I'm a new gun owner and just took a course this past weekend.  I'll definitely need to get some dummy rounds to practice loading, unloading, and just holding up a long gun before I feel confident enough to shoot live ammo at the range again.  (I am female so my lack of upper body strength does not help at all.)  The ones we used in my course were Snap Caps with brass on the end, but when I look online for dummy rounds, I find not just that kind, but also a lot of 3D printed stuff.  Anyone ever tried it, and would it be advisable to buy?

Here are some photos from some eBay listings.  (These are not my listings and I am not advertising them.)  I would be buying 12ga but I've also seen 9mm.

https://www.ebay.com/itm/12-GA-Gauge-Dummy-Rounds-Snap-Caps-Shell-Shotgun-Training-Dry-Fire-Ammo/154281795070

https://www.ebay.com/itm/9mm-380-Auto-45-ACP-Dummy-Rounds-Snap-caps-Training-Rounds-Made-in-USA/264867714105

3D printed  dummy rounds are an unknown quantity.   They will probably work as good as anything, but Snap Caps have been around for ages. 

Huh, I've got a 3d Printer and never thought of printing snap caps.

If they're made from PLA plastic (the 9mm auctions says they are), then you're likely going to see that they wear away quickly at any place where they touch sharp metal under pressure (magazine lips, extractor edge).  PLA is not a very durable plastic.  If there are extreme feed angles in your firearm then it's possible they could hang up on edges or crack under vigorous feeding.

PLA also gets soft at relatively low temperatures, so don't use them in a hot firearm.

Other than that, I don't see any issues with using them.

1 hour ago, DirtyDigz said:

then you're likely going to see that they wear away quickly at any place where they touch sharp metal under pressure (magazine lips, extractor edge).

I was thinking that too but don't know enough about 3d media to have commented on it.  Although the shotgun dummies look more like a novelty, I bet they'd work okay, but the 9mm look like they'd leave shavings in the action that could cause problems if the gun weren't cleaned after. 

1 hour ago, DirtyDigz said:

PLA also gets soft at relatively low temperatures, so don't use them in a hot firearm.

So, I guess a 3D printed house in Florida is out then.  

3 minutes ago, Scorpio64 said:

So, I guess a 3D printed house in Florida is out then.  

Printed with PLA?  Yeah.  But there's lots of other "printable" plastics with much higher temps before they get pliable.

Would hate for a piece of plastic to break off and jam the gun up, never know what could happen or when.  

Snap caps are metal, much more durable. 

10 minutes ago, DirtyDigz said:

before they get pliable.

My wife loves Playa Bowl.

I have used the 9mm variety without a problem, although I expect some wear (and hopefully not tear!) the more  they are used.

OK, I decided I'd just bite the bullet (ha) and buy them so I could be a guinea pig.  After some use, I'll report back.

39 minutes ago, fihe said:

OK, I decided I'd just bite the bullet (ha) and buy them

Keep your cleaning kit handy.

I do a lot of 3D printing and would not put a round in a gun. The prints are a hollow honeycomb, the density can be adjusted. Solid printed rounds won't print correctly, they aren't stronger. Use real rounds and be careful.

Lyman makes good stuff:

https://www.ebay.com/itm/Lyman-A-Zoom-Dry-Fire-Snap-Caps-Rifle-Shotgun-Pistol-Revolver-Azoom-Dummy-Rounds/311919803627?epid=20015128865&hash=item489fde7ceb:g:VEMAAOSwKM1agxpr

 

If you want actual weight and look, I believe these are the guys I used years ago. All veterans....
https://jmspec.com/

 

On 3/2/2021 at 11:46 PM, fihe said:

OK, I decided I'd just bite the bullet (ha) and buy them so I could be a guinea pig.  After some use, I'll report back.

 

Looking at the description they seem to be reasonably designed:

"J.W.S Dummy Rounds are printed in high visibility yellow high strength PLA for the body with  a soft 95A durometer TPU material used for the primer. The color makes them easy to find when ejected and the PLA material is strong so they will last and the soft 95A TPU absorbs the impact of the firing pin."

 

As others have said, keep a cleaning rod handy, but they should be fine...

They won't hurt your gun, but I'll bet the case rims get gouged to heck in pretty short order. For shotgun fiocchi makes 3-gun practice rounds that use real cases and those still get chewed up. 

https://www.midwayusa.com/product/1018805265

Amazon has a ton of dummies made on brass cases with polymer inserts. I't trust them more than those 3d pritned ones, especially given the orientation they all seem to be printed in. 

 

 

 

Well, I finally used my dummy rounds today for the first time, despite receiving them in the mail weeks ago.  They're already getting worn.  Two got stuck on each other in the gun in a way that would have been very dangerous were it live ammo.  One also got a little shredded in my gun.  That is a piece of plastic that came off.

Don't buy 3D printed dummy rounds.

Have a good night.

Yeah that is pretty much what I expected the result to be. 3d printing is fine for making inserts to make dummy rounds out of bras or hulls, but not for the whole round. 

 

12 hours ago, fihe said:

Well, I finally used my dummy rounds today for the first time, despite receiving them in the mail weeks ago.  They're already getting worn.  Two got stuck on each other in the gun in a way that would have been very dangerous were it live ammo.  One also got a little shredded in my gun.  That is a piece of plastic that came off.

Don't buy 3D printed dummy rounds.

Have a good night.

Just by the quality of the print job itself I would not have even tried them in a gun.  Thanks for being the guinea pig though.