What's the benefit of a free float rail system for my M4?
- Thread starter Citadel99
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TrapperReady
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Not 100% sure... so I hope some others chime in. My guess is that having a rail system free-floated is similar to having a float-tube installed on an AR designed for highpower or varmint shooting. When using a float-tubed gun, the stresses imparted to the sling (which can be quite a lot) are not transmitted to the barrel.
I would bet that a free-floated rail system would be similar in operation. It would keep the stresses of the added weight of accessories from being transmitted directly to the barrel.
In my mind, that would make sense... but I would also want to know a few more things about it. For example:
1) What effects does the system actually have upon accuracy?
2) How much weight does it add?
3) Is the particular model known for being well built? (I throw this in because there are a lot of float-tubes out there, and some are subtantially better than others).
4) Will having this system screw up anything with your unit armorer?
Personally, I never used anything other than a standard-issue bone-stock M16A1 or M16A2... so I'm a bit behind the times, aside from shooting some highpower the past couple years.
In any event, I hope your choice works well for you during your deployment. Good luck!
I would bet that a free-floated rail system would be similar in operation. It would keep the stresses of the added weight of accessories from being transmitted directly to the barrel.
In my mind, that would make sense... but I would also want to know a few more things about it. For example:
1) What effects does the system actually have upon accuracy?
2) How much weight does it add?
3) Is the particular model known for being well built? (I throw this in because there are a lot of float-tubes out there, and some are subtantially better than others).
4) Will having this system screw up anything with your unit armorer?
Personally, I never used anything other than a standard-issue bone-stock M16A1 or M16A2... so I'm a bit behind the times, aside from shooting some highpower the past couple years.
In any event, I hope your choice works well for you during your deployment. Good luck!
DevilDog
Member
A free float rail system will improve your accuracy. But unlike a full size tube on a high power rifle, there are other reasons for one (with rails) on an M4.
A vertical foregrip that attach to the handguards is not as strong as one attached to a free float handguard. In my limited research, it does seem that a vertical foregrip attached to handguards fails more often than one attached to a FF forend. Not a big surprise since M16/AR15/M4 handguards are not all that durable.
It is not practical to put any kind of red dot sight on the hanguards - you won't keep anykind of zero. But you can get away with putting one on a FF rail tube (although some advise against it). This can be important if the only rear iron sight you have is the detachable carry handle and you always want that rear sight available for use.
Lasers/lights are sturdier on a FF forend, but this advantage is minimal, imho.
One con - for an MR sized weapon, the FF forend will weigh (very rough guess here) anywhere from 8-12 oz, depending on the make.
A big plus for a FF forend I would think would be heat when it comes to high volume fire. Especially with a vertical grip added.
My general recommendation is that unless you are really trying to keep weapon weight down, get one.
I hope that helps. No doubt there are others out there smarter on this than I. Hopefully they will join in and confirm or debunk some of my info.
A vertical foregrip that attach to the handguards is not as strong as one attached to a free float handguard. In my limited research, it does seem that a vertical foregrip attached to handguards fails more often than one attached to a FF forend. Not a big surprise since M16/AR15/M4 handguards are not all that durable.
It is not practical to put any kind of red dot sight on the hanguards - you won't keep anykind of zero. But you can get away with putting one on a FF rail tube (although some advise against it). This can be important if the only rear iron sight you have is the detachable carry handle and you always want that rear sight available for use.
Lasers/lights are sturdier on a FF forend, but this advantage is minimal, imho.
One con - for an MR sized weapon, the FF forend will weigh (very rough guess here) anywhere from 8-12 oz, depending on the make.
A big plus for a FF forend I would think would be heat when it comes to high volume fire. Especially with a vertical grip added.
My general recommendation is that unless you are really trying to keep weapon weight down, get one.
I hope that helps. No doubt there are others out there smarter on this than I. Hopefully they will join in and confirm or debunk some of my info.
I have more questions... (pretty dumb too, I supposed)
a) It seems that a lot of folks have vertical grip attached on the FF rails. What's the benefit of using one?
b) From regular rail that I have seen (not on a FF handguard), some of them is pretty sharp. Would that mess your hand up? or ones from the FF rail is not as sharp. May be this is the reason why one would want a vertical grip.
