I think it’s well enough established that a free float handguard can improve on the precision of an AR because it reduces the number of factors that can affect the barrel, thus reducing variability in “barrel harmonics.” In other words, it reduces the amount of contact the barrel has on other objects which can change the way the barrel vibrates and moves. These minor changes affect the path of the bullet and reduce the precision of the rifle.
Is it possible that different handguards and different methods of mounting them affect precision as well? If such minor effects on the barrel change precision significantly (statistical significance, not practical), it seems probable that differing methods of mounting a handguard as well as the physical properties of the handguard itself can affect precision. Has any testing been done on this matter?
I am sure it does. Many precision upper builders only want to use their hand guards for that very reason. I am sure they have learned through experience what worked for them. I would like to see that testing if you find it.
another thing precision upper builders recommend is a clamp on gas block because the stress is evenly distributed around the barrel. Set screw and pinned gas blocks create point stresses. In fact I have read that set screws can even make a bulge in the bore of the rifle. You know that would effect accuracy.
I’m no expert, but as I understand it the barrel nut is more of a factor in accuracy. So to answer your question…technically, yes. But only insofar as they use different barrel nuts.
A nut that doesn’t require timing for the gas tube will allow you to achieve more favorable torque values. I can’t find any non-anecdotal evidence, but it’s generally accepted that tighter barrel nuts decrease accuracy, albeit marginally. Most shooters probably wouldn’t notice.
On my accurized rifles I went with an Aero Precision M4E1 upper so I can torque the barrel nut to any number I choose and don’t have to mount the handguard to the barrel nut. I’m probably not a good enough shot to notice though.
I’ve read this as well, though I really wonder how you could apply enough torque to such a small set screw do to this. Perhaps this is one of the reasons some builders use green loctite on the surface where the gas block meets the barrel… so less torque is needed to keep the block in place (i’d also read something about loctite dampening different harmonics between the block and the barrel).
More correctly, a FF tube can improve the consistency of an AR by isolating the barrel from external influences and letting the barrel vibrate naturally.
Pinning a gas block with a pin too large for the hole can cause bulges inside the bore. It’s also a problem when driving tapered cross pins in too deeply. This is why I prefer cutting an FSB without removing it from the barrel. Installing tapered cross pins does swell the hole a bit. That’s what holds the pins securely in place. Remove the pins and the holes will be lightly larger than when the pins were originally installed. To get the re-installed pins tight again, the pins have to be driven in a little deeper, increasing the possibility of causing a bulge. Set screw can also cause bulges when the barrel is dimpled too deep and the screws installed too tight. One has to be particularly careful when the barrel is only .625" at the gas block.
Barrel harmonics is a whole other subject. There are three ways to get a rifle to shoot good-
Find ammo that matches the harmonics of the barrel
Tune the barrel harmonics to match the ammo
Deaden barrel harmonics so it shoots well with nearly all types of ammo
Never. Haven’t you heard that M4 barrels are inherently more inaccurate because of the M4 cutout for the grenade launcher? That weak point causes the barrel to flex unnaturally at that point, throwing the bullet off trajectory :suicide:
Surely, you speak of the collective “you”, to include anyone out there shooting.
Ken Hackathorn once made a comment in a newsletter directed towards the membership of this forum and the type of shooting in which is emphasized here, that goes like this…
Practicing at the range from a bench rest or prone is great for zeroing or testing loads. Otherwise, shooting from a bench or prone is just like masturbating, you get the rounds off, but not the real thing.
Now I can understand how three gun and pistol competition could be a lot of fun. My problem is I am old and fat and certainly not nimble and quick.
I have been shooting all my life and never owned an AR till a couple of years ago. Bought one on a whim. That gun is a blast. I was like a kid with a new .22 rifle.
After reading a bunch about them I decided to build me one. I am hooked for life.
that said for me the only really interesting gun is an accurate one! Lots of details have to come together to create small 5 shot groups consistently. Now that is a challenge to me. Believe me compared to a bolt gun getting an AR accurate is challenging.
I really don’t understand the fascination many have for the M4 battle rifle. Not very useful for hunting, not very accurate and I doubt very many of the people buying them will ever take them into combat. Guess like I did when I was a kid its fun to dress up and play army.
When you say that they are not very accurate, what does this actually mean? Also, how they are not useful for hunting? Can I not kill a coyote with an M4???
When I am doing a precision build, I seek out barrel nuts like those from Geissele and BCM where the barrel torque value is set at 40LBS. Squeezing the receiver is never a positive thing IMHO. With that said, there are more important aspects to accuracy than the barrel nut torque value.
I would say the average m4 grouping at 100yrds is 2 to 3 inches. Oh I am sure I am going to hear about all those .25" AR’s but they sure aren’t posting targets in the MOA Challenge.
Makes a fun varmint rifle
Not for whitetails and mulies and elk and other medium and large game.
The AR15/M16/M4 family of weapons wasn’t designed to be a hunting gun. It was designed to kill people, just like the AK47. It doesn’t mean that it can’t be used as such. I am not a hunter, and don’t care about hunting at all. One thing I can tell you is that when people are hit with a bullet and fall down incapacitated and or die, they could give a shit less if that group was .025 MOA or 3 MOA.
If you think that is ineffective, you would be surprised to learn that there are a lot of dead people no longer breathing oxygen that will attest to it’s effectiveness. As for people dressing up and playing Army, it might also surprise you to learn that there are a lot of legally armed civilians who use them for personal and home defense. When I am on the road I carry an M4 of sorts in my vehicle ready to go. Quite simply I want something practical and more effective at putting down people than a handgun. YMMV