New cast bullet for the 300 Blackout

[Dolomite_Supafly]

As everyone knows by now I have embraced the 300 Blackout in full on retard mode. And in doing so I have tried every cast bullet "designed" for the Blackout and every single one of them sucks. I have been pretty disgusted with the cast bullet designs out there for the 300. On every single mold out there you have to load them to magazine length which can affect reliability in a standard magazine. You could seat the bullets deeper but then you expose the lube groove to the powder. This means in hot weather the lube will melt and contaminate the powder or it will be melted away during the process of firing. Either is a bad thing in the world of cast bullets.

On every cast bullet I tested, once I seated to a OAL of <2.20" the lube groove was exposed to the powder.

What did I do?

Well I decided to design my own. It allows me to seat the bullet to ~2.10" (depending on trim length) and still have no lube grooves exposed to the powder. This will make it more reliable in ANY magazine wihtout modification. It will also allow less powder to be used to get to the required pressures and velocities.

And about 2 weeks ago I placed an order for a 3 cavity mold using my bullet design.

And here are pictures of the actual mold:



Now I just need to settle down and cast some bullets. Then work on some loads. I have yet to get an actual weight but I suspect it will be close to 250 grains.

Enjoy!

[frogO2]

Very nice, thanks for doing this. Can't wait to hear the results, will be following. I am looking to cast as well been waiting to hear what works best.

[Jailer]

It will cast exactly at the weight for the alloy you listed when you ordered. Tom does some amazing work with his molds. I have a few and will be buying several more.

Curious, did you do a chamber cast or an impact slug of your chamber and throat? A good cast bullet design must fill the throat to be accurate. The dimensions of your gun should be the determining factor on the final design of the bullet. That's what's wonderful about ordering a mold from Accurate. You can order EXACTLY what you you need for your gun.

Very soon I'm going to be making an impact slug of my 300 blk chamber and getting a mid weight mold made for supersonics in my gun. The Lee 312-155-2R has shown promise but I do believe that a custom mold is going to be the only way to achieve the accuracy I'm looking for.

Get some of those cast up and post results, I can't wait to see how they shoot.

[L1A1Rocker]

What weight is that dropping at? It looks like the NOE mold with the bands moved up a bit, is that correct?

[Dolomite_Supafly]

It is NOT a NOE mold, it was made by Accurate. The driving band is higher than the NOE and the bottom lube groove has been removed.

I will be casting in the morning. After that I will post pictures of teh bullets in a cut away case to show where the lube groove sits. I will also weight them but as I said they are going to be close to 250 grains.

The original design was 240 grains but with the removal of the lube groove it will add weight. I do not see where he removed weight elsewhere.

Dolomite

[Ken73]

Anxious, very anxious. Looking at your modded Lee's and the unmodded Lee's along with the NOE design, and I see what you're getting at now. Makes perfect sense and hopefully this one will perform as you expect. All the others expose a lube groove or two to powder - what does that even do? Makes me wonder if that's what was causing the gas cutting.

[Dolomite_Supafly]

I ordered the mold as a .311" and the bullets are dropping at .31065". There should be no reason for me to size them. They are weighing an ACTUAL 244 grains using wheel weight lead. And just for comparison the MBC bullets listed at 247 are actually 238.

I will say that a brass mold is HEAVY. If I were to do it over again I would order a 2 bullet mold.

So here are some pictures of they "new" bullet design seated in a cut out case. The bullet is at 2.10" and in the upper most crimp groove. And most importantly it does not expose a lube groove when it is seated this deep.

I have about 75 waiting on their lube to dry then I will be shooting some for groups and try to work up a load.

At ~2.20" you will be in the second crimp groove without the lube groove exposed.

[Jailer]

Are you lubing the crimp grooves too or just the one lube groove?

Nice cut away, shows how designing your own has it's advantages.

I'm most curious now to see how it feeds with that .180 meplat.

[Whole Bunches]

This thread has me on the verge of getting back into casting, that plus my new TI suppressor can be taken apart for cleaning....

[Dolomite_Supafly]

I have shot about 100 so far and they run 100% at 2.11" overall length. I will say I did not load a full magazine and only ran about 5 at a time.