Anybody built a large monocore and have experience to share?

I'm building an integral on a large caliber rifle, around 2 inch diameter and 16 inches long.  
I like the monocore because it's simple and I can weld it in place to make the rifle not an SBR.

Monocores don't work as well for centerfire rounds, especially high pressure rifle rounds.  Doesn't mean they should be disregarded completely, but understand that your suppression in a given diameter and length will be appreciably less than a stacked baffle can.  For example, my 1.5" x 10" 6.5mm monocore is not quite as quiet as my 1.5" x 8" stacked baffle models, and has a noteworthy FRP.

My suggestion is weld the mount & tube assembly to your barrel and make a removable fully welded core of stacked baffles.

That's what I read everywhere.  I have a ghetto 22lr monocore I made and it works great, only thing I would change is that it has modest first round pop on pistols.  Given the size I plan to build i don't feel the need to chase the best possible efficiency.  The monocore is simple, durable, and easy to build.

Unsure on what caliber, but not for a shouldered rifle cartridge, leaning towards 44mag.  I want good performance with subsonic ammo and strong enough for supersonic, not concerned about noise with supersonic ammo.

I found some pictures of the inside of a couple of the integral 77/44 that various people make.  I was considering that design(pressed steel baffles with an annular expansion volume), but not sure it would be worth the extra effort to build?  I have a hybrid and it performs amazing with various subsonic 44/45 rounds - a monocore with 3-4x the volume can't be any worse I figure!

I've just never seen such a large monocore and wondering why.  I'm sure weight is a concern.  Many commercial silencers use monocore designs for rim fire, pistol, and rifle calibers and sell very well!

Well, if you're that impressed with a Hybrid, maybe a centerfire monocore will be satisfactory for you ;-)

Only a couple make heavy use of them.  Gemtech, YHM, Thompson Machine.

I set out initially to prove that monocores could be just as good as stacked baffles, and after many, many attempts, was forced to admit to myself that it just couldn't happen.  I tried it for everything from rimfire to big bore rifle, diameters up to 1-.75" and lengths up to 12".  My only active monocore design now is my Lynx .22 rimfire, and it's been mostly supplanted by the stacked baffle Ocelot.  I still do integral monocores for .22 builds, but completely skip them for centerfire anything.  I can make a stacked baffle can with the same dB reduction thinner, shorter, lighter and stronger.

Liberty centerfire monocores sound pretty good and their first round pop isn't too objectionable.

This is the second time you've remarked that the Hybrid's performance seemed lacking in your estimation.  I'm curious what hosts and calibers you tried it on and what front cap you used for various calibers.

It's not my estimation; my B&K 2209 doesn't lie.  Bottom line is that aside from big bore supersonic rifle, just about any respectable can performs better than the Hybrid.  The one I own hasn't seen a round through it in I don't even know how long, the couple of other maker's cans and all of my own being slimmer, lighter and quieter on all small & medium bore rifles as well as handguns and PCCs.

I've run it on every host I own, from .22 short to .45-70, .380 ACP to 45 & 10mm.  .17 Rem, 5.56mm, .220 Swift, .243, .25-06, 7mm Mag, .308., .30-06, .300 win mag, 10mm Magnum, .44 Mag.  The different end caps make very little difference, <2 dB on .308 going from the .46 end cap to .30 cal.

If someone were to come along and offer me a few hundred for it, it'd be gone in a heartbeat.

PM sent

Well there's no arguing with a good meter.  Perhaps I should have said 'in your experience' since I don't know how many you've sampled.   The experience across multiple calibers and hosts is always valuable input.  Anyway, if nothing else maybe this thread deflection got you an easy sale/offload of a slack resource.

Getting back to the thread, what baffle style, clip, BC size and baffle count/spacing do you recommend for a big bore build, say at least 1.5" ID and 10-12" long.  IIRC the Bowers can I looked at had a single step flat orifice baffle with a simple half ball mill scallop clip 180 decrees apart on entry and exit sides. They seem to be effective, and look really easy to fab.

Well, you haven't said specifically what round/loads you'll be trying to suppress, but in general, I find 65° cones with a ~.150" shoulder and integral skirt to work best for supersonic rounds.  In a 10" can, I'd do 12 baffles spaced 3/4" between blast and second, 5/8 second to third, 1/2" for the rest, or maybe shorten up the spacing on the last couple to .375 and .25.    That's just shy of 7" from blast baffle cone tip to front edge of front baffle skirt, which is gonna leave you about 2-2.5" of blast chamber, depending on your mount & end cap.  I would also absolutely incorporate a brake, my personal preference being helixed radial ports.

