View Full Version : KMR vs KMR ALPHA
GoldnBullet
04-01-16, 13:50
Is the original KMR worth the increased price of $80 over the ALPHA?
I was looking at the 13" versions with a difference in weight of 2 ozs.
Meh, the KMR is lighter. The Alpha is cheaper and probably stronger. The finish is definitely stronger.
GoldnBullet
04-01-16, 14:22
Meh, the KMR is lighter. The Alpha is cheaper and probably stronger. The finish is definitely stronger.
I keep hearing how people with the KMR complain about the finish being so easily scratched. One person stating the KMR finish is like "Wet Krylon Paint."
I have two of the originals but if I buy another one I'll go with the Alpha and save some money.
Depends on whether or not you think each ounce is worth 40 bucks. I have a 15" and had a 13". Both original recipe. If I needed another one today I would buy the original again.
https://www.m4carbine.net/showthread.php?174415-BCM-s-new-KMR-A-is-out-(on-their-RECCE-Rifles)&p=2197903#post2197903
See post #71 as written by BCM themselves.
EDIT: I went down this same road a few weeks ago when I got tired of waiting for complete KMR uppers to come in stock. I did a lot of online research from here and TOS, then bought the KMR-A.
I have one of each and while I don't have any complaints about the original I would happily just buy the 'more-available' alpha in the future. The finish doesn't bother me, it does come off kinda easy on the OG but owells, and I've not deformed either.
My reasons for liking the KMR (both,either) overall are:
-the profile/feel of it
-mount slots on all surfaces and not just 3,6,9 oclock like some other guards
-light
-the fact that I feel like BCM will back their product if I ever have a problem with it
The weight difference just isnt that big of a deal to me as printed. (my alpha is shorter than my OG (10" OG and 9" alpha) with different barrels as well so take that subjective statement for what it's worth and feel free to pick it apart as apples/oranges if you're ticky like that. I get that, it's cool.)
To be honest I've not seen KMRs in stock since the alphas came out. They may be briefly in stock from time to time but I haven't signed up for notify because I don't need another one and as previously mentioned I'd prolly just buy an alpha if I did.
Just out of complete trivial curiosity... does anyone know if BCM has produced and sold more original KMRs since they released the alphas?
JackFanToM
04-01-16, 17:04
Depends on whether or not you think each ounce is worth 40 bucks. I have a 15" and had a 13". Both original recipe. If I needed another one today I would buy the original again.
I agree with this. After humping issued gear in the Corps, the ability to choose items and cut weight just makes me feel all warm and cuddly inside.
I couldn't care less which one. I've got the original, I'd still probably buy the original over the Alpha.
dirkmagurk
04-01-16, 18:37
I have one of each in 13" and honestly can't tell a noticeable difference in handling. I'd say save some cash and go with the aluminum version.
steelheadr
04-04-16, 23:08
I like my 15" alpha.
And I like mine too.
GunFighter98
04-05-16, 22:46
I would go with the Alpha for the increased strength
Leonidas24
04-06-16, 03:11
I have one of each -- a 13" KMR and a 10" KMR-A. The original 13" came first and I decided having used it for a little over a year that I'd save some money and go with the aluminum version. Overall I'm happy with both as they both perform their duties well as handguards. Yet, I will say that if you've ever painted a rifle with rattle can, and want to remove it, be very careful of what paint strippers you use on the original KMR. I typically use Citri-strip and it took most of the original KMR down to the alloy. It's only slightly disappointing since I ended up recoating it with rattle can again, but I still occasionally check any scratches and dings for obvious signs of oxidation.
For the difference in price I'll be equipping future rifles with the alpha, primarily for the presence of anodizing, less cost, and the familiarity with aluminum. I believe alkali and alkaline earth alloys will eventually be a major part of the firearms industry, obviously BCM w/ the KMR, Geissele with their scope mounts, but some amount of development is still to be had.
I would go with the Alpha for the increased strengthThey are so close in strength you can't tell the difference. The Alpha is much cheaper = win
I would go with the Alpha for the increased strength
Who says one is stronger than the other?
Defaultmp3
04-08-16, 17:35
Who says one is stronger than the other?BCM did, though not by much, apparently.
Strength wise both metals are very similar with a slight edge to aluminum with a torture test. The finish on the KMR-A (alum) is going to be more durable, as its Hard Coat Anodized per Mil-A-8625F, Type III, Class 2.
Thanks!
Didn't know there was a strength difference. Might have to check them out.
