AR15.Com Archives
 High or Low Shelf AR Receivers? Which is What?
ramcdaniel1  [Member]
8/12/2008 2:54:00 PM EST
I need to know which of these receivers are high shelf and which are low shelf. This is in reference to RDIAS compatibility.

Ameetec - low shelf

Anvil Arms - low shelf

Armalite - high shelf

Bushmaster - low shelf

CMMG - low shelf

Colt - high shelf

Double Star - low shelf

DPMS - low shelf

DTI (Del-Ton) - low shelf

Fulton Armory - low shelf

LAR - low shelf

Mega - low shelf

Olympic Arms - high shelf ?

Rock River Arms - high shelf

Spike's Tactical - SL15 (before Oct 1/08) = high shelf / ST15 (available starting Oct 1/08) = low shelf

Stag - high shelf

Sun Devil - low shelf

Superior Arms - ?



Thanks for your help!


Edit: this is what I have so far. Thanks for the input. Please feel free to voice any corrections and continue to add to this list.
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Screech  [Team Member]
8/12/2008 2:56:06 PM EST
All these are EQUAL!! The only top shelf receiver is a COLT
platypusREX  [Member]
8/12/2008 3:21:41 PM EST

Originally Posted By ramcdaniel1:
I need to know which of these receivers are high shelf and which are low shelf. This is in reference to RDIAS compatibility.

Anvil Arms

CMMG

Double Star

DPMS

DTI

Mega

Olympic Arms

Spike's Tactical

Stag

Superior Arms



Thanks for your help!


Bushmaster is definitely a low shelf receiver.
platypusREX  [Member]
8/12/2008 3:22:20 PM EST

Originally Posted By Screech:
All these are EQUAL!! The only top shelf receiver is a COLT

Dude, you dont even know what the subject's about.
BRONZ  [Team Member]
8/12/2008 4:02:31 PM EST
I dont know about those, but LAR is low shelf.
Akula_Hunter  [Member]
8/12/2008 4:07:13 PM EST
dare I ask what a low shelf or high shelf is?
Beater9C1  [Member]
8/12/2008 4:10:35 PM EST

Originally Posted By platypusREX:

Originally Posted By ramcdaniel1:
I need to know which of these receivers are high shelf and which are low shelf. This is in reference to RDIAS compatibility.

Anvil Arms

CMMG

Double Star

DPMS

DTI

Mega

Olympic Arms

Spike's Tactical

Stag

Superior Arms



Thanks for your help!


Bushmaster is definitely a low shelf receiver.


What makes Bushmaster low shelf?
ftwm  [Team Member]
8/12/2008 4:24:53 PM EST

Originally Posted By Akula_Hunter:
dare I ask what a low shelf or high shelf is?


Low-shelf = RDIAS ready

High-shelf = needs machining to install RDIAS
Charger22  [Member]
8/12/2008 4:30:24 PM EST
what is RDIAS? Sorry new guy.
ftwm  [Team Member]
8/12/2008 4:31:16 PM EST
Registered Drop-In Auto Sear.

Putting one of these in your lower will turn your rifle into a machine gun, when used with the right fire control parts and bolt carrier.
Charger22  [Member]
8/12/2008 4:42:26 PM EST
Cool, is this like the Colt Match Hbar lower I looked at today that had a piece near the rear pin above the selector?
brdvictim  [Team Member]
8/12/2008 5:03:58 PM EST
Doublestar is a LOW shelf. And I know a RRA is HIGH.
ftwm  [Team Member]
8/12/2008 5:39:44 PM EST

Originally Posted By Charger22:
Cool, is this like the Colt Match Hbar lower I looked at today that had a piece near the rear pin above the selector?


I believe you're talking about the old style Colt sear block.

Is this what you saw?

Charger22  [Member]
8/12/2008 5:48:53 PM EST
Yes and I would like to know what it does. I had bought a Bushmaster lower for my Colt Hbar upper. At the fun shop today there was a Colt lower I might want to grab for the gun instead. Any info would be great. Would the Colt lower be a better choice for my upper?
ftwm  [Team Member]
8/12/2008 6:13:25 PM EST
It's a sear block. It prevents you from installing an RDIAS. Neither of my Colt lowers have this, my lowers have the new style sear block which is just an extra web of aluminum across the width of the shelf. I believe if you purchase that particular Colt lower, you can not run a full-auto bolt carrier because the sear block will interfere with it. You are fine with a Bushmaster lower, the lower doesn't affect the accuracy of your rifle. As long as your lower functions properly and it fits your upper, I see no reason to buy a Colt lower. Unless you just want an extra lower laying around as an excuse to build another complete rifle.
platypusREX  [Member]
8/12/2008 6:18:46 PM EST

Originally Posted By Beater9C1:

Originally Posted By platypusREX:

Originally Posted By ramcdaniel1:
I need to know which of these receivers are high shelf and which are low shelf. This is in reference to RDIAS compatibility.

