Extrema Ratio AMF Survival Knife Field Review

Hi so here is my first field review of the Extrema Ratio AMF survival knife. A top performer bashing it about in the Australian bush and rain forest. The AMF sports a classic blade geometry with a sturdy feel to it. See what you think!

Bohler N690 corrosion Resistance in the Field

N690 Corrosion Resistance in the Field
Extrema Ratio AMF Survival Knife

Wet all day in a hot humid rainforest environment, submerged for approximately 2 hours while exploring tannin stained freshwater pools, the Extrema Ratio AMF shows negligible signs of corrosion.

Recently I took a knife labeled as a "Survival knife" from the manufacturer diving into warm tannin stained (Acidic) tropical waters for about just over 2 hours.

This knife is not a specific diving knife but I figured if you're going to call your product a "Survival Knife" then you had better be making a good product and if it's a survival knife then it needs to be not afraid of water! 

I was not disappointed when I disassembled the knife at the end of the day. A burnishing, anti-glare finish had been applied to the entire blade surface. This is simply a physical finish. There is a trade off with corrosion resistance in stainless knife alloys; the higher the HRC the lower the corrosion resistance as the the amount of soluble Chromium present will be less than in equivalent alloyed steel at a lower HRC's. This knife was HRC58. Not too hard not too soft. Just right.

You can see some very slight staining on the blade, there was no pitting evident. The tang had been wet all day but no evidence of staining or pitting. The knife had been used to cut up many different jungle plants all of which contain sap of various acidity and very sticky too. The knife was used for diving in a fast flowing highly oxygenated river, stained with tannins (very acidic) for approximately 2 hours. There was no corrosion present in the small black threaded nut at the end of the tang either. For all other stainless fixtures (not made from N690) there was no evidence of corrosion. 

Field Strip of the Extrema Ratio A.M.F Knife

The Parts of the Extrema Ratio AMF Knife

Ok so Extrema Ratio indicate that the AMF is field strippable. What does this mean? Well it means if you have access to a 3mm Allen key wrench otherwise known as an Allen Key, commonly used for socket head bolts, you will be able to disassemble the AMF Knife in the field or of course at home in order to clean it if it gets submerged in salt water or any kind of fluid.

Here are the pictures, they are self explanatory I believe.

A 3mm Allen wrench is required to disassemble the Extrema Ratio AMF Knife

Once the stainless steel socket bolt has been removed, all the parts can be stripped from the tang.

The front guard is not symmetrical and can not be put on incorrectly (why it has been milled out in the centre, I do not know. I would have thought that hilt of the blade should have sat slightly recessed within this thick guard, but this is not the case. If it is milled because of a weight saving, then little weight is saved like this. BTW the black marks are from oil present from manufacturing and assembling (I cleaned it off).

The Allen bolt screws into (what appears to be a hardened) a female thread nut, which is retained within the end of the knife tang by friction. One must be careful not to loose this part, should it come lose, otherwise it will be very difficult (but not impossible) to keep the handle on. Ordinarily however, no outwards pressure is directed towards this bolt and fixture.

One thing I noted was that I felt based upon the machining workmanship of all of my other Extrema Ratio knives, the AMF's front guard could have been made with slightly better tolerances. It's not a huge big deal but still, this is purely based upon all of my (and it is extensive) experience with Extrema Ratio edged products.

The tip of the tang protrudes slightly above the Forprene grip, this then slots into the rear guard preventing the rear guard from twisting/rotating. The Socket head bolt sits shy of the butt cap in order to avoid damage to the head of the bolt if you strike the pommel onto hard surfaces.

The Tang of the Extrema Ratio AMF isn't full width but of course this would make the knife incredibly heavy and it would not be practical to put a handle on such a large knife with a full width tang. The tang however, is very very beefy and as you can see has not been milled out like on some "full width tang" knives whereby lightening the knife but at the same time weakening it's construction.

Stainless fixing hardware on the Extrema Ratio AMF.

Hi all I forgot to say something about all the parts and what they are made out of. Well placing a Neodymium magnet next to ALL parts EXCEPT the blade results in very little attraction- they are magnetic but exhibit poor attraction to powerful magnets. This is an indication of a low magnetic stainless steel grade. I asked Extrema Ratio and they did tell me that the fixing parts including the guards and pommel were of a Stainless grade. My guess is low low magnetic 300 series? Anyway the blade of course is strongly magnetic since it's N690.

EXTREMA RATIO AMF SURVIVAL KNIFE WOW!

