty of 223/556 brass. Any tips before I start?

Sticking with converting my 556 bass for now.

[delta6]

Got my dues and plenty of 223/556 brass. Any tips before I start?

Sticking with converting my 556 bass for now.

PM.. magaskins.. he is the local guru on the BO cutting, sizing and loading.

[Old Jeff H]

I started to go into a really long post, but I thought I'd ask this question first: Are you looking for any sort of accuracy, or do you just want to mass produce shootable 300BO brass without a lot of worry and fuss?

[Bigfoot]

I'm not sure that 556 is good to convert. I think they say 223 is best. There's a another forum that has a long list of good brass for it.

As far as process goes, I watched and read several different ways. Here's what I do and like.

1. Form brass with sizing die and no decapping pin.
2. Cut brass (harbor freight) with mini chop saw and jig for brass.
3. Trim/chamfer/debur with Giraud Triway trimmer.
4. Size, prime, powder, bullet, crimp, done (Dillon 550)

[ducatilover]

Im just looking for no fuss ammo and then work my way to subsonic when the can comes in.
I watched plenty of videos before starting and gave it a go. I stuck with 556 and cut 100rnd. I will try 223 on the next batch. I did use the HF cutter and a zepreloading jig which worked perfect. Sized, trimmed. Was pretty straightforward and easy. Almost too easy to believe.
Now I just have to find some powder. I have plenty for 308 and 223 but nothing for 300blk.

[ducatilover]

Anyone have any experience with berrys 300blk bullets? Or should I stick with Hornady 30cal? Looking at 150gr for starters.

[Bigfoot]

Anyone have any experience with berrys 300blk bullets? Or should I stick with Hornady 30cal? Looking at 150gr for starters.

So far I've only loaded 308 in 125 grain Sierra JHP. Worked great. I've got some 150's to try next.

[Old Jeff H]

Ready for some of my blah blah blah?

I sat in front of my Harbor Freight saw last night and chopped about 100 pieces which I had already run through the 300BO sizing die (decapping pin removed). There are (3) things I don't like about this particular method:

1) Occasionally (probably 1 in 10 or so), brass will have a nick/dent in the area where the new neck is being formed. Because the brass hasn't had an expander ball or mandrel/collet pass through it, the dent will remain. This will be felt when you chamfer/debur, or when you trim with a Giraud as the neck isn't a perfect circle at this point. (You would also need to adjust the position of the Giraud cutting blade if you switched to trimming another 308 caliber cartridge as the diameter of the neck in the other cartridge will be wider. Probably not a big deal for most, but I also trim a lot of 308 Win and getting that cutter exactly where it needs to be is a PITA for me.)

2) You have to run the brass through a sizing die twice using this method

3) You can't trim the brass using a Lee trimmer as the inner diameter of the neck is too small to fit over the case gauge

For me personally, it's better to cut the brass before running it through a forming die.

300BO Sizing Dies

You really don't want to use the Lee full length sizing die for forming 223/5.56 brass. The tolerances are too loose, and Lee admits this. I have the Hornady dies and the RBCS Small Base dies and they seem to produce similar results and measurements

Parent Brass Choices

5.56 brass works fine/great, but that appears to be restricted mostly to brass produced in the US. Once fired LC seems to be the brass of choice for a lot of people. A compilation of which 223/5.56 headstamps work and don't work can be found here: http://www.300blktalk.com/forum/viewtopic.php?t=88599

Some of My Personal Thoughts

300BO isn't famous for its accuracy, but I believe it certainly can be (and some of the commercially available ammo IS). Thanks to help from some board members, I gathered up a few rounds of factory ammo in order to obtain headspace measurements. I also measured some converted brass I have. The variations were surprising, to say the least. If you decide you want to go a little beyond just plinking ammo, I recommend watching the following video. It's very well done, and he does an excellent job of explaining why most people get disappointing results from their 300 BO ammo (as well as what can be done to improve it.


My final thought is there has to be an easier/faster way of chopping 223/5.56 brass than the HF saw and jigs. (An RT-1200 would be nice, but good luck getting your hands on one) There are a couple of guys out there using homemade jigs and a table saw/band saw, but the way they've designed them makes loading/unloading them cumbersome and slow. I think I know something that would work extremely well, but it would require either 3D printing, obtaining a chamber reamer, or milling down an EGW ammo checker. Unfortunately, I have access to nothing to accomplish any of that.

[/end of Old Jeff H's BS]

[ducatilover]

Thanks for the info Jeff. I too cut the brass before sizing and ran them through the sizing die twice. I have some factory Ammo to compare and it was pretty close for pinkling.

Now I just have to find some powder.

[Old Jeff H]

Thanks for the info Jeff. I too cut the brass before sizing and ran them through the sizing die twice. I have some factory Ammo to compare and it was pretty close for pinkling.

Now I just have to find some powder.

Not sure how helpful it was, but you're welcome.

Is there a particular powder you're looking for?

[ducatilover]

Anything that will work. Not picky.

[ducatilover]

If load data calls for magnum srp can I get away with non magnum primers?

[Old Jeff H]

My thought would be to try standard SR's and see if they work okay (which I'm guessing they will).

[Bigfoot]

1) Occasionally (probably 1 in 10 or so), brass will have a nick/dent

2) You have to run the brass through a sizing die twice using this method

3) I have the Hornady dies

4) 300BO isn't famous for its accuracy

1) I have not had this happen at all. I've only run a few hundred so far, so time will tell I guess.

2) Since I use a Dillon 550, this is no biggie as put the expander ball/decapping pin back in and just run the progressive press as normal.

3) I have the same dies.

4) I'm not looking for sub MOA groups and I can blow the hell out of a B-8 size target standing off hand no problem. I am able to blast a soda can at 100ish yards no problem either.

Each of us have our own wants, likes, and needs.

[omegaman]

They make a jig for the harbor freight mini chop saw. If you have is set just right it works great (no trimming after resizing) and fast. I have found as stated above size it twice and your good to go. Never paid any attention to the brass brand or 223 vs 556 Loaded subs worked great with h110 and Accurate 1680 -w- 220gr