Value depends on exactly how they have been dewatted, and on price/availability of the parts required to restore them to working order.

Some dewats simply cannot be fixed. It's rare, but there were very few written ATF dewat standards back in the '40s and '50s, when most were done by returning WWII GIs. And few were ever inspected or examined by ATF. I've seen some that were clearly still live MGs (a PPSh that had the firing pin broken off, and lead -- lead! -- poured into the chamber and muzzle. Others were overdone -- a BAR that had a honkin' big hole drilled and pinned through a crucial part of the receiver. Even if properly welded up, I don't think I would trust the receiver to withstand a steady diet of full-auto .30/06. So you really need to know the model you're buying, and inspect it very carefully.

In addition, depending on the model, you usually will have to replace the barrel, and often bolts, etc. That's no problem for a 1919, but many of the less common MGs have zero parts available.

However, IMHO, the market values rewetted original MGs higher than tube guns or conversions. Some show literally no evidence of the dewat/rewat process, and are very close in value and shootability to an uncut original.

When considering buying a dewat: First, be absolutely sure how it was dewatted. Second, check out the supply side for the parts you will need to rewat it, and if the work is beyond your personal ability, check with someone like Bubba at Black River Militaria -- he has probably rewetted more MGs than any living person, and can give you a good estimate of the cost of rewatting the MG you are considering.

Don't forget the time involved -- you must acquire it on a Form 5 before filing a Form 1 to reactivate it yourself, or a second Form 5 to a gunsmith, who will Form 2 it, then Form 4 it back to you. That's two waits, plus the time it takes to find and buy the parts, and if necessary the wait time for your number to come up at the gunsmith doing the work. It's not uncommon for the rewat process to take a few years, for the less common examples.

Yes, whoever reactivates a dewat must engrave it with name/city/state.

Add the cost of rewatting plus 10% for unexpected surprises to the price of the dewat. Then compare it to current market values for tube or side plate versions, uncut originals, and a properly rewetted MG will be somewhere between the two (and probably closer to the value of an original than to a tube/sideplate MG).

Your Mileage May Vary.

David, I just noticed that you posted this in the M16 forum, and were asking about REWATS. So my response was a little off, if you're speaking of M16s.

First, I have never seen an M16 REWAT. Instead, what you commonly come across are REWELDS. There is a huge difference.

A REWAT is an MG which was deactivated by any of several methods, but the receiver is intact, and has always been intact. It was subsequently reactivated to firing condition.

A REWELD is an M16 receiver that was somewhat randomly chopped in half for scrap metal, then thrown into a 55-gal drum full of other pieces. Enterprising 07/02s would buy these drums and sort through looking for a long front half, a long rear half, trim them to fit, put them in a jig and weld them back up. Rewelds always are two different MGs welded together. And quite often, the sections came from different manufacturers -- so you may have a Colt magwell attached to a GM Hydramatic rear half.

Because they are mixmasters, and because they were scrap alloy metal before being used to build "new" MGs, they are valued less than an uncut registered receiver of any brand.

I had a long talk with John Norrell, who did many of the "best" rewelds, a few years ago. He said up-front that a reweld would never be as strong as an uncut receiver. His reasoning: When an alloy receiver is made via forge, the tremendous pressure actually aligns the "grain" in the metal, making it more uniform than a simple casting. Once cut and welded, the weld material can never exactly duplicate the strength of the rest of the receiver. Weld material has never been through a forge: You can use stronger or weaker weld, but the receiver will always have uneven strength -- and, thus, weak spots, either in the weld line, or next to it.

Now, the reality is that an AR receiver is generally an unstressed part when properly handled and maintained. But a reweld will always break before an uncut receiver which can even distribute any stresses. And in today's market and at today's prices, that scares off some buyers.

BTW, this is one of the things you need to be wary of when buying a collectible ex-military M16. There are many, many rewelds being passed off as originals, at high prices.

FWIW. YMMV.