Anvil Arms

CMMG

Double Star

DPMS

DTI

Mega

Olympic Arms

Spike's Tactical

Stag

Superior Arms



Thanks for your help!


Bushmaster is definitely a low shelf receiver.


What makes Bushmaster low shelf?

A CNC machine. They are milled deeper inside the receiver so there is enough room to fit in a RDIAS.
Shelf area is in red.
shamayim  [Member]
8/13/2008 1:43:16 AM EST

Originally Posted By platypusREX:

Originally Posted By ramcdaniel1:
I need to know which of these receivers are high shelf and which are low shelf. This is in reference to RDIAS compatibility.

Anvil Arms

CMMG

Double Star

DPMS

DTI

Mega

Olympic Arms

Spike's Tactical

Stag

Superior Arms



Thanks for your help!


Bushmaster is definitely a low shelf receiver.



And so is DPMS
Stag is high shelf; as well as any lower with "CM" (Continental Machine) in front of the serial number.
ramcdaniel1  [Member]
8/13/2008 2:16:21 AM EST


I have put the type of shelf by each of the companies name for the ones I have answers for. Thanks for the input so far.

CB1  [Team Member]
8/13/2008 2:34:07 AM EST
Ameetec lowers are low shelf also
Grimjaw5  [Member]
8/13/2008 7:55:44 AM EST
From Anvil Arms web site - our lower receivers are fully compatible and completely ready for a registered drop in auto sear!
ramcdaniel1  [Member]
8/13/2008 8:15:06 AM EST

I just had an interesting conversation with a Superior Arms employee. No matter how I explained high or low shelf to this "tech" he had no clue what I was asking about. He was convinced I was referring to a full auto lower. It doesn't say a lot about a company who's employees do not understand the simplest thing about the AR.

I would still like to know however if Superior Arms has low or high shelf lowers. Their staff appears to be too incompetent to answer this question.


dpsix  [Member]
8/13/2008 10:28:30 AM EST
Armalite & Rock River = High Colt (older)= Low but has sear block
exocet  [Team Member]
8/13/2008 11:16:47 AM EST
LAR and fulton armory = low shelf
platypusREX  [Member]
8/13/2008 12:41:22 PM EST

Originally Posted By ramcdaniel1:

I have put the type of shelf by each of the companies name for the ones I have answers for. Thanks for the input so far.


Then why the fuck you put Bushmaster with a high shelf....for disinformation.
ramcdaniel1  [Member]
8/13/2008 1:16:10 PM EST

Originally Posted By platypusREX:

Originally Posted By ramcdaniel1:

I have put the type of shelf by each of the companies name for the ones I have answers for. Thanks for the input so far.


Then why the fuck you put Bushmaster with a high shelf....for disinformation.


Whoa. Settle down there Bevis. Did someone miss their medication today? A bit of paranoia there huh? Do you kiss your mama with that mouth?

It was a mistake and I have corrected it. I have no vested interest any any particular company nor do I have anything against any company. You are out of line to jump on me like that.
ftwm  [Team Member]
8/13/2008 1:20:59 PM EST
Ignore it. I like the idea of what you are doing, this question comes up every now and then. When you're done with it, you should post the finished chart in the Lower Receiver FAQ since that thread is already tacked.
Screech  [Team Member]
8/13/2008 1:27:03 PM EST

Originally Posted By platypusREX:

Originally Posted By Screech:
All these are EQUAL!! The only top shelf receiver is a COLT

Dude, you don't even know what the subject's about.


Bite me Dude! Same terms, different meanings! Sorry I was not on your thought trail!
TaylorWSO  [Life Member]
8/13/2008 2:17:37 PM EST

Originally Posted By Screech:

Originally Posted By platypusREX:

Originally Posted By Screech:
All these are EQUAL!! The only top shelf receiver is a COLT

Dude, you don't even know what the subject's about.


Bite me Dude! Same terms, different meanings! Sorry I was not on your thought trail!


wrong terms

It went from "high shelf" in the OP, to "top shelf" =poor reading comprehension.




mega is low, thats what I use

ramcdaniel1  [Member]
8/13/2008 3:34:39 PM EST

Originally Posted By ftwm:
Ignore it. I like the idea of what you are doing, this question comes up every now and then. When you're done with it, you should post the finished chart in the Lower Receiver FAQ since that thread is already tacked.


