Help please! Mega arms build not running right.

[Andrew1981]

Hello,

 

I'd like to start off by saying thanks for all the great info on this form. I have built around twenty AR-15's but know this is a whole different animal and it is my first 308 build. Knowing that this was a new platform, I took my time and did research on parts first. After my research I chose the following parts.

 

Mega arms Maten upper and lower 

Noveske 18 SS barrel

DPMS bolt and carrier

DPMS rifle buffer and spring

SSA-E trigger

Rifle length buffer tube with a magpul PRS stock

CCMG mag release.

 

 

I know that there is a difference between SR25s and AR10s thanks to this form and even chose the Maten based off what I have read here. I know that some say the Noveske barrels are for AR10's only but I found several people on forms stating that they had built rifles with DPMS bolts and Noveske barrels. On this form I saw a couple people saying the same. I have to admit that I am kind of a Noveske fanboy so went with it after reading it would work.

 

So here I am. I completed my build...... I loaded my 20 round Pmag and pulled my charging handle..... I noticed immediately that the round did not fully seat in the chamber. I extracted the round and tried again, same thing.

 

I pulled the bolt and bolt and bolt carrier and noticed that when you held the bolt carrier, pushed the bolt down and flog it, the bolt did not smoothly fly from the carrier. I am new to 308 builds but know that in AR15's the bolt normally fly's to the seated position when this is done. 

 

I also noticed that the bolt would not lock back like it should VIA the bolt catch. The Mega arms Maten comes with a bolt catch installed so I'm thinking they know what they are doing with there parts.

 

So I come to the conclusion that I have messed something up. I live in Austin so I run by Springco and got one of there heavy duty buffer springs. I run back home and throw it in the gun. Pull the charging handle and BAM it loads the round. GREAT! I Then I try to lock the bolt back and found that I have the same problem, it locks on the Pmag but when I release the mag, the bolt fly's forward.

 

Mega arms website stated that there upper and lower sets will work with either DPMS or Armalite builds. 

 

I did some searches on this form and found some threads with people stating similar problems, but not the same. I am pretty sure that PRS stock are rifle length and there for take rifle length springs and buffer springs.... That is the only thing that I can think of that would be causing this problem.

 

So in conclusion I am worried that I have the wrong buffer and buffer springs due to the BCG not locking back properly, and two am now questioning if I should used the DPMS bolt with the 500 dollar Noveske barrel that I just got.

 

Any help would be greatly appreciated, and thanks for all the great info.

 

I will post pics of the rifle if that helps with fixing the problems that I am having.

 

 

[Robocop1051]

Lol. You honestly just wrote that you built a Ford using Mopar and GM parts, and you can't figure out why it won't run.

First and foremost... get rid of anything CMMG. I'm dead serious. Don't make me bring out the memes.

Second. Borrow an AR10 BCG. If it works, you have your answer. While, technically, you only need the bolt and not the full assembly. We still recommend all matching parts.

I don't really read those "other sites" for information on a 308AR. If they were going to be the top dogs for information on the platform, they'd be called something genius like..... 308ar.com?!?!

Noveske barrels are AR10 platform. They need an AR10 bolt. Anyone who says different is either a.) a master gunsmith, b.) ignorant of what he actually owns or c.) a damned liar. I'm not calling you anything. I'm just saying that some people were trying to feed you a line of bullshit.

[Andrew1981]

Ha, ok, got you. Ditch the DPMS BCG and go with a Armalite BCG. I would have done that from the start, but couldn't find one for sale. I guess I'll hold off on firing the rifle until I find one. Do you thing I should replace the buffer and spring to armalite too? I have read that you should keep all the parts from the same company?

 

Thanks for the help.

[Andrew1981]

also I will replace the CMMG mag release :)

[edgecrusher]

All your other parts will be fine if you just change the bolt. Noveske is Armalite pattern. Wherever you heard otherwise is the source of your issues. I can assure you it wasn't here.

[Robocop1051]

also I will replace the CMMG mag release :)

Don't take offense to this. Lol

I just like posting these every opportunity I get... I'm not going to lie. I'm downright racist against CMMG.

This one is irrelevant, but one of my favorites.

