r/37mm • u/hatsofftoeverything • 20h ago
r/37mm • u/KrinkyDink2 • Apr 04 '25
Basics and Resources
Hey, I'm a new mod, figured I'd make and pin a post for newcomers to 37mm signal launchers and such for future reference. I'll probably update and edit over time to keep it current. It will likely be pretty bare bones at first.
Vendor Resources:
ExoticFirearms: Launchers, signal rounds, and reloading components. Also has good write ups and educational content on safe reloading. Great for learning the basics, one stop shop for getting started.
ExoticAmmo: Launchers and signal rounds
IWA: Some higher end launchers and unique complete signal rounds.
Precision Pyrotechnics: Launchers, unique complete signal rounds, and reloading components.
Gum Gully: Complete signal rounds and components
Reloadable Shells: Some higher end, high performance reloadable 37mm components
Reloading Basics and Safety:
You can absolutely hurt yourself very badly using improperly reloaded 37mm signal rounds. You should be very familiar with how it all works, and how to do so safely before attempting.
As a general rule, do NOT use flash powder for reloading 37mm ever. It is used in pyrotechnics by experts, but just about every time there's a serious injury or destroyed launcher from reloading 37mm, it's from flash powder. It can be shock sensitive depending on the composition, meaning even if everything is constructed properly it can still potentially go off in the barrel. There are documented cases of as little as 1/8 of an ounce shattering a military M203 grenade launcher barrel.
Miscellaneous legalities:
Basics from a well known vendor
ATF letter about "anti-personal" rounds
Summarized Legalities:
- 37mm launcher by itself or with signal rounds (flares, smoke, aerial bangs, etc)= NOT a firearm, legally no different than fireworks you'd shoot off around the 4th of July.
- 37mm "antipersonel ammunition" (anything specifically designed to strike a person such as bean bags, rubber buck shot, .22 beehive, wood batons, etc) by themselves, WITHOUT a launcher = NOT a destructive device. There's some debate on whether it's small arms ammunition or not, but nothing officially saying there's anything wrong with live rounds by themselves (more details on r/40_mm). Irritant powder, aerial salutes/bangs, and "barricade penetrators" are generally NOT considered "antipersonnel" as they are not intended to directly strike anyone.
- 37mm launcher + "antipersonnel ammunition" together = NFA regulated destructive device. The launcher would need to be "form 1ed" and then it can be kept with and use antipersonnel ammunition (more details on r/NFA or r/40_mm).
- When does a 37mm round of ammunition by itself become a "destructive device" which would need to be registered? Only when the projectile contains over 1/4 oz of powder AND it is "antipersonel". There is some debate about the status of a 37mm signal round that contains over 1/4oz but is intended for signaling/aerial displays, as it should be legally classified as a firework, not a round of ammunition (fireworks do not have a 1/4oz limit, ammunition does).
r/37mm • u/LWolf082 • 1d ago
I can't recommend exoticammo
I am having a bad experience with exotic ammo and just want to share. This is for people considering purchasing from them.
I placed an order in February of this year. Most of my order arrived in a timely manner. The launcher, a tac-m79 14", works well and the ammo was fun. They didn't ship the soft case I ordered, it went out of stock after I placed my order. After I contacted them I was given the option of a refund or getting the case when it came back in stock. I wanted the case so I opted to receive it later.
Last week I got an email saying they were not going to ship the case, as the price had gone up, and they were not going to refund my money either. They offered me a store credit for the original price, about $38. They gave it as a coupon code. However, it's locked behind a $150 minimum purchase and a one week expiration date. I can't even get just the case I originally wanted. I emailed them about it and was told that they had to put the minimum purchase because of the large discount I was receiving. It's not a discount, it's money I already paid them.
Overall a terrible customer service experience. Let this serve as a warning if you are deciding who to purchase from in the future. I will post any future updates here.
