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TonyNorCal
03-07-2005, 11:19 AM
Hi all,

Ordering a Fab-10 lower with fire control group.

1.) Is it difficult to attach a stock?

2.) Is the any weirdness or difficulty with assembling or attaching the upper (bolt and all)?

3.) Will I need any special tools for the above two?

4.) What is the difference between and A-3 and A-4 upper receiver? Are there other options? What's best if you want to shoot open sites and also want the ability to securely mount a scope?

5.) What does pre and post ban mean as it applies to CA law? With a Fab-10 can you have pre ban things (uppers, etc.)? How about a collapsible stock?

6.) What kits/manufacturers do those of you with Fab-10s recommend?

Thanks.

TonyNorCal
03-07-2005, 11:19 AM
Hi all,

Ordering a Fab-10 lower with fire control group.

1.) Is it difficult to attach a stock?

2.) Is the any weirdness or difficulty with assembling or attaching the upper (bolt and all)?

3.) Will I need any special tools for the above two?

4.) What is the difference between and A-3 and A-4 upper receiver? Are there other options? What's best if you want to shoot open sites and also want the ability to securely mount a scope?

5.) What does pre and post ban mean as it applies to CA law? With a Fab-10 can you have pre ban things (uppers, etc.)? How about a collapsible stock?

6.) What kits/manufacturers do those of you with Fab-10s recommend?

Thanks.

bwiese
03-07-2005, 12:05 PM
Tony..

Some answers to your FAB10 assembly... I am not a lawyer but have a pretty good detailed knowledge of the relevant CA (and old Federal) laws and own a pile of homebuilt ARs.

(1) Is it difficult to attach a stock?

No! You first just screw in the receiver extension tube ("buffer tube"). A good way of doing this so it doesn't loosen is to use your butt: sit on your lower and use a wrench on the flats at the rear of the buffer tube.

And you really should get some 'Moly Slide' molydenum disulfide (MoS2) lubricant and apply it to the buffer tube threads (and mating threads on receiver) - just a little dab'll do ya. Moly lubricant is available from NECO in Benicia and via Bushmaster and some other AR vendors. This serves as an anti-seize compound and allows you to disassemble the rifle 10 years later - no galling/heat corrosion, etc. This is required by milspec for building/ repairing M16s and quality gun mfgrs use this when they assemble their AR15s. (Do NOT use graphite-based lube: graphite is corrosive to aluminum and some of its alloys.)

Before installing the 'buffer tube', remember to first install the buffer detent pin and spring beforehand: the front lip of the buffer tube retains the buffer detent pin in place when buffer tube is screwed all the way into the lower receiver.

Then after this, just put on the buttstock and tighten the screw.

Factory-built ARs use some ThreadLok to stop screw from loosening - find the ThreadLok type that is not 'permanent' and just stops screw from walking out.

A quality buttstock assembly will come with a good buffer and spring. Make sure you get the right spring/buffer for your buttstock: the CAR/M4 stocks and A2 regular require different springs & buffers. Quality buffers have a yellowish-bronzish color with generally translucent plastic 'nose' - not a black plastic cylinder full of BBs/shot.

A real milspec buttstock kit comes with a buttstock screw that has a drain hole in it. Some cheapo vendors just supply a standard screw.


(2) Is the any weirdness or difficulty with assembling or attaching the upper (bolt and all)?

If you ordered a complete upper with bolt, carrier and charging handle, you're pretty much good to go. I am assuming your upper is a complete, barreled upper (so you don't have to figure out how to mount the barrel to the upper).

Just lubricate the hell out of everything with CLP (BreakFree). Bolt, bolt lugs and carrier should be 'wet' w/CLP, as well as interior of upper receiver, and on/behind the matching lugs in the barrel extension.

Lack of proper lubrication is the leading cause of AR malfunctions, esp on new guns. Lube the hell out of that upper w/CLP.


(3) Will I need any special tools for the above two?