Extrema Ratio AMF Survival Knife

What to say? I loved the 80's, everything about it. Including the cutlery from that era. Yes, I saw the Rambo movies and who didn't like, or want a damn RAMBO knife? Anyone who says they didn't isn't being honest with themselves. That movie set the scene for the romanticised lifestyle which is probably inherent in many of us, and dating back to our primeval existence on this planet with our pre-occupation about survival (knives and tools). This survival lifestyle has all but been lost by our civilized ways with the exceptions of those whose existence still depends on survival from the land and sea by their own hands free of mechanisation. For the rest of us, if we are lucky enough, we will never encounter a situation whereby our lives depend upon surviving from the land or sea or disaster*. Of course we can be challenged by disasters* whether man made or natural and become either voluntarily or involuntarily involved in such survival situations. Now many would like to think (romanticise- in reality, far from romantic) themselves in some sort of survival situation, where carrying a big knife is going to save the day. Of course if one has been truly involved in real survival situation as those mentioned above (with few exceptions of course), we know that these situations rarely involve the use of a knife big or small.
Now I digress....

By the way, the "sawback" on the RAMBO knife was NOT a saw at all but a series of wire cutting notches- that was made evident in the movie, where Sylvester Stallone used the knife to cut some wire. 

Gerber Legendary Blades in the USA brought out their  "Survival knife" in the 80's. I saw my first one over 17 years ago in a Tokyo camping shop, of which it took centrepiece under the glass at the front desk. For some reason, I never bought one (no, it's not because I thought they were crap- but at the time money was indeed "an object" for a poor post doctoral scientist!) but always lusted after one. Several versions were made, even one with wire cutter notches on the spine, just like the first RAMBO knife. Those Gerber (serial numbered) knives have now become collectors items.

Here Comes Extrema Ratio!

Now zoom fast forward to 2017/2018 and Extrema Ratio in Italy, with inspiration from that survival cutlery era of the 80s, has produced the A.M.F or ADVANCED MULTI-FUNCTION knife.

Ok, so Extrema Ratio are calling this AMF a "survival knife" and have it listed in their section encompassing their knives suitable for Survival scenarios, hence "Multifunction" applications!

Let me quickly say this, based upon my other articles I have written regarding what is a survival knife and personal experiences involving "survival" (and here I'm not talking about lounge-chair situations but the real McCoy) encounters), I can definitely say that the Extrema Ratio AMF suits this description. To summarise first, and then talk in more detail about the AMF.

Is the AMF a "Survival knife" according to my definition?

Use in very Cold weather or sub zero temperatures? YES, there is no exposed tang for one to freeze to the palm of their hand. Very hot conditions, same applies, no exposed tang at high temperature.

Extrema Ratio AMF here seen in the "tropics" later this year in the opposite environment

Minimal fixing hardware? Yes just one bolt  (3mm hex head driver) which sits (protected) below the butt. (strictly speaking, there are 5 parts that result from removing the 3 mm Allen bolt). See the next blog.

Big simple blade design at 8.25" LONG! 6.3mm thick! It's no butter knife!

Extrema Ration AMF spine (the fruits are from the tropical Pandanus palm-not a palm at all).

Survival food and "Survival knife"

Big grippy, all weather handle, made from Forprene to help reduce impact shocks to user's hand.


The Extrema Ratio AMF has a classic clip point (in this case a straight clip point) blade geometry (easy to maintain at HRC 58). The blade thickness is full width until about 2cm from the tip, yielding very good penetrating power. If you love big knives and big knives with functional blades, along with that "retro" look, then you are going to love this AMF knife too.  We have a slight departure from the usual Forprene grips seen on many of Extrema Ratio's knives, whereby there isn't a full encirclement of the tang closest to the hilt. In the case of the Extrema Ratio AMF knife, the tang is fully enclosed by the handle. The handle tapers towards the rear, and is less "angular" than their regular handle grips and is clearly bigger in circumference; it's a very solid grip, so wild swinging (and I'm not talking about crazy party action here) of this blade isn't likely to part company with one's hand.

The Extrema Ration AMF knife at home in the tropics

Generous Forprene grip

Functionality

The Extrema Ratio AMF Knife 

Laser etched model and serial numbered to allow exact tracing of individual models

has a very functional blade design. It has a good tip, perfect for gutting and filleting fish, piercing an animals hide for hunting. The Extrema Ratio AMF knife has a slender geometry but "beefy" cross section, yielding a knife which is quite capable for all camp duties, whether light or heavy.

Slimy wet hands are not going to slip onto this blade with the forward guard.

Can you feed yourself with this blade?

Food preparation with the AMF knife in camp or the hut* is no problem.

