Assuming one held out for top dollar what would the ballpark be?

http://www.machinegunpriceguide.com/html/sears_1.html

I am going to guess around $15,000 if you held out for the right buyer and were not in a hurry to sell.

Frank sees to auction these off for right around $14K by themselves on a fairly recurring basis and the high water mark was one that went for $16.5K but it came with probably  $1500ish  worth of extras (5.56 host, select fire kit, 9MM upper, KNS reinforce, etc.)

Good lord.  Can't you get a conversion RR for $14-15k?

Awesome link, thanks.

Pretty much, but some people like being able tp move from gun to gun.

Maybe if you're really patient and/or willing to accept a lower-tier receiver.

SP1 conversions are rarely under $17K these days.

True, but I would have to figure that some of the non-premium guns like Olympics have to be in the 14-15k range.  I mean, for as long as I can remember, RLLs were considered the bastard children of auto conversions, the cheapest and least desirable when compared to RRs and RDIASes.  I'm shocked they've levelled with some RRs.

I should have bought one a few years ago when they were like $9k ugh

I think it may still be possible to get a Olympic, Sendra, SP1 conversion, etc. Registered Receiver for $14K, however this is going to be more out of the norm and on the low end of the pricing range.  It looks to me like most non factory Colt M16s  are going over $15,000 now.  Ruben consistently asks  and moves these guns in the 17 to 19K range

That said I think that you might be able to find a RLL in the 12K range if you really looked and waited.  The OPs original question was regarding the high watermark on RLL pricing.  If you compare high water mark on non-colt registered receivers you are probably looking at $18K or more (vs. 15K RLL high price)

Not a lot of these come up for sale and all it takes is for one guy who makes a million a year to not want to bother trying to save a grand or two and just pay the high end of the market scale.

$15k for $1 worth of steel.....

It can be worse than that.  The high watermark for pricing on an HK Sear or DIAS is probably pushing $30K now, which makes the RLL look like a bargain in comparison.

I have found the real beauty in the RLL is in 30+ years mine has been in countless Ar configurations as well as a sweet 9mm and 300 blk.  If I wasn't so old now and trying to retire on a cops pension I would never sell it.

Transferable M16 machine guns and estimated market values:
RLL $14-16k
RDIAS $23-28k
RR Non-Colt Cast AR15 Conversion $16-18k
RR Non-Colt AR15 Conversion $17-19k
RR Colt AR15 SP1 Conversion $17-19k
RR Colt AR15 614 $18-20k
RR Colt M16 $21-24k
RR Colt M16A1 $23-27k
RR Colt M16A2 $28-33k

One currently for sale on sturmgewehr.com for $14k and I saw one on about a month ago on GB.com w/ host rifle for $15k

If you are looking to buy, there is no time better than thew present. Most MGs are appreciating at around 7% per year, much higher than inflation or about even to the historic stock market average.

$15k now will get you a LL, 2 years ago it could have got you a Non-colt RR, 5 years ago a Colt A1, 10 years ago a Colt A2.

Glad i bought a couple LL's for $1500 & $2000.  Not much more for one of my Oly RR's.  Co6ldnt imagine putting together a bunch of MG's now.    BTW nothing is for sale.