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Information and Education => Gunsmithing and Weapon Repair => Topic started by: Mississippi556 on August 13, 2013, 03:24:01 pm

Title: Need Advice on AR15 Magpul ACS stock fit
Post by: Mississippi556 on August 13, 2013, 03:24:01 pm
Thanks for checking out this post.   I've made a newbie AR mistake and am looking for the best solution.

Long story short.  I have only one AR15.  it is an M4gery build from various top line manufacturers on a S&W M&P 15 lower.  The relevant part is that the lower has a mil-spec carbine receiver extension or buffer tube.  Somehow in the build process I ended up with a commercial Magpul ACS stock rather than mil-spec.  I didn't even think to check when installing it.  I was so excited to find an ACS locally, which is what I wanted, that I did not even notice that it was for a commercial tube and really was too ignorant to pay attention. I had heard that sometimes those stocks can rattle a bit anyway.  When installed, it rattled and wiggled when moving it, but was pretty tight when the lock lever is depressed.  So, I assumed that was normal.   Well, you all know what assuming does.  Being a newbie to AR15's I was too ignorant to know different.

Recently I removed the stock, measured the buffer tube O.D., verified that the tube was mil-spec and that the stock was, indeed commercial.  I want a tighter fit.  It's too late to return the stock, which is now about 7-8 months old. 

I read a couple threads on other forums about guys who make this mistake and fix it by applying electrical tape to the tube to close the gap.   I think that is ugly, to be charitable.  Instead, I looked at the inside of the Magpul ACS stock and decided to apply the tape to the inside diameter of the stock rather than the tube.  It works like a charm, but I have durability concerns.  Fit is now perfect,  stock has no wiggle or rattle and slides well (if a bit tight) when retracted or extended.

Have any of you either made the mistake or corrected the mistake for someone else?

Seems to me that I have three choices:

1.  Get a proper Magpul mil-spec ACS stock, and try to sell this one.  I love the cheek weld and the storage on that thing.  That solution is about $110.  This is the perfect, but most expensive option.

2.  Get a good commercial receiver extension.  That is only about $25-40.   I'm now familiar with the debate about mil-spec v. commercial, same thread diameter and pitch but different cutting technique, different aluminum alloys, different tube wall thickness, all that stuff.  This is a less expensive solution, but no longer mil-spec.

3.  Just use the electrical tape "fix" as long as it solves the problem.  it's not as if this affects functionality or reliability of the weapon.  And if the mil-spec tube is stronger than commercial, it's inherent strength is still there.  Cost - nothing, just a couple strips of electrical tape I already had.

Perhaps there are other options I've not considered.

What say ye?  I'm unconvinced that mil-spec tubes are actually stronger than a commercial tube from a reputable manufacturer, but open to differing opinions from others.
Title: Re: Need Advice on AR15 Magpul ACS stock fit
Post by: booksmart on August 13, 2013, 03:58:36 pm
The only thing about the electrical tape fix I have a concern with is if any grit got in there and abraded the tape, making it harder to work the stock.

This is in direct proportion to the possibility of you throwing the rifle into the mud, then working the stock.  :shrug
Title: Re: Need Advice on AR15 Magpul ACS stock fit
Post by: Coronach on August 13, 2013, 04:01:24 pm
I would get a milspec stock and sell the commercial. If it is still in good shape and you can honestly sell it as LNIB, you'll take a small hit, but not too bad.

The only important difference between milspec and commercial (now that you have the wrong stock ;) ) is strength. The commercial tube is not quite as strong. However, it probably won't matter a bit, so if you went that route, you'd probably be fine, too.

Mike

Sent from my DROID BIONIC using Tapatalk 2

Title: Re: Need Advice on AR15 Magpul ACS stock fit
Post by: Mississippi556 on August 13, 2013, 09:58:28 pm
Thanks for the replies.  The "frugal" part of me says run the gun like it is for a while and see if I have problems.  The obsessive perfectionist in me will probably kick in if I see a mil-spec ACS stock somewhere.  If the price is fair, I'll fix this with a correct stock.
Title: Re: Need Advice on AR15 Magpul ACS stock fit
Post by: booksmart on August 13, 2013, 10:11:56 pm
http://dsgarms.com/ProductInfo/MGACS-LSTOCKKITBLK.aspx (http://dsgarms.com/ProductInfo/MGACS-LSTOCKKITBLK.aspx)

That's what I bought for my impending build.  :shrug

Take your pick : http://dsgarms.com/Category/318_1/Magpul.aspx (http://dsgarms.com/Category/318_1/Magpul.aspx)
Title: Re: Need Advice on AR15 Magpul ACS stock fit
Post by: Outbreak on August 14, 2013, 01:12:20 am
I would buy the correct stock, then start building another lower with a commercial tube, because I can't throw away parts and parts need to be installed on SOMETHING.

The only exception is A2 Pistol Grips. Those need to simply be discontinued.