Ontario 6141 MK 3 Navy Knife (Black), stainless steel

If you are looking for a rugged survival knife or are into collecting military knives add this one to your collection. The knife is not as sharp as it could be out of the box, but, two thoughts here: first, for the price I can sharpen it myself; second, if you can't stone a blade, don't play with them. It is an original copy of the USN Mk 3 Mod 0, same with the sheath. The blade is 6 inches from the hilt to the tip and has a black most likely phosphate finish similar to post ww2 small arms finishes. The handle is of a hard plastic with a rubbery grip, typical military. The sheath with it's retaining clips fits the knife snug and will retain the knife until you are ready to deploy the blade. From visual inspection, I can not say if this is a full tang knife, the pommel is a not magnetic alloy along with the hilt but are both meaty. The blade is attracted to a magnet, but from my experience a lot of stainless is magnetic. Overall, this is a good knife at a great price.

This is a terrific knife. Many others have written of the virtues of this knife, so I won't be redundant. I can't believe I hadn't discovered this knife before. It is a nearly perfect military issue in features, form and function. The knife is great, but the sheath has pros and cons. Other reviews have mentioned the matter of the sheath requiring significant effort to insert and withdraw the blade as well as the spring blade retention significantly scraping the coating on the sides of the blade a little more each time the blade goes in and comes out. The retention springs inside the sheath hold the blade very firmly causing scrapes along both flat sides of the blade from about midway down the blade to the tip. I take it the sheath was designed and constructed for very secure retention. If it is desired to keep the blade from having the coating removed along the sides of the blade don't use the sheath that comes with the knife. If that doesn't matter, the sheath is very solid. One reviewer says the knife becomes easier to slide in and out of the sheath with repeated use. The sheath has a one inch wide nylon strap that serves as a belt attachment. There is a wire clip at the top of the strap intended to attach it to a military web belt. Just below the top is the retaining strap with a snap to secure around the knife handle. The strap has a loop so up to a 2 1/2 inch belt may be slid through it. The sheath is perfectly functional and well made if you don't mind the damage to the blade coating by using it.I like the knife and that's why I give it five stars. The sheath is an accessory, and it's up to the owner to decide whether to use it.Update: after scraping up half the blade using the factory sheath, I decided not to do that any more. Using a "Scotch Brite" scour pad I rubbed out the scrape marks and made both sides of the blade look the same. It removed very little of the black oxide coating. Now the blade looks almost new. I work with Kydex, so now the knife has a new sheath and a new look.

The knife is a USN knife which was issued to SEAL team members. Excellent all purpose knife designed for use in the water so resists rusting and corrosion. It is one of the best military knives ever issued, and many former vets can tell you how well it performed under adverse conditions. Compared to the Ontario Air Force Survival SP-2 knife, however, the MK 3 is a half inch longer but far less meaty in the blade and thus less sturdy, and in comparing the two knives, I prefer the SP-2, without denigrating the MK 3, because I think it is more versatile. BUT my REAL issue is with the sheath sent with this MK 3, and I notice that many other reviewers have also complained. It is EXTREMELY difficult to even put the knife into the sheath; it is that tight. In fact, it is potentially dangerous because the blade might slip in the attempt which could cause injury. AND every time you pull the knife from the sheath, you take the coating off the blade. Not sure what the guys who came up with this plastic sheath were thinking. But your black knife will very soon have a silver blade and a scratched one as well. Sheath is LESS than useless because it actually damages the blade. Have ordered a Spec.-Ops. Brand Combat Master Knife Sheath which some have said will fit this blade well, but that sheath costs 50% of the price of the knife.

This is a heavy duty knife. Ontario Knife Company has ceased operations, so these will become hard to find in short order. This is the knife that has been issued to US Navy divers. It holds up fine in and out of the water.Dry it off and oil it before storing it.

You better buy this while you still can Ontario knife company has closed and all the workers let go. The Ontario name and remaining stock has been sold to another company their a distributor not a manufacturer. The new company is going to continue some of the offshore produced knives (Rat folders) and looking to keep US production on certain models probably Rat fixed blade etc. My guess is all the military knives and bayonets will be discontinued once the stock is depleted. I got the MK 3 from Amazon today and the quality looks fine it felt like it was dull as a butter knife but it sliced right through paper so it is sharp. The people complaining about the blade coating must not have much experience with this type of treatment lol besides it's made out of S.S.