.223 bolt gun coming together. Many thanks to Ron for fixing my barrel that was incorrectly profiled.

Bighorn Origin action with Southern Precision Rifles prefit-18" 1/7 Krieger in a KRG Bravo chassis

That looks badass.

Exactly! Bet it shoots like a dream as well!

Let’s meet up at Talladega CMP so I can shoot that thing! Nice work.

Mine came in after the long backorder wait. Now the next phase of waiting for it to come home with me.

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Hot.

That's what my barrel was SUPPOSED to look like.

That would be worth making a road trip if gas prices ever come back down again.

@Outrider That thing looks sweet.  We know it sounds killer already.  

I love this.  Clones are great but its always fun to see inspired builds like this.

Well done.

@k31user
@kaotic504
@bigbore

This is an interesting topic for me.  I am also looking to pick up a SCAR 20S to use with Ron's .30 cal suppressor, but I'm not going to spend all that dough until I know a proper brake/collar solution exists.

First thing to note is that the newer 20S barrels have a 1:10 twist and a thick profile out to the threads, so the shoulder is meaty enough to index a brake.  The original 20S barrels were 1:12 twist and have the stepped barrel where the first few inches at the muzzle end have the pencil profile of the 17S barrel and then step up to a larger OD further back.  For these original 1:12 barrels, using a shoulder ring is a crappy non-robust solution for mounting a brake.  You really need to use a brake that slips over the barrel ("OTB" brake) to index off of the actual muzzle face.  By the way, this is how the military-issued FN suppressor and Surefire FA762-SV and corresponding brakes worked.  Then, if you need to time the OTB brake, use these timing shims which were made specifically for this purpose - https://lga-systems.com/products/muzzle-device-timing-shims-for-scar-7-62mm-scar-17s-mk-17

So, now that we understand there are two different barrels for the 20S, I'd like to find out which style is going to be easier to mount the AE .30 cal suppressor on.  My first instinct is to track down an original 1:12 twist 20S so I can use a 1-piece OTB brake, which is more true to form to the original spec w/ reflex style suppressors.  However, I'm surprised to find that some of you are saying the 1-piece brake design is NOT preferred to 2-piece brake + collar setup.  I fail to understand why this would be the case.

Here's why I say that.  I have a few real USGI Mk12 "take-off" barrels and an Allen Engineering SPR brake/collar kit purchased from High Caliber Sales.  To my surprise, there is a bit of noticeable play between the fitment of the collar and the OD of the barrels.  It's certainly not a "precise" fit by any means.  This means that once the set screw is tightened, there is almost a guarantee of a lack of concentricity between the muzzle and the collar as the set screw pushes against the barrel and moves the collar off-center by whatever amount of play was there between the barrel OD and collar.  Never mind the fact that the barrel shoulder might not be perfectly square/concentric or that the AE brake threads might not be perfect either.  Hell, the runout of the barrel OD from the muzzle back to the collar area might be sloppy as well, adding yet another variable to contribute to a potential lack of concentricity using the 2-piece brake/collar design.

Compare that to a 1-piece OTB brake where you only have to ensure the brake itself was machined concentric from end-to-end and that the muzzle face of the barrel is square/concentric relative to the bore.  That's it.  At that point, the OD runout of the barrel profile is irrelevant.  It can be way off, and since the OTB brake is "floating" over the barrel and not even touching it, it won't affect a thing.

Am I missing something?  A 1-piece OTB brake actually seems like a better option, no?

Are you trying to mount an AE30 or an AEM5-30?

I don't have the suppressor yet, but it would be an AE30 unless there is a compelling reason to go with an AEM5-30.  I didn't realize the AEM5-30 was a thing though to be honest.  I'm working with Kevin @ HCS to order a few more of your supremely awesome suppressors!    Definitely getting another AEM5, probably a shorter .22 variant, and then possibly the AE30 if I can find a way to mount it up on a SCAR 20S.

What's your take on the 1-piece vs. 2-piece mounting, Ron?  Obviously, I would expect you to be an advocate of the 2-piece design, but I'm wondering if you find my argument above for the 1-piece OTB brake to be compelling enough to consider producing one just for us SCAR users?  The SCAR in 7.62 is a very popular weapon platform, and I'm sure the community would be very accepting of a proper reflex style suppressor that is true to the original military-spec suppressor setup.

Ae30 mounts with 5/8 threads. I don’t see how a one piece for that would be possible

Not approved yet but I was in the area and had the rifle with me.

Very nice looking rifle. I always wanted one in 6.5x.284.
RonA

God damn - that is a thing of beauty right there.

