Carbine SBR Planning

[Valk]

Since I finally got around to setting up my trust last week, I'm starting to plan out the "endgame" for my Scorpion carbine - a cut-down to 7.7" (or whatever the stock barrel length is on the pistol), an HBI pistol handguard installation, and the attachment of either a tri-lug or an ASR muzzle device to attach the SilencerCo Hybrid I plan to order next month. While SBRing the pistol is certainly easier, I bought the carbine on a whim back when 922r kits were rare as hen's teeth. My fault.

That said, there's immediately a few questions I feel I need to answer before moving forward:

• My carbine has a faux suppressor that I cannot for the life of me get off. I also have no vise and thus no way to remove the barrel nut even with the socket, meaning the entire rifle will need to be sent off when the barrel is cut down. Who can I send to do the cut-down and handguard install, and how do I ship it to them? Right now I'm looking at having either Taylor Pickerel or PMM do the cutting. PMM is looking more likely due to their ability to engrave the gun while it's in-house.
• What threading and length should I be looking to get on the cut-down barrel?
• Should I go with the tri-lug or an ASR mount for the Scorpion? My AR has an ASR device on it already, so standardizing around ASR means I have one less adapter to keep track of, but tri-lug seems to be the unanimous winner for best muzzle attachment system on subguns, though I'm not sure why.
• Is there anything I'm forgetting that I will need to either have done on the Scorpion or buy for the suppressor? This is my first time doing both things, and obviously, I'd prefer to get it right the first time.

Any and all help is appreciated in advance.

[WaltherP99]

Pickerell does engraving also. I just had my Scorpion to him for engraving, barrel rethread with tri-lug install and HBI pistol handguard install. All I did was send him my complete upper and he handled the rest. Did a bleep fine job also!

[mursalot]

1. I think you pretty much answered your own question. Since you have to send off your barrel to get chopped and threaded AND your receiver to get engraved, you really shouldn't worry about removing the faux suppressor. It's not going to add any length to your shipping package and will only weigh a few ounces more. Just gut your rifle of everything that doesn't need to go in such as; the lower control group, pistol grip, folding stock, bolt/recoil spring, charging handle, etc

2. https://silencerco.com/product-support/#tab-3
Since you're thinking about using using a silencerco muzzle device, might as well have your barrel thread to their spec. Just avoid the nightmare and don't go with left hand threading. 1/2x28 is your best bet for 9mm since almost everything is threaded for that considering projectile diameter

3. Huh? I thought you were going with the asr? People use trilug because it's a pretty universal quick detach system recognized by muzzle device manufacturers and suppressor companies alike. Asr isn't interchangeable with suppressors from other manufacturers. I say go for the asr and don't look back. If you're planning to invest in silencerco, then go all the way, don't look back and enjoy their goodies while you're at it. Buy once, cry once

4. If you decide on the asr muzzle brake, you may need to install shims to time the brake just right on the muzzle of your barrel. No need for time the flash hider. Whomever you decide to go with to cut your barrel, they may also be willing to install your muzzle device as well. Get ready for a long wait

[mursalot]

One more thing

As far as removing the faux suppressor. Heat is more than likely necessary. There are several ways this can be accomplished. Warm up your muzzle until hot to the touch then remove with some thick gloves or an oven mit. Sit in a chair with the butt of the rifle resting on the floor clamped between your feet and your inner thighs wrapped around the handguard. Point the muzzle AWAY from your head at about a 75 degree angle. Now both your hands are free to work off the faux suppressor

There are different options for applying heat. A heat gun with run you $15 - $20. A propane torch with propane bottle with cost you about $20 - $25 for a basic setup from Wal-Mart or Amazon. Or you can go super ghetto and insert a soldering iron into the muzzle and leave it there for few minutes while it heats things up. That might set you back $5 - $10

Don't forget to use leather work gloves and safety glasses at a minimum

[GA Jack]

If the fake suppressor could easily come on and off then they could not classify it as a rifle, it would be an SBR.

It is suppose to be permanently attached  (same concept as people pinning a muzzle device on a 14.5" barrel) -  if its not I'm not sure how from a legal standpoint they are getting away with it.

I would have assumed the fake suppressor has to be cut off.

(Edit: Oh nevermind, I see now, the fake suppressor actually covers a 16" barrel)

[cocowheats]

What's wrong with just a simple direct thread silencer these days?

Seems like everyone and their brother wants to add extra unnecessary pieces, weight and expensive proprietary parts to the end of their muzzles.

Direct thread muzzles/silencer gives the most universal and easy attachment method there is.  I mainly don't like proprietary silencer mounts because they force you on to have to buy their mounts to use the silencer on other host....

Nothing wrong with direct threads.

Most universal? Probably...

Most easy to attach? Hell no! 3lug for the win!


