quote:

Originally posted by ctsheepdog:

quote:

Thompson Machine SG2

Crash_Pro - Also looking forward to hearing more.

Quick and dirty volume calculations suggests internal volume of SG2 is about 15-16 cubic inches.

Gemtech MK9 is about 21 cu in.

Osprey 9 is about 12 cu in (not round so real guesstimate)

TiRant 9 is about 10-11 cu in.

Thinking is the larger volume allows more gas accumulation so that bullet can leave barrel and let more gas out muzzle rather than blowing back through chamber.

Any suppressor experts want to opine on interior volume versus blowback? Yes, baffles will have an impact as well but this is a layperson's "analysis".

Not sure how you calculated those numbers… I keep a spreadsheet of all silencers I’m interested to compare all the specs. Now these volumes are based on their external dimensions and not incorporating lost space by pistons/mounts/ or baffle designs. (Also not really sure how well the table will flow into this forum. Also note the SG-2 length and weight don’t incorporate the mount, so it’s actually going to be longer and heavier in real life but still lighter than the Gemtech by a large margin!!

The Gemtech does have some extra volume (19.18 vs 23.56) but I wouldn’t think it would be worth the extra weight (or sticker price!) I bought my SG-2, no mount, for less than $400 out the door. Plus, an Octane 9 is only 11 Cu In. and that is a great silencer!

Volume measurement (all but Osprey)=(PI()*((Diameter/2)^2))*Length

Company Model Length Diameter Volume Weight Caliber
SilencerCo Octane 9 7.50 1.37 11.06 10.8 9
SilencerCo Osprey 9 7.06 1.30x1.75 16.06 9.8 9
Thompson SG-2 9.25 1.625 19.18 11.5 9
Gemtech MK9K 7.50 2.00 23.56 20.0 9

I would agree tightness of bore and length both attribute to blowback. This is evident from a few of the silencers I already have. My Spectre does create quite a bit of blowback, so much so that the CCI Quiet ammo can actually cycle the slide and it’s way too weak to normally cycle semi’s. My GM-22 on the other hand does not, and being a mono-core does have a lot more FRP and louder at the muzzle, it seems more pleasant to my ears (could also be the tone). I do have an Octane 45, but the MPX is too loud to shoot in my yard to test it so I haven’t had a chance, but I can shoot .22 and 9mm pistols no problem.

One of the reasons I choose the SG-2 comes straight from the TM site, found below. While this might be all marketing, a local shop had it on sale literally the week I was looking for a large volume, low blowback for the MPX. Seemed like destiny, I had to buy it!

" The SG-2 is designed to minimize the blowback and ejection port pop that so commonly is the Achilles Heel of suppressed Submachine Guns."

Crash - I really did a rough guesstimate and will bow to your more diligent efforts. I simply took the diameter and length and shaved off a little for wall thickness and mount depth - nothing scientific at all. The Osprey is tougher given is rounded-rectangular volume so all I did was average the width and height and divided by 2 to get a radius.

While the price difference of the Gemtech does not bother me too much, I am wary of the weight different, especially since you can't bury the MK9 under a grip on a 4" barrel. Thus, you are carrying that 20 ounces out at the end of 8" which could make it very muzzle heavy, particularly with a light stock.

ETA: Why is it I am never in a shop when the TGTBT opportunity is there?

quote:

Originally posted by flatiron:
I picked this up last week, MPX-P 1480, cardboard box, no cleaning kit, Q detach low mount for sling, and a few rail adapters.

I am thinking generation 1, but not sure. I included the date of manufacture off the box.
Whats ya'll call, 1 or 2?




If I can help, perhaps I can take some measurements if ya'll need some?

I mic the ejection port today,
its 1.290" X .550"

Has anyone found a denier that works with the
MPX-P with the forearm collapsed? I am one who did not receive the hard case, and would like some sort of case for it. Denier, hardback? The 169 is steep for the deployment bag and thought someone may have found something similar?
THX

quote:

Originally posted by flatiron:

quote:

Originally posted by flatiron:
I picked this up last week, MPX-P 1480, cardboard box, no cleaning kit, Q detach low mount for sling, and a few rail adapters.

