Extrema Ratio AMF Survival Knife Field Review

Extrema Ratio AMF Survival knife. Advanced Multi Function Knife. AMF Survival knife (AMF Desert) tested out in the field. The Extrema Ratio AMF is a big 8.25″ Bowie style clip point knife with a design reminiscent of the Gerber BMF of the 80’s (minus the spine wire cutter notches) but with modern stainless tool steel Bohler N690, Forprene grip and stainless fittings. The Extrema Ratio AMF comes in either the Desert AMF or a Black Mil Spec coated AMF and corresponding black Cordura sheath. The sheaves are fully Molle compatible and come with 3, 2M brand malice straps. There is an optional “survival kit”.

Initially I was concerned with the rear guard of this big knife interfering with me using it but it proved not to be an issue at all. My hand size is about 8.5-9 so I guess about medium sized hand. The rear guard of the AMF Survival knife serves as good protection in the event of using the butt end of this knife to strike something which might cause injury to the fingers. I had the knife submerged over several days on and off and only stripped it once to dry it out and apply a small amount of good quality light machine oil. There was negligible corrosion present (slight staining-which was/is nothing). The water was full of tannins and as it was shallow (under 2 metres) probably high in oxygen content due to it’s fast movement.

The Forprene handle of the Extrema Ratio AMF totally encircles the tang, which the latter is very thick (6.3mm). The full blade thickness runs almost the length of the blade. The guards and pommel are of low magnetic stainless alloy and showed zero corrosion from submersion and use in a wet environment. There are 4 holes to which cordage can be secured in order not to loose the knife.
The Extrema Ratio AMF knife was very easy to keep sharp. I used a honing nail file about twice over a two week period. I never used the knife with gloves.
I carved sand impregnated rainforest hardwoods to test edge retention (which was excellent), cut up all sorts of tropical fruits (not shown) and bored with the tip to make a fire bow drill base board (not shown here).

As the Extrema Ratio Advanced Multi Function knife (AMF) knife is marketed as a “survival knife” it should be tough (in the true metallurgical sense and construction-physical sense), easy to maintain; offer good corrosion resistance in wet environments and where maintenance is not going to happen often; it should be of a design which lends itself to many tasks but an also take some abuse or perform functions generally relegated to other tools such as a machete or parang, such as chopping or prying (with care of course). I found that the Extrema Ratio AMF knife satisfied these parameters. it’s really no surprise as the blade design is not new and has been around for many many years.

Regardless of what one wants to call their knives, I found the Extrema Ratio AMF was/is well suited to some hard work and there is a good vibration absorbing grippy handle, especially when wet.

I think if you like the retro/traditional design look of this knife (ok you’ll only think of this knife as a retro look if you happen to be at least 50 years old LOL) and big tough but functional knives appeal to you, you might be interested in the Extrema Ratio AMF as your next big knife, only you can be the judge.


Lifetime warranty on the knife and 6 years on the scabbard.

To learn more about the Extrema Ratio AMF, please click on the blogger icon in the header and read about stripping the knife for cleaning and what my initial thoughts were plus a whole lot more information not presented here in this extensive video.
You can also see it here:


maritimespook says:

Thats a Beauty Francis ! Happy New Year Brother i appreciate ya ! That was awesome seeing that Eel ! He Wanted the Knife For Himself !! Rambo would be happy to carry that beast eh !! ;,;,;, Cheers my Friend !,,;,;, Spook

tim roth says:

Excellent video mate. Just an armchair question. How come you use “thick” blades out in the jungle? I all ways hear/read about poeples and there machetes.

Mandahla Alachii says:

Es un honor volverte a ver amigo .Bendiciones!!

Brad Griffin says:

That’s a proper good size eel mate. I know where one of similar size lives at my local river. They’re cool creatures.

NGMonocrom says:

Must admit, I wish I had bought a Gerber BMF when they were available. Nice to see a very modern knife clearly based on that design.

Brad Griffin says:

On the subject of the knife, that’s a cleaver, axe, and machete in one. A very nice tool. I just read your description and had to laugh. Maybe I immediately liked this knife because I’m 54 years old and carried three different knives on my belt when I lived in FNQ (Cooktown/Cedar Bay/ Mt Amos) in the early 80s. Everyone carried at least one knife back then up there. Back in the day when common sense was practiced by lawmakers and we were allowed to carry them in town as well as in the bush.

Darren Turner says:

Another great video. I love the size and shape of the knife, build quality looks amazing as per ER’s other offerings. Good chopper and looks to be a capable slicer too. For the work you’re doing with it, how does it compare with the TASK J?

nervsouly says:

The eel really appreciated the knife.

ja cr says:

Extrema Ratio has and probably always be one of my favorite brands, but I really hate those giant finger coils they have on the handles. But it’s nothing some gorilla tape can’t fix.

TurtleWolf Pack says:

Thats a hefty chunk of steel. Not surprised that it performed as well as it did!

ELMC700 says:

Wow is extremely beatiful, but my wallet dont have the money :c

Gruggs Giero says:

good knives but just way to $$$$$$$$$$$.

Brad Griffin says:

When say size 9, does that mean the circumference of your hand is 9 inches? Or 22cm? Is that how the sizing works? I’m a size 9 if that is the case.

Seventh Seal says:

That’s a slab right there.

carlos maureira gonzalez says:

is too big for the maneuver, uncomfortable in the grip.. I have the Jungle King 1 of Aitor… and so very similar to the AMF… they are very heavy and usually performs the work of hand axe. Thanks for show in reality how knives work.

 Write a comment


Do you like our videos?
Do you want to see more like that?

Please click below to support us on Facebook!