Nope - but this assumes your lower was preassembled w/fire control group, pistol grip, various detent pins+springs, etc. - and that your upper has the barrel already attached.

You'll just need a decent wrench (for buffer tube) and larger flat-blade screwdriver (for buttstock).

The spring and buffer assy can just be tucked into the buffer tube and are retained in place with the buffer detent pin . The barreled upper assembly should just drop on and be secured/released with push pins: no tools needed.


(4) What is the difference between and A3 and A4 upper receiver? Are there other options? What's best if you want to shoot open sites and also want the ability to securely mount a scope?

'A3' and 'A4' are common terms for an AR flattop upper. I know there is no M16A3 - I think A3 was just something that came up in commercial side.

BTW, there are some 'hi rise' nonstandard flattop uppers from DPMS that elevate the Picatinny rail 1/2" or more to offer clearance to big-bell scopes.

If you wanna mount a scope, you should get a standard flattop (A4) upper and put appropriate rings & scope on it. If you wanna go to iron sights, just put on the carry handle - or use a flip-up rear sight like the ARMS#40 series.

Make SURE you get the right carry handle for your upper: if you have a Colt upper, use a Colt carry handle - Colt flattop uppers differ from other brands by (IIRC) 0.040" in height. Putting a Bushy handle on Colt upper or vice versa may not allow you to zero elevation.

But rather than deal w/scoped vs iron sight changovers and re-zeroing, I personally would get two different uppers - one scoped, one w/iron sights.

BTW, the A2 (fixed handle) upper is a tad lighter than a flattop upper + carry handle combo.


(5) What does pre- and post- ban mean as it applies to CA law? With a Fab-10 can you have preban things (uppers, etc.)? How about a collapsible stock?

Preban and postban are customarily used to refer to configurations before or after the Federal Crime Bill assault weapon ban starting in Sept 1994. They do not really correspond to California law. The Fed AW Ban sunset (and was not renewed) in Sept. 2004 so there is NO legal status, and no FEDERAL legal defintion for pre vs post ban or assault weapon. Key preban items for AR-type rifles were folding/collapsible stocks, flash hiders and bayonet lugs.

(Existing CA registered AW owners can add/delete 'preban' features to their rifles too: they are already AWs and do not get any more or less 'evil' with parts changes.)

And since your FAB10 rifle has a fixed 10rd mag, it is NOT a semiauto assault weapon in California. Thus beside your pistol grip, your FAB10 can have whatever so-called "preban" options you wish - flash hider, collapsing stock, bayonet lug, etc.


(6) What kits/manufacturers do those of you with Fab-10s recommend?

Whether you have a FAB10 or regular AR is moot; they all take the same uppers, buttstock assy's, etc. as regular ARs. The FAB10 lower, except for fixed magazine, is essentially identical to an AR lower.

I'd recommend a Bushmaster, Armalite or Colt upper; these are premium vendors. Some say 'Rock River Arms' has quality items too. I also recommend that any newby's first AR-style rifle have a chrome-lined barrel w/a milspec chamber. Bushy and Armalite uppers, and most Colt uppers, have these. This will allow your gun to 'eat' a variety of quality and milsurp ammo without misfeeds, failures to extract/eject, etc. that can be caused by over-tight chambers. Rock River offers chrome-lined bbls as an upgrade option, not as standard items.

For lesser-known vendors, I've had good luck w/J&T Distributing. They stand behind their product and it's pretty good - though they don't offer chrome lined bbls at this time, it seems.



Bill Wiese
San Jose

TonyNorCal
03-07-2005, 12:11 PM
Bill and Ted, you guys are awesome. Thank you for a most excellent adventure in AR noobism.

bwiese
03-07-2005, 12:21 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Technical Ted:
Be carefull, it can get messy. </div></BLOCKQUOTE>

I have a big grey-black discoloration on my 5'x9' carpet in front of the sofa.

I've tried lotsa things to get it (MoS2) out, no luck.

Wear old clothes when you're using MoS2, and wipe the AR down good afterwards so you won't get dirty shouldering it a month later. Wash your hands well too.