I almost always take onions camping/hiking (they don't easily perish or squash). A good source of sulfur, plus onions can turn any bland meal into something great. Having a knife that can actually cut things up as apposed to mashing them and making a huge mess, is an essential item for camping trips.

* I personally wouldn't bring the AMF out in a hut unless I was the only one there. It might start scaring off other campers.

Extrema Ratio AMF Knife and Scabbard Construction and Specifications

N690 (N Six Nine Zero) Cobalt stainless tool steel, hardened to 58HRC.
I measured the following on my model.
Blade length 8.25 inches or 210mm
Blade only weight (484 grams or 17.1Oz.) It's meant to be pack carried as there is no "real" belt loop, however one can use the plastic straps or insert a belt within the loop of material directly behind the knife handle. 

I wouldn't advise inserting a belt within the plastic loops as I think this would damage them over time (I have no evidence to support this, it's merely conjecture and applies to my way of outdoor activities. The AMF knife is clearly meant for pack carrying due to it's large size.

Blade and scabbard weight: triple 6 (666 grams or 23.5 Oz.)
Blade Flat grind.
Forprene grip (Extrema Ratio's Desert version- A.M.F. Desert), virtually unbreakable and resistant to many commonly encountered chemicals.
High denier nylon multi-mounting Molle compatible carry system. (see below).
550 Paracord supplied.
Optional survival kit (You know I don't think much of these and do not own one).

Malice straps made in Italy by the following company
http://www.2mplasticbuckles.com/products/military-buckles/

The website says that the malice straps are made from GTR (Ground Tire Rubber) but They look to me to be made from polypropylene. Anyway they are made in Italy by 2M.

Removable plastic (Malice clips) straps to anchor this huge knife to your pack or any Molle compatible system. I'm not sure how strong or how long these types of plastic retention clips would last. That is how many times can they be opened and closed or how they are against nylon (your tactical belt) or leather belt; rubbing against them. Like I said this AMF knife is clearly meant to be strapped to a pack. (Initial testing in the field by me shows this knife carries very high on the waist, therefore it's better left strapped to gear).

Internal rigid plastic sheet to protect the scabbard. Tough non abrasive "foam rubber" inserts, also do not dull blade edge from repeated insertion and removals.

2 models of the Extrema Ratio AMF are available at present, this model Desert, non-reflective (Burnished) blade finish and the Mil-C-13924 Spec black oxide finish.
Quality finish as expected from Extrema Ratio, right down to the stitching (super thick thread) of the scabbard.

There are 2 guards present, both are made from very thick steel. I like the rear guard as it serves to protect your fingers should you use the AMF knife to bash something open, such as oysters, cracking open crabs, smashing hardened glass etc.

The rear guard

What's in a name??? 

So what's with this A.M.F. business??? What the heck does "Advanced Multifunction" mean???
Well I guess it can mean anything you like, as the naming of knives has no bearing whatsoever on their functionality and or intended purposes. It simply depends on how useful (or not) one thinks it could be to them in a particular environment or for a particular purpose. I use knives on both hemispheres, so I look for attributes that are suitable in both  arid to tropical and alpine regions in the knives i choose to take out with me. However, I want a knife that I can prepare food with and also do the harder tasks (it at all necessary). It has to have a good point and be easily multi-carried and must must be comfortable to use.
So I guess we can say,  "Advanced", as the AMF is constructed from advanced modern materials, such as Forprene and high speed stainless Cobalt enriched tool steel N690 (compared with the 80's survival cutlery-where N690 simply wasn't in existence for cutlery) the, "A"  for advanced is justified. How about Multi-Function? Without spelling it out, Extrema Ratio are suggesting both civilian and military applications, end of story. What those scenarios might entail is entirely up to the individual and or the situations they find themselves in. Now whether the AMF is a "Survival" knife, well as I stated earlier on, I think this knife would certainly fit that bill for me as a sturdy dependable design in tough situations. Let's put this to the test in the coming weeks and months. Stick around!


Life time warranty against manufacturing defects.
6 years on carry system.
Made in Italy.


Stay tuned for the field review on BushCampingTools.

Extrema Ratio T4000C

Compact, lightweight, deadly cutting blade. Good for gutting, food prep, hunting, camping.

I'm taking it to the jungle later this year. Lightweight, great a cutting and penetration

Camp cooking no problems, the T4000C has a great blade shape.

Coastal work no problem as the N690 has good resistance to seawater.

Extrema Ratio T4000C, C stands of course for compact and hopefully you have seen my field review on the this knife.
Totally recommend this knife.

