Cut down a CTL 312-160-2r Mold to make a ~116 grain SS bullet?

[dellet]

Th only thing that might be a problem is length and feeding.

A lot people have tried and failed with various 30 Carbine bullets. Your's will be close to the same size, but probably a better nose shape. It will be interesting to see what you get.

There might be a plated bullet closer to what you will end up with that you could try before cutting down a mold.

Or if you already have the mold seat the bullet to the length you think you will be and make sure it feeds

[GunFunZS]

Th only thing that might be a problem is length and feeding.

A lot people have tried and failed with various 30 Carbine bullets. Your's will be close to the same size, but probably a better nose shape. It will be interesting to see what you get.

There might be a plated bullet closer to what you will end up with that you could try before cutting down a mold.

Or if you already have the mold seat the bullet to the length you think you will be and make sure it feeds

Yeah, I've seen the failures with round nose 30 carbine bullets and knew to avoid that. Also the problem with 308 ball profile 147 grain bullets being possible to mimic the shoulder on a 556 and let dummies blow themselves up.

At this point, I think it is worth giving a try. My mold casts really cleanly for the 160 grainers. It is a 2 cav, so it's slower casting than I like. My debate at this point is whether I should mess up this mold, or just order a 6 cav and mess up that one. The whole point of 300 BO for me is cheap volume based action shooting. I can play at a lot more 2 gun and 3 gun stuff and get real practice time in with cast than is even possible with wolf 223. So a more efficient mold is definitely key.

This is all just a hold over for me while I develop the next phase, which is a purpose designed bullet profile. Unless someone else makes that first. (Which would be great.) It can serve as a good general proof of concept though and help generate load data, and give an opportunity to observe potential problems before cutting a custom mold. I also think if it works out well enough, that I could buy a bunch of mold blocks from LEE at a discount and face them down, and sell them on ebay or something. I can't be the only one seeking a bullet like this, and I think I could do a 6 cav for around the same money NOE, etc sell 2 cavs for.

The autocaster machine I'm developing will make the hand pour molds obsolete for me, but the CAD files for a custom design would come in handy, when it is time to make mold blocks for the machine.

[GunFunZS]

I got excited and drilled out the top of the mold to drive the pins.

It's getting cut tonight, most likely. Perhaps with testing later this week.

Here's a video of the first step of this project. I think I'll make a series of it and show the success or failure to the world.

https://youtu.be/tNnRmDuFoKs

[GunFunZS]

http://i.imgur.com/1SdePSU.gif

[yondering]

But I got a lot of lead in my BCG now. It seized the gas rings. Got that working now but need to get it out of BCG under the gas key.

And that is exactly why gas checks are needed for full power super loads in an AR, even with powder coating. I keep saying it, but people want to argue. BTDT

The bullet the OP is describing will do the same thing, if it's used in an AR.

Besides the lead buildup, accuracy deteriorates when the base is gas cut at the gas port.

[GunFunZS]

I used the full size projectile in a 308 AR variant, recovered bullets showed no signs of gas cutting. No residue was evident where the gas vented on the firearm.

Please convince me that this is a real issue, not a theoretical one, with quality PC and alloy hardness matched to chamber pressure. I would like evidence that my experience is not typical.

[dellet]

http://i.imgur.com/1SdePSU.gif

So what happened?

[GunFunZS]

http://i.imgur.com/1SdePSU.gif

So what happened?

Oh the horror, the horror.

Look on if you have a strong stomach.





I could polish this out, but I liked the jeweled look the gentle milling left.


Album:http://imgur.com/a/Texiq

Video of the process:

https://www.youtube.com/edit?o=U&video_id=tunnJHHM1AE

Okay, maybe I'm laying on the melodrama a bit thick, but here's the scoop.

I shaved down one less tumble lube groove than the original plan, by removing the amount I measured, which leaves 3 TL grooves instead of 2. So the projectile length is .802" and they weighed 124.5 +/1 .1 grain naked. They hand cycle nicely, both fast and slow, loaded in or out a bit from my projected OAL. A bit of paint showed no interference with the lands. I am particularly pleased at how clean the surface finish was for the machining, and that I trimmed at exactly the perfect depth to get a clean, semi bevel base effect from the tumble lube band. Exactly as I hoped.

I have the option of shaving the mold further to the original planned 0.789 if I need to still, but we'll coat these tomorrow and hopefully shoot them sunday. I know the lead won't have had the benefit of age hardening, but BHN should be in the neighborhood of 22-24 which is harder than needed. I don't think we have to worry too much about stripping the rifling as one guy on youtube was concerned about.

We'll see if I'm wrong. Or rather, since I don't have a practical way to catch the bullet, we probably won't. maybe a trash bag full of water?

[dellet]

That actually might not be a bad thing, you can have another try if this doesn't go so well. They look good in the pics, so they should work fine right

Being a YouTube guy I thought you would have seen this. It shows a bullet trap that probably all shooters have the stuff running around the house to make.

https://m.youtube.com/watch?v=DK0-ImFaSG4

[GunFunZS]

I completely missed that method.

I don't think I will get a chance to catch any bullets this sunday, but I should have a few test loads ready to go for tomorrow.

If the groups suck, then I will resort to extra complicated measures to diagnose the failure.

The loads I am anticipating are around 20k RPM in the 1-7, and 167,940 RPM and up for the 1-8. I think when I build my eventual pistol, I will be looking for a 1-8 barrel.