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GunFighter98
04-09-16, 00:02
I hope the Alpha is actually stronger. I have an original KMR that bent enough to cause a noticeable zero shift with my front sight. My rifle was never dropped or abused so hopefully mine was just a random defect and not common with the first gen KMR.
JackFanToM
04-09-16, 13:19
I have literally beat the hell outta one of my 1st gen KMRs. I have used it just as hard as the larue quad rail that was on my rifle previously, and no issue yet.
turnburglar
04-09-16, 13:40
I have literally beat the hell outta one of my 1st gen KMRs. I have used it just as hard as the larue quad rail that was on my rifle previously, and no issue yet.
yeah.
But this is the internet where people will argue to the death about a 1% difference on items they rarely use.
I have the original and love it. I'd buy the alpha today just based on availability. As too the finish durability? I covered mine in rail panels. BCM's keymod panels are far better than anything i have found in the MLOK flavor for my ALG rail.
JackFanToM
04-09-16, 13:46
Same, I covered mine as well in bcm's panels. They give the rail a round grippy feel that makes it easy to grip and hold firmly to as I manipulate the rifle. I'm pretty unconcerned about the coating as I'm one of those odd guys that think wear and patina add character.
I think both have their pros depending on what you plan to do with your rifle and what your goal is for it.
If you just simply like the design of the KMR rails for their mounting options, etc then I'd go KMR-A. I have one on my BCM rifle and even with it's 2oz weight gain over the standard KMR it is still extremely light weight.
Now if your goal is saving weight, I'd go for the original KMR. One of BCMs 14.5 ELW-F uppers with the original KMR rail and the V7 Weapon Systems titanium KMR barrel nut and titanium gas block would be about as light weight as I'd ever need.
If that's not your goal though then there really are no down sides to the KMR-A.
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I hope the Alpha is actually stronger. I have an original KMR that bent enough to cause a noticeable zero shift with my front sight. My rifle was never dropped or abused so hopefully mine was just a random defect and not common with the first gen KMR.
My guess is we'll see more and more of this. I've never quite understood the decision behind putting irons on a FF rail and then making said rails as light and thin as possible. You're essentially asking for that to happen. If they're simply backup irons, I guess no big deal. But if it's your primary sighting system, it seems like a FSB is still the most robust method, or at least sticking irons on a full strength quad rail.
https://www.boltcarrier.com/images/smooshed-upper-000.jpeg
My guess is we'll see more and more of this. I've never quite understood the decision behind putting irons on a FF rail and then making said rails as light and thin as possible. You're essentially asking for that to happen. If they're simply backup irons, I guess no big deal. But if it's your primary sighting system, it seems like a FSB is still the most robust method, or at least sticking irons on a full strength quad rail.
https://www.boltcarrier.com/images/smooshed-upper-000.jpeg
Would you mind telling us how the rail damaged pictured happened? Looks like it was run over by a truck.
Would you mind telling us how the rail damaged pictured happened? Looks like it was run over by a truck.
Yup. It was from the KAC pic thread on TOS. And I believe that's exactly what happened to it.
GunFighter98
04-12-16, 17:34
My guess is we'll see more and more of this. I've never quite understood the decision behind putting irons on a FF rail and then making said rails as light and thin as possible. You're essentially asking for that to happen. If they're simply backup irons, I guess no big deal. But if it's your primary sighting system, it seems like a FSB is still the most robust method, or at least sticking irons on a full strength quad rail.
https://www.boltcarrier.com/images/smooshed-upper-000.jpeg
You are absolutely right. It has definitely made me rethink my purchasing decisions. There is always a trade off with strength and weight. The juice has not been with the squeeze.
You are absolutely right. It has definitely made me rethink my purchasing decisions. There is always a trade off with strength and weight. The juice has not been with the squeeze.
You really need to rethink your decisions if you want a rail to truck proof! You need some bad ass juice!
GunFighter98
04-12-16, 18:42
You really need to rethink your decisions if you want a rail to truck proof! You need some bad ass juice!
No doubt! Perhaps a happy medium.
Relevant.
https://www.youtube.com/watch?v=eQYV96hHoGU
titsonritz
04-12-16, 18:46
I don't this whole run it over with a truck nonsense. I'm not going to use my rifle for a jack handle or ax either. Whatever.
GunFighter98
04-12-16, 19:00
I don't this whole run it over with a truck nonsense. I'm not going to use my rifle for a jack handle or ax either. Whatever.
