Matrix build

[dsdmmat]

so I was going to build a straight pull bolt AR308 but my barrel would not have a thick enough shank after all the work would have been done.  Now I have a matrix set upper and lower with handguard on the way. Should be here Friday. I have some concerns about the forward assist as I have read people are having issues with them not allowing the bolt to come back. I will be using a DPMS barrel and bolt carrier group. Does anyone have a fix for the FA problems I have read about besides buying a plug? 

[blue109]

I just took the plunger off. Button is still there but doesn't extend into the receiver. If you want a functional FA, maybe order a upper parts kit direct from matrix or one of their dealers? 

[guruofhotrod]

My buddy has a Matrix based DPMS type 308 with an AIM BCG and a standard AR15 F/A and it works fine, no interference problems

I've got a Matrix Based Rifle that is about 90% complete, I'll be bringing my upper to my local FFL in a couple weeks when I pick up a

Springfield 1911 that I horsetraded for - He has a nice reasonably priced nitrided BCG that I want to check the F/A engagement on

before I buy it - I'll post the results and a link to his website after I check it.

[jtallen83]

Don't get a 308 specific FA! I did for my Matrix build and it would not allow the carrier to come back, a d. wilson brand BCG. This may be just an issue with certain combinations of FA and bolt carriers but I never found any specific information beyond getting one from Chris at Central Florida Firearms.

Edited January 6, 2016 by jtallen83
clarity, I hope.

[blue109]

I tried a standard FA and it hung up on two different BCGs. 

[dsdmmat]

Thanks for the info. I will be getting a lower parts kit from Chris so I will just grab the upper completion kit as well.

[dsdmmat]

Got my upper and lower parts kit in and installed. The roll pin on the FA falls right in not snug at all. The first barrel nut they sent me was for their DPMS threaded upper and I have the Armalite one, so They sent me out a new one. I received it today. Now I have the issue of finding a wrench to fit it.  

 

I only need need to pick up a BCG, Barrel, gas block and gas tube to complete the build. Got a 1911 frame on the way to build. I am hoping to finish both guns this summer as funds permit.

[blue109]

Couple of us had the same issue with that roll pin. Best option is to run over to ace hardware and get one slightly larger.  There's a great deal on a barrel/bolt/gas block in the sale forum. I think geistacwm has a barrel to sell as well.

[dsdmmat]

Thanks for the info. I saw that stuff in the for sale forum, not the route I am going with this build. I prefer longer barrels and adjustable gas blocks. I figure I will be spending about 700 bucks more in the coming months to complete it then a few hundred more to put a scope on it.  On top of the 400 or so putting my 1911 together. I am trying to "be good" and stick to a couple hundred a month spent on gun parts. 

[ChaseFan9]

Hey dsd, did Chris send you the old or new design barrel nut?  If it's the old one, I've got a thread on here about it.  If it's the new barrel nut, you'll need a 1 5/16" crow's foot if you want to use a torque wrench.  I got one for like $10 shipped off amazon.  It's a cheapass POS, but that barrel nut is most likely the only thing I'll ever need it for.

[dsdmmat]

ChaseFan9 I got the old style nut and had Toolndie7 make a wrench for it. He does amazing work, the thing is a piece of art. I also have the newer style nut that is DPMS threaded so I may just have to pick up a hand guard later to go with it.  

[dsdmmat]

Just wanted to thank guruofhotrod for the FA pins he sent me in the mail.

[dsdmmat]

Took my matrix to the range today. It was short stroking big time. Only ejected 4 rounds out of 30 that I fired today. I have an adjustable gas block and had it wide open. I have an Anderson 20 inch barrel with a rifle length gas system. I figured it wasn't getting enough gas, since I didn't see any evidence of the bolt dragging on anything. When I got back home I measured the gas port .078, so I drilled it out to .093 I turned in my gas block one full turn so I will try it out again tomorrow. 

