Quietest PCP of all time!!!

[mobilemail]

HeeHee
Gotta love mad scientist stuff!!!!
Or is this James Bond type stuff?
Either way, most excellent Travis!!!

Travis McGyver. :-)

[shorty]

Supper excellent idea to port the barrel just behind the choke. I have done this once with great success (145db to 86db) a very very long time ago. Just shroud over that no baffles and shroud ported near the breach to allow hot fast gas to release slowly.

I did learn something very valuable though,
Drilling into the barrel is not such a hot idea as it can and will leave a burr. You may want to look into making the holes using EDM. EDM will not leave a burr and it will be a very clean hole.
Shops around be me are pricey. But, there is a hack to make an EDM from an old door bell ringer and a small power supply.

[oldpro]

I may switch it up a bit. Might do it on a Prod WHY because I already have a breech riser and a prod shroud fits inside a mrod shroud nicely and I have tons of prod stuff to work with.

[YEMX]

Im going to drill small holes before the choke into the barrel to vent the very high pressure into the shroud before the stripper THEN the air will be stripped off inside the shroud by a set of very unigue baffles THEN it will exit into a larger shroud that also contains a floating stripper and more baffles. the larger shroud will completely cover over the smaller shroud. This should in all theory completely eliminate all muzzle report so  next is the hammer and valve. Im going to use a large seat poppet valve to shorten dwell as much as possible THEN im going to put a aluminum hat on the valve poppet  with a delrin insert NEXT im going to use a delrin hammer and a ssg with and delrin pusher.  A few other things that will be in the gun cannot be discussed but I will post links when the time comes

Holes in the barrel directly, venting to baffling- Yep, just like the early suppressed Sten.  Wow, a 3 stage- Very intriguing!!!  I thought I was onto something with the 2 stage on my .22 Mrod build- 1st stage were the standard cups, the 2nd stage was a larger LDC by Neil Clague that threaded onto the barrel shroud, using the endcap threads...  THAT was a very quiet set up for 30 fpe (ask mobilemail  )...  But this three stage- sounds like a doozy!!  I can't wait to see the results!!

[Gertrude]

looking very forward to seeing this developed Travis.
 keep up the amazing work.

[FuzzyGrub]

I may switch it up a bit. Might do it on a Prod WHY because I already have a breech riser and a prod shroud fits inside a mrod shroud nicely and I have tons of prod stuff to work with.

FWIW: A prod shroud barely fits within a mrod shroud.  I have grafted Mrod shrouds to prod, and it only takes two layers of a soda can shim for a tight fit. 

[oldpro]

I may switch it up a bit. Might do it on a Prod WHY because I already have a breech riser and a prod shroud fits inside a mrod shroud nicely and I have tons of prod stuff to work with.

FWIW: A prod shroud barely fits within a mrod shroud.  I have grafted Mrod shrouds to prod, and it only takes two layers of a soda can shim for a tight fit. 

I know and thats exactly what I need it to do.

[Iamscotticus]

You may want to look into making the holes using EDM.

EDM=?

[Gerard]

Electrical discharge machining perhaps?

But I've had decent success in barrel porting using a sharp drill on a drill press fed slowly, followed by very careful use of a small undercutting Dremel diamond bit to just carve away the burr left inside the bore, no more. Of course EDM is superior, but it's not something to which I have access.

[Bicycleman]

You may want to look into making the holes using EDM.

EDM=?

Thanks, Scott; I was about to ask. 
Gerald, thanks for the answer.  It is going to be included in Abbreviations/Acronyms.

[Motorhead]

You may want to look into making the holes using EDM.

EDM=?

Electronic Discharge Machine .....

uses a preshaped CARBON electrode along with specialty controller to Create a controlled ARC of electricity that erodes away the metal to the exact shape of the electrode. 

[Gerard]

Ah, thanks Motorhead. Was just guessing, hence the '?' after my poke at expanding the abbreviation. Although 'electronic' seems a bit odd, considering it's an 'electric' arc, not an 'electronic' arc being used... but hey, I didn't invent it so I don't get to name it.

