guruofhotrod

I think you're referring to this thread: http://forum.308ar.com/topic/7587-armalite-non-forward-assist-bcg/?page=1 Beautiful build!!

I did manage to order one for one of my 308's at the $40.00 price (actually $53.19 with tax and shipping) They refer to it as a "compensator" I think I'll hang it on the end of the Ares 16" barrel that I recently purchased that is mounted on an Ares upper that will hopefully soon contain a Ares Nib BCG - kinda noticing a pattern developing here LOL I'll post a short review on it when it shows up. On the subject of Arms Unlimited, I'm a little leery of them - if I'm not mistaken a while back they were selling some knock-off products as the real deal (Raddlock mag lock comes to mind) shop carefully!!

Yea, I usually just assemble the barrel to the upper, remove the ejector assembly and then check headspace with the BCG otherwise assembled allowing it to go into battery with the headspace gauge in place of a round. Headspace results were as good as one could hope for with the "GO" gauge chambering correctly and both the "Field" and "NO GO" failing to chamber as it should be - this with 2 different standard DPMS bolts, one new, and one used. I think that since I put this barrel on a Ares Armor billet upper I'll probably buy one of their NiB BCG's for it when my $ allow.

Mine showed up yesterday - to answer D.R.D.'s question, the barrel has a somewhat shiny finish, possibly nitride, not phosphate I'll see if I can get it mounted and check headspace tonight!

Yes, they do - here's an example, if the barrel is stainless you should consider cobalt or even carbide, might take a little searching to find and since carbide is so brittle you would be best off with a vertical mill for accuracy and superior ability to hold the workpiece. http://www.travers.com/high-speed-steel-special-decimal-size-chucking-reamers/p/57908/?lite=true

I've got one of the same barrels on the way too - when it arrives I'll also check headspace and post the results.

The 16" mid length 4150 308 barrel for $124.99 looks pretty good! http://aresarmor.bmetrack.com/c/v?e=7D0E6A&c=84066&l=D8522BF&email=KxGROfWTlNaByy1bwtAlpbQR3BgPsWUo&relid=A0B0E05

Since the top rail on the Handguard/rail is against the front surface of the upper receiver, being able to run the barrel nut further down on the threads would result in the anti-rotation tabs engaging less into the barrel nut so, it looks to me like you have it assembled as intended by the manufacturer. I am noticing that the ejection port door pin isn't hanging out the front face of the upper as is typical of the large frame AR's - you should double check to confirm that the pin can't shift forward enough to allow the door to fall off during use <dontknow>

Looks like your handguard may wind up a little long but, it's difficult to know for sure without getting a barrel mounted and checking the location of the gas block relative to the end of the handguard. When I measured my upper with a BHW 16" mid gassed barrel installed I came up with the 9-5/16" measurement from the front of the upper receiver (where the gas tube enters) to the step on the barrel that locates the gas block. (this dimension can be affected by the manufacturing tolerances of several components though)

Looks like your combo is going to work out fine - from the front face of the upper (at the rail) to the rear face of the gas block you should be around 9-5/16" - as blue109 said install the barrel, gas tube and block first to determine the space you have for your handguard/rail then trim the rail ONLY IF NECESSARY - "measure twice cut once" absolutely applies here, your mid length gas tube should be around 11-3/4" in length (end to end) Also, when using the O-ring method to measure the gas key to gas tube overlap, make sure you remove the O-Ring before you try to fire the rifle (you don't want it breaking loose and possibly jamming things up)

When I built one of my uppers, (DPMS High pattern) I installed a Samson Star 10 in a 9.2" length: http://www.samson-mfg.com/mm5/merchant.mvc?Screen=PROD&Product_Code=STAR10-9-2&Category_Code=SHOP Along with the optional DPMS Barrel nut: http://www.samson-mfg.com/mm5/merchant.mvc?Screen=PROD&Store_Code=SM&Product_Code=DPMS-BN&Category_Code=308AR_STAR_ARMALITE Along with a PRI Railed gas block - even though the parts were designed for a Armalite AR10 they were a close enough fit that with a little "massaging" they worked out well for the mid length DPMS type platform I had to open up the anti-rotation tabs on the bottom of the rail where it locates against the front of the upper receiver and with a counter bore I relieved the back of the gas block to tighten up the gap between the gas block and the front of the rail (always check the overlap of the gas key and the end of the gas tube to ensure the tube isn't bottoming out in the gas key when in battery) (to check I slide a small O-Ring on the end of the gas tube inside of the upper and then install the BCG, lock it into battery, remove it and measure the distance from the O-Ring to the end of the tube and compare that to how deep the socket in the gas key is by inserting a loose gas tube into the gas key until it bottoms out, marking the location on the gas tube at the edge of the gas key then measuring from the mark you made to the end of the tube.) With this combo I used a standard mid length gas tube.

