I know nothing about 3D printing, but I've seen information about it online. Has anybody tried it?  Im not thinking large quantities, but 10 or 20 to try out an oddball cartridge.

What brought me to this is an 1860s Marlin vest pocket pistol in .30 rimfire I'm working with. I've made 5 reloadable rimfire cases, but the odd bullet size is a challenge. To date, I've lopped 3/4 of the length off a 7mm Mauser bullet. It works, but is not ideal. I dont want to spend $100 plus on a custom mold. I wont be shooting it that much. But the thought of a 3D printed heel bullet is appealing. It would be extremely light, but that's ok for a little plinking with this 150 year old pistol.

Has anybody done this? Online videos show people shooting them in modern guns, so they should work for plinking in old timers too. 

Does anyone have a 3D printer and want to try?

Steve

A polymer bullet will not give the required resistance for the
powder to burn decently. 
Another way to be able to shoot the 30 rimfire pistol would be
to get some round balls. Seems to me that a number 1 or 2 buckshot would work. Or maybe there is a suitable Lee round ball or buckshot mold. They are not expensive. 
beltfed/arnie

.30 rimfire bullet size is around .285" plus or minus a little depending on the source. There are no commonly available round balls or ball molds of this size. It may be a lot of work to design a 3D bullet, I have no experience with it. The .30 rimfire is my current project, but I also deal with other oddball heel bullet cartridges, so the technology is interesting.

moodyholler wrote on Feb 8^th, 2024 at 8:15pm:


Thanks, good to know there is another option.

Plastic don't shoot for crap. I was once looking for a way to conduct low-resource sustainment training for snipers using the German "Blue Plastic" they use for training in forest areas. By low-resource I mean no range, no safety personnel. Our barracks typically had very long attic areas with over 90 linear feet of possible shooting lanes. Because of the distance my intent was to conduct iron sight training with the Redfield sights on the M24 rifles. I set targets up at 25yds and fired over 100 rounds in 3-round groups. Grouping was dismal, typically two out of three would land close together while the third shot would go somewhere else. The flyer could be any one of the three shots and unpredicable. I gave up as I did not see any benefit to using the blue plastic since feedback to the sniper was in my mind of little value.

Hot glue, sounds like trouble waiting to happen. I can envision a barrel loaded up with hot glue that melted on firing.

A couple of tips I'll pass along, I wasn't making a lot of these but I was getting best results by filling the mold, then using my patented "black rubber forend bands"  to hold the mold handles together, set the filled molds in the freezer for 5 minutes and they'd fall out, on to the next.  A simple wipe down with powdered graphit and they were ready to go.
GT

There might be a technique adjustment, but a lathe might be able to turn a batch of simple lead bullets, finished up with some tumble lube?

It seems the 3D printed bullets got lost in the mail. He is going to print another batch and send them.  In the meantime, I went to the range today and tried out my five rounds of reloadable .30 rimfire ammunition using the cut down 7mm bullets. Here is a video of the fun.

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MANY years ago, I got from LEE some blank mould blocks, and cut some special moulds to suit a similar odd-ball requirement.   Don't know if they would supply them today.
CHRIS

Round ball the most often used simple loads in a pistol like yours. Cast with a proper mold is how the original was loaded and the best solution.

Low volume shooting, pure lead bullet, a bit too large for the bore, swaged to size in a simple shop made die & trimmed to length in the lathe would be my choice.

Plastic and 3D printing really most useful for complex shapes. Metal round projectile  so easy to shape with existing shop machinery no real reason to go 3D.Only plastics I have seen successfully used in bullets are primer or air propelled 

Opinion, others may differ 

Boats

I received the 3D and Lee 7mm soup can bullets. The soup cans will of course be cut way down and given a heel. I'll probably load one batch of each to try out in the Marlin. Then retire the little pistol to my collection.  Those remaining will be saved for the next little .30 rimfire pistol that follows me home 

I stopped at the range today and tried out the .30 rimfire 3D printed bullets. Check out the video.

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Indeed it is. Im also curious what velocity these 6.1gr bullets are moving out at.  Maybe another range trip to answer that question!