Screw it... I'll make my own.

[JeffWard]

Since it's taking so damn long to get back ATF Forms anyway... I'm seriously considering just building my own can on a Form-1.

Looking for a set of SIMPLE (first build) plans for a SHORT, direct-thread 5.56 can, for a 7.5" barrel... I'm actually a Mechanical/Aeronautical Engineer by education, so I understand all the principles of what is going on inside a can... but I'd much prefer to work off a proven design than start from scratch. No reason to reinvent the wheel...

I'd actually like to build a "chubby" 2" OD can about 4-5" long. Get my volume in diameter vs length.

Has anybody here built one? Happy with the results?

Jeff

[propeine]

Since it's taking so damn long to get back ATF Forms anyway... I'm seriously considering just building my own can on a Form-1.

Looking for a set of SIMPLE (first build) plans for a SHORT, direct-thread 5.56 can, for a 7.5" barrel... I'm actually a Mechanical/Aeronautical Engineer by education, so I understand all the principles of what is going on inside a can... but I'd much prefer to work off a proven design than start from scratch. No reason to reinvent the wheel...

I'd actually like to build a "chubby" 2" OD can about 4-5" long. Get my volume in diameter vs length.

Has anybody here built one? Happy with the results?

Jeff

It will take just as long to get a form 1 as it will a form 4. What is your skill set? (Also where did you go to school? Not many with a Aeronautical focus any more and I attended one quite a few years ago)

Length is more effective than volume but something like 1.625-1.75 would take the bark out for hunting purposes or in addition to muffs. Probably 5-7 60° cones with an integrated brake would work fine. It won't be hearing safe but it would be better than nothing. Alternatively, assuming you have pistol gas, you could get 2.5" of over the barrel mounting and have a 6-7" can with more volume still.

[T-Rex]

Take a look at the AAC Mini 4 and the Ops Inc M4S. While not having the larger OD, they are shorter designs (the M4S is 4.5"L)
Not sure how well the smaller design is going to be on a 7.5"bbl. Especially considering the bulk it will need to overcome the muzzle pressure.
I think you'll be able to tame the 7.5's bark, but I wouldn't expect anything you could shoot w/o earpro

If you have a bit of room behind the muzzle, how about adding some reflex/overbarrel volume as well, and getting it a tad longer? Unless, of course, a bark reduction is your ultimate goal.

There's a post here, on silencertalk, that reads "Pics of Ops Inc M4-S inside.". Photobucket hijacked the pics, but you might be able to pm the user to see them.

[John A.]

I had an 8.5" barrel and was always warned not to use a can on anything shorter than about 10.5" or so.

Mostly due to erosion and heat and pitting and such.

Of course, that didn't stop me, but after a few shots, I decided that it was just better to take the advice that I was given. Lots of sparking from the titanium baffles.

[yondering]

Since it's taking so damn long to get back ATF Forms anyway... I'm seriously considering just building my own can on a Form-1.

Looking for a set of SIMPLE (first build) plans for a SHORT, direct-thread 5.56 can, for a 7.5" barrel... I'm actually a Mechanical/Aeronautical Engineer by education, so I understand all the principles of what is going on inside a can... but I'd much prefer to work off a proven design than start from scratch. No reason to reinvent the wheel...

I'd actually like to build a "chubby" 2" OD can about 4-5" long. Get my volume in diameter vs length.

Has anybody here built one? Happy with the results?

Jeff

It will take just as long to get a form 1 as it will a form 4. What is your skill set? (Also where did you go to school? Not many with a Aeronautical focus any more and I attended one quite a few years ago)

Length is more effective than volume but something like 1.625-1.75 would take the bark out for hunting purposes or in addition to muffs. Probably 5-7 60° cones with an integrated brake would work fine. It won't be hearing safe but it would be better than nothing. Alternatively, assuming you have pistol gas, you could get 2.5" of over the barrel mounting and have a 6-7" can with more volume still.

I was going to say the same things but propeine beat me to it.