Lots of opinions on clipping, but I generally do a single radiused clip perpendicular to the cone wall, 1/2 aperture size and just over cutter diameter deep.   So, for example, if doing a .30 cal baffle, which I do with a .36" aperture, I'd use a 3/16" end mill, set the baffle to where the cone wall on the side I'm cutting is 90° to the axis of the end mill, and make the cut .200 deep.

Bullsh!t.

My mono core is as quiet as anything in the world.  It has produced stellar performance on everything from 338 LM down to 22 rimfire.  It is really good in 556 caliber.

The way a baffle is made is more or less irrelevant compared to the shape of the baffle.  The only reason people think mono cores are not as efficient as individual baffles is because they haven't got the smarts to design something good.

What you are gonna find is that milling out pockets on a piece of round bar that large becomes quite difficult.  You will be fighting vibration and trying to work-hold a part that isn't overly strong once much of it has been machined away.

I never tried to manually mill out any of my mono cores.   They were either EDMd or CNC milled with a specific method of work holding.

I would also caution against making assumptions that extra size/volume will automatically improve sound reduction.  Few years back I built a fairly big 9mm SMG can.  After initial testing I found the can to be too long.  So I shortened the tube by 2.5" and eliminated one baffle.  The result was the can got quieter.  How's that possible?  Dunno but the meter doesn't lie.

OK.  What meter did you use, what protocol, what weapon, barrel length, loads?

Sooooo.............you're effectively calling other people stupid whilst implying that you can machine the same baffle profile with a monocore that you can with stacked baffles.  Alrighty then.

I have a Lane Scorpion 5.56 can that is a monocore.   Ive used it on everything from .22 WMR to a 10.5" SBR with hot 5.56 ammo and .22-250 and .243

It has sounded pretty darned good.   It's quieter than my Gemtech Trek on the 10.5" SBR and .22-250.    I think my Griffin Recce 5 is quieter than the Scorpion, but not by much.   I do like that it is serviceable and I can clean it after shooting filthy Rimfire ammo through it.

Oops...double post.

That pretty much reinforces the point; the shorter, lighter, smaller diameter Griffin is quieter in your experience than the Lane monocore.

Another downside to monocores is that they tend to have a more dramatic effect on POI and accuracy, a product of baffles being necessarily very asymmetric.  It doesn't affect low pressure subsonic stuff as much, but something to consider.

Monocores are easier to clean, though.

From a manufacturing standpoint, consider that the monocore designs are faster & easier to manufacture and more material efficient than stacked baffles.  Rather little lathe work at all, and a CNC mill or VMC can punch out a mono in minutes, after which it's just metal treatment/finishing, then slipping on the tube, installing front cap, box & ship.   2-3 times the bar stock and many more steps go into a stacked baffle cans, especially welded ones.

A meter only measures sound pressure level.  The same pressure level can sound significantly Different to your ear depending on other characteristics of the noise that a meter can't measure.  Ie. The same 120bd from two different sources can sound very different.

I've also considered stamping cone baffles, but I was hoping to make this silencer offset(i.e. hang below the bore axis).   I like the monocore because it's easy to make, fits my application nicely, and im happy with the rimfire monocore I made.

B&K 2209.  I was trained to operate the meter by Al Paulson and have tested w Phil Dater and John Titsworth.  Does that meet with your approval?

Rifle was a 14.5" AR.  Can is a direct thread 1.5" x 6", weighs under 16oz and averaged in the 132's.

I made no such implications.  Those are yours.  All I said is that a monocore can most certainly produce sound reduction just as good as individual baffles without weighing a ton .... or words to that effect.

FWIW I have two US patents on sound suppressors and working on a third.  I have worked with various US companies and submitted designs to SURG and most recently the USMC integral suppressor project.

I'm gonna disagree with much of this.

With smart design, a monocore can produce good accuracy.  I've got one of mine on a 6BR and regularly use it out to 700yds with lightweight bullets.  Accuracy is mostly in the blast baffle.

In my experience a monocore is much more difficult and slower to machine than individual baffles.  The biggest problem is holding the part securely while the pockets are milled.  I've had some EDMd but that is a very expensive process.

Material efficiency is highly dependent on the baffle design but for something simple individual baffles will be much less material intensive than a monocore, which wastes a bunch of material between the baffles.

True.  Mostly it is frequency mix that seems to make the difference in how we perceive noise level.  I have a 9mm pistol suppressor that is a full 10 dB quieter than my 45 ACP pistol suppressor, yet the 45 suppressor sounds quieter to the ear because it produces a much lower frequency tone.

True.  Mostly it is frequency mix that seems to make the difference in how we perceive noise level.  I have a 9mm SMG suppressor that is a full 10 dB quieter than my 45 ACP SMG suppressor, yet the 45 suppressor sounds quieter to the ear because it produces a much lower frequency tone.

No need to be snarky, was a legitimate question based on the assertions.

