XM8 Assault Rifle

I’ve mentioned before that the biggest search engine draw to MO has been the XM8 assault rifle. Stryker searches bring in a lot, as well, but I’ve got an entire category devoted to the new combat vehicle and only one post about the new rifle.

Folks must be desperate for info on this baby. For a basic intro to the XM8, go to my previous post.


The XM8 (M8 if it’s adopted) assault rifle is a proposed replacement for the current M16 rifle and M4 carbine, the standard infantry weapons in today’s US military. The XM8 action is based upon the Hechler & Koch G36, a tried and true infantry weapon with a reputation for toughness and reliability. The XM29 OICW, which combined both an assault rifle and a smart grenade launcher, turned out to be too heavy, fragile, and expensive. The rifle part of the XM29 was adapted to become the XM8. The smart grenade launcher part of the XM29 is being developed separately as the XM25.

xm8b.jpg The XM8 is a modular weapon that can be adapted to different roles fairly easily. It can use any of four barrel sizes: 9″, 12.5″, 20″, and heavy 20″.

The 9″ barrel makes the weapon a submachinegun-like personal defense weapon (called the Compact Carbine) that would be ideal for vehicle crews. Also, I imagine that Special Forces types would find it useful for urban raiding missions and the like. With the buttcap (as pictured on the right, second from the top) it is less than 21″ long overall.

The 12.5″ barrel is the standard set-up, and with the adjustable buttstock, makes the Baseline Carbine variant. With the stock fully extended, it is 33″ long, the same as an M4 (which has a 14.5″ barrel). It weighs in at about 6.4 lbs, with a goal of being reduced to 5.7 lbs. The M4 with comparable accessories weighs nearly 9 lbs. The pic at right shows an XM320 side-loading detachable grenade launcher mounted.

There are two versions of the 20″ barrel. There’s a standard weight match-grade unit for sharpshooter work and a heavy-duty machinegun unit with a folding bipod for use as a sustained fire automatic rifle.

The XM8 seems to be an aberration in the military procurement sector. It is a model that seems to improve upon its inspiration in terms of cost and weight, while sacrificing none of the qualities that made the original so good. An XM8 Baseline Carbine, with its integrated sight, will cost around $1800. An M4 equipped similarly costs over $2500. That translates into a savings of $2.4 million to equip a 3,500 man brigade.

Cost notwithstanding, the biggest advantage of the XM8 over the M4/M16 is almost certainly the new weapon’s durability and resistance to jamming. The manufacturer claims that the XM8 can fire over 15,000 rounds without lubrication or cleaning, even in harsh conditions. While I seriously doubt that those numbers would translate into the field, it is indicative of the weapon’s reliability. The BARREL LIFE of an M4 is rated at 8,000 rounds.

The XM8 achieves this phenomenal reliability in part due to a unique gas-operated pusher-rod operated bolt. This system does not send carbon gasses into the receiver with every round like standard weapons, and therefore reduces greatly the amount of propellant that could potentially foul the action or attract material that could. Additionally, the seal between the bolt and the ejection port is much tighter than in current weapons, which will limit the amount of crud that can get in that way. Also, the weapon can be fired even if the action is flooded with water. No draining required.

While I doubt any squad leader would ever allow anyone to go an extended period of time without cleaning their weapon, regardless of manufacturer’s ratings, there is a fair amount of time savings still to be found. First of all, the XM8 can be field cleaned in 4 minutes. This compares to more than 10 or 12 minutes for an M4, which translates into a an extra bit of rest, patrol, or other duties for the XM8-equipped soldier. Weapons are cleaned at least twice daily, if not more, so this 5-8 minute savings is not insignificant when multiplied by three thousand soldiers in a typical brigade. Also, the integrated sight is zeroed-in at the factory and does not require continual re-zeroing in the field by the troops.

Dirty and jammed weapons seem to have contributed to the defeat of the maintenance group that included Jessica Lynch during the invasion of Iraq. Part of the problem seems to be that the Army-supplied cleaning lubricant isn’t effective, especially against the fine Iraq sand. But non-combat units probably don’t devote enough time to cleaning and maintaining their weapons. The XM8 could help alleviate that by reducing the time required to complete the task, which will increase the odds that the task is attempted, and by being more forgiving if/when the task is forgotten or ignored.

Another nifty feature is the ability to be quickly adapted to fire AK-47 ammunition. This would be especially useful in Iraq, since there’s more AK-47 ammo in Iraq than there is sand.