I'm a 3lug guy. I can pop my can on and off in 2secs. I don't have to check if my can is still tight after every mag either!!! Adds maybe a couple ounces in weight and doesn't add much length either(granted, my barrel is cut and threaded 1/2x28 so I'm using a small 3lug adapter). I also don't have threads to accidentally bang up, a thread protector to lose, or threads I have to keep clean....those are all wins over direct thread in my book.

LH threaded barrels(not using an adapter to go from RH to LH) are the way to go if going direct thread. They do not loosen up nearly as much as a RH thread. This is because RH threads loosen in the direction the bullet spins whereas LH threads tighten in the direction the bullet spins.

If you go 3lug and want to share the can on multiple host that have diff thread pitches, then you still only need one setup for the suppressor to jump hosts since you can get 3lug adapters in many thread pitches.

3lug is superior to direct thread in my book....I also always opt for LH threading when I have to direct thread as well. LH threads are superior to RH.

[Valk]

Thanks for the responses so far. Regarding ASR vs 3-lug vs direct thread, I plan on having adapters for ASR and direct thread at minimum, since my AR has a BE Meyers 556 ASR flash hider and my Glock 19 won't accept anything but a direct thread, and the Hybrid will be used on both (the main reason I'm getting a Hybrid is to cover as many platforms as possible the first time around). I may add an Omega 9K/45K to my lineup down the line as well, and the Omega K series does not accept ASR mounts to my knowledge, but I'll cross that bridge if and when I come to it.

Right now, the main question is whether there's any benefit to going with 3-lug over ASR or vice versa from an ease of use/performance standpoint. I keep finding people swearing by 3-lug for weapons like the MP5 series and its clones, but I can never find reasons why, which is what I'm trying to figure out before going one direction or the other for now.

[cocowheats]

....Right now, the main question is whether there's any benefit to going with 3-lug over ASR or vice versa from an ease of use/performance standpoint. I keep finding people swearing by 3-lug for weapons like the MP5 series and its clones, but I can never find reasons why, which is what I'm trying to figure out before going one direction or the other for now.

ASR is a silencerco thing where as 3lug is compatible across many diff. suppressor brands. That's one of the big advantages to 3lug since it's more universal across multiple suppressor brands.

Keep in mind, the factory Glock barrels are LH threaded. RH threaded pistol barrels are commonly considered a "silly American" thing. Glock, Sig, and HK all typically use LH threaded barrels on their pistols for good reason.

[Valk]

ASR is a silencerco thing where as 3lug is compatible across many diff. suppressor brands. That's one of the big advantages to 3lug since it's more universal across multiple suppressor brands.

Keep in mind, the factory Glock barrels are LH threaded. RH threaded pistol barrels are commonly considered a "silly American" thing. Glock, Sig, and HK all typically use LH threaded barrels on their pistols for good reason.

Are there any benefits beyond multi-brand compatibility for 3-lug relative to other mount styles, though? I keep leaning towards 3-lug just for the sake of ease if/when I buy an Omega 9K as a dedicated 9mm can (as mentioned, the Omega doesn't accept ASR but does accept 3-lug). Either way, I'll be using my SilencerCo credit from their current promo to buy something for the Scorpion, be it an ASR muzzle device or a 3-lug adapter for the Hybrid. It's just a matter of figuring out which.

As for the Glock barrel, I haven't bought one yet, but thanks for mentioning that. I'm planning on going with a Blacklist or KKM barrel in RH threading at the moment.

[mursalot]

I picked up a lone wolf "alpha wolf" barrel a few months ago and that thing is awesome! I tried aluminum, brass and steel cased ammo with absolutely no problems.

I've heard horror stories of using lone wolf barrels. Some needing to be returned for a good reaming and whatnot. Apparently those standard barrels are made out of country

The new alpha wolf is made here and doesn't have any issues that the original does. No break in, nitride treatment, and only a few dollars more

I know liberty suppressors will be selling blacklist barrels through their website if they don't already. I think silencerco even makes their own barrels

[Valk]

I picked up a lone wolf "alpha wolf" barrel a few months ago and that thing is awesome! I tried aluminum, brass and steel cased ammo with absolutely no problems.

I've heard horror stories of using lone wolf barrels. Some needing to be returned for a good reaming and whatnot. Apparently those standard barrels are made out of country

The new alpha wolf is made here and doesn't have any issues that the original does. No break in, nitride treatment, and only a few dollars more

I know liberty suppressors will be selling blacklist barrels through their website if they don't already. I think silencerco even makes their own barrels

KKM and Blacklist came up as #1 and #2 in Victory Gun Blog's recent barrel tests, which is why they're getting top consideration. SilencerCo's barrels fell way short, and while the stock Glock barrels generally did pretty well, Primary & Secondary's test battery of those barrels showed that accuracy was generally inconsistent from barrel to barrel with OEM. Either way, I want that 1/2-28 RH threading in order to standardize all my 9mm barrels, so aftermarket it is.

