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Posted: 12/19/2008 12:01:02 PM EDT
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I did a search and could not find an answer to this probably more than stupid question (however, I am purchasing my first lower so I need to learn):
What is the difference between high shelf and low shelf receivers, and what are the advantages/disadvantages of both? TIA |
| If you look inside the receiver, there is a shelf under the rear take down pin. This is the shelf in question. On some receivers, this shelf is low and others they are high. The low shelf allows you to use a RDIAS. Like the others have said, if you never plan on getting a RDIAS, there is no advantage to either one and you'll never notice the difference. |
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Quoted:
Neither of you fine gentlemen explained what the actual differences are, which, of course, was the question. Merry Christmas Bill True that It is best explained in photos and here they can be found It refers to the area of the lower receiver nearest the rear pivot pin. That area is milled out on low-shelf lowers, and is un-milled in high self versions HTH |
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It's simple really. The "Shelf" refers to the flat landing at the inside rear of the lower receiver just beneath/below where the take down pin sits when it is in the closed position. On a "High shelf" receiver, this area is not milled as deeply as the "Low Shelf" type. You can usually distinguish between the two by observing how much of the safety selector is visible (where the shelf meets the selector) when viewed from above (looking down at the selector). On a "High Shelf" lower, @ 0 - ¼ of the selector is visible (as viewed from above). On a "Low Shelf" lower @ ½ - all of the top of selector is visible .  Pros (Low Shelf):Has the ability to accept an RDIAS (IE: The potential to be converted to full-auto without milling the lower receiver itself) ...And I suppose bragging rights for being Anti-establishment/In-politically Correct/Tacti-Cool Blah blah blah... because it has such an aforementioned potential.  Cons (Low Shelf):Some would argue (wrongly) that such a lower is "weaker by design" when compared to a "high shelf" variety due to the "excess" amount of metal removed.  Harder to find/acquire than "high shelf" models. (Though to me this seems about half and half as far as what's out there.) High Shelf Pros & Cons are essentially the opposite of those listed above... Hope this helps you (And everybody else who asks this same question). ...Oh, and to answer your next question (Who makes what?): Low shelf lowers - Bushmaster and DPMS among others... High Shelf lowers - Rock River, LMT, Colt, Stag, Eagle Arms & Armalite among others as well. Occasionally there are exceptions to the above, depends on where they are presently sourcing their lower forgings. FlDiveCop71  |
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