Ya'll have convinced me to go with the 77 NATO Nosler. Now I need to either swap barrels on my Bush VMatch 16" w/ M4 to get the 1-7 or so twist or organize a complete new upper (with a better forend!).

1. Where can I obtain a milspec chrome 556 chamber 16+ M4 or LW barrel of top quality with 1-7 or so twist(e.g. Bush, Colt)? I have been happy with the accuracy of my M4 barrel and would like similar results.

2. Can I buy a top quality upper (e.g. Bush) with FFRAR (KAC?), and the above barrel? Or would I have to get an HBAR and sent it to someone to turn it down?

3. Should I just collect the parts piecemeal and assemble it myself?

Thanks

Bushmaster only makes 1-7's in 14.5 and 20 in length both in gov't contours.

So with bushy you would have to perm attach a FH or Muzzle break or extention to make 16inches.

I don't keep track of what Colt makes. I do think Colt might make a 16in chrome lined M4 barrel though.

You can find 1/7 Colts in 16", both lightweight and M4 (technically, LE6920) profile.  

Bushmaster has the 14.5's from time to time.  

I think DPMS is making a chrome lined 14.5, not sure about 16, or if it is truly "mil-spec".

I think your best bet is to assemble your own if you want it free floated.

the colt 1-7 16" chrome 556 LW sounds like a good direction, perhaps using a bush flat upper with all bush parts. Has anyone had experience with it's accuracy with match ammo and FF forend? Can I get to the <=MOA range?

thanks

Buy the parts and send them to me, I'll assemble them for you for a nominal fee....:-)

Do you have a post ban or a preban?

Do you want a folding front sight?



The 14.5" 1/7 M4 using Mk 262 will have the same range of fragmentation as a 16" 1/9 barrel using M193 but with greater accuracy and a larger wound channel at all ranges.  Just how often do you think you will be shooting people in the 150-200m range?

The 16" DPMS M4 is 100% milspec with the exception of the front sight which is cast not forged.  If you want a folding front sight this is a non issue.

If you want a 16" LW you have to go Colt or have a DPMS 16" M4 barrel turned down.

The cheapest solution is a 14.5" Bushmaster (I got mine for $195) Then DPMS at about $225 then Colt which is $300-400.

I got my Knights FF RAS and assembled it seperately myself, it was easy.

Hey DevL...What did the barrel extension look like for your Bushy 14.5?  I'm looking to swap my 16" for a 14.5" on my Colt M4gery.  Got the feed ramps cut into my reciever.  I'm not sure if I can use the origional Colt barrel extension with a new Bushy barrel.  Colt prices suck.

Thankx

Devl: I have a post ban. I also live in a very rural location, hence the long range and accuracy requirements. Want fixed front for this application. My current bush Vmatch w/ M416"1-9 does 4"/400yds still wind w/ 52g match ammo; MOA@400 chrome with 556 chamber is ideal for this. The 77NatoNosler looks like it will give me fairly good frag and penetration as well as better wind handling for longer range, but I need a faster twist.

Thanks for the pointer re KAC RACII and DPMS cast front.  Are there any reasons not to go with the Colt 16" 1-7 LW?

How hard is it to install a chrome 556 barrel that will be accurate?
thanks

Bushmaster does not do feed ramps.  Kurt Wala of KKF in the Industry section will do them for a minimal fee.  Thats where my rifle is headed.

The 14.5" barrel is no less accurate than the 16" barrel.  In fact if I had to guess the 14.5" M4 is probably more accurate than the 16" light weight.  All the barrels I have told you about are preban only so that means you must add a compensator to cover the threads and neuter the bayonet lug.  I am unsure if DPMS offers the 1/7 barrels in a postban form but Colt and Bushmaster do not have 100% milspec barrels that are post ban to my knowledge.

When installing a new barrel with FF RAS you must drive out two pins in the front sight base, pull it off and use the Knights barrel nut instead of the factory barrel nut.  Then the front sight goes back on and you tap in two pins (its easy)

The RAS II uses the factory barrel nut and the first step can be skipped.  All you need to do is put the upper in a vice block, get a barrel wrench and remove the current barrel barrel from the upper by unscrewing the nut.  Then it just pops out.  You can skip this step if you are not using a barreled upper.

Then pop in the barrel in and screw down the new barrel nut on your new barrel to 35 foot pounds and get the hole for the gas tube to line up on the next notch and your through.  All that is needed is to install the gas tube (pops in and held by a pin) and follow the instructions on installing the FF RAS or RAS II (they go on differently)  You cant make it more or less accurate during install.  I suppose if you didnt tighten down the barrel nut to at least 35 foot pounds or if you tightened it to like 150 foot pounds you could screw it up but you would have to try to do something that stupid to get it to be less accurate than is possible.  Seriously with a vice block, barrel wrench, punches, hammer and torque wrench any monkey and rebarrel an AR.  There is no skill or magic to it.  I was supprised how easy it was when I did it.

Devl: thanks again for all the useful info. I had wanted the 16" to max vel, given my wish for min winddrift.  I will look into the 14" as well.

I am going to show my total lack of knowledge: what is the deal with cutting the feedramp you mentioned?

Yes.  Thank you DevL.  I just got a return email from Bushmaster claiming that their M4 barrels will function just fine in a receiver with the deep cut feed ramps.  I'm not to sure this is so.  I think I'll be sending my rifle to Kurt as well.  

Thanks again.

Colt made a new feed ramp design to deal with the fast carbine action and weak mag springs.  If you have both together the bolt can strip a round faster than the mag can get a bullet up and the bullet nose can lodge just under the feed ramps.  The Colt M4 style feed ramps are extended lower than normal (normal = on barrel extension only) and they go from the barrel extension into the upper receiver.  If you do a search for "M4 feed ramps" you can find pics.  Troy has a pic that can show the differnce.  The problem with the reciever feed ramps and no barrel extended feed ramps is you make a ledge under the main feed ramp which can catch the bullet tips if it ever hits the reciever feed ramp.  This will not occur 99.99% of the time.  A reciever with feed ramps and a barrel without is the least desirable combination.

Thanks for the feedramp discussion. Sounds like the main problem is using a non colt barrel in a colt m4 upper.

BSBG mentioned Colt 16" chrome LW and M4s - anyone recommend a good source for these?

One last related question. I have an Oly upper and bolt assembly. Any accuracy or reliability problems with using them (I would replace the bolt) or would I be better off getting new Bush/colt/RR?

Your best bet is to keep your eye on the Equipment Exchange for a good used one.  They pop up from time to time.

In spite of the commotion last week, about the only place to find a new one is [url]www.specializedarmament.com[/url]

thanks!

I recently put together a carbine with the 14.5 1/7 bushy barrel ($195 & comes with swivel), silvered soldered on a phantom flashider.  I've only test fired but the barrel seemed to group well with all the ammo I used - surprising accuarte considering I didn't frre float it.