I'm using a Rearden Atlas with the SPB muzzle device, both nitride finish, and it's locked up with only 92 rounds after the initial outing of 124 rounds. I've only ever hand tightened the can without ugga-dugging it on. I had to smack the wrench to break the can loose off the muzzle device. The tapered surface creates significant resistance, where threading it on/off requires both hands. No carbon present behind the taper.

Does anyone else experience this with the Atlas? I'm happy it confidently stays on without secondary retention.

Edit: added photo

Yes, normal. Is flaw of the Sico Bravo thread pattern. The surface area of the Bravo mount on the can is weaker than the taper mount of the Q/Rearden system on the muzzle device. De-grease Atlas and Rocksett it into the can. That's the con of the multi-use cans that use it, you can't really use them hard with confidence that the adapter won't come loose. If you are going to use it other than plinking from a bench setting where you can check it every mag, you have to commit to something and Rocksett it. To undo, just soak that portion of the can in clean water overnight and then pop it off in an Energetic vise lock. I've never had the Q system come loose from the muzzle device or any issues.

Normal for it to carbon lock onto the muzzle device?

The SPB in particular fouls up like that. Mine got better with use.

I have not used a Reardon muzzle device on any of my rigs but my buddy does in conjunction with Q Plan B and he has never complained of carbon lock. I do have an Atlas on one can that is used with either Cherry Bombs or Liberty Machine brakes, no issues there. I mostly use Plan B and Cherry Bomb combos and no carbon lock there.

I recently just got a Rizon Dreadnought adapter that looks very well made and finished but have not used that one yet. But my buddy has one of their muzzle devices used with a Plan B and no issues…

Either way, carbon locking with this pattern set up isn’t “normal”, in fact locking to the muzzle device defeats the whole point. I suspect this is a tolerance stacking issue between that brake and the adapter.

What is happening here is something I call the "rivet effect".  It's what happens when carbon builds up ahead of the taper while shooting and you have to pull it back through the same hole that it entered (the small diameter at the end of the taper in the adapter).

To combat this effect, any feature ahead of the taper on the muzzle device needs to be smaller in diameter by whatever amount you're OK with the customer building up on there.  In the case of the KeyMo devices, it's quite a lot.  On the Xeno it's less, but still substantial.  

Another design element to combat this is that the inside of the adapter has a face that acts like a carbon cutter that can scrape some of that carbon off as its pulled back through.

The step-down is observed ahead of the taper.  It this case, it would have to build up a really, really, thick layer to reach up to where the taper starts:

It looks like a couple things are going on here.

1. Are you by chance shooting 6.5 Creed? The only time I've really seen this is on 6.5 Creedmoor, we usually recommend our PRS brake for that application, for some reason it is just nasty with carbon in the blast chamber. 6.5 PRC doesn't seem to suffer the same fate, for example. I have only seen it with the SPB on PRS rifles, the SPB is stripping all that gas and sending it to the sides, which in turn, coats the muzzle device thoroughly. The flash hiders and minis don't suffer the same fate, but they also don't serve the same purpose.

2. What Todd said is on the right path, what you're feeling is likely the atlas wiping it clean, we have a carbon "shearing" surface there. The carbon builds up after the shielding in the Atlas and when unscrewing it, it wipes clean, which obviously can take considerable force if there is a bunch of carbon in front of the shielding area.

3. The SPB is fully tapered, it should get easier after two turns.

4. We always recommend cleaning it after each use, usually with a good carbon cleaner and a rag it's fine for the next use. That will "Reset" any additional resistance you may be feeling.

If you need any help or have any additional questions past the little bit of advice I've given, just let me know. Message/email/call us.

Darren

Darren,

1. I'm currently using 6 creedmoor and have adopted Atlas for all precision stuff, which includes 6.5cm too.

Copy all 2-4.

Man, that sounds awfully similar to what I told the OP a few days ago.

My brother in Christ, keymo is the way. Sorry you hate weight.

I'm on a weight loss journey and as soon as I'm close to my target weight we'll release a lightweight KeyMo Adapter too.  

Also, I want to point out that my post above wasn't a knock on the Rearden design at all, it's just that it's good to know what it's intended use is and maintenance required.  If you understand the design intent, you can use it accordingly.

This is spot on, there are trade offs to all designs. When dealing with suppressors, everything can get stuck. Suppressors are a hostile environment, there is literally not a single system that can't get stuck.

They all have their ups and downs, anyone who claims their system is "the best" is just ignoring reality. What is best for one customer or application may not be the best for the next. If you're happy with your system, then it's the best for you. Any of the manufacturers who are in the top make a solid system, we could nit-pick other systems to death, but that is all it is. We are in a far better situation than when I started in this industry 15 years ago.

I think the problem is the idea of Quick Detach, rather than Quick(easy) Attach. Once a can is hot one has to wait for cooling anyway.

My approach for all right hand thread is attach with torque on body of can, detach with hand or tool on exposed mount only. This way I never inadvertently apply loosening force to bravo tube threads.

If carbon isn’t getting into taper and threads, those features aren’t carbon locking. So judicious torque there and never threading a warm can onto a cool muzzle device helps. Carbon buildup in the muzzle device forward/proud of the mount bulkhead eventually comes down to periodic maintenance.

Mix and match of parts is always a bit of discovery mode engineering. Seems like designs are maturing/refining and getting more robust.

I refer to ours as indirect thread, because I believe that is what it is. I use the same techniques at the range. I also am not afraid to dump copious amounts of water on things or dunk them in coolers when I want to do something with speed, haha.

Except the part where I needed a wrench to remove the Sierra 5 on a brand new keymo system after 80 rounds of .223.

Off topic.  Never seen it addressed, what do can manufacturers say about dunking cans to cool them off?

I have a bunch of Rearden\Liberty mounts.  What I've found is if I keep the threads really clean and add some light oil they're much easier to remove.  If the threads are dry and you crank down too hard they can really get friction stuck on there, even without shooting or carbon.

Nitride against nitride.

Can you expound on that?

They don't, the reality is it depends how hot it is when you dunk it and what material. I don't dunk them if they're cherry red. But I also will just replace it if I destroy it, I don't have to wait long.