I'm in the very early stages of considering my next MG (have a Laged M11/9 and S&W 76.) I've been reading about RRs for years so I have a very good idea of what I want, so the goal here is to get further info from those in the know. I'm interested in factory converted AR receivers, namely Sendras and Frankford Arsenals as well as any others that I may have overlooked (excluding Olympic Arms, I'm not willing to consider those.) I'd like to know how well the conversions were typically done, how many were produced, whether they were cast or forged, any known issues...you get the idea. Thanks!

The vast majority of the conversions were done on the following receivers.

Colt - SP1 or AR15A2s.  Virtually all of these are all large front pivot pin and without a mag release fence.

Olympic Arms - Olympic was a prolific reseller of lowers which ultimately ended up being branded/rebranded as Schuetzen Gun Works "Stopsign Logo", Police Automatic Weapons Service "PAWS logo", Frankfort Arsenal "Castle logo", SAW "Double Circle logo", Palmetto Armory "Palm logo".   Pretty much all of these are the same basic Olympic forged receivers except the older Palmetto can be milled barstock.

SENDRA  All forged to my knowledge.

Essential Arms "EA" -  These lowers are all cast.

The quality of the conversions can range from hackjob to almost indistinguishable from what would be considered "factory".   Technically Oly never sold factory machineguns so there really isnt a factory comparison, but the closest would probably be PAWS guns as all they had to do was drill the autosear hole.

The Oly guns are notorious for being slightly out of spec and require a trip to a gunsmith like M60Joe or US Anodizing for minor dimensional corrections.  The other option is to slightly modify each upper to fit as needed.

Sendra are known for their "purple" anodizing and at one point in time took a reputation hit in terms of metalurgy when Mike Klos refused to work on them due to problems.

EA are all cast and also look a bit funky compared to a mil-spec receiver and take a reputation ding on both accounts.

If it were me and I was shopping for a conversion gun, I would get either a well converted forged Oly variant (Frankfort, PAWs, etc.) or a Sendra.    I would  stay away from the Oly/Palmetto milled barstock guns like the plague.

Edited to add, I have no idea how many are out there.  In terms of the numbers that come up for sale....forged Oly variants and Colt SP1s come up the most, followed by EA, followed by SENDRA, followed by the rare stainless Group receivers (although those are technically factory guns).

In general there seem to be about 2X the number of Colt factory guns for sale at any point in time as there are conversion receivers.

Thanks, exactly the quality of input I was hoping to receive.

In terms of this purchase I'm interested primarily in shootability; collectability and historical accuracy in the sense of adhering to original Colt M16 configuration is not a concern. For example, lack of the fence around the mag release and a different finish I couldn't care less about. What would concern me is a lack of compatibility with certain parts/uppers, a reputation for being out of spec, difficulty in repair god forbid the lower cracked or was otherwise damaged.

I think Sendra will be my first choice. I passed on a Sendra two summers ago for $17k and went with my S&W 76 which was half that at $8.5k because I wasn't ready to spend that type of money. But in the process I read up a lot on Sendras and almost everything I read was positive, however I was not aware of their questionable metallurgy at one time. I'll need to further investigate this.

My concern with Olympic Arms is their practice at one time of replacing pre-86 transferable receivers under warranty with post-86 receivers and then remarking them with the respective registered info. As I understand it the BATFE issued a cease and desist order to Olympic Arms when they became aware of the practice but declined to take further action with respect to those that had been replaced.

For SENDRAs I would give Mike Klos a call.  He can be found at http://www.amer-mfg.com/ or post on subguns as he hangs out there on occasion.  He used to do many M16 receiver repairs and he could tell you what the issue was with SENDRAs that stopped him from taking work on them.

I wouldn't be concerned about the replacement Olys they are really easy to tell which receivers are the replacements.

All of the "gray area" replacement receivers were done in the late 2000s and are of modern A2/A3ish forgings and the engraving is totally different being larger/deeper CNC style engraving and the auto marking is just like the safe/semi marking.

The originals are all A1 forgings, with light pantograph style etching, and the Auto marking is quite often different than the safe/semi as it was stamped by the outfit who did the conversion.  (although PAWS auto markings are close to the factory safe/semi)

The remans vs. the originals is super easy to spot and navigate away from if you have that concern.

A "reman" Oly lower:

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vs. the original Oly lower

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Its like night and day difference.

Just letting you know an Olympic PAWS is a FACTORY machine gun. It is not a conversion.

The PAWS guns were converted by Bob Imel (Police Automatic Weapon Service) out of Salem Oregon, who was different FFL from Oly/SGW.

My understanding is that Oly sold him guns "prepped" for conversion so Bob didnt have to do much in the way of milling... but he did have to drill the autosear hole and if you look close the "auto" marking is a different font from the Safe/Fire.

When they come up for sale stripped  you can see the autosear hole clearly has no anodizing.

Here is one from Ruben.

http://www.sturmgewehr.com/forums/index.php?/topic/10453-brand-new-m16-lower-pawsolympic-perfect/

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Close up of selector markings where you can see how the "Auto" font is slightly different from the other position markings and the spot where it should be marked "semi" is marked "fire".

