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EasyEJL

Buffer tubes...

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Hey guys, not to hijack the thread but my question is pretty close to what we are talking about.

I just bought a 308/20" barrel complete upper with BCG and everything.

NO idea what brand it is but it came from 22modsfor all, 15" keymod.

I already had a new lower sitting here, a PSA PA-10.

So Im trying to combine these together.

I am also trying to use a new LUTH Tactical stock I just bought from a guy.

I dont have a buffer tube or buffer yet. Not sure which one will work with the LUTH and which one will also work with my mid length upper

and the PSA lower.

In fact, I dont even know which 308/7.62 magazines will fit this lower.

I've heard there were some weird issues with these PSA lowers?

 

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That's a DPMS-brand upper receiver, right there, made from an extrusion.  I'm not sure how DPMS uppers fit on PSA lowers.  Not sure if they fit great, or don't fit at all. 

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50 minutes ago, xxlfitness@yahoo.com said:

Not that i doubt anything you said but,

How can you tell its a dpms?

 

IMG_5461.JPG

IMG_5462.JPG

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13 hours ago, xxlfitness@yahoo.com said:

Not that i doubt anything you said but,

How can you tell its a dpms?

First, it's a curved back on it, so it's NOT an Armalite pattern at all.  DPMS uses a formed extrusion for their LR308 upper, then machines that. You can see it from the curves and lines in the upper, if you know what you're looking for/at.  They also piggyback the forward assist right into the shell deflector.

Take a look at that second pic shepp posted - that's your upper receiver.

The pic I posted below is from the link of me asking "if this was what you purchased... "

DPMS upper receiver.png

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1 hour ago, xxlfitness@yahoo.com said:

So is it a descent piece?.  How is the quality?

At this point in the conversation, and the thread, you need to start your own thread on this...

This is no longer about buffer tubes, as the original topic started.

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11 hours ago, madmike26120 said:

What Buffer & Spring should I get for my DPMS SPORTICAL 308.It has a 16 inch barrel.

DPMS 308 Carbine Buffer & Spring with Collapsable stock. Does your ST have a Buffer system already & you want to replace it or it doesn't have one & need a set up ? 

 Switching to an AR 10Armalite set up you will need an Armalite Receiver Extension ( Buffer Tube ) with their Buffer & Spring .

  DPMS uses AR 15 Receiver Extensions .An Upgraded spring could be a Tubb's Flat Wire Spring or one of the custom Spring makers .

Edited by survivalshop

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On 2/1/2013 at 1:09 PM, mrraley said:

I'll see if I cant brake it down a little bit for ya...

 

ArmaLite receiver extension tubes info are as followes...

 

•.223 / .308 rifle length 9-11/16” (inside depth)

•.223 carbine length 6-15/16” (inside depth)

•.308 carbine length 7-5/8” (inside depth)

 

Commercial size tube O.D. - 1.165” – 1.167” (don’t use this anymore)

Military (G.I.) size tube O.D. – 1.145” – 1.147” (carbine and rifle)

 

 

BUFFER SPRINGS

 

•.308 buffer spring rifle and carbine length 14-1/8” max - 13-3/4" min

•.223 buffer spring rifle length 13-1/2” max – 11-3/4” min

•.223 buffer spring carbine length 11-1/4” max – 10-1/16” min

 

BUFFERS

 

•.223 rifle length 5-7/8” – weight 5.2 oz

•.308 rifle length 5-3/16” – weight 5.4 oz

•.223 carbine length 3-1/4” – weight 3.0 oz

•.308 carbine length 3-1/4” – weight 5.4 oz

Just to revisit this - this information is just like gold.  It only goes up in value, even when people are ignoring it.  :thumbup::hail:

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On 10/7/2018 at 4:38 AM, 98Z5V said:

Just to revisit this - this information is just like gold.  It only goes up in value, even when people are ignoring it.  :thumbup::hail:

+1 on this. It is indeed! 

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On 2/1/2013 at 12:09 PM, mrraley said:

I'll see if I cant brake it down a little bit for ya...

That's GREAT info.

Thanks!!

This topic has a wealth of knowledge.

Edited by Whiskeyfish

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On 2/1/2013 at 12:09 PM, mrraley said:

I'll see if I cant brake it down a little bit for ya...

 

ArmaLite receiver extension tubes info are as followes...

