BM M4 vs M390

[sae]

How do they compare as far as toughness? I'm really liking how M4 looks from other makers and general info, but I'll probably miss the stainless.

At the hardness that BM production knives come out at, are the M4 and M390 going to be roughly the same in edge retention being that the M4 is 62-64 and the M390 is 60-62?

Which will take a finer edge, I like to finish with green or tan DMT, which works great on the 154 CM, but doesn't work that well on my s90v.

I'm looking for the longest lasting razor sharp edge with an extra fine finish, no less than 15 DPS, probably around 20 or so. I'm not willing to give up toughness though, if it's one sided.

The knives I'm looking at are the contego M390 or M4, rift (LE M4), ritter grip-- but mostly the contego.

 

[Timothy 75]

The rift has full steel liners but the contego has a thicker blade. I'd say its a toss up depending how important reach is to you. Good luck

 

[cchu518]

I'd say too close to call, get what you think looks better!

 

[Cypress]

I have the M4 Contego at 20 DPS. It is TOUGH stuff as the thickness behind the edge is robust. It doesn't have the "crisp" edge that a Spyderco Gayle Bradley has due to the geometry. I've put my Contego through hell and back, and it's still my go-to folder for "ruinous" activities.

You are right about the non-stainless aspect though. Mine edge has rusted before from being in my pocket during multiple sweaty days on the hay field.

I've had Benchmade's M390 and wasn't impressed when put against the M4. M4 tends to roll and deform but hold a working edge FOREVER. Every M390 (and S90V) blade I've have from BM has been what I would call "chippy", and chips are an absolute nightmare when it comes to steels that are as hard to sharpen as M4, M390, and especially S90V (stuff of nightmares).

 

[pbcg]

I have and use both CPM-M4 and M390 but most of my experience between the two (by large margin ) is with BM's CPM-M4. That's said for what you're looking for I think CPM-M4 would serve you the best. As stated it's though, wear resistant, and will take a very keen edge. In my case my sharpening skills are " adequate" but I find the CPM-M4 the easiest to sharpen of the two. Sorry but I don't have enough experience yet with S90V to offer an opinion based on experience.

As far as corrosion resistance I haven't had any problems with CPM-M4 but I also regularly oil my knives with Break-Free CLP so I'm sure that helps.

 

[arty]

I haven't used 390, but M4 holds a sharp edge forever. When I moved just over 2 years ago, my sharpening gear was packed. I used a MiniGrip in M4 to open boxes, and cut rope and cord daily. The knife got used when packing and when unpacking. I would estimate that the M4 didn't need to be stropped for at least 6-8 weeks of very frequent use.
It is great stuff.

 

[P_Meticulous]

This:

M390 takes preference for me. First, I dislike coated blades and will not buy them anymore (I’ve gone two years without doing so, passing up nice LE’s solely because they were coated). Secondly, corrosion/wear resistance are very important to me because I’m an outdoors guy and I like low maintenance. Lastly, if anyone has reservations on BM’s M390, they shouldn’t.. It’s one of their best steel offerings IMO. I can get my 810-1401 scary sharp and it stays that way for extended periods of time compared to my older knives in S30V..

I like CPM-M4 and have a lot of experience with it.. I carried the regular M4 810 for a year before upgrading to the -1401. The drawbacks for me are corrosion issues and the fact that I dislike coatings.. Otherwise it’s a great workhorse steel.

I prefer the clean, satin look :

Compared to this:

 

[jpm2]

First of all, not all cpm m4 from benchmade is created equal. Take for instance my two (2) 810 contegos. One is a late model with a stellar piece of m4. The other is an early model which I can guarantee is not 62-64 hardness. It makes huge burrs when sharpening, rolls, and prematurely dulls.
I also have two (yes 2) mini grip 1303 cpm m4's which exhibit the same characteristics as my early 810 contego, to a slightly lessor degree.

I've not tried m390 or the carpenter equivalent, but with all the reports of severe chipping and broken blades, I would take even my early cpm m4 over that steel any day.

If you decide on an 810 cpm m4, make sure it's been recently produced.

 

[P_Meticulous]

I've not tried m390 or the carpenter equivalent, but with all the reports of severe chipping and broken blades, I would take even my early cpm m4 over that steel any day.

I haven't experienced any of these issues at all.. I wouldn't of recommended M390 if I had.

I don't know if people are chopping down tree limbs or batoning through bricks with their knives, I use mine for cutting.. M390 holds an edge for a long period of time with no adverse effects.. (At least for me)

Don't believe everything you read on the Internet and I would especially try it out before you knock it.. My .2

 

[loonybin]

First of all, not all cpm m4 from benchmade is created equal. Take for instance my two (2) 810 contegos. One is a late model with a stellar piece of m4. The other is an early model which I can guarantee is not 62-64 hardness. It makes huge burrs when sharpening, rolls, and prematurely dulls.
I also have two (yes 2) mini grip 1303 cpm m4's which exhibit the same characteristics as my early 810 contego, to a slightly lessor degree.