I am thinking generation 1, but not sure. I included the date of manufacture off the box.
Whats ya'll call, 1 or 2?




If I can help, perhaps I can take some measurements if ya'll need some?

I mic the ejection port today,
its 1.290" X .550"

Looking at the picture I would say this is a gen 1. If you look at a gen 2 gun, the two steel pieces on the left side of the chamber actually create somewhat of a T shape, rather than the L shape in your photo.

quote:

Originally posted by ctsheepdog:

While the price difference of the Gemtech does not bother me too much, I am wary of the weight different, especially since you can't bury the MK9 under a grip on a 4" barrel. Thus, you are carrying that 20 ounces out at the end of 8" which could make it very muzzle heavy, particularly with a light stock.

Other problem your face is that the thread of the barrel is recessed into the handguard already and therefore probably won't even be able to screw on to it. Forgetting that problem, 20 ounces is very significant! My Saker 7.62 is about 20 ounces and its a heavy beast! It makes my 308 almost too heavy to hold free hand

quote:

Originally posted by gearedforacure:
Looking at the picture I would say this is a gen 1. If you look at a gen 2 gun, the two steel pieces on the left side of the chamber actually create somewhat of a T shape, rather than the L shape in your photo.

Lack of Keymod also a dead giveaway.

quote:

Originally posted by CRASH_PRO:

quote:

Originally posted by ctsheepdog:

While the price difference of the Gemtech does not bother me too much, I am wary of the weight different, especially since you can't bury the MK9 under a grip on a 4" barrel. Thus, you are carrying that 20 ounces out at the end of 8" which could make it very muzzle heavy, particularly with a light stock.

Other problem your face is that the thread of the barrel is recessed into the handguard already and therefore probably won't even be able to screw on to it. Forgetting that problem, 20 ounces is very significant! My Saker 7.62 is about 20 ounces and its a heavy beast! It makes my 308 almost too heavy to hold free hand

Great points. All the more reason to be eager to here your SG report.

Just got notified my MPX mags got shipped from Sig. I was late to order, so, the mags should be hitting retail volumes soon...

quote:

Originally posted by gearedforacure:

I wonder what the difference in suppression is between the 9mm and a 9mm through the .45 is?

SilencerCo website listss the db rating of 9mm in the osprey9 and 9mm in the osprey45. Of course on the osprey, you cant change the endcapa, but i know 5.56 thru a 7.62 can with a 5.56 endcap is quieter than a 5.56 can because of an overall size increase.

I own a osprey45 and use it on my g19. With subsonic ammo, its great at siund reduction, but i dont have a 9mm can to compare.

Hi Steve,
I am new to the forum and actually found it while searching for MPX foregrip options. I had purchased the aluminum one you are mentioning and although the mounting holes line up with the guard, there are 2 round lugs about 1/16" in depth on the bottom that don't allow it to sit flat so it wobbles a bit - I may grind them down to make a better fit.

A much better option that I found is to use a Magpul AFG M-LOK. The grip is just the right size to allow several grip positions using either the mag well or the handguard, or anywhere in between. I wanted a small foregrip so that I could use my Streamlight TLR-2 strobe with laser as a home defense weapon. The grip also puts the light/laser switch in just the right location for operation. I found that the M-LOK fastener locations are identical to the spacing on the SIG handguard, but you will need to modify it slightly by grinding off the polymer stubs on the bottom - they are tiny and grind off in just minutes. I will post pics once I figure out how this is done on this forum - any help would be greatly appreciated.