[Motorhead]

Ah, thanks Motorhead. Was just guessing, hence the '?' after my poke at expanding the abbreviation. Although 'electronic' seems a bit odd, considering it's an 'electric' arc, not an 'electronic' arc being used... but hey, I didn't invent it so I don't get to name it.

It actually is ... Electrical  ... my bad 

See: http://r.search.yahoo.com/_ylt=AwrT6Vnd.kVXOD8A1vwPxQt.;_ylu=X3oDMTByb2lvbXVuBGNvbG8DZ3ExBHBvcwMxBHZ0aWQDBHNlYwNzcg--/RV=2/RE=1464232798/RO=10/RU=https%3a%2f%2fen.wikipedia.org%2fwiki%2fElectrical_discharge_machining/RK=0/RS=10J6xFVAzxesg20MceSdaUmjPdM-

[aluminumfetish]

I was a Wire EDM machinist for a few years at a tool and die shop in Minneapolis. We made stripping dies for a lot of high end compound bows and the repopped HENRY rifles. Very cool stuff... EDM is expensive, but sometimes it's just the right thing. We cut tool steel that had already been machined and already been heat treated, as heat treated tool steel can't be machined since it's already as hard as the cutting tool you would use to cut it. The whole process is done underwater.. in de-ionized water. Crazy.

[shorty]

The only reason for suggesting the EDM was because when I ported my barrel and slugged it, the projectile had very unique marks on it from the very slight burr in the rifling edges.
I couldn't deburr the barrel good enough without making it worse. The porting is very small. I used a very shall angle drill bit very slowly with lot's of lubricant.

[crosman999]

WHAT???  Travis,I had the same thing happened to me when I was younger that has left me 80% deaf. Most everything sounds quiet to me these days although it's strange that I can sometimes hear things nobody else can.lol Can't wait to "hear" WHAT? You come up with!!

[Gerard]

Well certainly EDM is preferable. But for those without access to such wonders (and gosh darn it, what machinist wouldn't want an EDM setup, especially a mini mill, at home?) there's rotary tools. The one I've used to port barrels measures 0.125" but perhaps there's a smaller one made. I mark the barrel wall thickness with a Sharpie all the way around, then work in very light passes supporting the Dremel in both hands, starting and stopping with the bit centred in the hole. Tricky, but I've pushed pellets carefully through and find absolutely clear, uninterrupted rifling on both heads and skirts, no evidence of burr damage, and accuracy was not harmed when comparing groups before and after porting.

[Wayne52]

Very cool, I'll be watching this one   I've had inner ear infections many times especially when I was really young, I bursted my eardrum shooting an M60, then I burst the same one in a factory dumping scrap (even with earplugs in) I now have ringing in my ears all the time, every day 24/7, sometimes worse than others, kinda learned to live with it since the doc told me there's not much a person can do about it.  There are drugs that help but that's not my chosen route.  When I'm hunting I don't wear earplugs but when I'm target shooting I always do now.

[Gerard]

Even one loud gunshot can cause pain or sometimes damage to the ears. So whenever I'm going to be around loud noises like that, I pop in my custom moulded Etymotics active hearing protection. A client made me a set in exchange for some work and I just love the things. Had some silicone impressions made past the second bend of my ear canals by a hearing aid shop, sent those off to him and a little while later got my electronic earplugs back. Two settings (wish there was an 'off' switch though as that'd save me the trouble of pulling out the batteries between uses), one for completely dulling all sound and reactive damping of high intensity noises, the other amplifying ambient sound up to 6x while maintaining the same level of damping for high intensity noise like gunshots. The amplification is amazing for helping me pick out even the smallest sounds, though after a while it can get to be a bit of an overload of information. Especially if I hear people talking about me. 

[FuzzyGrub]

I know and thats exactly what I need it to do.

I made two of them a while ago and they have held up very well.  JB weld.   This worked better that dealing with a breech riser and a full diameter mrod shroud.  I have one left to do when I get around to it.