I also noticed multiple length... carbine, mid-length, Spectra?, full-length. I think I know about the carbine, and the full-length. But what about the mid-length, and Spectra? Are they the same length? What is the length for these?
Can I install one of this FF rail myself?
TIA
-Pat
a) It seems that a lot of folks have vertical grip attached on the FF rails. What's the benefit of using one?
b) From regular rail that I have seen (not on a FF handguard), some of them is pretty sharp. Would that mess your hand up? or ones from the FF rail is not as sharp. May be this is the reason why one would want a vertical grip.
I also noticed multiple length... carbine, mid-length, Spectra?, full-length. I think I know about the carbine, and the full-length. But what about the mid-length, and Spectra? Are they the same length? What is the length for these?
Can I install one of this FF rail myself?
TIA
-Pat
shoobe01
Member
Bartholomew Roberts
Member
I'm running a free-float KAC RAS on my rifle. The main advantages of the free-float is that the barrel is now independent of the handguards, so adding accessories to the rails, torquing hard on the sling and other changes don't affect your zero.
On my own personal shooting, a free-float let me tighten up my groups by about 0.5" at 100yds but only from a stable, solid position. In kneeling or standing, I don't think the position is solid enough you'll be able to appreciate the difference.
From a military use perspective, the free-float also distributes weight of accessories better. In a standard military RAS, all of the weight of the rails and handguards is attached to the barrel. Add heat and an aluminium receiver to a lot of accessory weight hanging off the barrel like a lever and the barrel extension can be moved out of alignment enough that the bolt of the weapon will batter itself on the extension. On a free-float, the load is usually better distributed (though different systems do it different ways).
Which free-float tube are you looking at? Most of them require higher-level maintenance to install if you are modifying a service weapon.
On my own personal shooting, a free-float let me tighten up my groups by about 0.5" at 100yds but only from a stable, solid position. In kneeling or standing, I don't think the position is solid enough you'll be able to appreciate the difference.
From a military use perspective, the free-float also distributes weight of accessories better. In a standard military RAS, all of the weight of the rails and handguards is attached to the barrel. Add heat and an aluminium receiver to a lot of accessory weight hanging off the barrel like a lever and the barrel extension can be moved out of alignment enough that the bolt of the weapon will batter itself on the extension. On a free-float, the load is usually better distributed (though different systems do it different ways).
Which free-float tube are you looking at? Most of them require higher-level maintenance to install if you are modifying a service weapon.
Freefloats also keep heat down during rapid fire, and vertical foregrips help during full auto/rapid fire for control.
I'd get a SureFire and attach it if your unit doesn't issue one (101st issued them to every guy in the battalion).
I'd get a SureFire and attach it if your unit doesn't issue one (101st issued them to every guy in the battalion).
I have this information from a 45B (armorer) who was stationed in Afghanistan. This did not happen in his unit, but they were given the information so they could be aware. A major advantage of the free floated rail system is that using the vertical foregrip while firing full auto can cause the barrel to flex downward, and they had a few cases of locking lugs breaking on the bolt because of the downward flex on the barrel during full auto fire. The free floated version does not have this problem since when using it the barrel isn't being flexed by handguard pressure.
Bartholomew Roberts
Member
The Knight's Armory version will require removal of the barrel and front sight base to install but it is the same version I use and very good. Make sure you install the system per instructions or the collar holding the tube on can become loose and your rails will rotate.
Haven't used the GG&G version so I can't comment. Supposedly it installs without having to remove the barrel. Weight is 16oz compared to 11.3oz for the Knight's system (standard M4 handguard and barrel nut is 9.2oz). Looks like it is more versatile but uses a lot of bolt-on rails which makes me wonder whether the tiny screws and rails would get lost in field use.
Haven't used the GG&G version so I can't comment. Supposedly it installs without having to remove the barrel. Weight is 16oz compared to 11.3oz for the Knight's system (standard M4 handguard and barrel nut is 9.2oz). Looks like it is more versatile but uses a lot of bolt-on rails which makes me wonder whether the tiny screws and rails would get lost in field use.
The KAC RASII is a free floating rail that does not require removing anything but the handguards. Of course you can't use it unless you have a flat top upper.
It is not hard to install at all. I believe all you need are allen wrenches.
It is not hard to install at all. I believe all you need are allen wrenches.
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