For those of you attempting to avoid the scarring of your lower from the sloppy charging handle - I have an easy fix that uses something called a mouthpiece cushion (I am also a sax player) that will temporarily stop the handle from hitting both the lower and upper receiver. It is a durable rubber patch with adhesive on one side, and just the right size (with minor trimming) and thickness to cover the entire area where the handle hits. It is so durable that so far it has permanently stopped any scarring. I will post pics of this fix in a few days once I learn how to.

I also wanted to compliment all users of this forum for your valuable information and professional posts and responses. I joined a sax forum once called saxontheweb and they were just a bunch of band pussies bullying eachother and ganging up on new members - I guess they were just getting revenge for the ass-kickings they got in high school. I read all 64 pages of your forum and was extremely pleased, and hence I am now posting!

quote:

Originally posted by Ferrari Steve:
Anyone running any foregrip on their MPX? Wondering what options are out there. There's an aluminum one I've seen online, but not many other options.

Reading ivy's long post got me to thinking about some low-friction strip material I used in a project several years back. I can't find the precise item (12" strips) but did find this tape version which might work.

This tape material is quite stout and can easily be replaced if it ends up being worn away by the charging handles contact.

http://www.findtape.com/JVCC-U...lene-Film-Tape/p443/

quote:

Originally posted by ctsheepdog:

quote:

Originally posted by Ferrari Steve:
Had to heat up the flash hider with a blow torch until it glowed red, then whack the bejeezus out of the wrench with the hammer (yes, I know it's left-hand threaded) to finally get the flash hider off.

Do you think they used Rockset to secure the hider? I had a similar experience getting an ACC hider off of a Noveske upper, and they used Rockset.

Rockset weakens when exposed to water. Just soak a rocksetted muzzle device in water for 24 hours and you should be able to wrench it off.

Reading ivy's long post got me to thinking about some low-friction strip material I used in a project several years back. I can't find the precise item (12" strips) but did find this tape version which might work.

This tape material is quite stout and can easily be replaced if it ends up being worn away by the charging handles contact.

http://www.findtape.com/JVCC-U...lene-Film-Tape/p443/

I see raeind is selling a MPX mag loader. Compatible with Gen 1 and Gen 2. $23.97

http://www.raeind.com/store/p1...nes_%28Black%29.html

quote:

Originally posted by ctsheepdog:
Reading ivy's long post got me to thinking about some low-friction strip material I used in a project several years back. I can't find the precise item (12" strips) but did find this tape version which might work.

This tape material is quite stout and can easily be replaced if it ends up being worn away by the charging handles contact.

http://www.findtape.com/JVCC-U...lene-Film-Tape/p443/

I ended up putting a small piece of self adhesive velcro on my UR at the point where the CH hits...

A believe a complete Gen 2 MPX just posted to Gunbroker. Has several pictures:
http://www.gunbroker.com/Aucti....aspx?Item=525433185
Shows KeyMod, Ambi charging handle, larger ejection port and comes with PSB.
Listed as: MPX-P-9-KM-PSB

quote:

Originally posted by Ferrari Steve:
Had to heat up the flash hider with a blow torch until it glowed red, then whack the bejeezus out of the wrench with the hammer (yes, I know it's left-hand threaded) to finally get the flash hider off.

The SilencerCo Osprey 9 with the XL piston (slightly longer) and the fixed barrel extension are a perfect fit on the MPX.

Steve - what VFG is that on your MPX if you don't mind sharing? Thank you.

quote:

Originally posted by JRC:
Steve - what VFG is that on your MPX if you don't mind sharing? Thank you.

Nothing fancy - just a $25 Magpul 412 from Amazon: http://amzn.to/1lEKUPE

The anodizing on the Gen 2 MPX's is a little off in color.

See below for pics

http://www.gunbroker.com/Aucti....aspx?Item=525581325

quote:

Originally posted by maddy345:
The anodizing on the Gen 2 MPX's is a little off in color.

See below for pics

http://www.gunbroker.com/Aucti....aspx?Item=525581325

That may be a function of lighting. I picked-up a Gen2 last week that is black.