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I would agree they are something like 98% a "factory" gun and make a great shooter but are not "factory" the same way a Colt M16 is a factory gun.

One of these days I really hope someone stickies one of JBNTEX’s posts or just makes a new stickied thread. Wealth of knowledge!

What exactly is a "void"? Is it as the name implies, essentially a gap/pocket within the receiver? Can it be unearthed using an x-ray?

I have one. And they are a factory MG.

Mines is a OLY/SGW 1985 produced...and it was NWAC out of Portland, Oregon that did my conversion.

No issues...and I do not believe he had to mill anything. He just drilled the hole and and installed parts into it.

that's it mainly.

Runs fine but M60 fixed up the hole issues but the anodizing is losing its bits.....but I am not bothering so much.....

So, if it’s factory, why is the sear hole bare and not anodized? What factory deliberately performed conversions after anodizing?

jbntex has a very clear post with evidence, including detailing how lowers were shipped, work performed, and supporting evidence.

What evidence are you bringing to the discussion to refute his point?  This is a technical discussion forum. Be technical so we can learn. Pithiness belongs in GD.

I think all of the guns were prepped and ready to go ....no matter who did the conversion.

I have seen several SGW RR and they didn't have missing anodizing...its just their sear holes were not anodized.

My experience with it is direct observations at SAR, and the old SOF convention sales and also my uncles LGS when he was a class 3 and the record number of them passing his shop to customers.

From what I have seen not all of the Oly/SGW  Semi-Auto stopsign era lowers were just autosear pin hole ready.  That said, Oly clearly offered sear pin hole ready lowers and/or rebranded lowers to other FFL/07s to complete the work.  (Like palmetto, SAW, PAWS, etc.)

I have one converted by Weapons Specialties, where its clear that extra work was done to machine the relief for the autosear selector leg.

Many of the older SGW lowers even have a unique feature where there is a selector anti-rotation pin sticking out of the side of the lower to prevent the selector from moving to the auto position.

I don’t know for sure why they included this feature but my guess is that based on many rumors of older Olys coming with a mix of full auto parts (like a selector) this was done so that the selector could not be physically moved to the auto position even if it had a mix of full auto parts.

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At some point Oly seems to have done away with this feature.... but on the later gen 80s era receivers even if the selector rotation pin is not there, you can still clearly see the forging mark where this vestigial selector pin stop was located in the dies and sometimes there is a small raised bump at this location.

Both of my Oly’s have this small forging mark where the pin feature in the forging dies used to be (and/or Oly started professional removing the pin as part of the machining process after the forging was done).

On one of the Olys that I had blueprinted and reannodized, prior to sending the receiver off to US Anodizing,  I very slightly sanded this  area to clean up the mark so its almost invisible after reannodizing.  I also reengraved the selector markings so they all match 100% and the Fire location properly says “Semi”.   My other Oly the selector anti-rotation pin mark is clearly visible (like it is on almost all 80s era Olys including many of the PAWS guns)

On more crudely converted guns you will see a blantant “dremel tool” mark where somebody ground this pin off.  One of these guns was for sale on Sturm recently for a good price, but had a really ugly grind mark on the side of the lower to remove the pin.

Shop around on google images for preban SGW lowers and there are plenty of images showing mid 80s era SGW receivers with the sear area not milled out.  Here is one here with a Z4xx serial which based off oly’s serial number list puts in in a 1985 manufacturing timeframe.  I had a preban Oly semi many years ago that had the same sear area not milled out but no selector pin either.

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GMTMaster and I have disagreed on this point of SGW/PAWS receivers being "factory" machineguns in the past.   Its really not a huge issue to me and everybody is welcome to come to their own decisions/opinion based on the information available.

I have one of the reman’s and it has transferred several times without an issue. I’d buy another one at the right price

I agree, you get a in spec receiver that's near new with all the A2 upgrades.

Jozsi and jbntex, thanks for the information.  I think I've learned more about these receivers this month than I have in the last few years of casual browsing.

I can see why some of these lowers would be considered factory MGs.  Compared to the thread we had recently where a dremel sanding wheel may have been used to remove material, or the SP1 recently listed (sold?) this spring with the sear pin hole down MUCH further down than normal, this work is heads and shoulders above in quality.

I can see why the pre-relieved lowers would be referred to as factory MGs, but in my eyes drilling the sear hole in a relieved lower is the definitive act of making an M-16.  I think the best modern comparison would be a BCI Defense lower.  It's "ready to go" but is not an M-16.  Anyone can buy the lower as a Title 1 AR-15 receiver, but after SOT conversion it's not a factory MG.

Not just in your eyes; this is how ATF views it as well.

From my recollection...

Nobody gave a crap about Oly doing the reman of old receivers.

ATF gave it their blessing as the 1st letter from Oly was for repair of defects and they allowed it.

But then from what I recall, Ruger was doing the same thing so that was where Oly got the idea but that is not true. Ruger wasn't making new ones if an AC went down..it was just replacing it with another one.