For a comprehensive comparison of the XM8 Lightweight Modular Weapons System (LMWS) Baseline Carbine to the current M4, check out this .pdf. Keep in mind that it was published by the manufacturier of the XM8.

For an 18 second video of a full-auto firing of the XM8, check this out. HK-USA also has what amounts to a product brochure for the XM8 here. It includes drawings of many of the interchangable components of the XM8 system.

The XM8 has recently finished heavy testing. The next step is going to be to equip two full brgades with the weapons. I’ve been unable to learn which brigades get to be the lucky ones to try a new standard weapon out for the purposes of working out all the bugs. Maybe they haven’t been determined yet. I’d suggest that, in addition to the the big tests, some individuals or small units deployed in Iraq and Afghanistan get them. We must learn how these things really perform, and no amound of testing and simulation can teach as many lessons as a few minutes on a real live battlefield can.

For all the apparent good news surrounding the XM8, one basic issue remains the caliber of round our troops need to be firing at the bad guys. The XM8 will fire the NATO standard 5.56x45mm round, the same as the M4 and M16. There is a lot of grumbling among the troops that this round is insufficient, especially when fired from an M4’s shorter barrel. The standard XM8’s barrel is two inches shorter than the M4, so this issue will be even more pronounced.

This is a very controverisal subject, with feverent believers on both sides. Many who think that a larger round, like the 6.8mm or the good ol’ 7.62mm, is needed admit that the 5.56 might be sufficient if the type of ammunition was altered instead of the size. There have been many reports from Iraq, Afghanistan, and Somalia that the current round just doesn’t cut it. I don’t know enough to have an opinion on the matter, but it certainly seems that something needs to be done.

Airborne Combat Engineer had a post back in November about the XM8 and the ammuntion debate. He notes that we’ve already got so much refinement and investment in the current M16 and M4 that it seems like a waste to start over with a new weapon. He asks why the current weapons can’t just be up-gunned with the new 6.8mm uppers that will soon be hitting the market. That’s a very good question, and one that I hope our military seriously considers.

Back in August I thought the same thing. But, if the XM8 performs in the field like it’s performed in the tests, we might be better off in the long run if we make the change. The cost, reliability, and adaptability of the new weapon may outweigh our experience with the current one.

UPDATE: A Sliding stock for XM8 compact carbine PDW has been added to the mix. Pictures and more.


  1. YEs i agree with travis.How could the XM8 fail, it can do so many things and is really reliable. I watched all the test clips about the Xm8 on how its easy to assemble, attatch a grenaid launcher and so on. Cmon the army would be fools if they didnt adopt the XM8. On one of the clips it shows the the Whole gun coverd in dirt and it still fired also when the gun was submerged in water it still fired when the gun was all wet.

  2. Not sure on all of the tests, but it did fail one that would of mattered the most. The body of the gun started to melt when it was being continually fired. Which anybody know wouldn’t be to good in combat. When I first heard about the gun I did a research paper on it. But now that I hear all this bashing about it. From other people that have known things for a lot longer that I. I start to think that this gun just might not be all that it’s cracked up to be. I know that H&K is a very successful company in the businness of coming up with and producing weaponry for military use. But they may have made a few errors in the design of this weapon. WE NEED A NEW WEAPON FOR BASIC INFANTRY!!!

  3. Matt: As far as that ‘melting’ failure you mentioned, that happened in early April 2004 and was addressed in the next-revision. Not sure what the current status is, though.

  4. Yes, I did mean the plastic body. I’m not sure either if they fixed the body problem. Murdoc, What would you say they should replace the current weapon M16-M4 series with? I heard someone say it should be the SCAR-L, on this forum. Do you think that would be a good weapon for the infantry?

  5. I posted something about the SCAR-L before and said that the SCAR-L looks clumsy and to chunky for a infantry weapon or special forces

  6. Scar does look chunky the M4 is fine until a new assault rifle is ready i like the Xm8 as long as when im in the army it doesnt melt in my hands like a choclate bar in afghanistan did anyone c that newer XXX (not porn) they had the XM8 in it and put on a grenade launcher for a M4 on it little mistake on the producers part

  7. i think the person who said about the changing to a bullpulp desighn for the xm8 would be an excellent idea.

  8. i had a intesting discussion about that a while ago well right now the XM8 has all those features on the trigger gaurd to drop the mag and release hammer they would have to some how move those to the back and i think its harder to reload a bullpup design weapon like the L85 the british use i have a airsoft gun of that and u have to move the gun around in weird positions to reload it but ya it gets a longer barrel for the size but i dont think its worth it cause all the fighting we are mostly doing now is urban so a gun that accurate isnt really needed when there that close

  9. oh right cool thanks mate hay this site rocks and hay talkin bout the L85 family for the british army i think that it is a terribal weapon which is very unreaible. the britsh goverment is silly not to change the the german H+K G36.

