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View Full Version : AR-15 dissipator rifles.....purpose???


Te Anau
July 10, 2010, 03:50 PM
http://www.del-ton.com/Rifle_Kit_p/rkt112.htm

Whats the purpose of these dissipator AR's.
:confused:

RoyP
July 10, 2010, 04:03 PM
they have the sight radius and gas tube length of a rifle with the barrel length of a carbine.

Crosshair
July 10, 2010, 04:23 PM
Whats the purpose of these dissipator AR's.
To jam and malfunction as often as possible because of the rifle length gas system and carbine length barrel resulting in a badly mis-timed weapon.

At least that is what I have seen from them in use. Some have a carbine length gas system under the hand guards and a fake gas block on the front sight. Those ones seem to work as well as a regular M4.

gunmoney
July 10, 2010, 04:49 PM
Most "dissipators" still only have a carbine length gas systems, not rifle length.

Technosavant
July 10, 2010, 05:03 PM
A "dissipator" (as per Bushmaster, who came up with it) has a carbine length gas system underneath a rifle length handguard. The gas block on the front sight is not actually used- there's neither a gas port nor a gas tube in that position.

It will function like any other carbine length rifle, but it has a longer sight radius and room for a longer handguard.

Bartholomew Roberts
July 10, 2010, 05:18 PM
Basically the idea of a 12" handguard on a 16" barrel is more rail/handguard real estate, better protection from a hot barrel, and longer sight radius.

You can do this with a carbine, midlength or rifle gas system; but a rifle gas system on a barrel less than 17" usually has problems with the short dwell time.

Zak Smith
July 10, 2010, 11:14 PM
The Dissipator configuration such as the original one Bushmaster made (and the Del-ton one that looks identical) is obsolete. Since float tubes have been made to fit over low-pro gas blocks, the concept has been generalized and there are much better options available.

RT
July 11, 2010, 07:10 AM
I think the "purpose" is to look cool.

ISC
July 11, 2010, 08:25 AM
As mentioned by others, it offers a significant increase in potential accuracy with iron sights due to a greater sight radius.

Te Anau
July 11, 2010, 07:09 PM
These dissipator AR's must be the oddballs of the AR world.Ive looked at various other forums and they seem to have a 50/50 love-hate thing going on.I like the look of them myself.

demigod
July 12, 2010, 09:49 AM
They work for those of us who like the robust Steel Forged Front sight base that is actually pinned to the barrel. There are no forged steel rail mounted sights that I'm aware of.

The original formula is less than optimal. A middy style dissipator is a better route.

http://i210.photobucket.com/albums/bb201/trixiebud/hudson057.jpg?t=1278946100

Meditator
July 12, 2010, 08:57 PM
I had that setup once. It worked great, but very front heavy. I traded it for M4 config which is much handier and lighter.

Evyl Robot
July 13, 2010, 08:56 AM
I love my dissipator! I built mine with rifle guards over the carbine-length gas system. The extra few inches of sight radius are wonderful and the set up looks cool. It kind of looks like a stretched out SBR to me.

demigod
July 13, 2010, 09:00 AM
I had that setup once. It worked great, but very front heavy. I traded it for M4 config which is much handier and lighter.

That would be a function of the barrel profile, not the gas port location. I suppose you have an extra few ounces of handguard material, but I doubt that would be realistically noticeable.

tirod
July 13, 2010, 09:46 AM
No doubt for the competition shooter a free float is the better answer, and the dissipator isn't a leading edge configuration.

Using a set of rifle handguards already implies competition ISN'T the main goal for the rifle except for Service Rifle, which it isn't anyway. That leaves more frugal pursuits like hunting and range shooting, especially if it's being built.

Cons: The FSB is heavy and further forward, making a relative change to muzzle heaviness. The extended sight length is only as good as the shooter, and mostly apparent at long ranges. The entire set up is heavier, as two gas blocks are installed, only one is used. If the sling swivel is used, it's further forward and exerts more leverage to move the point of impact.

All for the extended coverage of the rifle length handguards. That's the builders judgement call, for use or aesthetics. Things arent all bad, tho, there are ways to alleviate the negatives.

Don't use the FSB, use an aluminum rail height gas block and front MBUS. Optics are a better choice anyway.

Don't use a sling in the field or the range. Really, most don't need it, except for position shooting, and a dissipator isn't the tool for that. If some sort of tacticool reasoning requires a sling, the mounts are more often at the front or rear of the lower, not the front sight.

Work out the details, the dissipator can be lighter than a extended quad rail with FSB. It won't be lighter than a midlength set up with rail height gas block. Can't have your cake and eat it, too.

And as for looks, well, everyone makes their own decision. It does have a "cut down prototype" flavor from a 1980's perspective, if a straight slip ring is included.

I might actually get to handle one like that some day.:o

demigod
July 13, 2010, 11:16 AM
The FSB is heavy and further forward, making a relative change to muzzle heaviness.

Anyone who can feel the weight difference by sliding the FSB down a few inches needs to have their super sensory skills studied by scientists.

Don't use the FSB, use an aluminum rail height gas block and front MBUS.