Yep, out here we have to wait 10 days for even a stripped lower, nomatter how many you may already have - go figure <dontknow> Nice find Ed <thumbsup>

Got a reply from Chris: "Rather recently, to avoid any further inconvenience to my customers, I switched the thread pattern on all my uppers to DPMS so that a crescent wrench could be used to install the barrel nut. While I may have three or four of the Armalite thread patterned uppers left over, soon they will all be gone. I don’t plan on having the Armalite thread pattern available after these are gone. Thanks, Christopher Riedeman RiedemanFirearms@aol.com " So, no more Armalite threaded Matrix uppers - not sure how many of each are in circulation, definitely something to give extra attention to <thumbsup>

Looks like Genesis 80% lower: http://genesiscnc.com/ and possibly Mega, - The Genesis website lists LMT,La Rue, and Les Baer as being compatible with their lower in addition to Armalite and KAC - the do mention specifying a .281" pin size on their upper for LMT and KAC lower compatibility

Yea, not on the roster :sad3: Nice score Robo! <thumbsup>

In the case of an Armalite nut on a DPMS upper it will thread on about 3/4ths of the way before the threads get tight - with the opposite combination it threads on about 1/4th of the way before the threads start to bind. Checking the threads with a pitch gage the DPMS is 16 threads per inch while the Armalite is 18 threads per inch. I think the Armalite nut on the DPMS upper is the combo most likely to get an inexperienced builder in trouble.

Sounds like that may be the case, here's the response from Chris: "Nope. You just got sent the wrong barrel nut. Tell me which nut you need and I'll get it out. Thanks, and sorry. Chris" I have requested confirmation on the use of both types of threads, should have an answer soon <dontknow> A slight inconvenience but as long as we're aware of the possibility and exercise caution during assembly we shouldn't have any disasters :eek:

Here are a couple of pics showing the difference: Still waiting on a response from Chris - hopefully tomorrow, anyone assembling one of these should check this detail very carefully <thumbsup>

Hey Guys, Looks like there may be some Matrix uppers that have DPMS type barrel nut threads (They have been expected to have Armalite type thread pitch) I figured it out pretty quickly when the nut supplied with the Matrix rail wouldn't thread all the way on to the upper, a quick check with a DPMS barrel nut confirmed it - I'm awaiting a response from Chris Riedeman as to whether he needs this upper returned or wants to swap the Armalite type nut for a DPMS model - I know many of you guys are experienced enough to catch this before forcing the nut on and destroying your upper but some of the less experienced members might just think the threads are a little tight and try to force it the last of the way - DON'T DO IT!!! I'll post a pic later.

I'd be up for 1 or 2 plus spare parts <thumbsup>

I completely agree with you Brother, I'm a metal worker by trade and could pretty much do it in my sleep! Getting a hold of the mags to start with here in cali is a different story - nobody in their right mind will send them here to someone that isn't licensed to receive them. It really sucks that we have to neuter perfectly good parts to use them here.

Problem is, here in this not so free state we can't take delivery of them with full capacity, it's a felony :eek: My FFL buddy doesn't charge much for the service of pinning them (sure, it's not too tough but, it either has to be done out of state or in state by an authorized "07" FFL) It totally sucks but those are the rules we have to play by <dontknow> Edit: Here are a couple of pics of a pinned ASC 32 round 9mm mag that I bought from him for a very reasonable price <thumbsup> :

I need to call tomorrow to confirm my pick up appointment for the Matrix receiver set so I'll ask how much he wants to pin 4 mags and send them to you in San Diego - I called KeepShooting today and they indicated that we could buy them if they have the FFL send his info to them and they ship to said 07 FFL for mods to state compliance - at least we can get em!

I've got an 07 FFL in the LA area that can pin (rivet) them to 10 round capicity <thumbsup> He will then mail them to you - I'm thinking of getting a few for a future build - let me know if you want to go this route and we can have him do them all at once.

I ran across these guys recently when I was searching for extractors for a 7.62 x 39 AR Bolt (not very common) I couldn't help but notice the unusual design of their projectiles - quite a variety, they offer ammo and projectiles Since most of my shooting is at the range I doubt I'll have much need for this stuff but, some here might http://www.lehighdefense.com/