 

I have read that Armalite's 20 inch barrel has a .110 gas port and DPMS' port size is .0936. I figure I will try .093 then open it up more if It is still short stroking. 

[MikedaddyH]

The .093" should put you in the ballpark. Check the alignment of the gas block to gas port hole also.

[blue109]

Double check you have the right gas tube. Standard rifle length and AR10 rifle length are slightly different. Make sure your tube is protruding deep enough into the upper.

[dsdmmat]

I have a DPMS pattern rifle length gas tube, the barrel is a DPMS rifle gas length system. 

[blue109]

Cool. Just brought it up because we've seen it in here quite a few times. Even some DPMS pattern barrels require the slightly longer armalite gas tube, otherwise the carrier key separates from the tube too quickly causing an undergass/short stroke situation like the one you describe.

[392heminut]

5 hours ago, blue109 said:

 Even some DPMS pattern barrels require the slightly longer armalite gas tube, otherwise the carrier key separates from the tube too quickly causing an undergass/short stroke situation like the one you describe.

Exactly the problem I had with my Anderson barrel. The Armalite gas tube solved the problem.

[dsdmmat]

Well the larger gas port did the trick. I was even able to screw in the gas block adjustment another 3/4 turn. 

[dsdmmat]

duplicate post.

Edited March 20, 2016 by dsdmmat

[dsdmmat]

6 hours ago, blue109 said:

Cool. Just brought it up because we've seen it in here quite a few times. Even some DPMS pattern barrels require the slightly longer armalite gas tube, otherwise the carrier key separates from the tube too quickly causing an undergass/short stroke situation like the one you describe.

Thanks for the heads up. This will probably be the last matrix I build, I prefer to have everything interchangeable. It is not a bad rifle but, not having the ability to just stock replacement parts that fit everything is a drawback. 

[washguy]

Aint nothin stock with any of these 308's  lol....glad shes working for ya now    Wash

[jtallen83]

4 minutes ago, washguy said:

Aint nothin stock with any of these 308's  lol....glad shes working for ya now    Wash

Yep, I didn't have any issues with the Matrix factor of my 308 build but then I had the do's and don'ts already figured out for me here before I started buying parts. I went with a Matrix receiver set and rail for my lightweight AR-15 build and have been very satisfied with the parts on that one as well, great bang for my buck from Chris at Central Florida Firearms!

[blue109]

The matrix set is pretty sexy though. I like the lines.

[dsdmmat]

12 hours ago, jtallen83 said:

Yep, I didn't have any issues with the Matrix factor of my 308 build but then I had the do's and don'ts already figured out for me here before I started buying parts. I went with a Matrix receiver set and rail for my lightweight AR-15 build and have been very satisfied with the parts on that one as well, great bang for my buck from Chris at Central Florida Firearms!

This is the first one that I have built that I had issues with the 308 not cycling (and that is not the fault of the Matrix receiver set). Most of the cycling issues I have had in the past were from being over gassed (which is why I started using adjustable gas blocks in the first place). This forum is the go to place for all things in 308 ARs, lots of great people with more knowledge than one could accumulate in a lifetime on their own.

11 hours ago, blue109 said:

The matrix set is pretty sexy though. I like the lines.

I do like the looks of the Matrix rifle, if this was my first build I would probably build more on their receiver sets. As it sits right now it is the Cinderella with three ugly step sisters. I cannot really complain about the quality of the Matrix receivers and hand guard they are well built and beautiful to boot.  Realistically, I doubt I will build any more 308 ARs, if I do I will have to buy a bigger safe.  

All the others I have built are completely interchangeable. The Matrix is the only one I cannot do that to, it is not really a problem but, I do like to keep some spare parts on hand for things that will make a rifle go down hard. I will just have to get a set of pins and another bolt catch specific to this rifle to have sitting in the drawer. The plus side is that it takes the same magazines as my other 308 ARs and I got a cool looking barrel nut wrench out of the build.

The only thing left to do now is get a load worked up that will make the thing shoot less than MOA.