Bill Wiese
San Jose

TonyNorCal
03-07-2005, 12:46 PM
Does an A-2 upper allow for scope mounting?

Rascal
03-07-2005, 1:03 PM
Great stuff here guys!
Tony, Thank you for asking the questions that everyone wanted to know but were afraid to ask. http://calguns.net/groupee_common/emoticons/icon_smile.gif
Bill & Ted, Great information!!!
I am soon to be gathering my parts to make my own Kali legal AR and I believe that this information will definately make putting it together much easier. Thanks you both! http://www.calguns.net/bow.gif

03-07-2005, 1:13 PM
Bill & Ted's excellent FAB10 adventure!

schizrade
03-07-2005, 4:11 PM
J+T rocks my FAB10 and they do offer chrome lined barrels.

bwiese
03-07-2005, 4:30 PM
Schizrade..

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> J+T rocks my FAB10 and they do offer chrome lined barrels. </div></BLOCKQUOTE>

Coolness! Hope they're 5.56 milspec chambered and not 'tight'.

I had a J&T 16" upper which worked just fine. It was part of my 1st AR build. But it didn't have a chromed bbl and was an HBAR style (heavy) so I gave it to my cousin.

Bill Wiese
San Jose

BigAL
03-07-2005, 4:30 PM
+1 on Moly Grease getting messy. I always wear a pair of latex gloves.

If you ever plan on putting optics on the rifle, I suggest forgoing the A2 and getting the A3. And unless you really want the detachable carry handle, I wouldn't bother buying that either as you can just buy a nice Back Up Iron Sight (BUIS) to go with whatever optic you choose. This gives you the flexibility/ability to have the proper cheek weld for the scope while having the iron sights right there ready to go should the scope fail. With the technological advancements in optics (ie ACOG, Aimpoint M2/M3, EOTech) I dare say the A2 may be nearing being obsolete, but this is just MHO.

For collapsable stocks, most quality manufacturers will either stake the castle nut (Colt) or apply locktite (Bushmaster) to prevent the buffer tube from shooting loose. Probably not a big deal for a plinker/range rifle, but I would do it for anything that may be used for serious work.

Oh and get a chromelined bore and chamber if you haven't already figured that out.

bwiese
03-07-2005, 5:17 PM
Ted...

Thanks for clearing up A3 vs A4.

Glad you mentioned about 'chrome-moly'. It seems that term is really only touted by vendors, usu in AR world, when they're selling against competition offering true chrome-lined bores/chambers. Chrome-moly is just plain barrel steel: vendors of other styles of rifles just say "4140" etc.

Bill Wiese
San Jose

BigAL
03-07-2005, 6:05 PM
4140 and 4150 are both chromemoly, with 4150 being the milspec.

bwiese
03-07-2005, 6:14 PM
BigAL

What's the diff btwn 4140 and 4150?

Colt, Bushy, (maybe Armalite?) all use 4150.
Everyone else uses 4140...

Bill Wiese
San Jose

BigAL
03-07-2005, 6:29 PM
Got this from the Maryland AR-15 shooters site: " There are two types of Chrome/Moly that are used to make AR-15 barrels. The most common (an most inexpensive) is 4140, its a decent steel that is used on many firarms. The other (more expensive) type is 4150, its got more chrome in it and is more durable and corrsion resistant; only Colt, Bushmaster, and FN use 4150 steel for their barrels. A 4140 chrome/moly barrel is the least expensive barrel you can purchase - yet they can be quite accurate."

I know LMT and CMMG barrels are also 4150.