132 with a 1.5x6 on a short barrel sounds really optimistic to me, though.  Most of the production shorties I've played with are just this side of hearing safe if at all, regardless of internals.

I didn't say they couldn't be made accurate.  I said they tend to affect bullet flight more dramatically.

The core itself is more involved, but the overall process is simplified with no need to weld or make spacers, rear mount, end cap.  It's all one piece.

I don't see what's so difficult.  Even in a plain old 6" machine vise, I've never had trouble, and I've made some with pretty danged thin baffles and walls

10" .28 cal





6" .22 cal





Well, an 8" monocore uses 8" of bar stock plus the cap, maybe as much as .500" there.  An 8" stacked cone or radial baffle can with ~10 baffles winds up using 15-20" of bar stock, depending on baffle profile, by the time you make front cap and rear mount.  The entire cone portion does not count toward stack length, resides inside the baffle behind it.  K baffles are pretty efficient, losing only the width of a parting blade times the number of baffles.

I'm not regurgitating things I've read or pontificating based on one or two attempts.  I have quite a bit of experience screwing with monocores.

One of the groups I work with had several test models made and those were tested by Doug Olson.  Those units produced an average of 132.3 dB on a 14.5" bbl running M855 ammo.   On a 12.5" bbl that same model ran 133.4 dB with M855 ammo.

I have had a bunch of R&D test units average in the 132's and even more in the 133's on a 14.5" bbl, so these are not one-off or outlier results.  My monocore design is extremely efficient.  In comparison to the pics you posted, my 556 can runs a blast baffle and 4 primary baffles.   It is both light and extremely strong, while producing excellent sound reduction.

The data above is for a simple thread mount can.  When the tube was lengthened to accommodate a QD flash suppressor mount, the thing dropped into the 131 dB range on the 14.5" bbl.

Phil Dater tested an earlier version of the mono core, which produced a 133.4 dB average (14.5" bbl) on his Larson Davis sound meter.  Since then the monocore design went through several changes to further improve sound reduction.

I'm only interested in hard data, not optimism.

And I'm only interested in the truth, don't care for name dropping to lend credence to what I view as rather fantastical claims.  I don't care about patents, either; just because you hold a patent for an idea doesn't mean it was a good idea.  There are thousands upon thousands of patents for worthless crap.  I see someone who signed up 9 years ago but just now started posting actively, and then decided to engage me, someone you don't know from Adam, in a hostile manner, your first word in this dialogue being "bullshit!".  How receptive do you think I'm going to be?   You've given me nothing to go on regarding experience/credibility as a manufacturer; no pictures, no links, nothing.  Quite the opposite, in fact, with statements like "monocores use more material than stacked baffle cans" or that it's "a big problem to hold onto the work piece", which are demonstrably false.  As I made clear in another thread recently, I don't care who you are, where you went to school, who you work for or who you rub shoulders with; your claims and arguments need to stand per se.  Appeals to authority are nothing but off-putting to me.

I'm not saying it isn't possible to see low 130s out of short cans on short 5.56 rifles.  I am highly skeptical of SPL claims, as my own testing with 2 calibrated meters, a 2204 and 2209, has shown than many manufacturers are, shall we say, borderline with honesty in advertising.  TBAC is the only one whose products have consistently hit the numbers advertised, one of many reasons I have such respect for Zak and Ray.  The results mean that either my calibrations are no good, that my digital microphone calibrator is out of spec as well, and that Zak & Ray are rating their cans 4-6 dB higher than actual, or that so many of the others I tested are advertised 4-6 dB lower than real-world SPL.  It's no secret that some manufacturers are using protocols of their own, putting mics 3 or 5 meters from muzzles, sometimes behind the shooter, turning mics 180 from muzzle, showing wet numbers without making note of using ablatives, etc.

Do you have pics, or at least a "napkin sketch"?  If I were to try to apply blast (first), primary (full) and secondary (partial) baffle, the can 3 up from the bottom, a fully titanium 8" .32 caliber would have a blast baffle, 4 primaries and 5 secondaries.    The pistol can 2 up from that would have blast, 4 and 4.  But I really don't know how you're applying the terminology, haven't a clue what your designs look like, or what you think it is that makes them so much better.

The material efficiency & expedience of manufacture were why I initially set out to do better monocores, and I have done all of these on fully manual machines with no problem hanging onto the part in a 6" Palmgren vise with parallels.  Every one of those pictured and a dozen others were profiled, bored & threaded on a 17x60 Rahn-Larmon lathe, and the core cut out on my Lagun FTV-2 knee mill.  DRO and single axis power feed, that's it.  No stepper motors, no drivers.  And they weren't done gingerly with shallow cuts; I poked holes all the way through and then went after my features full DOC with long 4 flute end mills.  Some are 7075-T651, some are 17-4, and a couple of those pictured are 6/4 AMS 4965 Ti.

