Buffer and tube compatability issues

[Frenchy]

I'm building a moderately lightweight ar308. I purchased a mil spec carbine length buffer tube from 2a and went heavy on the buffer itself with a carbine length 2-stage stealth buffer from Armaspec. I'm not comprehending why the buffer is almost 3/4" too short for the tube. Did I get a mislabeled part? What am I missing here? I feel like Armaspec and 2a will probably both say I need to contact the other guy.

PS. I'm new to the forum and only have a couple of builds under my belt, so go easy on me please.

[edgecrusher]

Measurements are required 

[jtallen83]

First advice that comes to mind is return that stuff and buy the Armalite kit;

https://www.armalite.com/SACItem.aspx?Item=AR10REKIT01&ReturnURL=/Armalite/Product-Category/AR10-Parts-Accessories/Lower-Receiver-Parts&Category=ac614400-ff09-4cdf-9d35-419a654e7201

Going to need the inside depth of the buffer tube. That captured spring stuff is a regular on build doesn't work thread parts lists here.

[Frenchy]

15 hours ago, edgecrusher said:

Measurements are required 

The buffer tube is 7 25/32" internally, but the buffer turns out to be 7 3/32" so it's 11/16" more tube length or less buffer length than I need. I must've gone astray somewhere. Is there a difference in buffer systems between Armalite and DPMS? My build is DPMS.

Questions I should've asked...
 

Edited May 5, 2021 by Frenchy
Incomplete information

[shooterrex]

This will work. If the web says out of stock call them.

 

https://www.armalite.com/SACItem.aspx?Item=AR10REKIT01

[Frenchy]

Thanks guys, I appreciate the assist! All the best to you!

Can't wait to get more gun money from Biden.

[98Z5V]

9 hours ago, Frenchy said:

The buffer tube is 7 25/32" internally, but the buffer turns out to be 7 3/32"

The standard for the buffer should be 7 5/8" internal depth.  You're close enough.

That should run a buffer that's 3.250" long, and weigh 5.4 oz.   There isn't a buffer for these things made that comes out to 7 3/32" long.  Something wasn't measured right to come up with that number.

[DNP]

Silent captured system, right?  Designed for a shorter tube maybe?

[jtallen83]

20 minutes ago, 98Z5V said:

There isn't a REAL buffer for these things made that comes out to 7 3/32" long.

Fixed it......He has one of those captured spring thingy-ma-bobs,

https://www.at3tactical.com/products/armaspec-srs-stealth-recoil-spring-multiple-buffer-weights-available

 

[DNP]

What’s the depth of an ar15 tube?  Wrong part?  Just guesses

[98Z5V]

5 minutes ago, DNP said:

What’s the depth of an ar15 tube?  Wrong part?  Just guesses

Real Armalite number is 6 15/16" internal, common aftermarket that works is 7.000" internal.

 

7 minutes ago, jtallen83 said:

Fixed it......He has one of those captured spring thingy-ma-bobs,

https://www.at3tactical.com/products/armaspec-srs-stealth-recoil-spring-multiple-buffer-weights-available

 

No way would I be running one of those things in a .308AR.

[DNP]

7” sounds about right for that buffer. It ain’t for a 308. 

[jtallen83]

8 hours ago, DNP said:

It ain’t for a 308.

But it says AR10?  and it's "equivalent" to 5.7 ounces. Makes you question how much R&D was done when they can't even get the nomenclature right, not even a mention of what size carbine tube it fits, wonder if they even know there are different sizes?

• .308, 5.7oz Equivalent
  • For AR10 Rifles in .308 WIN, 6.5 Creedmoor, 6mm Remington, 6mm Creedmoor 

[Madhouse]

I've moved your thread to the Member Builds forum.

[Frenchy]

So as it turns out, the nice folks at Armaspec have a solution to the dilemma. Spacers! Oddly enough, I had done a search for spacers, assuming something would come up, but nothing did. When I was able to get in touch with an Armaspec rep, voila! $6.99 later, the problem is solved! I will be able to test this setup as soon as my charging handle arrives. 13 weeks so far...

[DNP]

I put 2 quarters in mine. They only cost me $0.50. And I get my money back if I ever take them out. 

Edited May 15, 2021 by DNP

[Frenchy]

14 minutes ago, DNP said:

I put 2 quarters in mine. They only cost me $0.50. And I get my money back if I ever take them out. 

That's cheaper than a round of .308 ammo... I'll remember that for my next build.

[DNP]

Learned that here. That was a 98 trick. 

[Frenchy]

2 minutes ago, DNP said:

Learned that here. That was a 98 trick. 

You, Sir, are a veritable wealth of information. 

[98Z5V]

Every quarter that you add gets you 0.069" of space-freedom.  Stack 'em if you have to, make up whatever space you need to.  In the old(er) days, it took $1.75 to make a pistol caliber carbine run with a regular AR15 buffer.   .

[Steve crawford]

I bought a lightly used DPMS LR-308 from a pawn shop.  I took it over to a gun shop and had them put a RRA adjustable but stock on it.  A few days later I found this site.  Yesterday I was giving the rifle a good cleaning.  I decided to weight the buffer.  Guess what.  I had a 3.0 oz. buffer that was 3.25 inches long.  I did some looking around here and found this thread.  I went to the Armalite site and found the carbine tube kit.  It was cheaper to buy the kit than just the buffer and spring.  This way I know that I have the correct tube, spring and buffer.  I called there customer service and verified that they had it  stock.  Now to see how long it will take to get it shipped.  😁😁😁 

      Steve

Edited May 21, 2021 by Steve crawford

[unforgiven]

Smart 🤓

[Steve crawford]

Finally got the RRA Marksman but off the buffer tube.  I just don't have the hand strength I need for this stuff.  Removed the Buffer tube and with the cheap steel tape I have.  The inside length is 6 15/16 inch.  So I now have an extra buffer tube that is the correct length for the Armalite buffer.  I need to get a good multi tool for the AR rifle.  The one I have has some kind of crinkle coat finish on it and it makes it hard to keep in the castle nut to break it lose.  🥴🥴🥴

    Steve

[Frenchy]

You can never have too many extra parts.

[shooterrex]

1 hour ago, Steve crawford said:

Finally got the RRA Marksman but off the buffer tube.  I just don't have the hand strength I need for this stuff.  Removed the Buffer tube and with the cheap steel tape I have.  The inside length is 6 15/16 inch.  So I now have an extra buffer tube that is the correct length for the Armalite buffer.  I need to get a good multi tool for the AR rifle.  The one I have has some kind of crinkle coat finish on it and it makes it hard to keep in the castle nut to break it lose.  🥴🥴🥴

    Steve

If it was built properly the castle nut should have been staked. That makes getting it loose a challenge till you break it loose.