Just posted on the original XM8 post

Skyhawk12k comments on a post from August of 2003:

I used to work for the coroner’s office in Riverside, CA, and I’ve seen the damage of 7.62 and the damage of a 5.56. Give the troops the 7.62 and they WILL stop any and all.

Works for me. Seems to be a general consensus that the 5.56 isn’t the answer. But the decision-makers don’t seem to see it that way.


  1. On the topic of the XM8… I read somewhere that HK will be using the relatively ‘new’ polygonal rifling for the XM8, and apparently this’ll lead to higher muzzle velocities from a given cartridge and barrel length (this is due to less of the chemical energy of the powder being used to deform the bullet into the rifling and more of it going into the bullet’s kinetic energy). Whether this makes up for the fairly short barrel of the baseline XM8 carbine I don’t know. I’d like to see some comparison tests done on a couple different cartridges fired from conventionally and polygonally rifled barrels. I’m slightly dubious of polygonal rifling being a substitute for an extra 2-3 in of barrel, but I’d like to be proven wrong.

  2. I wonder if anybody has looked at a magnum 5.56mm round (longer, but the same diameter, so the same number of rounds can fit in magazines. The longer shell would enable a heavier bullet at the same velocity OR a faster bullet at the same weight, either of which would deliver more terminal damage at even longer ranges. The receiver would only have to be, say 1/4 or 3/8 in. longer, which would add negligible weight. A burst of three slightly heavier 5.56mm bullets might have the same or better probability of deactivating a ragtag as a couple of carefully aimed shots with a 6.8mm SPC. There would be some risk of having an ‘overbored’ cartridge which would shorten barrel life, but if the barrels are chrome-lined, the impact should be less than 10%. Consider the relative power of the .357 magnum vs. the slightly shorter .38 special, both of which fire the same diameter bullet. Just a thought, off the top of my head. If I’m wrong, rip into me.

  3. PS to previous comment: Obviously, a very fast burning powder would be necessary for the 5.56mm Magnum round, to avoid wasted powder, excessive flash, reduced velocity, and reduced terminal ballistics in short barreled assault rifles, which are all the rage these days. We have the best chemists in the world, except for the Germans, and they’re quite willing to work for us. Given the challenge, they can develop a faster burning powder. ;-) Also, I should have noted the chamber pressure might be higher, in which case a somewhat heavier barrel end and bolt might be required. A 5.56mm Magnum rifle might have to weigh a pound more. BFDeal.

  4. faster burning powder? I seem to recall, vaguely, that the xm-8 development included not just rifle development but changes in the powder of the 5.56 as well. (and changing the brass casing to graphite or somesuch)

  5. Hey what’s up with bullpup? France and England are using them and Germany would have used the G11 if it hadn’t been for the collapse of the wall. As far as I can see it makes a lot of sense, shorter weapon/same barrel length. So why don’t our guys want to use ’em?

  6. I used to work for the coroner’s office in Riverside, CA, and I’ve seen the damage of 7.62 and the damage of a 5.56. Give the troops the 7.62 and they WILL stop any and all. I find it hard to believe that people are killing each each with military rifles. I worked as a cop in large city that was once the murder capital and saw that most homicides were commted with a handgun. Its kind of hard to walk around with a rifle and not be noticed

  7. It’s Riverside county, lots of people have military rifles, and many times when someone is killed with one, it’s usually the result of too much alcohol, combined with stupidity and loaded rifles, and not so much a pre-meditated thing.

  8. The 5.56 magnum cartridge discussed above is not feasible militarily. The entire point of the 6.8 mm SPC is that it fits in the same magazine well, and is not 3/8 or 1/4′ longer than the current round. The military, if it changes cartridges, wants one that will fit in the same length, and then it can just modify the upper receivers of the M-16 series rifle. You don’t need whole new rifles then. You just remod, and then you don’t have to spend as much. That’s the whole point to developing a new round. It has to fit in the 5.56 mm magazine well.

  9. I’ve actually shot a bullpup gun before, and I really like the way they feel. But when you shoot straight or up, the action goes down, so every burst or shot you los some feel of the gun becauseit tends to slip on the shoulder. But for CQB and for rooftop cover, you can’t get any better than a bullpup.

  10. The bullpup configuration is O.K., but you have other issues then. Try firing one left-handed, they all have right-side ejection. Right in your face. Also, the Brits have had reliability issues with their first generation. I’ve heard the Famas is reliable, and also the Vektor from S. Africa, and I think Singapore makes a good one, as well as Austria. However, the problem is not in the configuration, it’s in the caliber. The 5.56 mm just doesn’t leave a large enough wound channel. Hollow point rounds might help, but the Geneva/Hague conventions say those are a no-no. We NEED to go to a larger round.

  11. No, The hague conventions clearly specify that these types of rounds are not to be used. If they are being used, I don’t really care. There isn’t one insurgent that’s worried about following the Geneva/Hague conventions. I say that until they start following them, forget the Hague conventions. We should still abide by the Geneva conventions, I mean we are the good guys. But that Hague crap needs to go. Now, the government of this great country has decided that we will abide by both the Geneva and Hague conventions. Therefore, the bullet design is to provide more fragmentation, rather than greater expansion. The round we are using is not a ‘hollow point’ round. It has a point, and uses different materials, and a great deal of ballistic science to cause it to tumble and fragment. I just shut up and soldier.

  12. I say we just go back to 7.62×51. With current weapons technology we could get rid of most of the perceived recoil, and get better range and damage potential. Yes, the rounds weigh more. Oh, shucks, the extra 2.4 pounds it would add might just kill me. Combat load is so much already, give me a lighter helmet, lighter chem suit/gas mask, lighter body armor, and lighter radios, that are still effective, then I’ll worry about 2.4 pounds.