ATF put a stop when others complained and whined what a social injustice it was and totally unfair that Oly can do it but not Colt or others no matter who manufactured it.

I was about to send mines in until they stopped it.

Really sad....would have loved it.

That's the situation I recall as well.
That and the GemTax (Gemtech tax) were both developments that harmed NFA owners.

I also considered sending in one of my Oly's but couldn't figure out how they were legally doing it as Oly wasn't the manufacturer of the machinegun.

I remember a couple of us pressing Oly (Tom Spithaler) on this point on their Olympic Arms discussion forum (after they left AR15.com in a huff) and they eventually produced a letter from the ATF stating they could replace "PreBan" (1994 AWB guns) receivers with new receivers and the replacements would retain their preban status.

Olys preban replacement letter wasnt really applicable to what they were doing with full auto receivers that were clearly converted by another FFL.  

Eventually Oly shut down the program as the ATF made them stop, probably due to multiple inquires as to legality from current owners who were skeptical of the legality of an FFL replacing another FFLs converted receiver.  

In terms of "fairness" Colt has clearly has done replacement receivers given all of the transferable A3 style "M16A2" receivers out there, they just never had a formal program.   Ruger used a cache of pre-86 receivers for their replacement program.   Sendra, GI,  and EA  are no longer around so it was a mute issue for them.

My take is the Oly reman receivers will most likely be fine to own but there is always risk down the road.

All it will take is somebody to use these as an example as part of their own agenda and cross paths with the wrong administration.  

The most recent risk was the  Stephen Stamboulieh "Nolo" - Watson/Hollis v. Holder lawsuit where he was trying to dig up every transferable he could find with a possible 86 cutoff pedigree issue to support his equal protection claim in court.

He would play all coy to the masses in GD about "soon" and how he had evidence of conspiracy of Post-86 guns owned by "elites" and just needed more money to fight for discovery, etc.
 
Eventually he posted a couple folks approved Form 1s which were sent in prior to FOPA but approved after May of 86 as "proof" of his claims.   He also dug up the Catco M60 receiver situation and paraded them around  as proof of his Post-86 guns conspiracy to get full discovery of the NFRTR to dig up more dirt.    There was even discussion/rumors at one point he got the ATF to start eyeing HK sears that were Form 2ed on the last day before the ban.

In my opinion, Nolo was willing to sacrifice any transferable with murky pedigree history for a 1 in a bazillon chance he would win his lawsuit(s).   I was actually shocked the Oly and Colt reman guns didn't get brought into this lawsuit as evidence as well.

Ultimately, there are a lot of guns out there with pedigree issues.  The recent MP5 thread about how Neal Smith confirmed "he never made registered trigger packs" but yet look at all of the Neal Smith "registered trigger packs" that have been sold over the years with HK receiver serial #s.  

Ultimately, I think the odds are low that these specific Oly guns will have transfer issues in the future.  However, if somebody like Stamboulieh pushes the ATF on this the wrong way...... a bunch of guns (including the Oly reman guns) could be at risk.

They required you to transfer them to them for the remanufacture. According to what I was told each one had to be okayed by the atf before they were done. They just decided to quit allowing it like they have done on many things. Shortly afterwards they came out in their publication stated it was not allowed.

Oly did require an actual ATF approved Form 5 for "repair".   Its been awhile, but I believe this requirement was explained as due to WAs wonky laws about machineguns and Oly couldn't accept the receivers from unlicensed individuals without a formally approved Form 5.  (many folks used to just require one filled out but not actually approved)

I do distinctly remember folks being concerned about the "paper trail" of approved Form 5s back to Oly if the whole thing ever blew up.

However, to the best of my recollection there was no indication that the ATF was in any way "blessing" a wholesale receiver replacement schema.  They were pretty much just approving Form 5s that were sent to them for a temporary transfer to a 07/02.

There is a little box on the form you put why.

Agreed....and folks were just listing "repair".  I don't recall anybody confessing they were putting "wholesale receiver replacement" on their Form 5 submission at the time.

Granted its been about a decade+, but if somebody did list "receiver replacement" this was back when examiners where approving NFA forms with "Because chicks dig them" or  "Zombie Hunting" and other such nonsense.

In those days you could probably have put "M16 to M134 update" on a Form 5 and they would have rubber stamped it approved as long as the serial number and FFL were valid.  Doesn't mean any of those data entry examiners approving Form 5s had any authority to actually legally approve what was ultimately being done in terms of the actual repair.

You could have a letter from the the Chief of the ATF tech branch at the time personally approving a replacement of serial ABC123 and we know how much those are worth should the ATF change their mind.   Those letters in most cases are good from keeping an owner away from criminal prosecution (assuming you follow the enforcement action instructions), but forfeiture is always on the table should the winds blow differently under new leadership.

Ultimately I agree that the odds are extremely low of any type of enforcement action.  There are probably less than a hundred or so total remain receivers out there are not causing anybody any harm, but that doesn't change the fact that there is a pedigree cloud over them and I think their pricing reflects that.  (being a relatively new updated A2 style receiver that bring no premium over a 30+ year old original A1 Oly)