I've not tried m390 or the carpenter equivalent, but with all the reports of severe chipping and broken blades, I would take even my early cpm m4 over that steel any day.

If you decide on an 810 cpm m4, make sure it's been recently produced.

The first runs of CPM-M4 that Benchmade produced were at 60-62Rc, then they bumped up to 62-64Rc. My 520-1101 has the lower heat treat, and it doesn't hold an edge as well as any of the M390 blades I have had.

As for M390 chipping, that has happened on the latest run of Ritter Grips, but that is the only knife I've heard chipping complaints about. My 581, 586, and my 810-1401 exhibited no issues, and I even hack and baton branches with my Contego.

I found that M390 holds an edge as well as CPM-M4, but is slightly harder to sharpen. It's not an issue with my Edge Pro, but it takes a little longer. Neither one holds an edge as long as s90v, but you really ought to have diamond stones for resharpening that!

I haven't experienced any of these issues at all.. I wouldn't of recommended M390 if I had.

I don't know if people are chopping down tree limbs or batoning through bricks with their knives, I use mine for cutting.. M390 holds an edge for a long period of time with no adverse effects.. (At least for me)

Don't believe everything you read on the Internet and I would especially try it out before you knock it.. My .2

The only complaints about M390 have been the Ritter Grips. My experience with M390 has been the same as yours: stellar edge holding.

 

[jpm2]

The first runs of CPM-M4 that Benchmade produced were at 60-62Rc, then they bumped up to 62-64Rc. My 520-1101 has the lower heat treat, and it doesn't hold an edge as well as any of the M390 blades I have had.

As for M390 chipping, that has happened on the latest run of Ritter Grips, but that is the only knife I've heard chipping complaints about. My 581, 586, and my 810-1401 exhibited no issues, and I even hack and baton branches with my Contego.

I found that M390 holds an edge as well as CPM-M4, but is slightly harder to sharpen. It's not an issue with my Edge Pro, but it takes a little longer. Neither one holds an edge as long as s90v, but you really ought to have diamond stones for resharpening that!


The only complaints about M390 have been the Ritter Grips. My experience with M390 has been the same as yours: stellar edge holding.

Didn't you have an m390 blade break? BM 710 if I remember right.

 

[TheEdge01]

I recently bought a Contego in CPM M4. It is a large knife but it has become my edc. The day I bought it, I was also considering the Nakamura in M390. M390 is far more corrosion resistant to M4 but if you keep a light coat of oil on the blade it should be fine.

 

[loonybin]

Didn't you have an m390 blade break? BM 710 if I remember right.

Nope. The only 710 I owned was a 710sbt when they were first introduced in 1999. ATS-34 steel back then. Didn't care for it all that much, either, because the recurve was such a pain to sharoen on a Sharpmaker.

 

[jpm2]

Nope. The only 710 I owned was a 710sbt when they were first introduced in 1999. ATS-34 steel back then. Didn't care for it all that much, either, because the recurve was such a pain to sharoen on a Sharpmaker.

Sorry yeah, it was Gocker199 that broke his 710-1.

 

[jkarp_53]

Maybe due to issues with sharpening, I've noticed the recurve on many current models is less pronounced. I prefer M4. It seems to hold an edge forever and comes back quicker than does M390. We've moved twice in the last year and a half, and my 525BK-1101 got most of the opening box duties and still remains sharp.

 

[lamanian]

I have the M4 Contego at 20 DPS. It is TOUGH stuff as the thickness behind the edge is robust. It doesn't have the "crisp" edge that a Spyderco Gayle Bradley has due to the geometry. I've put my Contego through hell and back, and it's still my go-to folder for "ruinous" activities.

You are right about the non-stainless aspect though. Mine edge has rusted before from being in my pocket during multiple sweaty days on the hay field.

I've had Benchmade's M390 and wasn't impressed when put against the M4. M4 tends to roll and deform but hold a working edge FOREVER. Every M390 (and S90V) blade I've have from BM has been what I would call "chippy", and chips are an absolute nightmare when it comes to steels that are as hard to sharpen as M4, M390, and especially S90V (stuff of nightmares).

I realize this is a necro thread but I simply must say M4 is awesome steel one of my favorites in fact, benchmade m390 is far from a chippy steel however. I have a m390 ritter grip and it has a very thin edge, slices like a champ, and never chips. I strip alot of wire with my knives at work and have had alot of knives chip on me as a result, my m4 paramilitary and m390 ritter never do.