[Zebra644]

Oh crap you got him going why oh why did you have to mention CMMG?  <laughs> 

       First of all welcome Andrew, nice build. To back up Robo here, the 5.56 platform is pretty much all interchangeable kinda like Lego's with the exception of KAC's bolt due to the lug design if I remember correctly. The SR-25 / AR-10 have different bolt stops / catches, Bolts and BCG's  thus different barrel extensions, as well a magazines and lower receivers to match the mags. The SR-25 pattern is pretty much every thing but Armalite which now makes 2 models that accept either their proprietary designed magazines or P-Mags.  They still operate the same as the AR-15 M-4 rifle length extensions / buffer tubes must have rifle length buffers and springs the same with carbines. The place where it gets tricky is when you put a UBR on a .308 which requires one of Slash's heavy buffers that fit the UBR in .308. So you should be good with the PRS and rifle length buffer and spring. 

 

      So the Noveske barrels are awesome but in the .308 platform they have the Armalite bolt patterned barrel extensions. So either change the extension, or change bolts and I highly recommend that use change the entire BCG as well. If worse comes to worse call Noveske and describe your build and see what they recommend or call Mega Arms as I hear they have great customer service before you start dropping coin, but I'd bet matching the AR-10 pattern bolt to AR-10 pattern barrel extension will solve your problem. Let us know what you change and if it fixes it,please. 

[washguy]

Andrew   I have several Mega builds...I can assure you that the Mega upper/lower isnt the problemo

you have a Noveske barrel which uses an Armalite (ar10) barrel extension and your bcg has a dpms style bolt....two different bolts...thats why you got the problemo    :)  Wash

[Andrew1981]

UPDATE

 

Ok, I took it to my departments gunsmith. He throw in a DPMS carbine buffer and the bolt now lock back properly. I thought that the buffer tube was rifle length but guess i ordered wrong. The bolt would not close on the go gauge but knew that would happen. He told me that I could just change out the barrel and keep everything else the same. I think that's the easiest fix due to me building a complete SR-25 and putting a AR-10 barrel on it. I guess Ill return this Noveske barrel and get a Rainer arms ultra-match instead.

 

Thanks for all the help guys. I know that ya'll probably spend a lot of time helping people like me that make noob mistakes and you have better ways to spend your time.

[shepp]

That's why we're all here, to help and to learn

[Zebra644]

As an option look into Hart, Lilja, and Criterion barrels. Are you returning or selling that 18" Noveske

Edited December 29, 2014 by Zebra644

[FaRKle!]

UPDATE

 

Ok, I took it to my departments gunsmith. He throw in a DPMS carbine buffer and the bolt now lock back properly. I thought that the buffer tube was rifle length but guess i ordered wrong.

Uh, this doesn't sound right. When you say DPMS carbine buffer, do you mean the short LR-308 carbine buffer or DPMS AR-15 carbine buffer? Either way that is not the correct buffer to use. In your original post you mentioned a DPMS rifle buffer and spring. Did you get the LR-308 specific rifle buffer and spring, or DPMS AR-15 rifle buffer and spring? Nomenclature is VERY important in determining what parts somebody is using, which is why I stress using the terms LR-308 and AR-10 (also DPMS has multiple patterns now).

[Andrew1981]

I looked at my order and found I did order the rifle length buffer tube but it say for M-16 and 308. Do they both use the same length tube or did I buy the wrong one?

 

Farkle, The buff is a DPMS lr-308 carbine and is 2.4ish inches long. I cant get a good weight on my digital scale for it because it is too heavy. Im not sure what spring he put in so I will call and ask him tomorrow. I can now see that the rifle length buffer was too long and would not allow me to pull the bolt back far enough to lock it on the bolt, it was only catching the bolt carrier. After reading more I think this buffer is for a M-16 and not the correct one.

 

I have messed up a lot of things on this build, but a least I didn't test fire this monster rifle I built.  

 

 

 

[washguy]

go for the Rainier barrel....you will be happy...and most of the time they have em on the shelf

:)  Wash

[Andrew1981]

Ok, I see what you are saying now Farkle I should get this (http://www.brownells.com/rifle-parts/receiver-parts/recoil-parts/recoil-buffers/rifle-buffer-prod42989.aspx) and the spring that goes with it for it to be correct.