Absolutely. That is nice!!

Ron, sent you a message when you have time.

I wonder what it'd take to mount this to a 14.5" LMT MRP barrel.

Has anybody done that?

Had some free time, and really got into this thread today. Apologies if I'm being obtuse or have simply overlooked the answer, but I'm asking for a few clarifications and confirmations from the experts in this thread:

An Allen Engineering M24 is equivalent to the OPS Inc 3rd, correct? The AE30 (not the AEM5-30) is the same suppressor, but approximately 2" shorter?  

If I recall my numbers correctly, the M24 and 3rd model reflex over the barrel by 4.625" and the AE30 by 2.625"?

All of these used direct-thread (no muzzle brake) mounts with 5/8"x24 threads? (Aside from a few with 11/16"x24 threads, IIRC)?

So, the AE30 would fit on a properly SPR-contoured/collared barrel in .30 caliber, with a 5/8"x24 thread, as opposed to the typical SPR muzzle brake, correct?



On to .22 caliber questions:

Was there an OPS Inc 3rd model in .22 caliber available to the public? I gather that the 1993-era (i.e., Gordon suppressor) were near one-offs with .22 caliber baffle stacks inserted into .30 caliber suppressors (presumably 3rd models, or something similar). This is essentially the M4 (not AEM4) suppressor that Ron has recently released in small batches (re-released ???).

So, the M4 naming is AE, not OPS Inc? Whereas M4-S and M4-M (which I realize are a different mount) was OPS Inc naming?

Do all of these .22 caliber non-muzzle brake suppressors use 1/2"x28 thread, or are there one-offs?

This would then suggest that AE22 is a shorter M4? (Edit: I note that the AE22 DOES use 5/8"x24 threads).

Thanks in advance!

Answers added.

Thanks! I'm such a dork ... I have a spreadsheet and everything :)

Okay, as a follow-up to my questions about a 1-piece adapter for mounting the AE30 on a SCAR 20S or 17S, I was able to get some measurements of the original spec 1:12 twist 20S barrel and also took measurements of my own 17S barrel before coming up with something that I believe would work.  *edit* Replaced rough sketch with dimensionally correct 3D model.  See below.

20s 1:12 twist:

Full diameter .782
Small diameter .667
Step to shoulder 1.91

17s 1:12 twist:

diameter .667
muzzle to shoulder .706 (should be same on 20S although I couldn't confirm this measurement because person who measured for me had a brake installed on his 20S)


Taking this info, we know the distance from the muzzle to the step on the 1:12 twist 20S barrel is 1.91 + .706 = 2.616".  




All you would have to do is make a 1-piece adapter similar to what is shown above with the exterior dimensions as shown on the AE30 barrel profile drawing from the Allen Engineering website.  The internal dimensions would basically just need to accommodate the profile of a 20S barrel.  This means the rear-most internal step would have to be about 2.6" away from the muzzle indexing surface i.e. just a little shorter than the 2.616" muzzle-to-step distance calculated above to ensure the muzzle bottoms out before the step contacts the internal rear-most step.  Also need to make sure the 1st internal step is less than .706" away from the muzzle indexing surface for the same reason i.e. so the muzzle bottoms out before the shoulder does.  The thinnest section of the wall inside this adapter would be .092 thick, which seems plenty adequate.

(.850 - .667) / 2  = .092

This would work for the 1:12 twist 20S barrel and the 17S barrel.  You could make this work with the non-stepped 1:10 twist 20S barrels as well, but this would require a single internal diameter of .782, which means the walls inside the adapter are going to be thinner at .034" thick.

(.850 - .782) / 2 = .034

Using my digital calipers, this seems pretty thin.  I'm not sure if there would be issues with rigidity or otherwise.  I'm also curious if there is enough clearance inside the AE30 suppressor to increase the O.D. of the barrel/adapter profile spec to something a little thicker than .850 at the expense of eating up a tiny bit of the surface area at the 20-degree taper surface... if so, you could increase the .92 MIN diameter to compensate and provide a little more of that 20-degree taper surface, but that's also assuming the rear of the suppressor has a little extra 20-degree taper surface to mate with it.

Either way, the 1:12 twist 20S/17S version seems like it would be worthwhile.  There are a ton of 17S owners out there suppressing their rifles who would like a reflex style suppressor as an option to mimic the Surefire FA762SV-BK reflex suppressor that was issued on the Mk17 13" and 16" battle rifles and is no longer being produced by Surefire.  What better replacement than an Allen Engineering suppressor?  The new 1:10 twist 20S barrels can also easily be re-profiled to the same stepped profile as the original 1:12 twist barrels, and people are already doing this for "clone correctness," so it could work on the newer 20S rifles as well with that slight modification.  Again, that's assuming a thinner walled adapter for the 1:10 twist barrel is out of the question.

