300 blackout subsonic bullet mold options?

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newman0912
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300 blackout subsonic bullet mold options?

Post by newman0912 » Mon Jun 20, 2022 9:21 am

Hi. I've just started casting my own bullets and bought the Lee 230 grain .309 mold and following up with powder coating then sizing the bullets to .309. The bullet tip is pointed and loads perfectly into my AR15 rifle.
I'm focusing on subsonic loads - my suppressor is in the works but I don't have it yet.
I'm using CFE BLK powder, about 11 grains and this all seems to be working fairly well so far. I haven't had a single loading/cycling jamb, I'm getting pretty good accuracy and consistency at 50 yards, and it's been a lot of fun to start this new part of my reloading process.

I've been looking for another mold to try that's less weight than the 230 grain bullet, but the only options I see from Lee are all 'round nose' bullets. I'm concerned that a round nose bullet will not cycle in my AR15 - but I have no reason to say that because I haven't tried any.

Anyone have a suggestion on a mold for me to try that's maybe around 180 to 210 grains?
And, has anyone had success using a round nose bullet in their AR15?

Just for Information, I don't hunt, I don't shoot more than 200 yards, and I only target / plink practice.

Thanks!!!

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BJK
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Re: 300 blackout subsonic bullet mold options?

Post by BJK » Mon Jun 20, 2022 12:13 pm

It should be easy to take lighter bullets and make them subsonic... in a manually operated action. The AR CAN be manually operated. But in a gas gun the pressure curve needs to be such that when the gun gets the gas it needs to function and that means that enough pressure needs to be available at the gas port. It may be possible to get what you want, but the lighter the bullet the more difficult it will be and keep it subsonic. Maybe build an AR specifically to handle what you want? IDK. I'm just speculating.

My 300BLK build was built to run both heavy subsonic and light supersonic loads and it does that, but a subsonic light bullet load? I'm not even going to attempt that and think it will cycle the gun. Currently I'm loading NOE 225s with a gas check and they run fine and are almost subsonic (like being almost pregnant I suppose) it either is or it isn't. But with a slight drop in pressure they might be subsonic, but also might not function the gun since the same bullet w/o a gas check has slightly lower velocity and doesn't have 100% function. I'm leaving the load alone and allow it to flirt with supersonic velocity and keep the gas check on the base.

https://noebulletmolds.com/site/shop/bu ... cavity-gc/

Full disclosure... I do have a load for a lighter 158 grain bullet, just to use them up since the factory went belly up and I can't get more. If memory serves it pushes the bullet to 1400ish fps and cycles the gun. Nothing special about the load. I did load them down but brought the pressure back up to get 100% function.

I will load another lighter bullet, but for supersonic loads only in the 300BLK. The link is to the lighter bullet with a gas check, but they have one with a plain base. I have both so that I can experiment. I'd like to get 1600-1800 fps but I don't know if that's possible in a 10" barrel.

https://noebulletmolds.com/site/shop/bu ... gc-311414/

I'm going to take my own advice and while not a 5.56 or .223 and for a subsonic plinking load will either cast or buy light bullets to use in a Contender handgun chambered in .32/20 (.308 bore). I figure .30 Carbine bullets might work fine if I don't want to buy a mould.

OK, now I have to ask, and there is no wrong answer as far as I'm concerned, if you have a heavy subsonic load that works why the lighter subsonic bulleted load? Just curious. Again cycle the gun manually and it should be easy to do. Just start high and work down.

Do you have a chronograph? I think it's mandatory for what we do.

My $.02 worth. There are folks on the site who will have a better answer for you.

newman0912
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Re: 300 blackout subsonic bullet mold options?

Post by newman0912 » Mon Jun 20, 2022 5:48 pm

Thanks for the great response. My only reason to reduce the grain from the 230 grain bullet I'm casting now is that I've heard from many people that this particular mold I'm using is an SOB to get good fill with. So far, I've only accomplished to get about 60% 'good' bullets with no wrinkles, and 40% are substandard in my opinion. People call this cast bullet a "missle" because it's so big and long. So, I thought, maybe I should tone it down a little and try a lighter bullet, just to experiment a little.
With all that said, I believe a lot of my success problems are my own inexperience. I've got a lot of suggestions on how to pour better, how to get the mold 'hotter', etc. If I can get the success rate up to something more acceptable, I'll probably just keep using it and be very happy with the results.

The other thing that I wonder is... I watch a lot of Youtube vids on this topic. Honestly, I don't want to accuse anyone of anything sneaky, but I often wonder. With the magic of video, I wonder if the result they show are absolutely so great or if they hand pick some of the finished results and then start the video up again. I know, I know. Conspiracy theories, right? :)

Thanks again.

I love this hobby. I feel as though the 'art of reloading' is really the first step. But casting your own bullets out of what you dig out of the ground, and then powder coating and loading them? Well, I think that's another level of expertise (and fun) altogether. Right?

BJK
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Re: 300 blackout subsonic bullet mold options?

Post by BJK » Tue Jun 21, 2022 3:59 pm

OK, I'm glad I asked the question.

Get your mould hotter. Maybe get the lead hotter too, but you'll need to figure it out. You can even dip the edge of the mould into the melted lead to heat it up, but get the thing hot.

OK storytime. When the left was burning their cities on the left coast 3(?) years ago I needed some #4 buckshot and everyone was out of stock. That was my start in casting. I knew to get the mould hot, but I didn't know exactly what hot meant. That first try I had limited success, but better than I thought I'd do. I asked some questions on The Cast Boolit Forum and got the advice I gave you above. So I got the mould really hot and the lead hotter than I had it and my success improved immediately. Mould temp' is so important for that mould that I don't take nay breaks when I'm casting buckshot. I move fast to keep the lead going through the mould to keep it hot. I was happy that I learned to cast on possibly the most difficult thing there is to cast because everything else is easy in comparison. I'm not suggesting you cast #4 buckshot. I told you that to explain the importance of heat.

See why this mould needs to be hot? All those balls are connected by very small holes. Too cool and the lead doesn't flow. Hopefully the link works.
https://external-content.duckduckgo.com ... %3DApi&f=1

The bullet is steered from the base so that's what is critical. If the base is screwy I reject the bullet. I'm tolerant of creases above the base as long as they aren't too bad. But get the mould hotter and they should disappear. Oh, and again, work with lead temp' too.

Could it be oil contamination? Maybe. It'll burn off eventually. Use oil on the steel parts very sparsely. I put synthetic oil on a cotton swab and put a thin coat of oil on those parts. Be very cautious in putting oil near the bullet voids in the mould.

You'll get it eventually. There just aren't that many variables that can be changed.

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