Interesting old rifle...

https://www.gunbroker.com/item/976041353

From the site:

Now here’s something you don’t see every day — an original Barret M82 (not an M82A1) .50 BMG semi-automatic rifle with a 33” barrel. And there’s more! This is probably the second most collectible serial number out there aside from the first rifle ever made (SN 0100, which is in Ronnie Barrett’s personal collection). Feast your eyes on serial number 0050. This is the only two-digit serial number in existence for an M82 and, according to Barrett, was a specially requested serial number for the now-deceased Dick Swan, the founder of A.R.M.S., Inc. and inventor of the 1913/picatinny rail. Production started with SN 0100 and went up from there. Although numerically this is the lowest serial ever made, it does not pre-date SN 0100. Dick Swann purchased two M82s — SNs 0050 and 0164 — so it’s likely this gun was made around the same time as 0164. Higher resolution images are available here: https://imgur.com/a/DUsHYmE

The M82 is the original .50 BMG rifle that gave Barrett Firearms its start. This is the direct descendent of the M82A1 and M107A1, although it shares no parts with those newer guns. This is a production rifle and not a prototype. Per Barrett, up to a few hundred of these rifles were produced and sold in small quantities to a few countries like Sweden and the U.S. As the vast majority were sold to militaries, very few are in private hands (three confirmed). We are able to find evidence of just one other rifle having been sold at auction. When we reached out to Morphy Auctions about potentially consigning it, they had never seen nor sold one. Consider also that Forgotten Weapons, a company and YouTube channel that features hundreds of rare firearms, does not have a video on this model.

Another fun fact about this rifle is that it is pre-ban. For customers in our home state of Connecticut, this is the only legal, not-banned-by-name option for a semi-automatic .50 BMG rifle.

This rifle at the time of its production very likely included either a weaver rail for mounting scopes. That rail disappeared sometime in the past 35+ years, but the original riser remains welded to the receiver. It is drilled and tapped for a rail to be attached.

This rifle is in very good condition. Externally, the finish is close to pristine. It was previously coated in oil, and while that has been largely removed, the exterior metal retains a slight tackiness. The rifle has certainly been fired (although the most recent owner never fired it) as there is some visible pitting on the bolt face. Please refer to the photos to see the exact condition of the rifle.

One original 10-round magazine is included and ships in a new Pelican IM-3100 case.

Because this is such an old and rare rifle, Barrett is on record as saying that they cannot provide support for the gun in case of parts breakage. They recommend a very limited firing schedule (1-2 magazines per year) as any replacement parts will have to be custom-made.

The following is what Barrett Firearms told us in response to our inquiry for information on the rifle:

Original 82s were only made up to a few hundred. We cannot support this rifle at all. By that, I mean if something breaks or is damaged, we have no compatible parts with 82A1s that can be interchanged hence the design change. [We recommend shooting it at a ] bare minimum (e.g. less than 10-20 rounds per year or something). One to two magazines a year probably will be fine, but no magazine dumping or crazy range days. Again, we will always try to assist in this, but we have no parts left for those. We can usually fix things but it is hit or miss on what we can do (e.g. no barrels or major parts like bolt carriers).

The rifle was designed by Mr. Barrett as a production run of his initial prototype. The rifle was initial[ly] sold in small quantities to a few countries like Sweden and the US government. It is a very crude rifle compared to modern manufacturing techniques but either way they worked. Once the 82A1 came in around the 86-87 mark, it was redesigned and similar to the design we see today.

We started at serial number 0100. That is number 1 and in Ronnie’s personal collection. This was a special request and the only one below 100 and was sold to a personal friend Mr. Dick Swan from ARMS Inc. Mr. Swan wanted it due to the .50 BMG and 050 serial number correspondence. Just a neat little tidbit story. Technically it came after serial number 0100 of course just in terms of numbering it is before.

Direct "ancestor", not the direct "descendent" of the M82A1 and M107.
I am seeing this mistake more and more often, are people these days that ignorant, or do they just not care that they are showing they don't know English?

WOW! That is cool.

Unreal!

The recoil system looks almost the same as the modern M82A1.  I wonder why it has all the holes where the recoil spring sits?

Wonder if Barrett could even fix it if you had any issues?

How many people work there that have that level of knowledge about the early M82's? Other than Ronnie himself?

There is only one of the original employees that work there now that was part of the "worked in Ronnie's garage" crew.
There is another guy that is a long term employee that has worked on the old rifles. I had worked over quite a few of the really old style rifles.

There were parts for the old guns back by the shipping area. We stored what we called "The Archives" , those were parts for discontinued rifles that we still had parts for.
Over the years that small amount of parts were slowly used up by people sending in old guns to be repaired.