I'm considering getting a 16" barreled version of an M4 carbine, Bushmaster, preferably.

Besides complying with the minimum legal requirements, I'd prefer to aquire one that's as "correct" as possible to the real thing.

However, I've noticed in the Bushmaster catalog that getting one with the step-down on the barrel which accomodates the M203 grenade launcher is significantly more expensive for my forseeable uses.

What I'm looking for are possible real-world civilian uses for this step-down, justifying the added expense as well as keeping the carbine's "look" as military as possible.  If there are after-market additions that attach to this step-down that I can use as upgrades down the line, I'm very willing to keep an open mind to any of them you all out there can come up with.  And if you can, where can I find them?  Any and all options will be seriously considered.  Besides, keeping my options open with such a capability is a plus, so that I don't regret not having it in the future when one or more catch my fancy.

Thank you.  :

Even in the military I used the step portion of the barrel to mount a tactical light with a dual clamp type mount. Other than that........ Nothing..... But I am sure there is something out there. I have just grown accustomed to the look....

The M4 barrel is for looks(hey that's why I bought one) and half pound weight savings.

Quoted: The M4 barrel is for looks(hey that's why I bought one) and half pound weight savings.

As long as you don't buy newer RRA R-4 barrels as they are still heavy under the handguards.

You could wrap flowers around the barrel in that area.

doesn't the 37mm flare launcher use it?

Quoted: doesn't the 37mm flare launcher use it?

Depends on the model.  Most don't require the step-down as there are different size barrel clamps available.

BTW: I am pretty sure at least one of the para-cord fetischists which inhabit this board already has his barrel step-down tightly wrapped in tactical OD para cord.

Yes... you can attach a 37mm flare launcher that is suppose to simulate the military M203.

You can get them  at Firequest International

You can get all kinds of specialty 37mm ammo at 37mm.com

Quoted: Yes... you can attach a 37mm flare launcher that is suppose to simulate the military M203. You can get them  at Firequest International You can get all kinds of specialty 37mm ammo at 37mm.com

wow!

that firequest web link could be what some call the 'soft under-belly of the internet'

3 cheers for the 1st and 2nd Amendments

I use the cutout on the front part of the barrel in front of the front sight post for mounting a bipod.  It keeps the bipod from sliding up or down the barrel, and allows it to hold it just right for when my daughter is trying to shoot from the bench.

Firequest doesn't sound like a very reputable or honest dealer.  Check this out from their catalog section for "Armor Piercing Ammo"

Armor Piercing .223 Ammo. The optimum choice for defeating reinforced targets. This is SS-109 delivering a 63 grain bullet at 3100FPS. We have been able to secure a LIMITED SUPPLY of this scarce ammo. So don't delay.

I won't preach to the crowd about how misleading that little paragraph is.  They also sell tons of junk/novelty 12 ga.  shotgun rounds and make wild and completely unfounded claims about their effectiveness and/or lethality.

Back to the point of the topic.  Was it Remington (I can't remember) that makes a version of their pump 12 ga shotgun that will go under an AR just like an M203 does?  Any remember for sure what I'm talking about and where to find it on the web?  It's short-barreled too (The shotgun), so I would imagine if you can find a dealer that sells it to civvies you still have to go through NFA hoopla.

Quoted: Back to the point of the topic.  Was it Remington (I can't remember) that makes a version of their pump 12 ga shotgun that will go under an AR just like an M203 does?  Any remember for sure what I'm talking about and where to find it on the web?  It's short-barreled too (The shotgun), so I would imagine if you can find a dealer that sells it to civvies you still have to go through NFA hoopla.

Masterkey

Good question, Pistolerom14!  I need the same answers.

Yeah...a Masterkey would be really, really cool!  For lack of funds and licensing for a short-barreled shotgun, I may opt for something that, frankly, looks almost as good to me.  Remember some of the M4s in Blackhawk Down?  More specifically, the scene in which Hoot requests "permission to proceed to crash site number two on foot"?  When he pops through the wall, we get one of the best gun views of the movie: a camo M4 with a slender light fastened to the underside of the barrel via the stepdown.  Anyone know what these were called or if they're still available?  Or any good?  (I don't want to hijack, so if you plan to respond anyway and know what Sanderson's optics were, please include that in your post).  Seems like all the Blackhawk Down stuff was discussed here several months back.  Lots and lots of cool M4 stuff!

My Bushmaster M4 arrives next week.  So many accessories, so few dollars...  Enjoy your purchase, Pistolerom14!

Phlybox

My firearm mentor once said that the step down is a weak point in the barrel.  Since this part is thinner then the rest of the barrel it will heat up faster and warp faster then a barrel of equal thickness.

Anyone know if this is true?

Just another SCARY feature to make liberals think that they're machine guns...

Most people who buy the M4 barrel dont buy it for the step down area, but for the weight savings.  Whats not seen in the pics is that under the handguards, there is a skinny profile to that barrel. (except for RRA's R4)  With all the do-dads and addons which make things fun/tactical, you can always use the savings, especially over the standard HBAR.  And as the Military uses the M4 profile, you can bet that things will be developed down the road for use with the step-down area.