When the Shit Hits the fan

My ONTOS with my version of what I need to take with me if in a hurry to leave the house. I don't need to take the "kitchen sink" with me

See above items listed below

I'm not a "PREPPER" however, I do think one should be prepared to be able to leave ones house in a hurry if you have to. What do I mean by this? Well in the first instance, let's say you need to evacuate the area you live in. It's late at night, you were unexpectedly awoken from some crazy dream to find yourself immersed in a real crazy situation. The last thing you want to have to do is to rummage around trying to find a flashlight/torch etc because, hey guess what there is no power when you hit the switches.

So I keep a few items all together in a known place accessible by all family members.

A big very sharp knife, a rugged and field tested (by me) tactical, bash proof torch which uses Lion batteries which have a very very long shelf life (several years), they will even perform at very very low temperatures. I carry a spare of one of these batteries in a splash/water resistant-proof container (better if waterproof) along with this torch (which BTW has an SOS flashing signal mode too). In the same small Molle pouch there is a fire steel, and a small plastic bag of first strike reliable tinder material. The only other item is a diamond file to keep that blade sharp if need be.

The passports are also not lost in the house so they can also be quickly mobilized if necessary.

The car is always kept gassed up and ready to roll. Car keys and house keys not kept under a pile of cloths.

All of this is common sense, just like one should indeed keep a flashlight ready to hand in case of blackouts/power failures. The addition of a cutting tool and some way to make a fire simply adds a bit more feeling of security without having to "overdue" it. The key is to be able to move fast, not spend hours getting out of the house.

Don't forget the wallet too!

BCT

Some random if not useful advice for beginner/novice campers regarding Outdoor Adventure Advice and purchasing a knife (other than a folder) for camping.

Choosing a knife for your requirements**

**One days full walk  (rugged terrain) or greater from any help/other people, no mobile phone signals based on experience in rugged Australian bushland.

* I'll discuss satellite phones later in another blog.





Choosing a knife can be seen as a rather daunting task on the outset when one considers the plethora of knives available today. Right, let's stop right there and ignore that first statement, why? because that's garbage.
As an absolute beginner and as an absolute "expert" in the wilds, the choice of the knife you take into the wilds with you should be based on the following outlined below.


BUT BEFORE TALKING ABOUT CHOOSING KNIVES I WANT TO TALK ABOUT YOUR OUTDOOR SKILLS, because these are going to be much more important than "what knife am I going to take/buy for my outdoor trips"?, and here's why:

Going "bush" means many things to many people, so I will give you my take on this.

Be prepared, that's right just like the Scouts say. You can't really do much better than this.
Know first aid and if you don't, then take a course and then come back and read the rest of this blog.
Take a recognized advanced first aid course. Make sure others going along also know first aid and are qualified because they could be the ones to save your life! Practice these skills outside of the course (they can easily be forgotten over time,  if called upon you must be able to perform them flawlessly and in a timely manner).

Now are you saying, "heck, I know shit about first aid"! OR thinking you do, is not the same as knowing from proper training!

Know how to take compass bearings,  read a map, follow, choose a path  in your sleep.
Be comfortable walking at night (with a headlamp of course).
If going where you have never been before, Get the facts from people that truly know about this region and or go with one of these people at least 2 times to get to know the area before leading any trip yourself. Lead the second trip yourself with one of those "experienced" people as a backup.
Learn/know how to find water and extract it out of thin air if necessary! What do I mean by this? Simply this, if you are leading a trip and don't know every damn place to get water along the way and or how to find it if the area is totally dry, then you shouldn't be leading any trips away, except from the kitchen to your bedroom and back.
Know how to setup your tent in all weather conditions and in the pitch dark without a torch/headlamp.
Know how to set up everyone else's tents that are going along-just in case.
Know the limitations of those amongst your party.
IS everyone fit and healthy? If not then don't allow them to come along.
Tell someone where you are going and for how long and make contingency plans for the "troops" to be alerted if you fail to return by a certain date.
Have a positive attitude regardless.
Learn to read the weather and not just rely upon your "Casio G Shock" which, BTW I now know what the "G" stands for, that is, a GINORMOUS! watch that looks like you are wearing an instrument panel out of a 777 cockpit- LOL just joking here and no offence to Casio G Shock owners/users.
Know how to cook properly and not just eat that dehydrated dog food stuff. Yes, I did some time with that crap until I met others who knew better and educated me a thing or two about camp cooking. No more dog food for me. Do I look like a dog? There is absolutely no reason (regardless of the distance hiked per day) to eat that dog food type camping food sold by camping stores- they all taste crap. To walk hard and far you need to be fuelled properly, don't let anyone tell you otherwise. So yeah, learn how to cook. 

Knives Knives Knives!!!!