 

•.223 / .308 rifle length 9-11/16” (inside depth)

•.223 carbine length 6-15/16” (inside depth)

•.308 carbine length 7-5/8” (inside depth)

 

Commercial size tube O.D. - 1.165” – 1.167” (don’t use this anymore)

Military (G.I.) size tube O.D. – 1.145” – 1.147” (carbine and rifle)

 

 

BUFFER SPRINGS

 

•.308 buffer spring rifle and carbine length 14-1/8” max - 13-3/4" min

•.223 buffer spring rifle length 13-1/2” max – 11-3/4” min

•.223 buffer spring carbine length 11-1/4” max – 10-1/16” min

 

BUFFERS

 

•.223 rifle length 5-7/8” – weight 5.2 oz

•.308 rifle length 5-3/16” – weight 5.4 oz

•.223 carbine length 3-1/4” – weight 3.0 oz

•.308 carbine length 3-1/4” – weight 5.4 oz

So based off this info I would assume:

The .223 carbine length 6-15/16” (inside depth) is what manufacturers list as 7" (overall length) buffer tubes

.308 carbine length 7-5/8” (inside depth) is what mfg's list as 7.75" BT's

I've yet to come across a "rifle length" buffer tube besides Armalite.  Can someone direct me to other manufacturers that make those?  Are there adjustable styles or are they strictly for fixed stocks?

 

Secondly, due to the industries I've worked in I know a thing or two about coil springs so maybe someone can explain this to me.  Giving the overall length or number of wraps of a coil spring doesn't mean jack.  The only good that does is when comparing two identical springs from the same manufacturer of different lengths.  It doesn't take into account spring rates, thickness, materials, progressiveness, manufacturing processes, ect.  Even two identical springs by the numbers can perform completely differently in the field depending upon their quality, break-in, ect.  Looking at spring rates can be deceiving as well.  A cheap spring with a lower spring rate may perform much stiffer then a high quality spring with a higher spring rate.  A low quality spring may also quickly break down and lose it's specified spring rate.

 

The buffer information is a good starting point but it doesn't take into account BCG weights, barrel and gas tube lengths and other mitigating factors. 

Based off this info the standard buffer for the 308 platform is a H3 @ 5.4 oz.  Of course, this needs to be paired to the correct spring. 

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On 2/20/2021 at 10:49 PM, Snow_N_Surf said:

 

Secondly, due to the industries I've worked in I know a thing or two about coil springs so maybe someone can explain this to me.  Giving the overall length or number of wraps of a coil spring doesn't mean jack.  The only good that does is when comparing two identical springs from the same manufacturer of different lengths.  It doesn't take into account spring rates, thickness, materials, progressiveness, manufacturing processes, ect.  Even two identical springs by the numbers can perform completely differently in the field depending upon their quality, break-in, ect.  Looking at spring rates can be deceiving as well.  A cheap spring with a lower spring rate may perform much stiffer then a high quality spring with a higher spring rate.  A low quality spring may also quickly break down and lose it's specified spring rate.

 

The buffer information is a good starting point but it doesn't take into account BCG weights, barrel and gas tube lengths and other mitigating factors. 

Based off this info the standard buffer for the 308 platform is a H3 @ 5.4 oz.  Of course, this needs to be paired to the correct spring. 

  I am glad that Snow N Surf posted this,   I would like to comment on this as well.

It appears that different industries or professions view information about particular topics as guarded or secret . Not just with springs, but a lot of stuff across a vast range of items. It boggles my mind that a spring for a particular application is purchased (or used) based on it's over all length. Maybe that is supposed to make things easier, but it confuses things fairly quickly in my opinion. 

I feel that it would be so much more beneficial to the firearm community as a whole, when talking about coil springs, a standard be used to describe springs more accurately. This thread is a perfect example that it touches on the issue, but doesn't take the mystery out of the equations.

Wire diameter, number of active coils, coil diameter, installed length, spring rate, and cycle life are all valid parameters that could be stated when describing a spring for a specific use, in this case a buffer spring.

I am not trying to be critical, it just seems that finding reliable information is necessary to grow the build community in a positive way.

 

Steve 

   

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29 minutes ago, DOCTORDEMO said:

Wire diameter, number of active coils, coil diameter, installed length, spring rate, and cycle life are all valid parameters that could be stated when describing a spring for a specific use, in this case a buffer spring.

That's what makes this place so great, you can find the part numbers and links to springs for all applications that are known quality, that work. For the large frame AR's the Armalite spring runs both rifle and carbine system, I like that for stacking spares.

    PSA has proven you can sell a pile of large frame rifles while ignoring those "parameters" above. 

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