There's no way an MBUS or any other rail mounted sight is as strong as a forged steel barrel pinned FSB. Back up sights have their role, but if a shooter wants irons only, a real FSB is the best way to go. (I do have a gun with a rail mounted DD front sight tower for what it's worth - I just would be leary of using it for defensive purposes)

Optics are a better choice anyway.

Which ones? And for what? If someone doesn't need magnification, Irons are infinitely more accurate than a 4 MOA red dot sight. That's too broad of a generalization. The ONLY time, I personally have felt that an optic would have helped me was when shooting with a helmet on. The suspension made getting on the irons effortful, and having a lower 1/3 red dot would have been easier.

thesheepdog
July 13, 2010, 02:45 PM
There's no way an MBUS or any other rail mounted sight is as strong as a forged steel barrel pinned FSB. Back up sights have their role, but if a shooter wants irons only, a real FSB is the best way to go. (I do have a gun with a rail mounted DD front sight tower for what it's worth - I just would be leary of using it for defensive purposes)

I agree. The FSB are almost impossible to remove. Even with the right tools, it's a hassle.

Which ones? And for what? If someone doesn't need magnification, Irons are infinitely more accurate than a 4 MOA red dot sight. That's too broad of a generalization. The ONLY time, I personally have felt that an optic would have helped me was when shooting with a helmet on. The suspension made getting on the irons effortful, and having a lower 1/3 red dot would have been easier.

I agree on this also. Irons are definitely more accurate than Red-dots.

bennythemook
February 23, 2012, 11:23 PM
I orderd an ar-15 from rra factory and my barrel is stamped dpms? Confused!:confused:

madcratebuilder
February 24, 2012, 10:47 AM
I think the "purpose" is to look cool.

WIN!

As if the dissipator is not funny looking to begin with, people well add optics!

tirod
February 24, 2012, 12:23 PM
That's not quite why I built mine that way.

Longer sight radius, yes, but I planned on an optic anyway. Red dots are much faster than irons, period. On a hunting rifle used at shorter ranges on whitetail, red dots have delivered for me since the late '70s - yes, they've been out over 40 years. All we had was irons or scopes, they filled the huge gap in sights for adverse use.

Gas length should always be timed from the muzzle, regardless. Take a longer look, most optimal AR's are 5-7 inches from the muzzle, not whatever measured from the chamber. We've taken the location of the FSB as gas length when maybe we shouldn't - the carbine gassed 16" M4gery was the exception, and it's overgassed and timed too early. Some just get away with it, you don't have to. Look again, carbine gas was for 14.5", and working from there, you go mid length on 16", intermediate on 18", and rifle on 20". That's 5-7 from the muzzle every time. Proper optimal timing.

So, mine's midlength with a lo pro block set screwed under regular rifle handguards.

Why rifle handguards? Because, they are. Handguards are there to protect your hands, I built this as a cold season hunter, a cold skinny barrel isn't fun to grab in November, or after qualifying on a range in August. Not at all. Covered mine up to keep from getting frozen or burned, it's what handguards do. It also allows reaching futher forward when you do shoot - since the AR is light, you don't have to heft it up as much, and can use the option of holding out at the muzzle to move it around quicker. That makes it point faster.

Goes to, shorter range hunting on live game - which seems to appear as if by Star Trek transporter in my woods. Deer materialize and you don't get to watch them wander in for 5 minutes, more like poof! and the timer is ticking away. They don't hang around once they scent you, see you move, or make an out of place noise, like snapping off the safety. Get a red dot on one good and pull thru.

I prefer the FSB for sights, they are much more rugged. Unfortunately, when building a dissipator with a more normal barrel profile, it's not .750 where you mount it behind the muzzle. I used an Armalite NM clamp on. Some would question not pinning it would be chancy. It's a hunting rifle, optics first, if it gets bashed out of alignment I did something really forcefully dumb. It's been said by those removing the flash hider that they can break out the pin in the upper trying to screw it off - on a hunter, I'd rather the sight rotate first. I don't need to add to the problem, I'm paying for repairs, not the taxpayer. It's not life and death for me sitting in the woods enjoying the view.

Some think dissipators aren't what they are used to in the AR. I built mine that way, in Foliage Green, because Black is more wrong to me than having enough handguard. I put my priorities for a hunting carbine first, and it worked out fine. If a forged or billet aluminum FSB was out there for $48 I would have done that, but the slight amount of weight isn't all that in a 7 pound rifle to begin with. It sits in my lap while I wait.

There's very much a place for dissipators, it's all about the priorities.

Bartholomew Roberts
February 24, 2012, 01:03 PM
I orderd an ar-15 from rra factory and my barrel is stamped dpms? Confused!

I am not sure why you are posting this in this thread from 2010; but if your barrel is marked "DPMS" I would guess that it is not an RRA factory produced rifle. Have you tried calling RRA? They would at least be able to tell you how the receiver left the factory and whether they use DPMS barrels.

chris in va
February 24, 2012, 06:46 PM
July 13, 2010, 02:45 PM

1.5 year necro thread, not too bad.