Who Will Be The First To Put A SD Front End On Their Mac Style RR?

[CKxx]

Well, if nothing else, this thread could be considered market research.

 

[Slowmo]

Completely unscientic explanation:

If 147 has the same powder charge as 115, the heavier bullet will travel slower, but think of newtons law about action reaction.

It’s pushing a heavier bullet and the bolt is reacting rearward more so

Now it all depends but I’d suggest that a 147 subsonic prob has a little more powder than your typical 115, bc it’s 27% heavier but only 12% slower (I know it’s not a direct correlation - but just for illustrative purposes) to get it to 1050fps or so. (115 is typically 1190)

If you want more power and faster shots, go with 124 NATO

It’s pushing 124 at 1200. So heavier bullet near same speed as typical 115

Caliber Multi: 9mm NATO
Muzzle Energy: 396 lb/ft
Muzzle Velocity: 1200 fps

Compare to 124 lawman 1090 and 124 federal 1160

Wwb115 is 1190
362 lb

So nato is about same speed w heavier bullet so see the energy rating.

Energy won’t necessarily mean what you feel but when comparing similar loads it’s probably a good proxy

I’m not entirely sure I followed what you were saying, but a 115gr 9mm load typically has more powder than a 147gr load, assuming the two are using the same powder, are loaded to similar pressure, etc. For example, Hodgdon’s Titegroup data has about a 33% higher powder charge for 115gr than 147gr. The 150-165gr “hush” type loads use even less powder. This is another reason why subs are quieter.

 

[Deerhurst]

You get the same/similar pressures with less powder due to newtons laws. That's all it is.

More mass, same force = slower acceleration and overall speed before the energy is depleted.

Powder is/should be well burned before the bullet enters the can. If it is still burning you have lost energy and therefore wasting money just burning powder for no good.


In the case of something like the MP5 can which the barrel is ported close.to the chamber the goal is to bleed off excess pressure causing less pressure in the barrel and therefore a lower overall velocity.


All a suppressor does is capture the burp of high pressure gasses coming out of the muzzle and slows and cools the gasses before they leave the suppressor to reduce the pressure wave your ears hear as a gunshot. Same thing a car muffler does.

 

[LawBob]

9mm NATO is +P, the last thing you want to use if you're trying to be quiet.

Yes. It was for comparison purposes re velocity.

Lawman 124 or Blazer Brass 124 is subsonic and less powered than typical 124s. So the rpms are less as well than a 147, generally.

 

[LawBob]

I’m not entirely sure I followed what you were saying, but a 115gr 9mm load typically has more powder than a 147gr load, assuming the two are using the same powder, are loaded to similar pressure, etc. For example, Hodgdon’s Titegroup data has about a 33% higher powder charge for 115gr than 147gr. The 150-165gr “hush” type loads use even less powder. This is another reason why subs are quieter.

If a typical 147gr bullet is hitting 1050 and a 124gr lawman is hitting 1090, then the 147 has MORE powder charge.

I can assure you that the 124 lawman is much slower RPM than the 147.

It’s a lot heavier bullet doing about the same speed. Ergo…

When we drop to 115gr bullets they go about 1190.

I have no idea whether most of the subsonic capabilities are due to the heavier bullet or a lighter charge bc I don’t reload, but I’d suggest that it’s probably a very similar charge and the weight of the bullet is what slows it down. Otherwise why not just use a 115 w reduced charge.

 

[LawBob]

Reloading Data Center – Hodgdon Reloading Data Center

hodgdonreloading.com

115g loaded to 1167fps is 5.1grains of 231 powder = pressure of 28,100 CUP

Having trouble getting 147gr to 1050…
4.1grains of xxx gets to 947fps and 32,200 CUP

Ramshot Sillouette powder
147gr take 4.6grains to get to 981fps
115gr take 5.3grains to get to 1147fps

So it’s a little of both

I was also assuming subs were 1050fps so to get the 147 up to that speed would take a little more.

Edit: 124gr take 5.4 to get to 1082fps

My experience is that lawman 124 is basically subsonic probably due to short barrel and open bolt.

 

[Slowmo]

If a typical 147gr bullet is hitting 1050 and a 124gr lawman is hitting 1090, then the 147 has MORE powder charge.

I can assure you that the 124 lawman is much slower RPM than the 147.

It’s a lot heavier bullet doing about the same speed. Ergo…

When we drop to 115gr bullets they go about 1190.

I have no idea whether most of the subsonic capabilities are due to the heavier bullet or a lighter charge bc I don’t reload, but I’d suggest that it’s probably a very similar charge and the weight of the bullet is what slows it down. Otherwise why not just use a 115 w reduced charge.

Reloading Data Center – Hodgdon Reloading Data Center

hodgdonreloading.com

115g loaded to 1167fps is 5.1grains of 231 powder = pressure of 28,100 CUP

Having trouble getting 147gr to 1050…
4.1grains of xxx gets to 947fps and 32,200 CUP

Ramshot Sillouette powder
147gr take 4.6grains to get to 981fps
115gr take 5.3grains to get to 1147fps

So it’s a little of both

I was also assuming subs were 1050fps so to get the 147 up to that speed would take a little more.

