AR Barrel Profile?

[Oh Shoot]

So, what's the actual engineering purpose of a "different step" AR barrel, like the M4 type, which I guess this is, over just a constant outside diameter one?

[Guest FIST]

I'm not sure what you mean by different step but I'm going to throw something out any how. The front cut is to mount a M203. Between the FSB and Delta assembly the reduction is for weight savings.

[TMF]

I'm not sure what you mean by different step but I'm going to throw something out any how. The front cut is to mount a M203. Between the FSB and Delta assembly the reduction is for weight savings.

Have you seen those fancy new HK grenade launchers that Joe is sporting? I wonder if those require the notch cut in the barrel too. Any grunts on the board know the answer?

[Guest FIST]

Are you talking about the 320? Side loading, can be removed and used as a standalone weapon.

[Dolomite_supafly]

I hope the new HK's are better than the older HK69A1. Those things were miserable. The trigger had to weigh 25 pounds. We used them and I thought they would be great the first time I seen them. After we got them I wanted a 203 back.

Those cuts in the barrel are for mouting the 203 grenade launcher. It doesn't appear as though the HK needs the cutouts because it mounts using a picatinny rail.

Dolomite

[TMF]

Are you talking about the 320? Side loading, can be removed and used as a standalone weapon.

Probably. I started seeing them last year. They're the ones with the pistol grips on them. Do they require the cutout?

[Guest FIST]

I don't believe they need the cutout. I've used them messing around at a range as a standalone but never mounted.

[Guest 6.8 AR]

So, what's the actual engineering purpose of a "different step" AR barrel, like the M4 type, which I guess this is, over just a constant outside diameter one?

I guessed it was to use the same core for making two different barrel lengths from the same batch. It

looks like the notch is the same as what is threaded for a flash hider. At least that is what I always thought.

Edited August 26, 2012 by 6.8 AR

[Dolomite_supafly]

The part under the handguard is for weight savings, nothing more.

Dolomite

[scoutfsu]

The 320 does not require the step/use a barrel clamp for mounting. Ideally, it can be used with it's standalone mount for a more flexible, effective grenadier.

[Guest 6.8 AR]

I'm pointing out in front of the post, not under the handguards, Gordon.

[mikegideon]

I'm pointing out in front of the post, not under the handguards, Gordon.

That's for the grenade launcher. M4 profile barrels are usually a little more expensive than the ones with straight tapers in front of the block. Not a cost saving thing.

Edited August 26, 2012 by mikegideon

[scoutfsu]

[ProjectDexter]

what about behind the flash hider? whats the point in that?

[TMF]

what about behind the flash hider? whats the point in that?

Haha, for MILES gear, of course!

[ProjectDexter]

haha every barrel should be equipped with them!!!

[mikegideon]

When are they gonna incorporate on of these in the barrel profile?

[ProjectDexter]

When are they gonna incorporate on of these in the barrel profile?

I'm sure they have an adapter for the Bayonet lug on ebay somewhere LOL

[scoutfsu]

what about behind the flash hider? whats the point in that?

For the Bayonet IIRC

[ProjectDexter]

For the Bayonet IIRC

I think you are right.

[Dolomite_supafly]

The bayonet never goes past the flash hider. It doesn't sit on that false shoulder. The loop just sits around the flash hider and the rear of the bayonet is stopped on the bayonet lug that is part of the front sight.

That shoulder right behind the flash hider is NOT for the bayonet to index on.

Dolomite

[Dolomite_supafly]

Here is a pretty good indication of where the bayonet sits.

http://www.quarterbo...thread.php?t=43

Dolomite

[Guest 6.8 AR]

Ahh, didn't know that. Thanks!

[TMF]

I'm telling' ya it's for the MILES. It would make sense that the Army would require that shelf be the same thickness as an A2 barrel rather than purchasing a $2 shim adapter to accommodate it.

[scoutfsu]

You know, I think you're right. That stupid box goes right there. I didn't think about MILES....worthless as it is.