AR Newbie. Rail question

[Ten9ofhearts 0]

Just waiting for my nics check to come back to get my ar but I purchased a sig sauer m400 and was wondering if I need a free float or non free float rail system. I'm pretty sure I need non free float but just wanna make sure before I buy and make a mistake. Thanks for your patience

[DargZ 5]

It looks like all the Sig Sauer M400's have a delta ring and hence not free float. If you want a direct replacement with minimal work, you would need to go with a non-free float rail. Just make sure you have the right length rail. There is carbine, mid-length and rifle. It looks like it is a carbine but make sure.

 

You can also opt for a free float rail. There are some manufacturer's that make free float rails. You would need to cut the delta ring and the front handguard cap. The new would have space for a front sight post if you have one.

[Ten9ofhearts 0]

Ill stick to non free float. Thank u for your input. Appreciate it.

[HavocMan 13]

Just a little FYI in case you didn't realize it - a free floated barrel will be more accurate.

 

Exactly which version of the M400 are you buying?

 

Just waiting for my nics check to come back to get my ar but I purchased a sig sauer m400 and was wondering if I need a free float or non free float rail system. I'm pretty sure I need non free float but just wanna make sure before I buy and make a mistake. Thanks for your patience

[vladtepes 1,060]

Just a little FYI in case you didn't realize it - a free floated barrel will be more accurate.

 

Exactly which version of the M400 are you buying?

 

while I understand how on paper free float is more accurate... I have to just put out there that for me personally.. in real world shooting.. I have not seen any significant distance in free float VS non free float on an AR weapon system... I have shot tight groups at 50... and hit steel plates at 300.. with a non free float 14in AR.. so I am not sure at what point this increase in accuracy happens..

[High Exposure 5,678]

Just FYI: The Daniel Defense Omega 7 and 9 (carbine and mid-length respectively) are free floating and use the delta ring for installation. No dis-assembly required further than removal of the hand guards. I have an Omega 7 and an Omega 9 on two of my work rifles. They are good pieces of gear, but expensive. Especially if you don't really need a FF rail. The rest of my guns have Magpul MOE hand guards on them.

 

If you are running a single point sling or setting your 2 point to connect close to the receiver instead of up by the front sight assembly you should be fine without a FF rail.

 

If you only want to mount a white light and vert grip and do not have a requirement for visible or IR lasers that need to maintain zero, a non FF rail or Magpoul MOE hand guards will serve you fine and save you quite a few bucks.

 

A FF rail does insulate the barrel from external forces that could effect accuracy when firing around barricades, but if you don't see yourself doing this too much, you should see no difference in performance between a FF and a non FF system.

 

You can influence accuracy by around 4 MOA when applying pressure to you barrel and hand-guards (either by tightening a sling or pressing into a barricade or cover) while not using a FF rail system. If you are to a sub 4 moa shooter, you won't notice a difference. Keep in mind that rack grade accuracy for this type of rifle is around 3.5-4 MOA anyway and you are probably not shooting match ammo all the time.

 

ETA:

 

 

while I understand how on paper free float is more accurate... I have to just put out there that for me personally.. in real world shooting.. I have not seen any significant distance in free float VS non free float on an AR weapon system... I have shot tight groups at 50... and hit steel plates at 300.. with a non free float 14in AR.. so I am not sure at what point this increase in accuracy happens..

 

Vlad, it is not a more accurate vs less accurate situation. It is that the FF system can insulate the barrel from outside pressures if cinching a sling or tightening you position against cover. I have seen Paul Howe create 4" of deviation to his POA at 100 yards by using cover effectively and cinching down his sling.

 

Edited April 28, 2013 by High Exposure

[vladtepes 1,060]

Just FYI: The Daniel Defense Omega 7 and 9 (carbine and mid-length respectively) are free floating and use the delta ring for installation. No dis-assembly required further than removal of the hand guards. I have an Omega 7 and an Omega 9 on two of my work rifles. They are good pieces of gear, but expensive. Especially if you don't really need a FF rail. The rest of my guns have Magpul MOE hand guards on them.

 

If you are running a single point sling or setting your 2 point to connect close to the receiver instead of up by the front sight assembly you should be fine without a FF rail.

 

If you only want to mount a white light and vert grip and do not have a requirement for visible or IR lasers that need to maintain zero, a non FF rail or Magpoul MOE hand guards will serve you fine and save you quite a few bucks.

 

A FF rail does insulate the barrel from external forces that could effect accuracy when firing around barricades, but if you don't see yourself doing this too much, you should see no difference in performance between a FF and a non FF system.

 

You can influence accuracy by around 4 MOA when applying pressure to you barrel and hand-guards (either by tightening a sling or pressing into a barricade or cover) while not using a FF rail system. If you are to a sub 4 moa shooter, you won't notice a difference. Keep in mind that rack grade accuracy for this type of rifle is around 3.5-4 MOA anyway and you are probably not shooting match ammo all the time.

 

ETA:

 

 

Vlad, it is not a more accurate vs less accurate situation. It is that the FF system can insulate the barrel from outside pressures if cinching a sling or tightening you position against cover. I have seen Paul Howe create 4" of deviation to his POA at 100 yards by using cover effectively and cinching down his sling.

 

I hear you... and have heard it a thousand times over... maybe I just do not shoot well enough to see those changes.. or maybe I am simply not putting enough force on the rail?

 

I shoot pretty tight groups with my ARs.. but who knows..

[Ten9ofhearts 0]

I really not puttin attachments on to it other than a angled foregrip. Thanks for all the input

[High Exposure 5,678]

Then you should be fine with the MOE setup or you can just buy a rail section and bolt it onto the handguards that comes with the rifle.

 

How do you know you like the AFG? I bought one and hated it. Sold it after about 3 months of trying it out. It didn't fit my hand or my shooting style.

 

You should shoot the rifle for a bit as it comes out of the box before deciding on the accessories you may or may not want.

 

Good luck!