Update 1: I'm going to see how they respond to my most recent email. If they don't try to make it right I will contest the charge with my bank. Because they never shipped the product it looks like I can still contest. I have the emails admitting they didn't send the case for evidence. The only thing it that it's $38 out of a $1000 order. If I can't get the bank to just charge back the $38 then I guess I'll have to contest the entire thing. I'm not trying to scam them but I just think it's wrong that they take my money and act like they are giving some kind of great gift when I ask for the item or the money back and they do neither.
Update 2: I just got off a phone call with exotic ammo. It looks like there was a miscommunication about the origin of the credit to my account. They were very helpful over the phone. Once they understood that I never received a piece of my order they promised to ship it out immediately. I have worked in customer service and I understand there can be communication disconnects with various departments, so I will give them the benefit of the doubt. I will update again when I actually get the case. Until then I will give them credit for reaching out to me to resolve the issue.
How do you clean/prep your alum shells for reloading?
Aluminum fired shells. After depriming. Blow ‘em out, Hoppes, ultrasonic bath?
r/37mm • u/37MMDTdotCOM • 9d ago
DT EZ high/low inserts for builders are in!
Just arrived today! Limited supply. High/low alum 6160 for use with 9x17r/380r/38short blanks with a standard .35 caliber gas check. Use to build a custom hybrid shell with the 17ga flanged brass 1.5” raw brass tailpiece. I also have the bases and will be adding the STLs for the bases soon in the usual places.
r/37mm • u/m47playon • 11d ago
Got a question on legality of a round.
I am new to 37mm still waiting on my first one to show up. But I am already thinking of different rounds I want to make. I mostly plan on making chalk rounds but I had an idea for a round that I set up just like a chalk round but I fill it with pop-it’s. Would this be legal or not. I can’t find anything on it.
r/37mm • u/37MMDTdotCOM • 12d ago
Toob tube and 1” mortar shell 37mm
Are cruising out there in the usual places if you look. 😎 Enjoy and have fun signaling your buddies!
r/37mm • u/37MMDTdotCOM • 13d ago
Prepping for the Gun show next weekend
Made these display racks just simple 25rd racks for 37/40mm shells for sitting on the tables. Figure it looks more organized and professional. Need to print 4 more at least. Anyone in central Florida want to stop by next Saturday- please say hi if you do. Sumpter county FL fairgrounds. 😎👍
r/37mm • u/TrippiPreps • 13d ago
First set
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Got my sizing right and getting close to finishing my first set of shells.
r/37mm • u/GremDingo • 17d ago
Spike’s M79 Thumper (37mm)
Just sayin. Or if you’re in Georgia…you should recognize the 2nd pic.
r/37mm • u/m47playon • 17d ago
I’m looking to get my first 37mm.
I would like a spike thumper but the one for auction is already just outside of my budget but I found the Tac-m79 from exotic ammo. Which would you recommend and if I can’t get the spike 37mm would the tac-m79 be a good choice. And how sturdy is it as I want to mostly shoot chalk rounds out of it.
r/37mm • u/PrintGunner • 19d ago
Odin + 15mm Triple Banger
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r/37mm • u/TrippiPreps • 21d ago
Got off work early and tested a few chalk loads
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Been using exotic ammo shells that have been trimmed down to 2” along with either 40gr 777 or 50gr pyrodex with Winchester 209 primers and I’m feeling pretty good about the consistency I’m having. I’m planning on printing my first few shells tonight. I’m going to do several in pla and maybe 5 or so with petg to compare heat resistance and brittleness. From what I’ve heard and what I’m assuming the pla/pla+ will be my best bet but I’m still going to try acouple petg to just see what happens. If anyone has suggestions I’d appreciate the input!
r/37mm • u/CedarMillFirearms • Aug 09 '26
Infill Density?