I agree, running over with a truck is overkill. I think people like myself just want a product that can hold up to accidents like being dropped or maybe something a little more severe. I am not convinced that uber-light rails can hold up to much abuse. I personally like to have 100% confidence in my rifle and equipment. That is why we spend the money on quality products.
I agree, running over with a truck is overkill. I think people like myself just want a product that can hold up to accidents like being dropped or maybe something a little more severe. I am not convinced that uber-light rails can hold up to much abuse. I personally like to have 100% confidence in my rifle and equipment. That is why we spend the money on quality products.
How many have you abused?
Rifleman_04
04-12-16, 19:27
How many have you abused?
Just the one that had a Troy front sight, wml and a sling on it that I wouldn't consider abused and the rail twisted. Gradual adjustment of the rear sight over time until it was almost maxed to the right. Every time that gun came out we had to confirm zero on the irons until we figured out the rail was effed. Aimpoint T1 zero was always solid. Second KMR I've seen do that. Someone else here posted a pic of another.
ZipZopBoop
04-13-16, 16:45
Does BCM still even make the orignal KMR? I haven't seen them in stock on their website for 5 months+. I got mine on Primary Arms and it was the last one of an uncommon length.
Just the one that had a Troy front sight, wml and a sling on it that I wouldn't consider abused and the rail twisted. Gradual adjustment of the rear sight over time until it was almost maxed to the right. Every time that gun came out we had to confirm zero on the irons until we figured out the rail was effed. Aimpoint T1 zero was always solid. Second KMR I've seen do that. Someone else here posted a pic of another.
Pictures or it didn't happen!!! Not that I don't believe you. I just don't believe it happened.
elephantrider
04-14-16, 01:55
I agree, running over with a truck is overkill. I think people like myself just want a product that can hold up to accidents like being dropped or maybe something a little more severe. I am not convinced that uber-light rails can hold up to much abuse. I personally like to have 100% confidence in my rifle and equipment. That is why we spend the money on quality products.
Yes, the truck stuff is ridiculous. There aren't many, and maybe none, FF handguards that could come out unscathed from that so what is the point?
An impact from a fall/drop onto a hard surface, or being accidentally swung into a wall or vehicle is much more likely. In these cases, I would thing that hitting an attached accessory such as a light would give the greatest chance for realistically bending or deforming a FF handguard.
IIRC, forum member 'Slippers' (of Arisaka Defense) tests their light mounts by giving the handguard a good smash into a hard surface with the accessory/mount impacting first. The FF handguard usually bends before the mount gives or breaks.
elephantrider
04-14-16, 02:02
Just the one that had a Troy front sight, wml and a sling on it that I wouldn't consider abused and the rail twisted. Gradual adjustment of the rear sight over time until it was almost maxed to the right. Every time that gun came out we had to confirm zero on the irons until we figured out the rail was effed. Aimpoint T1 zero was always solid. Second KMR I've seen do that. Someone else here posted a pic of another.
So what exactly was the problem with the rail that was casing the zero shift? Was the handguard bent, or twisted somehow, or was it slipping on the barrel nut? Whatever the issue was it sounds like it was progressing since the rear sight needed "gradual adjustment." Curious what it was being subjected to that caused the issue to progress.
Rifleman_04
04-14-16, 19:27
Pictures or it didn't happen!!! Not that I don't believe you. I just don't believe it happened.
didnt take pics. boxed it and sent it back to BCM for warranty.
Rifleman_04
04-14-16, 19:32
So what exactly was the problem with the rail that was casing the zero shift? Was the handguard bent, or twisted somehow, or was it slipping on the barrel nut? Whatever the issue was it sounds like it was progressing since the rear sight needed "gradual adjustment." Curious what it was being subjected to that caused the issue to progress.
the whole rail body was twisting, you could look down the top rail and see the twist.
if you have ever looked at a KMR you would know the rail cant slip on the barrel nut.
It was being subjected to a fit adult male using a gun in the way professional grade weaponry is intended.
elephantrider
04-14-16, 22:22
the whole rail body was twisting, you could look down the top rail and see the twist.
^This clarifies things a bit.
if you have ever looked at a KMR you would know the rail cant slip on the barrel nut.
^No need to reply if you are going to be presumptive and rude.
It was being subjected to a fit adult male using a gun in the way professional grade weaponry is intended.
^Vague.
JackFanToM
04-14-16, 22:28
I would suspect that you got one that came with a manufacturing issue of some sort, as I have 2 original KMRs, I'm 6'2" 216lbs and in above average shape for a 44 year old man. I run my guns hard, and I torque them hard with the slings (mine are all the way out at the end of 13" rails) and they don't even flex. I'm not questioning the validity of your claim, but you had a sample of 1, and it was an exception to what seems to be the rule.