Found this on Bushy's site: "A. Stainless steel is better at preventing erosion than regular 4140 steel, but we use mil. spec. 4150 ordinance steel. Then, our barrels are chrome lined and a chrome lined barrel will easily out-last a stainless barrel. A very good article on barrel manufacturing can be found in the '96 Shooter's Bible (Pg. 33). A typical stainless barrel is made from 416 stainless steel and then broach rifled. This process has been around for about 100 years. Our chrome lined barrels are made from 4150 ordnance steel and then button rifled - a process that's been around for about 50 years. This same process has set virtually every record for the National Bench Rest Association (NBRA). Shilen, McMillan and Browning barrels all use the same process but not the same steel. Mil. spec. calls for 4150 steel - same as used in aircraft machinegun barrels and all military small arms barrels. It costs more but we think its well worth the price. The button rifling process work hardens the bore - making tough steel even tougher. Then, after the barrel is fully machined, it is chrome lined, making it even tougher yet - and virtually impervious to rust or erosion. This chroming process isn't like car bumper chroming. It actually welds each chromium molecule to the steel bore. This chrome lining is far more resistant to wear than a bare steel bore and it gives slightly increased velocity due to the lubricity ("slipperiness") of the chrome. And, you'll see less fouling and easier cleaning with a chrome lined barrel - all in all, a superior product"

schizrade
03-07-2005, 7:29 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by bwiese:
Schizrade..

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> J+T rocks my FAB10 and they do offer chrome lined barrels. </div></BLOCKQUOTE>

Coolness! Hope they're 5.56 milspec chambered and not 'tight'.

I had a J&T 16" upper which worked just fine. It was part of my 1st AR build. But it didn't have a chromed bbl and was an HBAR style (heavy) so I gave it to my cousin.

Bill Wiese
San Jose </div></BLOCKQUOTE>

No it's not "tight".

C.G.
03-08-2005, 12:53 PM
In a week I'll be picking up my Fab-10 receiver and independently came down to most likely Busmaster and possibly J&T for uppers (mostly from AR-15.com research). After reading this I think Bushmaster is the answer. It is not that much more than J&T Kits, it will probably hold a better resale value and if Kali-ban lifts, I can always get a Bushie stripped lower and have a complete Bushie.

bwiese
03-08-2005, 1:55 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by cg:
..after reading this I think Bushmaster is the answer.... </div></BLOCKQUOTE>

For all-around pricing, customer service, and general quality, that's prob the way to go.


<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
...and if Kali-ban lifts, I can always get a Bushie stripped lower </div></BLOCKQUOTE>

We all can dream!

Bill Wiese
San Jose

maxicon
03-10-2005, 7:43 AM
Back to the optics question, you should think about how you're going to be shooting it. As was mentioned, there are a ton of mounting options, but they get really expensive to try out if you go for quality stuff (which is the way to go. I've probably spent $400 on used mounts and sights to play around with, which is more than I spend for most guns!

Read up on the optics forum at www.ar15.com, (http://www.ar15.com,) and keep an eye out for good deals on the equipment exchange at same. I've bought an assortment of used or discounted mounts that I'll be able to resell for about what I paid for them if I don't screw them up. Also, Armalite has some very nice high rings on their clearance page that have various camo paint, but are substantially cheaper than their black ones, if cost is an issue.

So, here are some considerations.

As was suggested, a flattop is best for a variety of optics. You can always add a carry handle, risers, rings, whatever, but you can't make a hi-rise or A2 upper any lower.

If you've got some specific scopes or optics you want to use, ask for suggestions at ar15.com, and you'll save a ton of time and money. Those folks love the top-drawer stuff, though.

If you're a tinkerer, and will be swapping stuff around, particularly from other guns, the sky's the limit. Be sure to buy good quality and good brands, and you can easily resell what you don't end up needing.

If you're thinking about a Bushnell or Eotech holosight, they'll sit right on a flattop with no risers needed.

If you want back up iron sights (BUIS), you'll need higher rings to clear them with a standard scope with an eye bell.

I like pretty high mounts on mine, it turns out, so after trying a wide variety, I'm thinking an ARMS #5 riser will be good for mounting my scopes that I switch around from other guns (various Leupolds, Ultradots, and such). This lets me keep the standard rings installed that work well on other rifles (like the SU16) and still get enough height on the AR.

