what buffer and spring ? AR-15 .308

[Norsemen308]

Okay, I am at my whits end with my gunshops and need soem guys who first hand experince... I have a ar-15 .308 CMMG lower.I am using a DPMS upper(because the cmmg is designed for it). I want to know what buffer and spring you are using. I am very cautious when building a gun and this is the first .308 ar i have assembled. One shop that builds alot of .223 ar's but not so many .308 ar's is saying to use a ar-10 stock, buffer and spring, I know that is false as the reciever is a AR, therefore I have to use a AR stock, the Ar-10 is a different stock depth, tube and spring... its shocking how stupid some people are and they are calling themselves "armorer's" In my mind, you should be able to use the ar buffer, spring, stock and be fine.. however, I am getting heavy resistance from local shops.... please hel me, i would hate to put together a gun that does not function.

 

[dbsinh2o]

Re: what buffer and spring ? AR-15 .308

Here's your answer right off the CMMG website...


You will need four special parts to complete the lower.

* .308 Specific buffer and recoil spring (either rifle or carbine)
* Front and rear take down pin

The rest of the lower components are standard AR-15 parts.


Found right here...

CMMG

 

[AXEMAN]

Re: what buffer and spring ? AR-15 .308

look in midwayusa's catalog or on the website. all of the parts you need are there, listed as 308 parts. oh and unless CMMG is different than DPMS or JD machine or MEGA MA-10, you will need a bolt catch screw and possibly a bolt catch as well. i cant say if the catch is different as i did not compare it with a 308 version side by side, but the ar15 platform uses a roll pin where the lr308 platform uses a threaded pin with a hex head. i think the hole may be a bit bigger. as for stocks, you can use any AR15 stock and buffer tube/extension with an lr308 rifle whether it be rifle length or carbine, AS LONG AS the correct buffer and spring are used with it. dpms has a pardus 6 position thats identical except for the buffer and spring for the ar15 and lr308. the PRS has a 308 version so the cheek rest wont impede the charge handle, but other than that, you are G2G

and armalite is a different animal. i know they use a longer and heavier buffer. thats about all i know since i built on the LR308 platform.

 

[dlxcupid]

Re: what buffer and spring ? AR-15 .308

First things first, you do not have an Ar-15 lower. You have a 308 AR type lower. Like dbsinh said, you'll need .308 specific buffer spring and buffer in either rifle or carbine length depending on what stock you'll be using. There are <span style="text-decoration: underline">certain</span> stocks that are AR-10 type specific like the Magpul PRS, if you put the AR-15 model on, you won't be able to pull your charging handle back if the cheekpiece is up. That's not to say that you can't put AR-15 stocks on your build, some stocks have 308 specific.

Sounds like that smith is correct after all. Figure out the facts before you go on and bitch about that shop when you yourself is not too sure about it. Like you said, they're known for building ARs. I'm guessing they've must know a thing or two about ARs.

 

[Norsemen308]

Re: what buffer and spring ? AR-15 .308

hey when I am wrong, ill be the first to step up and say I am, and this appears to be the case. Just everything I have read on the internet said the ar-10 and ar-15 receivers are completely different, I must have lost somethng in translation.

thank you for all the help! sorry it was brain numbingly easy lol. I thought it would have required some work..

so for my AR.308, i need to use a AR stock BECAUSE the ar-10 wont let my charging handle clear? I am planning on using the PRS as this rifle will solely be a bench gun

thanks agian for the help,

 

[Mike_in_FL]

Re: what buffer and spring ? AR-15 .308

This has been posted many times on this and other sites. The 15 version of the PRS can be used on a .308 lower. But the charging handle will hit the cheekpiece if it is elevated at all.

Therefore, buy the .308 version of the PRS and the cheekpiece is mounted further rearward in the stock to clear the charging handle regardless of it's elevation. You can use any 6 pos stock for an ar15 if you use one of Slash's buffers, check out heavybuffers.com I believe.

Use the link to the google search engine in my sig line. You'll get all kinds of hits from this site on this topic.

 

[KillShot]

Re: what buffer and spring ? AR-15 .308

+1 on what FngMike said. If you're going to install a Magpul PRS, get the .308 version and do it right the first time or you'll be spending extra time and money to do it right later on.

 

[branson1369]

Re: what buffer and spring ? AR-15 .308

www.heavybuffers.com or Armalite for the buffer and spring. I just recieved my Heavy Buffer in for my MA-TEN build and I think it was a good approach

 

[Norsemen308]

Re: what buffer and spring ? AR-15 .308

thanks guys! anyone know of a good place to find Mags for this thing? need them in 10 and 4 round

 

[Badshot308]

Re: what buffer and spring ? AR-15 .308

Which lower did you order, the CMMG MK-3 that takes DPMS/SR-25 mags or the CMMG MK-8 that takes the G3 mag?

 

[Norsemen308]

Re: what buffer and spring ? AR-15 .308

mk3 lower is the one that I have.

 

[Badshot308]

Re: what buffer and spring ? AR-15 .308

The Magpul PMAG's are probably the most popular of the DPMS pattern. MidwestPX has reduced capacity versions http://midwestpx.com/index.php?cPath=15&osCsid=v89sa9gb0vdj86umibffdfel91 . DPMS has a four round magazine for those who need it to comply with hunting laws http://www.midwayusa.com/viewProduct/default.aspx?productNumber=833990

 

[Norsemen308]

Re: what buffer and spring ? AR-15 .308

thanks badshot!!

looks like the upper, lpk, magpull stock will be on there way tomorrow. woohoo.. its coming together...


anyone with the PRS stock, did you have to use the tube spacer? or is it not needed.

thanks again!

 

[Badshot308]

Re: what buffer and spring ? AR-15 .308

No, you do not use the A2 spacer when installing the PRS.

 

[AXEMAN]

Re: what buffer and spring ? AR-15 .308

and just to error on the side of caution, get the 308 LPK. i know you were gonna anyway, i just had to say it.

http://www.midwayusa.com/viewproduct/?productnumber=894635

the picture is wrong, too funny

they are out, but thats a great price if its not a long wait. if not, google it and you will find everything hopefully where you find the LPK so you dont pay multiple shipping