BufordTJustice
04-15-16, 08:19
I would suspect that you got one that came with a manufacturing issue of some sort, as I have 2 original KMRs, I'm 6'2" 216lbs and in above average shape for a 44 year old man. I run my guns hard, and I torque them hard with the slings (mine are all the way out at the end of 13" rails) and they don't even flex. I'm not questioning the validity of your claim, but you had a sample of 1, and it was an exception to what seems to be the rule.
I'm 5'10" and built like a weight lifter. I've been unkind to my original KMR as well and i agree. It's been just as tough as any DD bolt-up rail I've used. Especially during entry work in my job as an LEO.
I just sent a 13" KMR back to BCM due to my rear sight being adjusted all the way to the left. I had first thought by reading threads like this that maybe they are too lightly built. I'm not easy on my equipment but haven't used this carbine much. Then I thought well let's just bend it back over (measuring the inside front of rail to the barrel on each side) but while I could move it, it sprung back to where it originally was. I think mine was possibly machined or installed crooked, probably the latter, I now have no worries as to how tough they are.
BCM stood behind their rail whether it was their fault or mine.
I just sent a 13" KMR back to BCM due to my rear sight being adjusted all the way to the left. I had first thought by reading threads like this that maybe they are too lightly built. I'm not easy on my equipment but haven't used this carbine much. Then I thought well let's just bend it back over (measuring the inside front of rail to the barrel on each side) but while I could move it, it sprung back to where it originally was. I think mine was possibly machined or installed crooked, probably the latter, I now have no worries as to how tough they are.
BCM stood behind their rail whether it was their fault or mine.
Usually if a handguard is not parallell with the barrel, it's because the face of the upper receiver isn't square and the barrel is actually what is on a little crooked. I have two cheap Anderson uppers that have this problem. The fix is to either lap the upper, or buy a better quality one.
The problem with your theory in my case is the Leupold VX6 scope in it's LaRue mount went on and sighted in with minor windage or elevation adjustments from another gun who's irons are centered. The upper was a Rainier Arms w/o FA and was not "cheap". The new rail cured the problem.
So no, it was the rail.
Rifleman_04
04-15-16, 16:06
I would suspect that you got one that came with a manufacturing issue of some sort, as I have 2 original KMRs, I'm 6'2" 216lbs and in above average shape for a 44 year old man. I run my guns hard, and I torque them hard with the slings (mine are all the way out at the end of 13" rails) and they don't even flex. I'm not questioning the validity of your claim, but you had a sample of 1, and it was an exception to what seems to be the rule.
Same 13" and slung up that rail does flex a lot. My sample size is 1 but someone else here posted a pic of theirs that did the same thing I think in the keymod failure thread.
Rifleman_04
04-15-16, 16:08
I'm 5'10" and built like a weight lifter. I've been unkind to my original KMR as well and i agree. It's been just as tough as any DD bolt-up rail I've used. Especially during entry work in my job as an LEO.
This 13" keymod replaced a 10" DD Lite and i have not found it to be as tough at all.
Rifleman_04
04-15-16, 16:09
Usually if a handguard is not parallell with the barrel, it's because the face of the upper receiver isn't square and the barrel is actually what is on a little crooked. I have two cheap Anderson uppers that have this problem. The fix is to either lap the upper, or buy a better quality one.
Could also be improper barrel nut torque.
In my case the barrel nut was and is torqued to 42' lbs. I believe the spec is 40-50' lbs?
Rifleman_04
04-15-16, 17:50
In my case the barrel nut was and is torqued to 42' lbs. I believe the spec is 40-50' lbs?
Yep, you're good then.
BufordTJustice
04-15-16, 20:40
This 13" keymod replaced a 10" DD Lite and i have not found it to be as tough at all.
Ironic, because that was the last rail i compared to it. The DD has a brittle finish that was easily marred and the pic rail surfaces were easily dented. Not so with the multiple KMR rails I've used and abused. You're in the minority. That's reality.
boombotz401
04-17-16, 18:12
I've got both and couldn't tell you the difference unless I'm looking for the A on one of them.
Unless your counting the ounces on a scale just grab the A and use the spare cash to grab some BCM keymod covers, now those things add some nice grip
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Strider5.56
06-02-16, 19:16
https://www.m4carbine.net/showthread.php?174415-BCM-s-new-KMR-A-is-out-(on-their-RECCE-Rifles)&p=2197903#post2197903
See post #71 as written by BCM themselves.