Which brings me to the point of KNIVES. Make sure whatever knife you take with you, you can use it to prepare food with or at least eat with in a semi civilized way and not like some maniac trying to eat off the end of their knife like some RAMBO would be.  CUT YOUR MOUTH AND INSTANTLY BECOME A LIABILITY! In other words, machetes 

Machetes and the like are great for cooking and keeping the weeds/brush down in any self respecting tropical jungle farm. These multipurpose tools are great but outside of their cultural environment, you may attract unnecessary attention and or frighten people off who are not used to seeing such big knives in action! 

The same goes for "survival" type knives. Better to keep them for wilderness areas where you will not encounter the general public, ie they will and you will look out of place on a group camping trip (unless everyone is sporting these types of knives LOL) or pulling one out in a hut on a regular trekking route (except in the jungle).

are great if you are doing all of the above in the tropics but you may need to take another small knife 

Small knives are very practical for camping where one needn't have to hack apart large logs in order to build fires or maybe areas where open fires are strictly banned.

Small knives are perfect for day hikes too where speed and sensible pack weight can enable you to move fast and far to see and do the most in a single day. On such hikes there is absolutely no need to bring a large chopper unless you plan on showing off or indeed frightening the people you are traveling with. My advice is to resist the urge on such hikes to bring that big monster along. Recently, I was witness to someone who took a huge brunt of criticism for bringing such a chopper on a large camping trip, mainly though because it was inappropriate for many of the food preparation and eating tasks LOL.  As he was a complete "beginner" he was quickly forgiven but rest assured if he wasn't he would have been in for a hard time.

with you in this type of environment, especially if you are not that highly skilled with a machete or parang. But that's ok.

 No fires allowed? Then a fuel stove may be necessary- learn how to use one, inside out and in your sleep; be able to conduct field maintenance on it.

I once got a call at after midnight from another country from a friend who couldn't light their stove (first time they ever used it!) , three days into their bicycle touring trip! Ok I fixed the problem for them over the phone.


If fires are allowed......


Camping in wet weather will require a knife that you can, if you have to, remove wet wood in order to gain access to dry inner wood to start a fire if need be.

It might be very cold, in fact, so cold, and stupid you have lost your gloves, or even more silly, just didn't bring any and now having to use your knife, realizing it is freezing and damn uncomfortable in your wet cold hands (because the snow has now turned to slush! What i'm trying to say here is make sure any knife you choose is comfortable in ungloved hands. If you have to wear gloves to use a knife, then better leave it at home and take another one.

All of the above plus more can be gained/learnt by joining a reputable hiking club eg at a university but of course not limited too.



What is this "Survival knife"business???

I'll tell you what it is, it is in fact Bullshit. Because no knife no matter what it is will be any use to you unless you possess the skills to use it and make the best use of it, regardless of any survival situation you might be involved in (on the receiving end, ie need to be rescued, or part of a rescue party).
Just let me say this. Whatever knife you choose to take away "camping" remotely, should be sturdy and not too heavy. What do I mean by too heavy? Well if your chosen knife weighs about as much as two or three days worth of food then leave it behind, it's too heavy! (unless you are planning just an overnight trip***
Your chosen knife must be razor sharp, yes that's right razor sharp, not just sharp or "ok it's sharp enough". WHY??? Well it is possible you may need to cut something in a hurry and that dull blade is going to be a real problem if it can't cut in a hurry.

However, a "survival knife" in my opinion should satisfy these criteria**

Well made, with as few parts as possible. No one part, if a failure occurs in this part should the knife be rendered useless. Leave all knives with metal handles at home, ie I refer to knives which only have metal as a handle; I don't mean cord wrapped knives. Know how to use the knife you take with you for tasks other than chopping. There is definitely a plethora of "review videos" on YouTube which only show knives being used to chop. WTF is that all about?? Is it that these people simply can't demonstrate the myriad of cutting and other tasks knives should and can be used for? 

Coastal walks/trekking/camping/hunting: take a stainless blade unless you  have access to lots of fresh water in order to maintain your knife. The handle should be comfortable so that gloves are not needed-but can be used. Don't kid yourself about this latter point, be smart about it.
Make sure it is a knife you know how to sharpen and carry a small stone to touch up the blade if necessary. Knife size: Up to 7 inches in length or greater if working in the tropics.

In other words a "survival knife' is simply a simple but practical knife design for a given environment. It is NOT a knife u can hack your way out of a plane cockpit with, unless you are a pilot who may need to hack their way out of a cockpit. A super thick knife is NOT a prerequisite for a "survival knife" anyone who advocates this has no idea and has never been or has no real experience in survival. Fact.