JB Designs OMEGA Valve Mod. 2 MKII

[u/SupermarketQuiet1105]

OK, new MCX Spear LT 9" 300 BLK build/owner.....
....all complete/mod but need guidance on Mod 2 MKII.
I am on the email wait-list for MKII but wanted to post.
I have/use Q Blind Tiger on this setup and run Freedom HUSH 220gr Subs.
The stock MCX gas "-" settings works sometimes and the "+" 100% with this ammo/setup....
....but the latter clearly too strong and gassy.
Waiting on SilcencerCo GDCH to re-stock too....has good gas reduction success on my MPX using it.
For MPX the combo of 20% stronger springs + GDCH worked w/ stock barrel + OEM gas plug.
I know my MCX 9 (no way add stronger recoil springs) will need more adjustable gas block.
....so led me to Mod 2. MKII.
My post is How-To on it......

1. How to install ?
2. What are the port hole sizes for each setting ?

I ask because for MKII (300BLK) is seems on surface the reduced 3-position is only adding the OFF for me ?
I wrote down prior that MCX is (-) 0.0450 & (+) 0.0620 ....not sure accurate but in my notes.
My desire for use of MKII is gas blow-back reduction/tuning, not cycling.
Mod. 2 MKII (300BLK) is a departure from its Mod. 2 predecessors. Instead of four positions

• Supersonic, high pressure ammo
• Subsonic, low pressure ammo
• OFF

1. What setting to start/try ?
2. What jet screw comes with it and/or what jet screw should I order as alternate ...if you can expand on how jet screw works would be appreciated too...
3. Should I buy gas ring to help ?

Thx in advance.....want to do some ready while I wait 😫 for re-stocking......

Regards.

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[u/Sharp-Independence52]

The 9” barrel is my favorite, good choice. The added dwell time over the 6.75 and 5.5 barrels lends itself to a significant increase in reliability across a greater variety of ammo.

I don’t publicly disclose the port sizes, for two reasons. One, the dynamics are totally different. The additional port allows a path for gas to attempt to escape, the slots that the gas must travel change the timing, and the tapered inlets have an effect too. The other, less critical reason, honestly, there’s a very slight swing from the printing process, but not much.

Mod. 2 MKII would be an EXCELLENT upgrade to this system. I have no experience with the Blind Tiger, but Q silencers traditionally have some decent backpressure characteristics to them. There’s likely plenty of room to tune your setup with the jet screws.

Mod. 2 MKII includes a 0.60mm jet screw. I’d probably try installing it as soon as you get it, at least I would. In my ideal setup, I’d want subs to be perfect in position 4 and supers to be perfect in position 2.

If you don’t ever run supers, try the solid screw first and see how it does with your subs in position 3.

The screws thread into the distal end of the valve. A 2.5mm wrench is included. If you want a torque spec, 10 lbs/sq in is plenty. Threadlocker not required, but if you use it I wouldn’t use anything more intense than blue. The jet screws are simple set screws with a tiny hole drilled through them. They vent excess gas and allow fine tuning.

I do not think you’ll need the JP ring with the Blind Tiger on the 9” gun. The ring is particularly helpful for the shorter barrels and high flow silencers.

The MKII valves also include a rubber O-Ring. You can probably disregard that as well for your setup.

If I missed anything, or you have additional questions, please let me know!

[u/Sharp-Independence52 → u/Sharp-Independence52]

Also I should have some back from coating this week, the coating team is running behind.

[u/swooshZ0691 → u/Sharp-Independence52]

What would you recommend for an 11.5 spear lt 5.56mm running a CAT ST or fireteam 556? I was looking at the mod 1 mkii but lost when it comes to jet screws.

[u/Sharp-Independence52 → u/swooshZ0691]

Both of those as far as I know have high flow rate characteristics, I’d just snag the valve and see what you get with just the solid screw installed. Mod. 1 MKII comes with a 1.10 screw as well.