Edit: 124gr take 5.4 to get to 1082fps

My experience is that lawman 124 is basically subsonic probably due to short barrel and open bolt.

I wasn't talk about specific loads that may be anemic.

I was responding to your statement that "I’d suggest that a 147 subsonic prob has a little more powder than your typical 115, bc it’s 27% heavier but only 12% slower." If you're comparing apples-to-apples (same powder, same bullet construction, same pressure level), the 147gr load will use less powder, not more.

 

[StenAtopia]

There have been so many threads about a SD barrel and suppressor for a Mac style upper here. But the SD ports would be inside a standard upper where the bolt needs to go. I know there are some that have looked into 9mm for the Lage Max/15 uppers. I think that it would be cool to combine the HK SD ported barrel and suppressor with the Lage upper.

This is something that I would like to do with my Tenko 10-16. Funds have been very short, so I have not done it yet. But I have the SD style suppressor which would be the biggest hurdle. So who will be the first to have a SD Mac? There is the recent FW video about an AR style SD upper.

Scott

Short answer. Know-one! Lol

 

[A&S Conversions]

Unless someone does it with a Lage Max-/15, it will be me with a Tenko. That is the short answer. I have already talked to the owner of Broad River Tactical, the maker of the AR SD upper. I want a rotary delayed blowback SD upper.

Scott

 

[Gaujo]

An integrally suppressed barrel for M10 doesn't sound all that difficult. Little machine time and some research into how to build integral cans and I could probably slap one together. As long as I started with enough barrel!

It's not the length of the barrel, it's the energy of the projectile.

 

[Deerhurst]

It's not the length of the barrel, it's the energy of the projectile.

Uhh, one affects the other since smokeless powder does not explode but burns rapidly.


A factory length barrel would likely not have enough length outside the receiver for mounting and porting the barrel. Hence, more barrel!


Just putting a can on the end and picking the right load is easier and cheaper.


Most of my barrel stubs are pretty short, darenger short or really long with a 0.311 bore. Neither would work so I need a long enough barrel to even think about it before making sure there is enough to port.

A big part of the struggle with a MAC is the amount of barrel in the receiver. With a fast powder everything may be burned by the time the bullet reaches the trunnion so this again goes to finding the right load and when you find the right load it's still cheaper and easier to thread the barrel and put a can on it vs integrally suppressed.

I'd have to run some numbers and see where the pressure curves fall off with the powders I run to get a better sense of where porting would need to happen. I pulled my barrel, threaded it and run a can on it so I have no desire to integrally suppress to save an inch of length or less and have more difficulty with ammo sensitivity. Not worth it.

 

[Gaujo]

Sorry was trying to make a joke ala motion of the ocean ;-)

 

[Deerhurst]

Sorry was trying to make a joke ala motion of the ocean ;-)

Totally went over my head!

 

[BlackBelt]

I was told there would be no math today...

 

[b_saan]

Uhh, one affects the other since smokeless powder does not explode but burns rapidly.

The correct answer was... "that's what she said."

 

[Deerhurst]

The correct answer was... "that's what she said."

I'm not known to not be oblivious.

 

[MPXGuy]

I think an integral suppressor like this would work with the Mac without modifying the receiver.

 

[Hey...]

I think an integral suppressor like this would work with the Mac without modifying the receiver.

That won’t work on a MAC. The barrel/trunnion/bolt on an M10/11 is a totally different setup than an M16

 

[Galil#1]

Build it and they will cum!

 

[A&S Conversions]

But the Lage Max-/15 and the Tenko 10-16 adapter are AR based. "MitchWerbellsGhost87" did post a similar suppressed setup, to the Angsted Arms suppressed upper in the video above on the first page of this thread. The AA video above mentioned the HK SD but didn't do a side by side comparison to the SD. Both the M11/NINE upper on the P.P. and the Amstead Arms uppers are simple blowback. Only the Max-11/15 uses a standard AR-15 length bolt group. So the AR blowback bolt would need to be modified for use with the Max-11/15. I would think that the Max-11A/15 and the Max-10/15 could use the RDB bolt in the Lage custom carrier. I don't know how, without custom work that the other Lage Max-/15 models could be used with an AR blowback system because of the custom Lage carrier length.

The Tenko 10-16 adapter is designed to use standard AR-15/M16 upper receivers. The Broad River Tactical SD style upper uses either simple blowback or radial delayed blowback. Since the Broad River Tactical uses ports similar to the HK SD ports which is set up for use with the SD suppressor and the lighter RDB bolt group moving around in the gun, would tend to have lighter recoil from the lower mass of the lighter bolt group. I think the Broad River Tactical RDB SD upper would be my choice. Especially since I already have a HK clone SD suppressor. No need to buy another suppressor. YMMV.

Scott