  10. thats wat i was saying its annoying to reload and the H&K series of guns are really good except 4 them trying to capitolize on COLTS M4 that was stupid and annoying it went to a law suit and crap

  11. I reckon the best guns to this day sre most likely the M4 carbine and the H&K G36. Oh yeah i would like to know whats the difference between a NATO round and a basic round. Plz post something about it. thanks

  12. oh yeah i think some one already posted this but it is said that the xm8 can fire 7.62 mm ammunition like the AK-47 kalishnikov. Correct me if im wrong.

  13. To my knowledge I don’t think it has ever been able to shoot 7.62mm, but there is a possibility of me being wrong. I don’t think there is any difference between NATO and regular if that’s what you want to call it. I was looking on H&K and saw what looks to be a new series of the G36. It’s the G36-C. This weapon is very compact, and I think with a little longer barrel and some fine tuning. This could be a future competitor for replacing the M-16, M-4. Comments?

  14. The G36-C has been around for a while and has been in service for several years. Germany’s special forces and German Tactical police use the G36-C. C meaning cut-down or smaller version of the original G36.

  15. does anyone know weather american special forces use the xm8 or are going to be ? because i keep on seeing it featured on special forces computer games.

  16. does anyone know weather american special forces use the xm8 or are going to be ? because i keep on seeing it featured on special forces computer games.

  17. there planing on using it if the weapon checks out like they think that it is a combat effective weapon 4 example the M-16 was very good on the range but when it was sent to vietnam it was very bad due to jamming and also the NATO round is 5.56 and also 7.62 which is the NATO machine gun round all other rounds are the wierd ones no one cares about like some of the chinese odd ball sizes like 6.something i forget and also like a P90 uses a 5.7 and a NATO round is just so if we go to war that all of NATo is uses the same round so that we can help eachother out like if germany goes to war and needs aid when american assistane comes in we would have the ammunition they need its just for versatility and fuctionality these rounds have been proven ime and time again in diffrent weapons so there here to stay

  18. The two things I think thexm8 does are it address the gas system which is a factor of firing failures in the field, and the upper conversion for the m16 which in the begining will save the govt. a lot of money. The shell used as long as its close if not a 30 cal. should be decided by military ballistic experts and not lay people .

  19. The two things I think thexm8 does are it address the gas system which is a factor of firing failures in the field, and the upper conversion for the m16 which in the begining will save the govt. a lot of money. The shell used as long as its close if not a 30 cal. should be decided by military ballistic experts and not lay people .

  20. this is a blog where us lay people can talk about these things we arent making the descision 4 the weapon were just talking and r u some ballistics expert who gets to speak about the gun?

  21. So how come no one isnt adding posts about the weapon anymore its been a couple of days already and no one had added anything new yet. Except travis who has a good point.

  22. It’s not like were going to have any effect on anthing having to do with the weapons these companies produce or w/e. But I guess it’s somewhat pleasant talking about them.

  23. I have to disagree it looks and sounds not much different from the H&K G-36 series which my police force uses. We have seen the G-36k reach out to 400m. Also the XM8 if you read up on it has a sharpshooter config for long range firing specifically. Of all the versions they range from 12.5′ to 20′ and theres no knowing what length the standard rifle will be for the military. These are simply the variant designs they have made for this single rifle so it can be field striped and parts changed to make it into any one of these designs in minutes. So debate all we want if it performs like or better than the G-36 then I’ll take one in a heartbeat. Every ex or retired military person I meat that joins the police force falls in love with the G-36 over the M-16 or AR-15. Its way more accurate especially with the red dot system. So the XM8 I have to say I will love it if its comparable to the G-36.

  24. Actually just to let Edward know the last I heard was 10k where with the marines being field tested. But H&K decided it was anything radically different than anything they already make so the rumor is they are being recalled and that production of the 416 I believe is being doulbe for the US. I hope this isnt true but who knows.

  25. and something im just throwing around is y the XM8 does not have a special special forces for close quarters i have a M4(airsoft)but still real size and i love a 2nd handle on most guns with 2nd handles (G36C)I think are more comfortable and alot better in close quarters which is becoming the mass of our battles these days with the war on terror we are within 20-50 feet of the enemy so sorry to say who cares if u can hit him at 500m if hes that damn close i mean in a war yes that range is wonderful against some guy who cant aim a kalashnikov but when ur that close monuverability is key and i think they need to make a special forces model and just like the 203 grenade launcher system it should just slide on when u take off the fore arm and does anyone think that they will make a bayonet 4 the XM8? many people thought having 1 4 the m4/m16 was stupid because there not supposed to get that close yes i know it is just a knife with a loop on it.