The ARMS #5 comes off easily to mount my Eotech or to use BUIS. This is looking like the optimal combination of simplicity and flexibility for me.

For just putting a standard scope on and leaving it there, it's hard to beat a set of sturdy high or ultra-high rings, since there are minimal connection points between the upper and the optics.

YMMV, as always, and it's a whole 'nother adventure getting optics all tweaked in on an AR.

asahi1259@yahoo.com
03-15-2005, 8:11 AM
I am wondering that if you have one standard A2 upper from J&T and decide to buy a flattop, can you go and take out the bolt carrier from the A2 upper and use it in the flattop? Would you need to check it for "Go" "No Go" before hand


<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by bwiese:
Tony..

Some answers to your FAB10 assembly... I am not a lawyer but have a pretty good detailed knowledge of the relevant CA (and old Federal) laws and own a pile of homebuilt ARs.

(1) Is it difficult to attach a stock?

No! You first just screw in the receiver extension tube ("buffer tube"). A good way of doing this so it doesn't loosen is to use your butt: sit on your lower and use a wrench on the flats at the rear of the buffer tube.

And you really should get some 'Moly Slide' molydenum disulfide (MoS2) lubricant and apply it to the buffer tube threads (and mating threads on receiver) - just a little dab'll do ya. Moly lubricant is available from NECO in Benicia and via Bushmaster and some other AR vendors. This serves as an anti-seize compound and allows you to disassemble the rifle 10 years later - no galling/heat corrosion, etc. This is required by milspec for building/ repairing M16s and quality gun mfgrs use this when they assemble their AR15s. (Do NOT use graphite-based lube: graphite is corrosive to aluminum and some of its alloys.)

Before installing the 'buffer tube', remember to first install the buffer detent pin and spring beforehand: the front lip of the buffer tube retains the buffer detent pin in place when buffer tube is screwed all the way into the lower receiver.

Then after this, just put on the buttstock and tighten the screw.

Factory-built ARs use some ThreadLok to stop screw from loosening - find the ThreadLok type that is not 'permanent' and just stops screw from walking out.

A quality buttstock assembly will come with a good buffer and spring. Make sure you get the right spring/buffer for your buttstock: the CAR/M4 stocks and A2 regular require different springs & buffers. Quality buffers have a yellowish-bronzish color with generally translucent plastic 'nose' - not a black plastic cylinder full of BBs/shot.

A real milspec buttstock kit comes with a buttstock screw that has a drain hole in it. Some cheapo vendors just supply a standard screw.


(2) Is the any weirdness or difficulty with assembling or attaching the upper (bolt and all)?

If you ordered a complete upper with bolt, carrier and charging handle, you're pretty much good to go. I am assuming your upper is a complete, barreled upper (so you don't have to figure out how to mount the barrel to the upper).

Just lubricate the hell out of everything with CLP (BreakFree). Bolt, bolt lugs and carrier should be 'wet' w/CLP, as well as interior of upper receiver, and on/behind the matching lugs in the barrel extension.

Lack of proper lubrication is the leading cause of AR malfunctions, esp on new guns. Lube the hell out of that upper w/CLP.


(3) Will I need any special tools for the above two?

Nope - but this assumes your lower was preassembled w/fire control group, pistol grip, various detent pins+springs, etc. - and that your upper has the barrel already attached.

You'll just need a decent wrench (for buffer tube) and larger flat-blade screwdriver (for buttstock).

The spring and buffer assy can just be tucked into the buffer tube and are retained in place with the buffer detent pin . The barreled upper assembly should just drop on and be secured/released with push pins: no tools needed.


(4) What is the difference between and A3 and A4 upper receiver? Are there other options? What's best if you want to shoot open sites and also want the ability to securely mount a scope?

'A3' and 'A4' are common terms for an AR flattop upper. I know there is no M16A3 - I think A3 was just something that came up in commercial side.

BTW, there are some 'hi rise' nonstandard flattop uppers from DPMS that elevate the Picatinny rail 1/2" or more to offer clearance to big-bell scopes.