Back to suppressors and SBRs, I did a bit of work earlier tonight charting out some of the best/most intriguing suppressors I've been considering. You can see my spreadsheet here. What I found is that the Hybrid is significantly heavier than most pistol cans (and some rifle cans like the Omega 30, for that matter). On top of that, it's fairly long and doesn't suppress 9mm that much better than less expensive pistol cans, which can often be user-serviced and are modular to allow for reduced length. Add in the fact that I don't shoot 5.56 that often (and it doesn't suppress well anyway), and I'm now reconsidering whether or not to even go with a Hybrid at all in favor of a dedicated pistol can now and something ASR-capable like an Omega (or the Hybrid) later.

Right now, the Rugged Obsidian 45 is becoming my new can candidate, with the Omega 9K close behind. Does anyone have any experience shooting one of these, ideally on a Scorpion? If I go with the Obsidian, a 3-lug will become my mount of choice, and I'm not sure if I need the fixed barrel adapter in addition to the 3-lug adapter or if I'll get by just fine with the 3-lug.

[mursalot]

Modular suppressors are the pimps of the silencer market. Pimpin ain't easy. Things get heavier and longer when you start threading extensions onto a can to accommodate larger calibers

[Valk]

I've decided I'm going up to Silencer Shop (3-minute drive if traffic is *bad* from where I live) and buying a Rugged Obsidian next week. One problem down!

Anyhow, something I thought of earlier today - I know the pistol Evos use a lock-tab system to keep the muzzle device in place with hand tightening, much like the AK-74 has. This really intrigues me and makes me think I would really like to have my carbine cut down into the same system, with a dual-thread system like the pistols that will let me swap between the "stock" Evo flash hider and the HK Parts Scorpion 3-lug adapter. The extra length with the 3-lug on is a price I'm willing to pay for modularity.

The issue that I have is that I still want to use the HBI pistol-length handguard. Will I be able to use the pistol barrel nut with a non-OEM pistol handguard, or is the CZ polymer handguard the only way to go if I want the dual-thread system? For that matter, is the lock-tab part of the pistol barrel nut, the flash hider, or neither? If the latter, I might have to see who here swapped over to a different handguard and is willing to cough up their entire system.

[mursalot]

I've decided I'm going up to Silencer Shop (3-minute drive if traffic is *bad* from where I live) and buying a Rugged Obsidian next week. One problem down!

Anyhow, something I thought of earlier today - I know the pistol Evos use a lock-tab system to keep the muzzle device in place with hand tightening, much like the AK-74 has. This really intrigues me and makes me think I would really like to have my carbine cut down into the same system, with a dual-thread system like the pistols that will let me swap between the "stock" Evo flash hider and the HK Parts Scorpion 3-lug adapter. The extra length with the 3-lug on is a price I'm willing to pay for modularity.

The issue that I have is that I still want to use the HBI pistol-length handguard. Will I be able to use the pistol barrel nut with a non-OEM pistol handguard, or is the CZ polymer handguard the only way to go if I want the dual-thread system? For that matter, is the lock-tab part of the pistol barrel nut, the flash hider, or neither? If the latter, I might have to see who here swapped over to a different handguard and is willing to cough up their entire system.

Keep the barrel nut on and will act as a jam nut up against your trilug muzzle adapter. The locking tab is part attached to the barrel nut.

Warning though, the tab doesn't always line up with the notches on the hkparts 18mm trilug muzzle adapter when fully torqued. That's the reason manticore arms got rid of the notches and went with wrench flats on their trilug adapter. There's too much variability from evo to evo during production to keep everything exactly to specs when all compared with one another

[Valk]

I've decided I'm going up to Silencer Shop (3-minute drive if traffic is *bad* from where I live) and buying a Rugged Obsidian next week. One problem down!

Anyhow, something I thought of earlier today - I know the pistol Evos use a lock-tab system to keep the muzzle device in place with hand tightening, much like the AK-74 has. This really intrigues me and makes me think I would really like to have my carbine cut down into the same system, with a dual-thread system like the pistols that will let me swap between the "stock" Evo flash hider and the HK Parts Scorpion 3-lug adapter. The extra length with the 3-lug on is a price I'm willing to pay for modularity.

The issue that I have is that I still want to use the HBI pistol-length handguard. Will I be able to use the pistol barrel nut with a non-OEM pistol handguard, or is the CZ polymer handguard the only way to go if I want the dual-thread system? For that matter, is the lock-tab part of the pistol barrel nut, the flash hider, or neither? If the latter, I might have to see who here swapped over to a different handguard and is willing to cough up their entire system.

Keep the barrel nut on and will act as a jam nut up against your trilug muzzle adapter. The locking tab is part attached to the barrel nut.

Warning though, the tab doesn't always line up with the notches on the hkparts 18mm trilug muzzle adapter when fully torqued. That's the reason manticore arms got rid of the notches and went with wrench flats on their trilug adapter. There's too much variability from evo to evo during production to keep everything exactly to specs when all compared with one another

I didn't consider that. However, since I'm having the barrel cut down rather than going off a production barrel, I would assume I could send the trilug along with the parts and just have the gunsmith make sure that it indexes properly.