What does everyone think?  I'm proficient in AutoCAD and can whip up a legit 3D drawing in Fusion360 in no time if there is real interest for running an AE30 on the SCAR battle rifles.

*edit*  Got bored after wife went to bed.  Figured I'd just go ahead and knock this out.  @k31user , let me know what you think!  If you wouldn't mind sharing what your bore exit diameter is on the AE30 suppressor, I'd like to update my adapter's bore exit diameter to the same size.  I have it at a .358" diameter for now just as a placeholder.  All exterior dimensions are to AE30 spec per your drawing.  Internal barrel diameter clearance is .025" greater than the .667" barrel diameter for a close fit without an unsightly gap around the barrel.  The internal 5/8-24 threaded section is .05" shorter than the .706" muzzle-to-shoulder distance I measured on my 17S barrel so the shoulder of the barrel doesn't make contact before the muzzle is fully seated.  Similarly, the rear of the adapter stops the same .05" short of reaching the step on the 1:12 twist 20S barrel.  This thing should work without any issues.

@k31user - Does your AEM5-30 mount the same way as the AE30?  I don't see the AEM5-30 or specs for it anywhere on your website.

@Shlouf - That is a beautiful rifle!  What the heck is it?  LOL... Sorry, not a bolt gun guy, but been meaning to get my feet wet one of these days.  I love everything about that build from the round contour stock forearm to the full length pic rail on top for mounting clip-on NV gear.  Also, how do you have that front sling swivel/loop mounted?  It looks like it might be attached to the Harris bipod somehow or is it just tucked right behind it?  Either way, it's a very tidy setup as it doesn't have obnoxious sling QD sockets all over the place, a sling hanging off the side, etc.  You might have just given me a reason to pick up an AE30 even if I don't end up running it on the SCAR.  Details on your build, please!

It's an M24A2, a proposed modernization of the M24 with an Ops Inc suppressor and the rail. The stock has two sling swivel attachments on the front of the stock; one for the bipod, one for the sling. Things were happening very quickly when it was proposed, the XM2010 being one of them, so it never really entered service.

@Shlouf - Great info.  I appreciate it.  Looks like I have lots of reading to do on this platform.  Again, very nice rifle build!  Let us know how it shoots with that AE30!

Fox pretty much covered it. Very few M24s got the upgrade to the A2. OPS 3rd model is the can that was originally selected. There is a big M24 thread on snipershide in the bolt gun section. The guy who designed the M24a2 and a3 posted alot of good info there.  link

What I have is the M24 suppressor (3rd model), not the AE30. It is the same as the AE30 except it reflexes over the barrel 2 more inches.

Good stuff.

I've got a AEM5-30 with no home and an R700 LA receiver from my abandoned Mk13 project. Maybe a M24 type project would be a suitable new direction...

Do it. But like Ron said, I'd probably go with a better caliber for the long action.

Great work man! If you find someone to produce one, let me know.

Oops.. I didn't even notice that it was @Markius-Fox who chimed in.  Thanks Fox!  One thing that ar15.com doesn't do well that other forums do is make it easy to see who each post belongs to.  Something about how the avatar pics are above the posts and the names are in small font... oh well, I digress.

I appreciate all the M24 info/links, gentlemen!  Cheers!

Yes, sir!  I'm hoping Mr. Allen himself will take it on.  Hint hint @k31user !

*edit* Check out what I found on page 1 of this thread.  AE30 on a SCAR!  I wonder how this person made it work.  1-piece adapter like I came up with or did they re-profile the already skinny SCAR barrel and remove material to give it a step for a collar?  I wonder...

Can someone help me out and point me towards AEM5-30 info/specs?  Trying to figure out if this would be a better fit for the SCAR vs. the AE30.  The AEM5-30 product description on various vendor websites says it works on any SPR profiled barrel, but there are no drawings or info about the mount (brake or 1-piece adapter?) and dimensions, so I have no idea if it can be adapted to the SCAR barrel somehow.  I did see that it's supposedly 11.25" long.  That's even longer than the AE30 by 3/4", so I'm also wondering how much it reflexes back over the barrel vs. the AE30 @ 2.5".  

Is this the Allen Engineering take on the original 12th model PSS .30 cal suppressor by any chance?  The specs of the 12th model PSS on page 1 of this thread says it's 11" long and reflexes 4" over the barrel, but the specs for the AEM5-30 are not given, so I'm a bit unsure how these suppressors compare.