[survivalshop]

 As far as 308AR's go , they share the same Receiver extensions ( Buffer tube ) as the M16/M4/AR15 , the Armalite , AR 10 uses a some what different system & can be used with special attention to components .

 

 As far as a DPMS /SR25 pattern of receivers using a M16/AR 15 rifle Receiver extension , you need a DPMS 308 Type spring &  308 rifle Buffer .

 

  Which is out of stock at Brownells , but there are a lot of places selling them .

[FaRKle!]

Ok, I see what you are saying now Farkle I should get this (http://www.brownells.com/rifle-parts/receiver-parts/recoil-parts/recoil-buffers/rifle-buffer-prod42989.aspx) and the spring that goes with it for it to be correct.

Yup, you need the 308BS11 buffer part and 308BS10B action spring.

Alternatively, you can go with the AR-10 rifle buffer and AR-10 action spring. The AR-10 rifle buffer and LR-308 rifle buffer are the same size and weight. Armalite is having a sale right now with coupon code "12DAYS" for 25% off.

[98Z5V]

I think you're using a DPMS AR-15 rifle buffer, myself.  With it's spring.  Can't do that in a .308 AR.  Verify that part.  It sounds like the source of your problems.  Don't change any other parts until you verify what buffer that is.

 

 

Don't run a DPMS carbine buffer in a rifle-length receiver extension.

[Rsquared]

As far as your barrel is concerned. I'd be patient, and just replace your BCG with an Armalite one. That would fix your whole upper assembly issue. Noveske makes some damn nice $hit. I've got a couple of their barrels on some of my builds. They're definitely top shelf equipment.

**** - side note. what gas length is that 18" barrel (mid-length I presume)? just wondering......in case you're gonna sell it. <laughs>

 

For the lower, you already have the PRS stock. Verify that you actually have a rifle length buffer tube, then go to heavybuffers.com and get one of Slash's setups for a rifle length setup (you can get rifle buffers and springs elsewhere.......but he's a loyal sponsor of this site). You'll be just fine after that.

 

Otherwise.....you're chasing problems all over the rifle all at the same time. We've all done it brother.......and it can frustrate the $hit outta you.

 

Remember the rule of KISS. Keep It Simple Stupid.

[98Z5V]

 

For the lower, you already have the PRS stock. Verify that you actually have a rifle length buffer tube...

 

Absolutely positively has to be a rifle receiver extension, or the PRS never would have mounted to it in the first place.  I'm just sayin'...

[Rsquared]

I meant for the buffer and spring. But I see what you meant there. I didn't specify that I guess. Just trying to make it easy on the guy to get him back to "running" status.

[98Z5V]

I meant for the buffer and spring. But I see what you meant there. I didn't specify that I guess. Just trying to make it easy on the guy to get him back to "running" status.

 

Need to know what that buffer is.  It's an AR-15 part, betting money on that.

 

This one is still my all-time favorite, hands down.  There are no other winners, and everything else is a loser.

 

This one is irrelevant, but one of my favorites.

[planeflyer21]

For those of you interested about the back story on Tom and his balloons, here's how it all started:

 

https://www.youtube.com/watch?v=AhGLI7yyzYM

[98Z5V]

***  THAT BASTARD!!!***

 

<lmao>

[Andrew1981]

As far as your barrel is concerned. I'd be patient, and just replace your BCG with an Armalite one. That would fix your whole upper assembly issue. Noveske makes some damn nice $hit. I've got a couple of their barrels on some of my builds. They're definitely top shelf equipment.

**** - side note. what gas length is that 18" barrel (mid-length I presume)? just wondering......in case you're gonna sell it. <laughs>

 

For the lower, you already have the PRS stock. Verify that you actually have a rifle length buffer tube, then go to heavybuffers.com and get one of Slash's setups for a rifle length setup (you can get rifle buffers and springs elsewhere.......but he's a loyal sponsor of this site). You'll be just fine after that.

 

Otherwise.....you're chasing problems all over the rifle all at the same time. We've all done it brother.......and it can frustrate the $hit outta you.

 

Remember the rule of KISS. Keep It Simple Stupid.

Ha, It's a mid-length.

 

I think I going to just hide it from the wife and have a back up barrel for my N6 Ill be getting in a few months.