If you wanna mount a scope, you should get a standard flattop (A4) upper and put appropriate rings & scope on it. If you wanna go to iron sights, just put on the carry handle - or use a flip-up rear sight like the ARMS#40 series.

Make SURE you get the right carry handle for your upper: if you have a Colt upper, use a Colt carry handle - Colt flattop uppers differ from other brands by (IIRC) 0.040" in height. Putting a Bushy handle on Colt upper or vice versa may not allow you to zero elevation.

But rather than deal w/scoped vs iron sight changovers and re-zeroing, I personally would get two different uppers - one scoped, one w/iron sights.

BTW, the A2 (fixed handle) upper is a tad lighter than a flattop upper + carry handle combo.


(5) What does pre- and post- ban mean as it applies to CA law? With a Fab-10 can you have preban things (uppers, etc.)? How about a collapsible stock?

Preban and postban are customarily used to refer to configurations before or after the Federal Crime Bill assault weapon ban starting in Sept 1994. They do not really correspond to California law. The Fed AW Ban sunset (and was not renewed) in Sept. 2004 so there is NO legal status, and no FEDERAL legal defintion for pre vs post ban or assault weapon. Key preban items for AR-type rifles were folding/collapsible stocks, flash hiders and bayonet lugs.

(Existing CA registered AW owners can add/delete 'preban' features to their rifles too: they are already AWs and do not get any more or less 'evil' with parts changes.)

And since your FAB10 rifle has a fixed 10rd mag, it is NOT a semiauto assault weapon in California. Thus beside your pistol grip, your FAB10 can have whatever so-called "preban" options you wish - flash hider, collapsing stock, bayonet lug, etc.


(6) What kits/manufacturers do those of you with Fab-10s recommend?

Whether you have a FAB10 or regular AR is moot; they all take the same uppers, buttstock assy's, etc. as regular ARs. The FAB10 lower, except for fixed magazine, is essentially identical to an AR lower.

I'd recommend a Bushmaster, Armalite or Colt upper; these are premium vendors. Some say 'Rock River Arms' has quality items too. I also recommend that any newby's first AR-style rifle have a chrome-lined barrel w/a milspec chamber. Bushy and Armalite uppers, and most Colt uppers, have these. This will allow your gun to 'eat' a variety of quality and milsurp ammo without misfeeds, failures to extract/eject, etc. that can be caused by over-tight chambers. Rock River offers chrome-lined bbls as an upgrade option, not as standard items.

For lesser-known vendors, I've had good luck w/J&T Distributing. They stand behind their product and it's pretty good - though they don't offer chrome lined bbls at this time, it seems.



Bill Wiese
San Jose </div></BLOCKQUOTE>

bwiese
03-15-2005, 9:16 AM
Hi, Asahi12...

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">asahi12 wrote
...wondering that if you have one standard A2 upper from J&T and decide to buy a flattop, can you go and take out the bolt carrier from the A2 upper and use it in the flattop? Would you need to check it for "Go/No-Go" before hand? </div></BLOCKQUOTE>

Do note the bolt carrier assembly does not determine headspacing, etc. If you have multiple AR uppers you can use the same bolt carrier.

However, headspacing on ARs is largely determined by the interface of the barrel extension to barrel, along with any bolt & lug wear. [On ARs, headspace is NOT determined by the upper receiver. Changing barrel + bbl extension to different upper receivers will NOT affect headspace.]

You could in theory move your bolt across varying barreled AR uppers, trying to balance wear across each one. But over time that prob doesn't work: one of your ARs will be a real 'shooter'. The big issue is in situations where you somehow could end up w/a very used bolt going into a very used barrel + bbl extension, excessive headspace could occur, and this is why a good USGI 5.56mm "Field" Go/NoGo gauge is useful.

From a practical standpoint, quality bolt assys are only $50ish. Just put new bolt on carrier for each upper. But bolt carriers are only $55-$60, and complete assembled bolt+carrier assemblies are only $110ish so you're not saving that much money trying to skimp.

