Loading considerations for open bolt SMG?

[Dan Forrester]

I would like to develop a load for my full auto MAC10.

The gun is a full size MAC but chambered in 9mm with an UZI mag well. Any special loading considerations for an open bolt?

I’m planning to load some of what I believe is Hornady’s discontinued #35597 which is a 147 FMJ encapsulated boat tale.

I have some blue dot in my inventory. This is the only powder I have on hand that I have 9mm data for.

Per the Hornady 7th Edition book it shows loads from 4.2 grains up to 5.7 for Blue Dot. Looking to load around 5.4 grains which should give around 950 fps.

Does this sound reasonable? I’m just working with what I have on hand for now for a trial run.

Thanks,

Dan

 

[FROGO207]

You just need to work up your load by inserting one bullet at a time to make sure there is no chance of another discharge after a possible squib. With my 45 caliber MAC10 the best function was almost at max. I bet you end up there as well. As a side note the BD works best and burns cleaner at higher pressure.
Also I seem to remember 9MM SMG ammo was manufactured on the hot side. Like +P territory.

 

[SingleActionAndrew]

FA with Bluedot Take a video?

 

[Dan Forrester]

Yes I have also noticed my gun runs best with hotter ammunition.

I worked up to around 5.4 - 5.6 grains blue dot shooting a few rounds at a time in my back yard. According to the Hornady book max is 5.7 grains so they are on the hot side.

They are not very quiet but are not breaking the sound barrier. According to the Hornady book they should be getting around 975 fps. At least that is the velocity listed in the Hornady manual through the S&W Model 39 test gun.

I’ve got 83 rounds loaded up. Will shoot them later today and report back.

Thanks,

Dan

 

[Dan Forrester]

Ok I fired off all 83 rounds and and it didn’t go so great. Here’s my observations:

• it seemed excessively loud. I had a sound suppressor on the entire time and the rounds were definitely not going super sonic but seemed unusually loud.
• Bright flash even some flames out the ejection port. I imagine the muzzle flash would haven really been something if I took the sound suppressor off.
• Unburnt powder on my forearm which is beside the ejection port.
• Thing was jamming a lot. I don’t think the bolt was traveling rearward far or fast enough to eject the empty cases. It was however traveling far enough to pick up the next round. So every 4-5 rounds I would end up with a fresh round in the chamber and a crushed case in the ejection port.

So I think I need a faster powder. I just made these up with bullets and powders I had on hand. It was also my first time reloading 9mm and the actual loading process went very well.

Any suggestions which powder to get that would be better suited to 9mm? All my powders are for revolvers. I do see in the Lyman cast bullets book some reloading data for 147 grain cast lead bullets with Bullseye and Unique which I have on hand. Just need to pick up some cast bullets.

Thanks,

Dan

 

[FROGO207]

I think you will get the results you want looking at the 9Mm +P data and use whatever propellants you find there.
I have had good luck with RedDot/Promo using 124 grain and heavier bullets both jacketed and lead in all my 9MM ammo. Also use any of the shotgun/handgun propellant on the fast side say from 231 and up. You definately need a faster propellant for what you want.

 

[Dan Forrester]

Thank you FROGO207! Will start looking at some +p data and grab a can of some more appropriate powder and report back.

Appreciate your help!

Dan

 

[Mark_Mark]

Cool Club here^^

Dreams of owning a full auto and loading it on a progressive!

 

[jmorris]

I have used N310 and TG with 147’s and I have to be at pretty high pressures for them to run as well. I also never use Federal primers in them.

 

[FROGO207]

Cool Club here^^

Dreams of owning a full auto and loading it on a progressive!

Nothing $30K-$60K won't cure these days. Long gone are the $1K SMG deals. And don't forget that tax stamp from BATF.
Or volunteer with uncle sugar and get your toys and ammo for free

 

[Mark_Mark]

30-60…..NAW MAN! NOPE

Vegas has rentals for a few Hundred

 

[jmorris]

. And don't forget that tax stamp from BATF.

I’m not sure it’s even significant anymore. Was a big deal before it cost me $150 for a tank of fuel though...

Heck, if you’re going to pay $100/1000 for primers, that’s not even an afternoon’s worth of fun..,

 

[GeoDudeFlorida]

30-60…..NAW MAN! NOPE

Vegas has rentals for a few Hundred

You can shoot one long enough to get a selfie.

 

[GeoDudeFlorida]

30-60…..NAW MAN! NOPE

Vegas has rentals for a few Hundred

I believe you might find that there is a flaw in your plan: rental ranges require the use of their ammo. No outside ammo is allowed; and especially not handloads brought in from outside their shop.


Sorry, you’re going to have to pony up for an SMG or give up the idea of loading for one. You can have one, not both.

But you can still get a selfie.

 

[Mark_Mark]

I believe you might find that there is a flaw in your plan: rental ranges require the use of their ammo. No outside ammo is allowed; and especially not handloads brought in from outside their shop.


Sorry, you’re going to have to pony up for an SMG or give up the idea of loading for one. You can have one, not both.

But you can still get a selfie.

I don’t blame them, $20,000 full autos, Heck No for the hand loads. and I’m not trying to explain to TSA why I have 5 Gallon Ziplock bags full of grease 9mm