AR guys: help me build a dissipator

www.adcofirearms.com

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They make "cruiser uppers" that have the Dissy LOOK with the MID LENGTH GAS. LINK HERE.

Since you already order from PSA, why not a ready made dissy? http://palmettostatearmory.com/inde...sa-16-hammer-forged-midlength-dissipator.html

It is mid-gassed btw.

1KPerDay said:

Kay, let me explain. I'm receiving the lower and upper as a gift. Part of the gift is that I have the experience of assembling an upper (which I obviously have never done). So complete uppers are out for now.

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Excellent.

Assuming you just want the "look" of a super long hand guard, you can make whats called a 'mock dissy' with lo-pro GB on a middy. Thats how Id do it anyways.

Im assuming the military of things is for mil spec lowers..not 100% but im atleast 80% lol

mil spec is made from a better aluminum but is thinner..you can tell cuz the threads are taller than the tube...commercial is a lesser aluminum but thicker..threads are cut into them and sit level with the tube they are generally cheaper... mil spec is overall stronger but unless ur bashing ppl in the head or banging it on the ground to unseat a jammed shell then it doesnt matter what you use just make sure the stock is also mil spec for mil spec buffer tubes and commercial for commercial tubes...stocks will not interchange between them because commercial is a bigger diameter

BCM makes the lightweight barrel you're looking for. A light weight 16" barrel with carbine length gas system. Unfortunately its out of stock
And I don't know how to install a gas blocks though... but this might be what you want
http://www.bravocompanyusa.com/BCM-16-LIGHT-WEIGHT-Barrel-Stripped-p/bcm-brl-car 16lw std.htm

You could get this kit and sell off the parts you don't need
http://palmettostatearmory.com/inde...ged-mid-length-mock-dissipator-rifle-kit.html

I've done this.

Use midlength gas, is more appropriate for a 16" barrel. AR timing is all about having the gas block 5-7 inches from the muzzle for correct timing, it's not a style option. So, with a dissipator, you either compromise the gas length, or go 'mock' to enjoy the actual benefits.

Install the low pro block, gas tube, and handguards of choice on the bare barrel.

Here's the sticky widget: Barrels aren't usually .750 all the way forward to the muzzle threads. If your barrel isn't, then there are two ways to do it: Have a shop pin the non working flash hider at the appropriate location, which means they have to work out how to fit a .750 FSB on a .700 barrel - the Problem in a nutshell.

Or, use a Armalite clamp on National Match sight as the most AR looking one around. It has the advantages of no shop labor fee, it's removable later to do other work, and your all important criteria, you do it.

But how to make up the .050 misfit? Well, if the barrel is typically too small, and the sight typically too big for it, something has to fill the gap. I've not found anything on the market to do that, because dissipator makers order a special barrel that is .750 all the way.

I used feeler gauge strips cut to fit. A cheap feeler guage set from a tool store or auto parts house is $5, and you can stack the strips in the .025 range to take up the slack. It doesn't have to be numerically equal, the clamp on sight will take up to a .025 misfit - but that will close up the sling swivel ears too much to mount one.

Pick strips to get about as close as you can, curl them around to fit the barrel, then cut to length and start assembling. It may work better to slide them under the sight as you install it, or slide them in after, just don't get cut by corners or crimp them. Once in place, tighten the set screws to get the sight v-e-r-t-i-c-a-l . Witness marks on the barrel and sight at the front might help.

Doing this allows you to preset the tension on the handguard delta spring for no rattle. The result is a dissipator you can change to a free float later, or swap sights, or not at all. The barrel won't have pin holes drilled thru it, and it will look close to issue.

I did try grinding a .625 pencil barrel FSB out to make it fit, didn't work out, it's too thin to mount now. I looked into using a set screw modification, but the issue I had was a flare at the muzzle threads that swelled to .725 - still leaving a gap to fill. Since getting a working gun in a reasonable amount of time to use for hunting season was important, I went the Armalite NM front sight. An hour after getting it out of the mailbox it was done.

For a rear sight I cut down a $32 surplus M4 carry handle with windage and elevation. Cheapest milspec rear BUIS on the market.

If you ask craigC buy a book and lots of tools!

Tirod do you have pics of the finished product?

IIRC M4 profile bbls are .750 where the rifle FSB would land - but this will vary with manufacturer, and you cant really measure a mail-order bbl...

CMMG offers a mid-length bbl with the rifle sight radius, M10M, however its a medium contour, a little heavy for my taste. But you can have it drop-shipped to adco to turn it down to an A2 profile if you want.

All I know is I like the way dissys look.

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I think they look goofy...

But I have two. Would have more if 9mm and .45ACP bbls were the correct diameter or I didn't have them on the back burner. I really like the carbine bbl with the longer sight radius.

I just built a PSA dissy. Ordered from PSA a complete dissy upper with the mid length gas and then ordered lower and parts kit and bam thats all you need OTD for 700 or less