Just my $0.02

Tex78

Civilian uses for M203 step-down on M4 barrel? - None.

How about for a civilian that owns an M203?

Yes, you can get one if you jump through the proper hoops and if you state allows it (many do).  They run about $2K for a LMT or Bushmaster, more if you want a Colt or Knights marked unit.  You can get practice ammo for around $6 a round.  You can get more exotic ammo if you scrounge, but HE ammo requires many more hoops to be jumped through.

Joe

Quoted: Most people who buy the M4 barrel dont buy it for the step down area, but for the weight savings.  Whats not seen in the pics is that under the handguards, there is a skinny profile to that barrel. (except for RRA's R4)  With all the do-dads and addons which make things fun/tactical, you can always use the savings, especially over the standard HBAR.  And as the Military uses the M4 profile, you can bet that things will be developed down the road for use with the step-down area. Just my $0.02 Tex78

My RRA R4 is stepped down under the handguards. I will admit I got mine because of looks. I think the HBAR 16" looks like ass.

Quoted: Quoted: Back to the point of the topic.  Was it Remington (I can't remember) that makes a version of their pump 12 ga shotgun that will go under an AR just like an M203 does?  Any remember for sure what I'm talking about and where to find it on the web?  It's short-barreled too (The shotgun), so I would imagine if you can find a dealer that sells it to civvies you still have to go through NFA hoopla. Masterkey

Why the hell is that thing so expensive?

Colt M203 for $5,000



You can get it here if you got the $$$.

Quoted: However, I've noticed in the Bushmaster catalog that getting one with the step-down on the barrel which accomodates the M203 grenade launcher is significantly more expensive for my forseeable uses. What I'm looking for are possible real-world civilian uses for this step-down, justifying the added expense as well as keeping the carbine's "look" as military as possible.

You're not paying extra for that little 'notch', which by the way is pretty much useless for a civilian carbine except to 'look like a real-deal M4'.

Whay you paying for is all that unneeded weight being machined off the barrel under the handguards (which you don't see - but definately FEEL).

If you want to 'look' like an M4, or if you want the shortest non-NFA carbine you can with a flash supressor then get a 14.5" M4 type barrel with a permanently attached Phantom flash supressor.

If you want a really useful carbine then get a 16" Lightweight barrel, as it's even lighter than the M4 style.

Thank you for your replies.

As to the rest of the carbine,  I'm going to get it with the Stubby stock, A3 upper (for more future flexibility), and a muzzle brake.  It has to be a "Post Ban" permanent brake added onto a 14.5" barrel.  I'm leaning toward the Y-comp;  but what about Bushmaster's "AK" brake?  How do they differ and compare especially for muzzle blast?

Also, I'd welcome your opinions as to getting the small rear flip-sight for the A3 upper, and/or getting the extra detachable carry handle?  I'd even listen to anyone who advocates just getting the A2 non-detachable upper instead.  I prefer the "correct" military look and the down-the-road flexibility that the A3 offers, but cost-saving is also welcome. I'm willing to keep a completely open mind in this catagory.   Any opinions are appreciated.

I do like the idea of reduced weight because I want this carbine as handy as possible.  That's why I like the idea of the Stubby stock.  Many people, for example, find the AK-47 stock to be too short.  But I find it very handy and quick to employ,  even with my large size.  The AR-15 A2 stock is good, but is a bit cumbersome to shoulder,  in comparason.  I don't find the shorter stock to be an impediment to accuracy at all.   Also,  the stubby stock seems a hell of a lot more durable to the pinned-open CAR stock.  This particular CAR stock seems to be the WORST of both worlds- less handy and more cumbersome to employ than the Stubby, and less durable than the full-size and Stubby stocks.  IMHO, the pinned-open CAR stock is just a gimmick to appeal to those Weekend Commandos out there.  I know: each to their own, but this is the way I feel.

Thanks for listening and helping.

Quoted: My firearm mentor once said that the step down is a weak point in the barrel.  Since this part is thinner then the rest of the barrel it will heat up faster and warp faster then a barrel of equal thickness. Anyone know if this is true?

I would say get a new mentor. If it was true then all barrels would have"weak spots" except for the bull barrels that don't taper any. I mean I'm no metallergist and I don't condsider myself an expert after some 30 years of avid shooting but I really doubt the military would go with something like this if it had those properties. I think it would have to be a more sevier step down than is on current profiles. Just me 2 cents. Take care.

Quoted: If you want a really useful carbine then get a 16" Lightweight barrel, as it's even lighter than the M4 style.

+1...The M4 look is just that...a look.  For the same $$$, go ahead and get the rest of that weight took off.

Quoted: Quoted: If you want a really useful carbine then get a 16" Lightweight barrel, as it's even lighter than the M4 style. +1...The M4 look is just that...a look.  For the same $$$, go ahead and get the rest of that weight took off.

+2

Quoted: Colt M203 for $5,000 img94.exs.cx/img94/5455/whitem203b.jpg You can get it here if you got the $$$.

That. Website. Has. An. R. P. G. *creams self*

that web site is so over priced..... you can get all that stuff cheaper elsewhere. M203 from bushmaster or colt only costs arround $2,500 new. + $200 tax.