Finally, if not a remake of the 12th model PSS, what is the purpose of having the AEM5-30?  I'm confused on why it even exists.  Who actually makes a .308 or other mid-caliber barrel with a SPR profile, and if it has to be custom profiled anyway, why not just profile it for the shorter AE30 suppressor and avoid having the mount setup all together?

If you have a properly set up MK 12, an AEM5 in .22, 6.5, or .30 cal will all fit on the rifle. If you remove the brake and install a 1/2-28 to 5/8-24 thread adapter
an AE30 will fit on the rifle. Both go back over the barrel the same amount. The blast chamber on an AEM5 has to have room for the brake to fit inside, the AE30
dos not use a brake so the chamber is shorter. That's why the AEM5-30 is longer than an AE30.

RonA

@CPshooter1 let me know what you need, I have both cans and can get the specs for you (AEM5 and AEM5-30).

But I believe Ron answered your question, they use the exact same mount, but the -30 is longer and of course 30cal. I think it would make a great can for 6.8 or 6.5grendel.

Yes, Ron did answer my question (thanks @k31user), but I guess I'm still not seeing the advantage or why someone would choose to run the AEM5-30 over the AE30.  Is it basically made for people who can only afford one can and want to run it on their Mk12 clone and also a 6.5, 6.8, 7.62, etc?  If the brake/mount is the exact same for both suppressors, does that mean the brake in the SPR brake/collar kit has a bore diameter large enough for a .30 cal bullet to pass through?  I could have sworn the SPR brake was made for .22 only...

Ron will machine it to fit a 30 cal projectile or whatever projectile you need to pass through it.

You can get 6.5 and 7.62 5/8x24 brakes.

@kaotic504 @Outrider

That definitely clears up a few of my questions.  I'm really just trying to figure out if it makes sense to look at the AEM5-30 instead of the AE30 for use on the SCAR platform, hence all my questions.  From what I'm understanding though, it doesn't sound like the AEM5-30 is an option for the SCAR 17S with the straight profile pencil barrel.  Thinking out loud here...There is no step on the 17S barrel to secure a collar, and even if you create one by re-profiling the front couple of inches of the barrel to be even skinnier, you would still not be able index the brake off of the shoulder because the shoulder on the 17S barrel is already practically non-existent, and making the barrel even skinnier up front means you would literally have no shoulder left at all.  You might be able to get around that problem if the brake allows for a slight modification to open up the rear so that it slips over the barrel a bit, but that would also require that the inside of the brake has an adequate square surface to index the muzzle off of (example: the KAC QDC flash hider allows for this modification).  All that to say, the juice probably wouldn't be worth the squeeze here because no one is going to want to re-profile their 17S barrel even skinnier anyhow.  Even on the 1:12 twist 20S barrels where you already have a stepped profile for a collar, you still have the same issue with the brake needing to be modified to index off the muzzle instead of the inadequate shoulder.  And shoulder rings are just a bad idea on the SCAR no matter what the companies who want to sell you one will tell you.  

I think the AE30 w/ the 1-piece adapter I came up with would be a far more streamlined solution for both the SCAR 17S and 20S, and now that Ron confirmed both suppressors reflex back over the barrel by the same distance, the AE30 would be the more compact solution as well.  Plus, you wouldn't have to modify your barrel at all or even have a collar set screw marr and affect resale value of a $1000+ barrel assembly.  

Probably been asked, but will the Smith Vortex with 22-1mm threads fit an Allen AEM5 can ?

Yes. It was made for the Canadian C8 contract to be used with Ops 15th cans. I have one and use it with my AEM3

One of my barrels has a Smith on it.  Works just fine with my AEM5.  I also have one of the Spikes brakes on my other host.  I do have an oem brake from Ron but I haven't decided what type of upper yet I'm buildling next.  I might finally go down the clone rabbit hole and shoot for a Mod H of some sort.  

Every time I visit this thread I get the urge to build a bolt gun with a profiled barrel. Sexy and super quiet.

You owe it to yourself to do it. I shot mine for the first time recently and it lived up to the hype I had built in my head.

I might get a .224 cal of some sort spun for my rifle and have it contoured for the AEM5.

What are the details on yours?

Zermatt/Bighorn Origin action with a Bugholes prefit barrel. 18” 1/7 Krieger. It was supposed to profiled for the AEM5 but they missed the taper angle. Ron helped get it squared away with a collar. The prefit is nice where you can change barrels at home. It’s like building an AR.

I put about 60 rounds through it recently and didn’t wear any ear pro. Sounded phenomenal.