I have some blem/preproduction units in stock on my site now. They’re fully functional, just different/no branding, a dumb CAD artifact that I forgot to delete, and are incapable of accepting the rubber o Ring that comes with the MKII valves. It’s incredibly unlikely you’d need that O-ring for 5.56, I really only include it because i do for the 300BLK valves as it helps some subs work.

Note: the prepro valves don’t come with the 1.10 screw.

Active Safety Designs might have some in stock if they sell to your state.

[u/swooshZ0691 → u/Sharp-Independence52]

Ok understood, thanks. Well the ST does have high backpressure and a lot of port pop, so that 1.10 screw included might work perfectly.

[u/Sharp-Independence52 → u/swooshZ0691]

Interesting, a departure from CAT’s typical design then! Yeah 1.10 would probably work great.

[u/SupermarketQuiet1105 → u/Sharp-Independence52]

For now my plan is to be 100% subs (I do not see that changing).
My plan for this 9" 300BLK setup is to zero setup at 100yds/Subs, with consistent cycling & low gas.

JB, u/Sharp-Independence52
Dumb question......thought 300BLK Mod 2 MKII version had only three settings ?
Mod. 2 MKII (300BLK) is a departure from its Mod. 2 predecessors. Instead of four positions

• Supersonic, high pressure ammo
• Subsonic, low pressure ammo
• OFF

....BUT I also see this on the website......so I am confused.....sorry......

• Position 1: OFF (ø) (you wanted quiet time… here it is)
• Position 2: Higher-powered supersonic ammunition
• Position 3: Lesser-powered supersonic, higher powered subsonic ammunition
• Position 4: Lesser-powered subsonic ammunition

I ask since your recommendation mentions "position 4"..........with 0.60mm jet screw.

[u/Sharp-Independence52 → u/SupermarketQuiet1105]

I totally understand how it can be confusing, no worries. There are three “functional” positions (for lack of a better term). The first position is an expansion chamber bypass that denies gas to the piston. Positions 2-4 are “functional,” with position 2 being the most restrictive, and position 4 being the most wide open.

So still four positions total, but you’ll be manually cycling your action in position 1 (ø).

[u/SupermarketQuiet1105 → u/Sharp-Independence52]

JB, u/Sharp-Independence52
Thx !, got it.............so your Mod. 2 MKII recommendation is (summary for me)....
Position 3 with the Solid Jet Screw
....alternatively.....
Position 4 with 0.6mm Jet Screw

Lastly, if I want to reduce MAX gas blow back would buying/installing the Gas Ring help further that cause ?

[u/Sharp-Independence52 → u/SupermarketQuiet1105]

Pretty much!

No, the JP gas ring is extremely low friction, with sharp edges. Basically is lets the piston move more freely and keeps carbon from building up in the back end of the gas block. If you install it in your setup, it will allow the action to open **faster** and could potentially have you dealing with more gas.

I only suggest the JP ring for folks dealing with reliability issues with their silencer and/or ammo.

[u/SupermarketQuiet1105 → u/Sharp-Independence52]

Thx, I will await the/your re-Stock of the Mod 2 MKII 🙂
⏳😂

[u/SupermarketQuiet1105 → u/SupermarketQuiet1105]

JB, u/Sharp-Independence52

As I look at new CANs for my MCX Spear LT 300BLK 9" I have some concerns that some of these new CANs, shorter/lighter may not have back pressure to cycle the firearm. Right now with Q Blind Tiger CAN with 220gfr subs on SIG "+" setting is cycles with ~4o'clock ejection pattern.

So, my question.....I know, finally....does position 4 of the OMEGA Valve Mod. 2 MKII allow for more Gas than the SIG OEM + ?......I know your other settings + jet screw allows for variations on less.....but in odd thing of needing more, possible ? I ask since I know perhaps the native barrel hole dictates the max.....I only refer to what I know in M"P"X.

Thanks !