Look, I'm showing you my work, telling you how I did it, and I'm not making wild claims about the performance of my products.  Yeah, I make a 1.56x5" 5.56 can, and it meters 139 dB on a 10.5" 5.56 AR, properly measured 40" perpendicular to muzzle with the mic at 90°.  And guess what?  That's 2 dB louder on average than the 6" 5.56 cans I've tested, some of which advertised similar SPL to what you're claiming but actually registered 137+.  I saw less than 1 dB further reduction on my 12.5" host.  A 14.5 has lower uncorking pressure than a 12.5, but not 4 dB worth.  These cans didn't hit the low 130s advertised until they were screwed onto 18" and 20" guns.

I don't just pontificate about this stuff anonymously on bulletin boards, either.  I make raw, unedited videos for the world to see who I am and what I build, and I spend a lot of my hard earned money on R&D equipment.

https://www.youtube.com/watch?v=rpLd44szJq8

You got a point there......



I am going to award bonus points for all the cool baffle pron you posted.  How did that brick/square shaped one sound?

I haven't got around to metering that one, but I'd say dBs are around 135-137 with a somewhat sharp tone (typical of square profiles).   It's also kinda heavy at 12-1/2 ounces and, while short at 5.3" long, bulky with 1.5x2.5" outer dimensions.  The housing is 6061, and that's as far as I could go with lightening cuts, still required screws down the center to keep it from bulging.   The first housing I thinned out much more, and it ballooned badly.

SiCo's Osprey was an obvious inspiration, but their custom housing extrusion worked out a lot better than 6061 rectangle tube stock!

So, it was a fun prototype, but I decided without hesitation that it wasn't a design to pursue.  My Phoenix IX, a stacked cone & K baffle can, is 1.25x8" and 8.5 ounces including booster piston, averages 124.3 dB with subs dry and can handle the higher pressure of .300 blk and .357 magnum no problem.

Sound suppressors are not my primary business and for the most part I have focussed on my own work rather than copying the work of others.  Hence I have not spent so much time on ARFcom.  I have been designing, building and testing sound suppressors for more than 12 years now, just not posting here about it.  I'm not appealing to authority and I don't care what you think.  I only noted that I was, in fact trained to sound test silencers by the very people who initially developed the test protocol because there are loads of people out there who don't know any better and just make up a "method" to suit their needs.  If you don't care then thats cool too.

I agree there are loads of crap patents.

I'm not a manufacturer.  I do R&D work only.

I only posted because you made the blanket statement that monocores are louder and heavier than conventional baffles and in my experience is that is not true.  The work holding issue is related to how fine the monocore machining is.  Thick, heavy baffles offer more stiffness for work holding.  Thinner, more complex designs are less easy to hold onto because they will deform under pressure.  As to material usage, I did note that it depended on the baffle design.  I wasn't making a universal statement with respect to material use.

I don't disagree at all.  Phil Seeburger used to test everything from 100m downrange os something so that all the sound reductions exceeded 40dB.  I'm well aware of the kinds of tricks used to make cans sound better than they really are.  But for me that would be self deception and only hurt my own work ... so I don't engage in that because it serves no purpose.

You can believe my data or not ... thats your prerogative.  Those who I know and associate with know my data is not massaged or manipulated and thats all that concerns me.

I'm not gonna post pics because the design in question is still current and has been submitted to various potential govt contracts.  There is a patent out there w drawings if you really need to know.

As to what makes it good?  The performance for size is what makes it good.  I never said it was "better" but I will say that it is good.

Yes, please. And the patent number is...?

+1

Want to meter a form1 in the near future?

Sure.

Lots of good input to your question from some experienced gents. I'll throw in my two cents.
Building a monocore is easy with the right equipment. Getting it to perform well and not be a boat anchor is another story.

The reason is designing a light and effective monocore is much harder that going with individual baffles. Good tried & true monocore designs are far and few between with very little design details available to the public.
Lightweight, efficient baffle designs are well established and detailed examples are on the net in several forums.

As an amateur I would strongly advise you to go with a proven baffle design and decrease your can dimensions. 60 degree cones in a 1.5 inch OD tube 10 inches long will give you very good performance. Even 8 inches will perform great with decent baffles.
My recommendation for amateurs like us is as follows.
K baffles work extremely well in typical pistol applications. Make them from either 7075 aluminum (anodizing them is a must) or titanium. Aluminum or titanium for the tube.
For high pressure cartridges use either 60 degree cones or omega baffles. These are proven designs and not complicated to make. Use either 17-4 SS or titanium. 304/316 SS or titanium for the tube.

Look over this thread for a huge number of complete builds.
http://www.silencertalk.com/forum/viewtopic.php?f=10&t=79895&sid=f1f85248b7095db58660e4a048678957