  26. For all you who think that H&K ‘can’t make a bad weapon,’ they can and have. First off, the Mk23 pistol is going to be replaced in the near future w/ our SOF teams because it is too big and heavy and unsuitable for its role. The XM8 failed many tests, the worst of the bunch being the melting of the plastic and a failure in the gas system. Rather than correct the problem, H&K (according to a soldier I talked to) denied it. Because of the problems we had in Vietnam with the early M16s, we were not about to put a defective rifle into combat. Improvements were finally made, but the rifle has reportedly no advantage over the M16 now that new gas systems are being put on many M16s. The XM8 may, just MAY, be in the running to replace the M16 in the future, but it is highly unlikely. At any rate, it will take a superb rifle to replace the great weapon that has served our nation for over 40 years! For those of you who haven’t shot an M16 series rifle before, it is solid weapon. I’d trust my life to it in combat!

  27. I guess the xm8 is a pretty shitty weapon. If that’s the kinda words you people think of when you refer to the weapon. I used to like it before all of the failed tests. Not sure anymore. I still think we should be coming up with a new and improved weapon. I mean we can’t just stop here because we think it’s the best. There’s always room for improvement. I mean look at our technology in this day and age. It’s amazing, well kinda. But I think we can come up with something better to knock the pants off of our rival nations. And once and for all show them that were always going to be No.1

  28. i think that we shouldnt scrap the XM8 it looked like a great weapon and we have scraped alot of promising projects 4 a few failures for instance the comanche was going to be the most frikin awesome helicopter ever and they scraped it and for u that dont no what the comanche is it was a stealth helicopter yes u read correctly stealth small radar cross section and low heat signature the m16 was so shity when it was first made so i think they should push through these problems get a better material for the shell so no melting fix minor internal probs because i like the XM8(if it were more reliable) the M4 is cool 4 now

  29. I think H&K should invest more money in there new weapon projects and make sure they dont skip any important parts for example the XM8’s plastic shell. You cant place a price for a soldiers protection.

  30. I just read those comments from Mike. What a disgrace, he is obviously some misguided Muslim, pretending to be a westerner, although there are those western lefties who speak that crap. On every argument he is totally wrong. About the Israelis and who gave the they’re land back to them, on the US in Vietnam- everyone knows the US won the battles, on everything. At the end of the day, anyone who can defend a cause or group/s that includes killing innocent civilians as part of they’re agenda deserves no part in human society. As far as Im concerned they are just as bad as those that commit such crimes.

  31. Hey Aussie what are you talking about. And travis, yeah i am talking about the plastic melting. I dont even know that the XM8 had problems when it falls on the ground and doesnt work.

  32. Hey Aus what are you talking about. And travis, yeah i am talking about the plastic melting. I dont even know that the XM8 had problems when it falls on the ground and doesnt work.

  33. Travis i was refering to the melting plastic and does the XM8 have a problem when the gun is droped or something.

  34. no i was asking cause u said there plastic shell i didnt know if it was weak or if it was the melting but i havent heard that it breaks being fallen

  35. yeah i dont know if the gun brakes if it hits the ground but like i said b4 all i know is that the XM8’s plastic melts when it is fired in full auto.

  36. well travis mentioned earlyer about the comanchi and how good it was well i do think that it did look good but it just wasnt practical and it also couldnt hold half as many weapons as the current apachi can so it was doomed from the start really.

  37. Hey travis i think the military scrapped the F-22 raptor because of costs. I heard that the F-22 was in the sum of cloose to a Billion dollars per fighter. I think my onfo is right if some one knows the exact price well then correct me.

  38. Yea, Murdoc is right. I don’t know where you got your info Michael. But he’s right, I knew also that they didn’t scrap the F/A-22. I don’t think they ever will. Now I agree that the cost is astronomical, but you also have to think. The more this world increases in technology. The more we have to stay ahead of everyone. Even if that means spending greatly. this jet alone i’ve seen take on five F-15 fighters with no problem whatsoever. The F-15 pilots said afterward that they never even seen the F-22 Raptor. Only heard it speed past them,lol.