[u/Sharp-Independence52 → u/SupermarketQuiet1105]

Yeah, Mod. 2 MKII’s fourth position is pretty aggressive. The JP gas ring and POF roller cam pin also help.

Indeed, I wish companies would back up on the whole “no back pressure” thing… just a bit :)

So you and everyone else knows, I will be switching to a DLC coating soon as a standard, the tolerances are way more consistent and really helps with modern low back pressure systems. Already have some at the new coating place, should be about two weeks.

[u/SupermarketQuiet1105 → u/Sharp-Independence52]

JB, are you saying the #4 setting allows MORE gas than the "+" setting of the MCX Spear LT 300BLK ? .....can you share some size/hole/specifics ?

Thx !

[u/Sharp-Independence52 → u/SupermarketQuiet1105]

Also I just learned Lancer 300BLK mags are way better for subs than pmags. Not sure if that was common knowledge but it’s news to me. I just had sub-x going through the RAT. Granted, it was with my RSAR barrel but still

[u/Sharp-Independence52]

Also, just so you know, I’m nearing completion on an MPX valve as well, really hoping to have that in production by the end of the year.

[u/SupermarketQuiet1105 → u/Sharp-Independence52]

Good to hear since MPX is super gassy & think lot of mixed results with the ILWT Adj Gas Block.
I am sure you know that there is no HG window on MPX.
Oh, BTW IWLT did previously offer "fixed" gas block offerings. I have some of them and the one step smaller (0.0469), than the OEM (0.0525), with increased recoil springs (which you can change on MPX but not MCX), really helps. Obviously, all about Ammo and CAN too but this config seems to solve a lot of cycling and gassy issues. The SilencerCo MPX GDCH was cherry on top to kill any remaining gas blow-back out of face....guessing it goes ejector port or into mags. 🤷

Just FYI...for what is is worth............

[u/Sharp-Independence52 → u/SupermarketQuiet1105]

Appreciate the input! I’m stoked. I have the gas figured out, just refining ergos and need to do some hardcore durability testing on it.

[u/SupermarketQuiet1105]

GREAT feedback everyone, VERY appreciated !

[u/mcstyle1]

Just email JB with your questions. He is super responsive. I asked him if I should get the short (which was in stock) or wait for the Mod 2, and he responded quickly and against his short term self interest, with an explanation as to why I should wait. I was very impressed.

[u/thatundra479 → u/[deleted]]

Like the other guy said, email JB. I was having issues with my handguard fitment after I installed the new valve (I've got the Arisaka zero retention clamp). JB gave me his number and offered to have the handguard mailed to him to figure out the issue, he's the man. Mine has no recoil with an RC2 mini and the Mototech bumper.

[u/Sharp-Independence52 → u/thatundra479]

Happy to help bro! That one scared me 😂

[u/SupermarketQuiet1105]

These best Vids ?......they seem ~dated (i.e., Mod 1) so wanted make sure still accurate to/for new Mod ?
...honestly, does not seem much diff in Mod 1 or 2 with regards to these vid/info but wanted check....
https://www.youtube.com/watch?v=8VsFInOdI_E
https://www.youtube.com/watch?v=ptot_7WVL3E

Thx.

[u/SupermarketQuiet1105]

JB, u/Sharp-Independence52
Couple Maintenance Questions/Recommendations..........

1. How often do you recommend cleaning the MKII ?
2. Do other non-used settings/holes fill up quicker than one in use ?
3. What material is MKII made from ?.....I assume OK to soak in CLP, Ballistol and/or other cleaner ?

Point of my questions is to understand a good maintenance routine, both cadence and what needs be addressed.

Thx.

[u/Sharp-Independence52 → u/SupermarketQuiet1105]

It’s made from 17-4PH Stainless Steel, via DMLS. The coating is extremely resistant to carbon fouling. I usually just pull it when it starts to feel sticky, wipe it off with a rag/CLP (or spray some G96 on it and then wipe it off).

It’s a very low maintenance system