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Can some please explain in laymans terms how free floating a barrel works?
I have free floated barrels on several of my rifles. But my mind tells me if I could support/lock the barrel on both ends, it would be stationary and should be more accurate. It seems like it would eliminate barrel whip and cut down on harmonics. But obviously, I'm wrong.:confused:
Jay Cunningham
08-04-10, 17:11
I typed "float" into the site Google search and got these on the first two pages:
https://www.m4carbine.net/showthread.php?t=43533
https://www.m4carbine.net/showthread.php?t=7766
https://www.m4carbine.net/showthread.php?t=34609
https://www.m4carbine.net/showthread.php?t=50856
https://www.m4carbine.net/showthread.php?t=9386
Jay Cunningham
08-04-10, 18:22
Re-opened after OP let me know he did not find any answers.
Thanks Katar for the links.
I'm not asking about the benefits of free float-less stress on the barrel, mounting capabilities for accessories-I know that aspect.
What if you were able to use the free float hand guard but be able to secure the muzzle end also? Would that not make the barrel even more stable? It seems that the barrel would not have the ability to move.
I'm asking if this would be a step forward or back for accuracy, or if anyone has ever attempted this.
Thanks Katar for the links.
I'm not asking about the benefits of free float-less stress on the barrel, mounting capabilities for accessories-I know that aspect.
What if you were able to use the free float hand guard but be able to secure the muzzle end also? Would that not make the barrel even more stable? It seems that the barrel would not have the ability to move.
I'm asking if this would be a step forward or back for accuracy, or if anyone has ever attempted this.
My take:
Lets assume the problem is a loss of accuracy due to barrel whip.
I think I get where you are going and lets assume you have a 16" carbine barrel. Lets use a 16" rail and pretend there is a means to attach the barrel to the end of a hand guard rail, lets assume a Larue rail and assume the mount to the upper is rigid.
What will happen is the rail will prevent the muzzle from moving, essentially acting as a 2.5" diameter barrel. In doing so, you will be transferring some energy somewhere, most likely back to the upper. I cant say that this will be good or bad. The other issue is that the gas tube is still in the barrel and there are forces exerted inside that will cause movement of the barrel because the gas block exerts force on the barrel not along the axis. The barrel will still flex and have some form of a wave action inside the barrel, just restrained at two ends and it might very well be at a much higher frequency. This may or may not cause problems as well.
Now consider that a free float tube is designed to keep the support hand from influencing the barrel. You now have direct contact again, negating the gains of a free float tube. It may not behave like jerking on the sling, but there will still be issues. You have also potentially subjected optics (and small screws) to a vibration they were better isolated from with the current set up.
The unknowns over time do not seem to address any problems (loss of accuracy due to whip) as we do not fire our next shot until the recoil has been addressed and the target reacquired anyway. So even if the barrel is cut out of a dumpster sized block of steel, the time it takes to get the next sight picture is longer than it takes the barrel to stop. I would imagine the trigger reset takes longer than it takes the barrel to stop whipping.
Okay, so vibration, regardless of how secure the barrel is, will still influence the accuracy.
Thanks for answering the question.;)
I had a 10/22 that had the stock bedded. It just never shot as well as I thought it should. I took a chance and put bedding in the front of the stock so the barrel was actually resting on it, and the groups got better. That's what got me questioning.
The 10/22 was probably a fluke.
Dave
Okay, so vibration, regardless of how secure the barrel is, will still influence the accuracy.
Thanks for answering the question.;)
I had a 10/22 that had the stock bedded. It just never shot as well as I thought it should. I took a chance and put bedding in the front of the stock so the barrel was actually resting on it, and the groups got better. That's what got me questioning.
The 10/22 was probably a fluke.
Dave
No, with the 10/22 you were using, you probably were just not exerting enough force to really move the barrel.
In the case of an AR, if it is your first shot accuracy you seek, resting the muzzle-restrained gun on anything or holding the rail will move the barrel. The better option is to not move the barrel when you support it. Second shot accuracy will depend more on your reset and second sight picture than the barrel whip, but I believe all of those are secondary to the ammo you are using. Long range type shooting isn't my game, mechanical engineering is.
Thank you for the answers. ;)
a hanging barrel is a more accurate barrel than one that gets moved around by pressure on the handguard.
if you could come up with a handguard so rigid that it was un-moveable, you could immobilize the barrel with it... but something like that would probably be too heavy to have any practical application. fortunately, simply letting the barrel hang gets the platform as accurate as it needs to be.
What got me thinking was a video I saw of a rifle being fired in slow motion. The barrel whip was unbelievable. My simple mid can't wrap around a barrel moving that much and being as accurate as a stationary one.
I talked with my buddy that went through sniper school. He explained the harmonics, vibration, ect...
I know that's the way it is, so I'll just take it as that.
High speed cameras open our eyes to vibration/harmonics big time, in all things, not just firearms. Watch an AK get shot on the highspeed, it is worse.
What got me thinking was a video I saw of a rifle being fired in slow motion. The barrel whip was unbelievable. My simple mid can't wrap around a barrel moving that much and being as accurate as a stationary one.
I talked with my buddy that went through sniper school. He explained the harmonics, vibration, ect...
I know that's the way it is, so I'll just take it as that.
As long as the barrel moves the same way after every shot. This is why a free float rail is nice to have. No matter how you hold the gun (prone, standing, resting against something, bipod, etc.) or if you add accessories to the handguard, the barrel has the same forces acting on it and is more consistent.
Dustin
The reason why a bedding pad at the end of the barrel channel on the stock makes rifle more accurate at times is because the stock is very, very flexible. As the barrel whips, the stock also whips. On flimsy stocks, the stock whips into the barrel. The whip is inconsistent causing a change from shot to shot due a number of factors. By bedding it, whether its actual epoxy or other bedding compound (which should be less temperature sensitive than the wood or plastic material), it applies constant pressure on the barrel, reducing, to a degree, impact of the whip.
That makes perfect since. It was a Houge over molded stock. Very flimsy.
Would there be any benefit to tensioning the barrel in some way? Like they do with .50 cal. MA2 ?
Yes....Volquartzen has tension barrels (for the 10/22) that are very accurate, but they are also free floated when in the stock. The old Dan wesson revolvers had them and some of the new S&W Shrouded Barrel Revolvers use them too.
One of the reasons that benchrest shooters play with overall length in minute increments (0.005) is that they are trying to hit the lull in the barrel vibration as the bullet exits (top or bottom of the extreme travel). At that point, the barrel stops moving for a microsecond before switching direction. If the bullet exits in the middle of the vibration/barrel sine wave, the muzzle is moving its fastest, and you get inconsistent groups.
As you touch a barrel, you affect the harmonics diferently every time, so your groups will be inconsistent (many factors affect the degree of change). If you have a free float handguard you can't affect the barrel harmonics, and you allow the barrel to work its best. OAL still plays a part, but if you are buying your ammo, you are stuck with whatever OAL the factory uses. If you handload, you might be able to improve your groups.
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