One suggestion, since it's such a short barrel, is to make the blast baffle fairly thick with a blunt face, and use H900 17-4 stainless if you can heat treat it, or maybe get fancy with inconel or whatever your equipment can handle. BTW, heat treatment of 17-4 can be done with some simple equipment at home; I use a $60 lead casting pot and $100 PID controller, although a patient guy doing just a few baffles could skip the PID and just use a thermometer and manually adjust the pot.

[0101silent]

--

[John A.]

First time I've seen that article from Doc. Thanks for linking it. Lots of great info in it.

[Hannibalbarca]

Since it's taking so damn long to get back ATF Forms anyway... I'm seriously considering just building my own can on a Form-1.

Looking for a set of SIMPLE (first build) plans for a SHORT, direct-thread 5.56 can, for a 7.5" barrel... I'm actually a Mechanical/Aeronautical Engineer by education, so I understand all the principles of what is going on inside a can... but I'd much prefer to work off a proven design than start from scratch. No reason to reinvent the wheel...

I'd actually like to build a "chubby" 2" OD can about 4-5" long. Get my volume in diameter vs length.

Has anybody here built one? Happy with the results?

Jeff

It will take just as long to get a form 1 as it will a form 4. What is your skill set? (Also where did you go to school? Not many with a Aeronautical focus any more and I attended one quite a few years ago)

Length is more effective than volume but something like 1.625-1.75 would take the bark out for hunting purposes or in addition to muffs. Probably 5-7 60° cones with an integrated brake would work fine. It won't be hearing safe but it would be better than nothing. Alternatively, assuming you have pistol gas, you could get 2.5" of over the barrel mounting and have a 6-7" can with more volume still.

I was going to say the same things but propeine beat me to it.

One suggestion, since it's such a short barrel, is to make the blast baffle fairly thick with a blunt face, and use H900 17-4 stainless if you can heat treat it, or maybe get fancy with inconel or whatever your equipment can handle. BTW, heat treatment of 17-4 can be done with some simple equipment at home; I use a $60 lead casting pot and $100 PID controller, although a patient guy doing just a few baffles could skip the PID and just use a thermometer and manually adjust the pot.

Wait so you just drop in the baffles into the molten lead pot, take them out and quench them?

[yondering]

No quench needed either, but otherwise yes. The H900 condition is achieved by starting with annealed 17-4, holding at 900* F for 1 hour, then air cool. That's it. Hardness should be 42-44 Rc. The H900 condition actually machines really well but is harder to drill, so I prefer to make the baffles before heat treating. I find it turns really nicely on the lathe either way, using some cheap carbide insert tooling.

The Lee 20lb casting pots work well for this, and a 1,000* thermometer is all you really need, although a thermocouple readout is nicer and a PID controller setup is the best way to go.

Some lead will stick loosely to the baffles, but comes off with steel wool or bead blasting. Sometimes I'll spray a dry moly coating on them first just to help prevent lead sticking, but that's not important. I've considered trying a molten salts bath instead of lead, but lead works well so I haven't got around to it yet.

[Capt. Link.]

Since it's taking so damn long to get back ATF Forms anyway... I'm seriously considering just building my own can on a Form-1.

Looking for a set of SIMPLE (first build) plans for a SHORT, direct-thread 5.56 can, for a 7.5" barrel... I'm actually a Mechanical/Aeronautical Engineer by education, so I understand all the principles of what is going on inside a can... but I'd much prefer to work off a proven design than start from scratch. No reason to reinvent the wheel...

I'd actually like to build a "chubby" 2" OD can about 4-5" long. Get my volume in diameter vs length.

Has anybody here built one? Happy with the results?

Jeff

Many good comments but the reality is its going to be loud and burn out fast unless you take steps.The flash and heat from a 7.5" barrel is huge.I would honestly build it more old school style using a diffuser section with possibly stainless mesh and a ablative.I've built suppressors for full auto fire in 5.56 using grease or oil with good results.If you were to build a 3.00"x 5.00" suppressor using edge porting to encourage flow to the outer perimeter the overall performance would be greater than using simple cones.Its very difficult to get large diameter suppressors to perform well without careful porting.The use of ablatives is often discouraged but it works well if the suppressor is designed for it.
-CL