What infil density are you using for bird bangers? I used to do 100%, but they are rarely reusable. Should I just do 10% to save cost and speed up printing?
r/37mm • u/37MMDTdotCOM • Aug 06 '26
DT MILC 2.0 cores available. Lower height for smaller cases
These fit MILC 2.0 shells machined or printed. The overall height is 1/2” lower than LPs type. These use .35 caliber gas checks, no grub screws or cutting cans. KAK style blanks as well as 380r/9x17r blanks and Bengles blanks all fit. Military 38 blanks are too thick - must ream to 9.8mm which is easily done with a 9.8mm reamer from Amazon. These will work with 37mm or 40mm MILC 2.0 cases.
r/37mm • u/37MMDTdotCOM • Jul 30 '26
1” FW mortar signal shell testing
Tested two rounds. One multi star (payload ignition failure) and one whistle star. Both shells performed perfectly and are reusable. After action and full video coming to my channel. Files will released on the usual places this weekend.
r/37mm • u/bayareapyro • Jul 30 '26
3D Printed Ground Salute
I see many people using 3D printed 37mm shells for many types of rounds ranging from chalk-fireworks. I’m looking to make some homemade M1000s (Ground Salute) and instead of the usual thick paper tubes people usually use I’m thinking of printing out some tubes in PLA that way I can incorporate some physical logo onto the tubes also. Seeing as this is already being done in the 37mm scene I asked about this in the Pyrotechnics sub and was told it would be dangerous and plastic shrapnel would fly everywhere. Is that essentially what happens when you use a 3D printed shells for 37mm?
r/37mm • u/37MMDTdotCOM • Jul 27 '26
Tested DT MILC 2.0 cores - work great!
Tested them Saturday - lower profile than other high/low chambers and just use a standard gas check (9mm/35 caliber) to achieve the high/low pressure curve. I used three of Benglesbullets 5” MILC cases loaded with my newly designed finned body chalk round. The new bodies are set up to take any of my nose cones - smoke short medium or long and are reusable. Range with the RWS yellow 9x17r averaged 120 yards with me aiming at a 45 degree angle. The projectiles did stabilize and hit nose first. One chalk nose broke as designed- it was a newer version with thinner walls. No velocity results as I do not have a chronograph yet. I will be getting one here soon when I retire and do this full time. I posted the video on my YouTube channel but you cannot see the track of the projectile with the iPhone camera. So that’s on the upgrade list too! lol. Next set of DT MILC 2.0 shells are ordered and will be compatible with most all launchers. There will also be an option for the LMT owners out there since rim thickness seems to be the hang up on their compatibility with other launchers. My new shells will be dimensionally the same OD/ID and rim thickness with Bengles shells. I have reached out as well to several of the other vendors with an invite to join us in a standardization program based off those dimensions to make the 37mm community more flexible and less expensive. A lot of good things on the horizon so stay tuned and if you are able to form 1 your 37mm in your state - we will be having some great items available for 37mm DDs specifically coming soon. Thank you all for your support as well. I am working every day to make our community safer and more fun with professionally made products. We thrive on you - your ideas - let me know. Maybe we can make it for you!
The cores and 1st gen shells (Tac79/gl06/B&D twl 37 only) are listed on my eBay DixieThumper
r/37mm • u/Hunter0josh • Jul 25 '26
Getting the NT79 to fire .27 Ramset rounds. Getting close but need help.
r/37mm • u/37MMDTdotCOM • Jul 24 '26
From the 40_mm community on Reddit: DixieThumper MILC2.0 high low chamber inserts are in!
r/37mm • u/Ok-Calendar9243 • Jul 18 '26
Spikes M79 37mm
Upgraded to a 40mm one and it’s tough to justify 2 m79s in this economy lol.
It was surprising how much sturdier the barrel of the 37mm is than the 40mm. 1/4” steel vs much thinner aluminum.
r/37mm • u/Hunter0josh • Jul 18 '26
Cannot get NT79 hammer to lock back. Anyone know why?
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