  39. The F22 has the potential to be a great fighter, but I think it will be awhile before it sees any air to air combat, which is what it was designed for. There’s no enemy nation with an air force that can compete with ours. I’m glad they scrapped the Comanche though. What a waste of taxpayer money that was! They wanted to replace the Apache, which was still brand new and still the greatest attack chopper in the world. I believe in the old saying ‘If it ain’t broke, don’t fix it,’ although the government seems to have the philosophy of ‘If it ain’t broke, fix it till it is.’

  40. They wanted the comanche, because it was stealthy. And thats what’s happening right now. Were getting stealth everywhere to cut down on human lives. Like with the F/A-22. It’s stealth. GET IT!

  41. ok im not sure y but i posted a scenario idea for the comanche but its not here so here it is again ok thers a spec ops team sent in to take out a SAM that is french made and has powerful enough radar to detect a B-2 so the special orces move in on the radar station when they recieve heavy fire the ask for support but we cant send anything cause the SAM is still there well a comanche can fly right over the ground and come in and help suppress the enemies yes a Apache can fly low to but is vulnerable to shoulder fired stinger launchers which are very portable wher as the comanche can fly under the strong radar and not have to worry about stingers the F-22 and F-35 are great aircraft the F-22 actually i saw on the discovery channel take on 8 F-15’s and still won and the guy that was killed first said nothing was on radar and then he was dead and the F-22 flew right over him we have ordered 300 F-22 and with results like that, that means a squad of like 2 F-22 could take out 10-15 migs(not a actuall number just guess) because migs arent as god as F-15’s the only aircraft that poses a minor threat to a F-22 is the Euro fighter that also has super cruise and very advanced air to air combat features with a AWACS a F-22 could be brought down to a better playing field but still not equal the F-35 is also a great multi roll aircraft having 3 models 1 for the marines the VTOL model to replace harrier another fo the navy to replace the F-18 which doesnt need to be replaced but ok, which is a multi roll aircraft a fighter bomber and also a more bomber model for the airforce has anyone seen the planes for the FB-22 looks awesome haha talking about aircraft in a assualt rifle blog hehe

  42. Yes, let’s get back to assault rifles…anyway, what the military needs to do is look to improving and enhancing what we have rather than buying something entirely new. What we have is the top of the line in the world, but there is always the need for improvements; we’d be foolish if we thought otherwise. The most reliable and favored weapons in the military are the older ones anyway, i.e. the M14, the M16, the M2, 1911A1, the C130 Hercules, the Pave Low, etc. you get the point. The M2 is approaching 80 years and the 1911A1 is nearing 100! And yet, they are still not obsolete. The league of paper pushers, videogamers, and armchair generals seem to think the military should be armed like this: The XM8 in 6.8mm with the Land Warrior system for the roles of submachine gun, assault rifle, sharpshooter, and SAW until the OICW can be perfected. The XM312 as the heavy machine gun The Comanche as the primary attack chopper. The soldiers consensis is something like this: The M16A4 for the primary assault rifle. The M4 for CQB The M25 or SOPMOD M14 as the DMR The M249 or the Mk48 as the SAW. The Apache as the top assault helicopter. As we are fielding all these weapons already, it seems that for now, we don’t need to spend a billion dollars for a change.

  43. well thanks for correcting i always assumed they scrapped it because of the price and i thought that the F-35b took over the skies.

  44. america is supposed to be the top of the line military if we start falling back on old weapons it will make us look cheap i do like alot of the older guns like the M14 and 1911 pistol but we stoped using those because of weight a combat ready soldiers pack can way around 80 pounds now does he need to go up 10 pounds for those older weapons cause some paper pushers dont want to spend the money we need new weapons to keep the massive edge we hae over other militaries if u havent noticed europe is right next to or just behind us on alot of military things there aircraft and tanks are behind us but the G36 is much better than the M16/M4 we need to get the infantry edge back the German leopard 2 is literally almost as good as the abrahms and the british tank(forgot name sorry) is right next to the leopard the french tank is behind all of them and the euro fighter is already in service and already has super cruise where as our F-22 which could kick its ass is just being deployed so we cant fall back on old weapons is what im getting at the XM8 is going to be a great weapon once they fix its problems hay look at the First M16 of vietnam it was a piece of crap the only thing that it had going for it was that it was light and accurate but in vietnam u werent having long range battles u need a weapon to do the job or the war of the future not past yes the M14 is still used by special forces and law enforcement but we need a new assualt weapon that is lighter and better than the m16

  45. Oh yeah travis do u know how u said that europe has has the super cruise jet fighter, The U.S has nothing to worry about because that plane was designed as a joined operation which involved the U.S government and some of the ueropean Gorvernments.