Bill Wiese
San Jose

Rascal
03-20-2005, 4:53 PM
OK Guys, I need some opinions here.
M.O.S. 16 inch Chrome Lined Bore and Chamber, M4 Profile, USGI 1/7 Twist and factory M4 feedramps. These are built with an T-Marked Flat Top Upper Receiver with factory M4 feedramps, forged front sight base, Mil-Spec hard coat anodized with Teflon coating receiver. Aluminum delta ring, ejection port cover, forward assist, gas tube, and handguards with aluminum heat shields. These uppers are assembled, and headspaced.
with chrome lined bolt carrier group and charging handle. $515
Is this a good deal?
What is the differance between the 1/7 twist and 1/9 twist?

bwiese
03-20-2005, 5:07 PM
Hey, Rascal..

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Rascal wrote:
M.O.S. 16 inch Chrome Lined Bore & Chamber, M4 Profile, USGI 1/7 Twist and factory M4 feedramps. These are built with an T-Marked Flat Top Upper Receiver with factory M4 feedramps, forged front sight base, Mil-Spec hard coat anodized with Teflon coating receiver. Aluminum delta ring, ejection port cover, forward assist, gas tube, and handguards with aluminum heat shields. These uppers are assembled, and headspaced. with chrome lined bolt carrier group and charging handle.
$515 - Is this a good deal?
What is the differance between the 1/7 twist and 1/9 twist? </div></BLOCKQUOTE>

Who/what is "M.O.S." - brand? distributor? seller?

$515 seems a bit high. I can't pull up Bushmaster website now, but aren't their complete barreled uppers w/bolt assy around $400ish or so? And Bushmaster is of known decent quality.

A Colt M4 upper will go for $695 - $800ish, just because of Hartford Horsey logo.

It seems the 'improved' M4 feedramps aren't really necessary except for full auto. Disadvantage is you really don't wanna mix a M4 feedramp bbl w/nonfeedramp upper & vice versa.

For most AR shooters, 1-in-9 twist (= 1- turn -in-9") is fine for the variety of ammo encountered by most shooters: 55gr - 68gr. The mil today uses 1-in-7" twist due to possibility of tracers, etc. and that majority of ammo they're using is 62gr M855 as opposed to mix of M193 55gr FMJ, 62gr FMJ M855, etc.

I myself would buy a 1-in-9" over 1-in-7" - but I wouldn't get my shorts in a twist over twist if the deal was good. (As long as it's not the old 1-in-12" twist, which is NOT suitable for 62gr & heavier bullets.)


Bill Wiese
San Jose

Rascal
03-20-2005, 8:23 PM
Hi Ted,
I was looking on BravoCompanyUSA at the M4 uppers page. Right under the CMT link is M.O.S. (Military Ops Series). It doesn't say who the reciever manufacture is. I do think that I will pass on this, as I believe that a 1/9 barrel twist would be what I need.
I did see on the AR15 board that "Legal-Transfers" (login name) is selling RRA NEW Factory Fresh A4 16" CAR FT uppers in stock with Chrome lined barrels
Nato Chamber 1/9 twist
$429 shipped
Complete with Bolt Group and CH. Any problems with Rock River Arms?

BigAL
03-21-2005, 6:26 AM
$515 isn't too bad considering it includes the bcg. Uppers are CMT and ER Shaw barrels are MP inspected on a random sampling basis similar to Bushy. The only thing I would want that isn't included is a F front sight post. I'm a big fan of 1/7" barrels considering they can shoot bullets 55 grains on up to the heavy/superior terminal ballistics OTM. Plus Bravo company is willing to sub in the heavier M16 carrier at no extra charge and give free shipping.

The RRA CAR upper is not going to have the same barrel profile as the M4. It may or may not be heavy profiled under the handguards, which I feel adds un-needed weight. Also, I think RRA barrels are 4140 chromemoly, which is fine for any plinker/range gun but is not the 4150 milspec steel.