EDIT: I went down this same road a few weeks ago when I got tired of waiting for complete KMR uppers to come in stock. I did a lot of online research from here and TOS, then bought the KMR-A.
This is why I love M4carbine.net. Once again my go to place for great info. I have been looking for this info all afternoon. Thanks.
I've got the space metal KMR and I'm happy with it, but I haven't run it hard. I like the fact that my 15" rail is lighter than most 12-13" rails and even some 10" rails. My father's DD quad rail isn't bad, though.
This is why I love M4carbine.net. Once again my go to place for great info. I have been looking for this info all afternoon. Thanks.
I second that.
Orangeracer
07-14-16, 21:44
Cool thread, will be joining the KMR club soon! Just had to go with alpha since regular wasn't in stock. I'll just keep my eyes out for a used one. Can't wait for rail to get here!
The original KMR rails are pretty much unobtainium these days are they not?
Orangeracer
07-14-16, 22:42
The original KMR rails are pretty much unobtainium these days are they not?
I spoke with BCM this week, they are still producing the 13" and 15" original KMR's but have slowed down in production due to shortage in magnesium alloy. But they will still make them as they acquire the materials though. They said they will no longer produce KMR's in anything shorter than that since the average person can't feel a "perceivable" weight difference. Here's a quote from one of my emails from them earlier this week.
"In order to fill the void we have created in our customer base, we developed the Alpha as a new generation of KMR. Alpha is identical to the original KMR in every measurable way, however it is made from pure aluminum and hardcoat anodized. The weight difference is approximately 2 ounces, generally below what an average person can perceive when comparing by hand. The other benefit to the Alpha is the hardcoat anodizing used to coat the handguard. The alloy used in the original KMR could not be anodized so instead, an aeronautic coating was applied to accomplish a similar effect to anodizing. Hardcoat anodizing Type III Class 2, which is identical to the process used on all milspec upper and lower receivers, accomplishes not only a corrosion resistant and non-reflective finish, but also, and primarily, greatly enhances the strength of the entire handguard. "
Definitely makes me feel content with the alpha I ordered.
Almost makes me want to swap out my original 13" kmr for an alpha.
Orangeracer
07-14-16, 23:03
Almost makes me want to swap out my original 13" kmr for an alpha.
Haha I'm sure your regular KMR handguard is just fine, but if you do ever sell yours PM me :) lol
Orangeracer
07-15-16, 13:09
I actually forgot to post the last sentence of the email I previously pasted. I thought it was worth adding. See in bold.
"In order to fill the void we have created in our customer base, we developed the Alpha as a new generation of KMR. The Alpha is identical to the original KMR in every measurable way, however it is made from pure aluminum and hardcoat anodized. The weight difference is approximately 2 ounces, generally below what an average person can perceive when comparing by hand. The other benefit to the Alpha is the hardcoat anodizing used to coat the handguard. The alloy used in the original KMR could not be anodized so instead, an aeronautic coating was applied to accomplish a similar effect to anodizing. Hardcoat anodizing Type III Class 2, which is identical to the process used on all milspec upper and lower receivers, accomplishes not only a corrosion resistant and non-reflective finish, but also, and primarily, greatly enhances the strength of the entire handguard. A hardcoat anodized aluminum piece is 20-30 times stronger than a non-anodized part of identical material composition and dimensions.
Please let us know if you have any additional questions,
Bravo Company USA, Inc"
So my magnesium KMR definately has some flex to it, is that not the case with these anodized aluminum KMR Alphas? If it's really that much stronger for the cost of just a little bit of weight, that seems like a good trade off.
So my magnesium KMR definately has some flex to it, is that not the case with these anodized aluminum KMR Alphas? If it's really that much stronger for the cost of just a little bit of weight, that seems like a good trade off.
How are you measuring/observing this? I can bend my barrels/receivers in all my free float rails. But I DO NOT think that any (KMR or Pic rail) hand guards are flexing. It's the friggin barrel and upper.
How are you measuring/observing this? I can bend my barrels/receivers in all my free float rails. But I DO NOT think that any (KMR or Pic rail) hand guards are flexing. It's the friggin barrel and upper.
You may be right, I'm not doing anything scientific, just grabbing the barrel with my fingers and pulling while I push the rail in the opposite direction with my thumb and observing some flex. I assumed it was the rail, but it could definately be the barrel, I hadn't thought of that.
I just tried it again markm looking at it from a different angle and it clearly is the barrel bending and not the rail.
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