Thanks ftwm. I was hoping to get this stuck somewhere as it is good info to have on hand. Thanks for the direction. I will get it in there as this nears completion.
Charger22  [Member]
8/13/2008 3:46:10 PM EST
Learned alot off of this too bad some guys still have to cat fight. And if anyone cares I am keeping the Bushmaster lower. Colt fit a little looser and his best price wasn't worth it for me. I have a wife and two girls would rather send the money on ammo.
ramcdaniel1  [Member]
8/13/2008 7:39:23 PM EST

Originally Posted By Charger22:
Learned alot off of this too bad some guys still have to cat fight. And if anyone cares I am keeping the Bushmaster lower. Colt fit a little looser and his best price wasn't worth it for me. I have a wife and two girls would rather send the money on ammo.


Good choice Charger. To me Colt is over hyped and over priced. It is just not worth the extra dough and the Bushmaster is a fine lower. Also, the fact that Colt has gone to so much trouble to babysit everyone where the DIAS issue is concerned just plain irritates me.

I just don't understand why some have to gripe and belittle. Life is too short for that nonsense. Glad you learned a lot from this. I did too.
platypusREX  [Member]
8/13/2008 7:58:34 PM EST
Settled down and happy. I try for Butthead but alway get Beavis.
shamayim  [Member]
8/14/2008 2:13:39 AM EST

Originally Posted By dpsix:
Colt (older)= Low but has sear block


Not if you've got an SP1 or SP2.

Those were the pieces that the DIAS was created for.

Of course, way back then a DIAS was considered the mall ninjas way to get Select fire (sometimes), and totally looked down upon by anyone with good taste.

Which is why I had my own SP1 converted to a "real" select fire piece by a registered mfr.

Akula_Hunter  [Member]
8/14/2008 2:26:09 AM EST

Originally Posted By ftwm:

Originally Posted By Akula_Hunter:
dare I ask what a low shelf or high shelf is?


Low-shelf = RDIAS ready

High-shelf = needs machining to install RDIAS



Thanks, I learn something everyday but it's not hard when you don't know much


Can I assume that low shelf and high shelf are physical characteristics of the lower like what you see in the pictures of the Colt on page 1?
dpsix  [Member]
8/14/2008 3:14:39 AM EST
Akula, The 'shelf' is the internal lower area of the receiver that runs from behind the take down pin holes foward to the safety switch. The Colt pictured has a 'low' shelf but also has a sear block pinned in place.
ftwm  [Team Member]
8/14/2008 7:04:10 AM EST

Originally Posted By Akula_Hunter:

Originally Posted By ftwm:

Originally Posted By Akula_Hunter:
dare I ask what a low shelf or high shelf is?


Low-shelf = RDIAS ready

High-shelf = needs machining to install RDIAS



Thanks, I learn something everyday but it's not hard when you don't know much


Can I assume that low shelf and high shelf are physical characteristics of the lower like what you see in the pictures of the Colt on page 1?


Yes. The shelf is the area in front of the buffer, above the selector. It either has a deep pocket machined out (low-shelf) or it has a shallow pocket (high-shelf).
ramcdaniel1  [Member]
8/14/2008 11:05:20 AM EST

I just got off the phone with Jamie at Spike's Tactical. All I can say is wow, I'm impressed with this company. She was extremely knowledgeable and really took the time to answer my questions and to explain any and all aspects of there products. That is a lot more than I can say for some of the other companies who were downright aggravated that I dare call and ask questions about their products and their downright ignorance (Superior Arms and Olympic Arms for example). Two thumbs up Spike's!

Starting Oct 1 Spike's Tactical will be selling low shelf receivers manufactured by LAR. At present their receivers are high shelf and not compatible with a drop in auto sear. Not a concern for many but some may have plans to purchase a registered DIAS and this info is good to know!

ramcdaniel1  [Member]
8/15/2008 10:30:36 AM EST
I have modified and posted this information on the AR Lower Receiver FAQ. I hope you all find the information useful. It is of course a work still in progress.

Perhaps it needs its own tack?

ftwm  [Team Member]
8/15/2008 10:45:34 AM EST
Nice work, you can edit that post in the tacked thread and mark Sun Devil as low-shelf.
ramcdaniel1  [Member]
8/15/2008 11:33:07 AM EST

Originally Posted By ftwm:
Nice work, you can edit that post in the tacked thread and mark Sun Devil as low-shelf.


Thanks. Edited it for the Sun Devil. You think this could use it's own tack?
ftwm  [Team Member]
8/15/2008 11:53:02 AM EST
Yeah, this would be nice to have tacked but they probably won't. Keeping it where it is should be fine, not too many members post in that thread so it's not like your post is gonna get lost. Just remember what page it's on, and next time someone asks about this you can direct them to the thread and page number.
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