Update with pics. Suppressor Torture Test!!

[ken226]

On October 2, 2014 i loaned a suppressor to a government agency for some torture testing. I told them to abuse it in whatever manner they saw fit. The original plan was to get 10,000 rounds through it before i cut it open for inspection. Due to the impending DHS shutdown i decided to alter the plan and get it back for inspection a little early. They were up to 7000 rounds when i got it back.

Observations:

The finish was cerakote over manganese phosphate parkerizing. It was heated to 900f several times during extended full-auto fire and the cerakote was destroyed immediately. The parkerizing seemed to hold up quite well!

The tig fusion welding process which was used to weld the baffles together, as well as the end caps to the tube held up very well. They resorted to dipping it in a bucket of water to cool it between stages of fire, doing mag dumps of up to 6 mags back to back at a time.

The 4140 blast baffle held up pretty well. Most of the full auto fire was on an HK 416 10 1/2 inch piston gun. There wasn't as much blast baffle erosion as i expected.

The carbon buildup wasn't that bad. I don't think carbon buildup is much of a concern on a .223, especially on a 10 1/2 inch barrel.

Corrosion and rust were non-issues. Despite being dipped in water and shot very wet for nearly a week, and used in the rain several times, there were no signs of corrosion. The rear end cap, front cap, tube and baffles 2 thru 5 are 4130. The blast baffle is 4140.

Several times it suffered baffle strikes. These were due to the 1/2 - 28 threads coming loose during full auto fire. The front end cap bore hole was oblonged by the baffle strikes. Accuracy wasn't effected, it still shot 1 1/2 moa groups (at 100 yards), despite the oblong exit hole. The POI shift after the baffle strikes was significant though. POI shift when new was about 4 moa, after the baffle strikes it was about 5 feet @ 100 yards.

The direct thread mount is a weak point. A QD mount would have prevented these baffle strikes. Probably a non-issue on most guns, but for a gun being abused and shot without checking tightness every few mags, it could be a problem.

Once, at about the 3000 round mark, it started to cause rounds to impact the target sideways. I think this is when the front cap baffle strikes occured. The more diameter of the blast baffle was about .22 in diameter at the time too. I believe the muzzle blast had peened the steel in the nose aperture and reduced the diameter. I cleaned it out with a drill bit to open it back up and it started shooting good again.

Ammo was a mix of Federal JSP and Speer Gold Dot JSP.

[john.t.little1]

Thanks for the write up very informative and the design is pretty interesting. What would you change in the design and testing methods now that you've looked at the can and gotten results?

[john.t.little1]

Is that a screw where the weld is?

[ken226]

I'm thinking a larger diameter bore in the blast baffle and perhaps hardening it as well. The .265 diameter hole closed up pretty quick from carbon and/or peening and at about 3000 rounds, it the hole was small enough it was contacting the bullet.

Symetrical clips. i've experimented with 3 clips, 120 degrees apart and had less POI shift than with 1 clip per baffle.

I'll also try and steer customers toward QD mounting systems. Direct thread is more succeptable to coming loose during heat/cooling expand/contract cycles. Also, the flash hiders and muzzle brakes seem to help the blast baffle take less of a beating.

yes, its a screw. I put 4 screws in the blast baffle, and machined the heads so that they would hold the baffle stack centered during the welding process. I've since changed that design and now use a blast baffle with radial spokes to hold the stack centered. There are pics in the "all else equal" thread.

[john.t.little1]

I figured that's what they were for looks good thanks man

[T-Rex]

Did you treat the steel, at all?
Carburize, nitride?
Was it PH?

More or less wondering what condition the steel was in to sustain the abuse.

I like that design.

[ken226]

No, it wasn't treated at all. the blast baffle was machined from cold rolled 4140 1.25 diameter round rod stock.

Im guessing the hardness is about 35-40 rockwell, same as typical 4140 barrel steel.

[Mueller]

Held up pretty well for as abused as it was. Very nice.

[Pat M]

great pics and write up, suprised at how little material is in the outer gap around the inner tube.

[gunny50]

It is interesting to see how wel the scoop worked the gas as Carbon i settles one side of the baffles.
I think if the blast baffle was a little further from the Flash-hider as discussed on the previous post the gas might have worked that volume better.

Gunny

[CMV]

H or C series Cerakote?

[ken226]

It is the H series. Oven cured.

they also make a Hi-temp cerakote which may hold up better to 900+ degree temps. they advertise it as being able to take 1200 degrees, so perhaps the fact that it was applied over parkerizing reduced its heat resistance.

[T-Rex]

I dont know about the heat resistance being compromised, but the park probably didn't help adhesion.
I've used Cerakote twice and they do not promote the use of anything on the surface once it has been prepped.

An acquaintance Cerakote'd his motorcycle exhaust in a matte black color.
Looked really good and is still a pristine finish, even up the headers.

It's not too expensive for a small container and only takes about an hour to cure.
Give it a try.
I think they even recommend using it on the inside of the exhaust and a coating is only about half a thou so doing the inside of the tube and baffles might be an option, too. Just not Al baffles

[pyrofx]

You need the C series. H will burn off quick. Park under os fine as lpng as you have a good "tooth" for it to hold on to
I use about a gallon a year.
Great stuff!
Greg

[CMV]

Parkerizing is a GREAT base for Cerakote. So long as it's very well degreased & sweated out.

Try the C series. Not intuitive at all, but the heat cure is low temp & the air cure is for high temp applications.

[sizulku]

Thank you Sir for showing this build.