OSS 7.62 or Omega 300 on 8" 300 blk build?

[eugevita]

Greetings,

About to put together an 8" 300 blk build with the following parts and need to decide which of my two cans to use with this upper: I own a Si CO Omega 300 and a OSS HX QD 762 TI.

- 8" aero 300blk 1-7 twist 5R rifled barrel, BCM upper, BCM Fixed GB, and BCM MCMR. Lower that I will be using is running a law folder, though I have a non LAW folder lower as well that will see some use

My initial thinking was to use the OSS 762 since I hate gassy ARs and the OSS has run like a champ on every AR platform I have used it on. The question is though will it have trouble running subs which I would like to sometimes run in this build. If the consensus is that this platform will not run with subs than perhaps I should go with the SICO Omega and just deal with the gas blow back....perhaps it wont be too bad with subs. I talked to Aero yesterday and they recommended I run a carbine buffer if I use the OSS can.

Curious if anyone here had experience with this sort of setup. Thanks!

 

[RockFarmer]

This is belated, but just came across your thread. I built an 8" 1-7 twist 300blk similar to yours and I have an OSS 762ti . With my JK SCS H2 buffer, the subs are cycling, but the bolt doesn't lock back on last round. I love the can in general, since it moves around to different hosts, but I'm looking for a different can to be dedicated to this 300blk platform.
I did order some lighter JK buffer weights and spring kit to fool around with, but I like how it runs supers/subs as is and I won't settle for feeling too light of a buffer for the supers in order to get the lock back with the OSS. I was already planning on a dedicated can so this doesn't upset me much. In the meantime I will try the lighter buffer and see.

 

[the monk]

I dont really see the point of 300 blackout subs unless they are quiet and I would assume the Omega will be far quieter than the OSS.

 

[RockFarmer]

Yes, agreed. The HX-QD 762 is not a great match.

 

[MSTN]

Flow-through designs like the OSS/HUXWRX are not your best choice for the .300 BLK subsonic loads. According to the people much smarter than me over at Pew Science, subsonic ammo requires mucho back pressure to be seriously quiet.

The Surefire SOCOM300 SPS is the quietest can I've tried with subsonic .300 BLK ammo. It's also rather big and heavy. Expect a lot of gas in your face with it.

 

[phantasm]

I went the Nomad-30 route on my .300 8" SBR. With 220's it is dead quiet.

 

[the monk]

The OG Sig cans or the Q cans are what you want for quiet, low tone, 300 blackout super quiet.

 

[Ape_Factory]

I ran the OSS 762Ti on an 8.5" and 10.5" barrel and found it to be pretty damn quiet. I've moved on to a piston Sig and run it on that setup currently. I don't really have anything to compare it to yet but will have the Diligent Defense Enticer S Ti in a few months and the new 7.62 Flow in 7-8 months. I've stood behind another shooter and ear pro was definitely optional. I'm sure there are quieter options but it was very easy to go back and forth between supers and subs with this setup.

On the DI gun, I ran a lightweight BCG (RCA) and a lightweight buffer (Odin Works adjustable) with one steel and two aluminum weights if I remember correctly. Flat wound spring, normal strength. I also used an adjustable gas block. Ran everything with no real adjustments, supers or subs, with the exception of the Hornady 190 grain Sub-x rounds due to bullet shape. I want to say there were four clicks of adjustment between supers and subs using the Superlative Arms gas block.

 

[RockFarmer]

@Ape_Factory Really nice weapons you have there!
I'll add that my DI 8" 300blk does not have an adjustable gas block. After reading your buffer setup, I'm encouraged to test lighter weights for my JK buffer. Interesting you like it for the piston gun. Is it 300blk as well? Interestingly the platform I especially like my OSS 762ti on is a 16" PWS 5.56. Curious that Pew Science found the FLOW 762 to perform wonderfully for 556.

Congrats on choosing two more awesome suppressors. I just ordered a Hyperion, but have plans to order the FLOW 762 next.

 

[Ape_Factory]

The Sig is indeed a 300 blackout with a 9" barrel. I think the DI gun is softer shooting than the Sig. The Sig with subs is super easy but it has some kick with supers. Not quite 308 territory but not far behind. I don't find that to be true with say my POF P415 piston vs. my DI rifle in the same caliber. But we're also talking 5.56 vs. 300 blackout so not apples to apples.

But the Sig is a tidy package and it seems to run everything, subs or supers, and with the stock folded, it's very compact. The DI gun, having a slower twist, is more flexible in terms of what projectiles you can run safely with a suppressor. Actually working on having a new barrel made for the Sig with a slower twist with the help of Bartlein and Craddock.

 

[Deepwoods]

I was in a similar quandary as the OP. I want to use on OSS--lefty and hate gas--but found subs dont seem to provide enough back pressure. My Noveske 10.5" cycles unsuppressed with subs and usually locks back--Ive not tested all the 200, 208 and 220 options I have. My guess is if it does that, it would cycle fine with a flow thru.

But I got tired of swapping muzzle things and suppressors, so it has an owned-prior-to-OSS Nomad30 now. Its quiet, aside from the action, and I can stand a few feet away sans ear pro and its fine. As far as gas... its not bad, especially if Theres a breeze.

The V7 8.5 has the SF 300 sps and it is very quiet. But there is much more gas. This set up won't reliably cycle subs without a can.

I ponder opening up the gas port to use a flow-thru, but then run out of mojo...

 

[mewillis]

I run an Omega on my 8.5 BO but it's subs only. Quiet, accurate and dialed in @50yds. I would think the OSS is more designed for overgassed or a precision rifle platform.

 

[TheHorta]

I have both, and on my SR-30 there is no comparison — specifically when it comes to subs.

MSTN was 100% correct. The HUX *need* high/supersonic pressures to be effective. It doesn’t do well with subs. The Omega will be notably more quiet.

That said, the zero-backpressure design on the HX QD is amazing. The Omega will fill your face with gasses, foul your chamber, and your gun will cycle differently due to the increased backpressure.

Equally as important, the HUX can *crushes* the Omega when it comes to SUPERS. It is much more effective at suppressing supersonic 7.62 than the Omega, and it keeps all of the zero-backpressure benefits.

So, if your primary criteria is heavily weighted toward sound reduction of subsonics than the Omega is your choice. If you can live with the increased sound on subs to get all of the other benefits, that HUX brings to the table, then the choice would be clear.

The HUX would be my clear choice, provided subsonic sound suppression wasn’t the overriding factor in my decision.