[MarkR]

Went to the local GS and they had a rack full of SIG M400's and one of them followed me home. Seems to be a solid rifle with good reviews. One question regarding the buffer, this has an unmarked buffer, which I think is a carbine buffer - should this be replaced with a H marked buffer?

I'll post pics and report after I take it to the range later this week.

 

[atctimmy]

Shoot your gun for a while before you buy any parts for it. Get to know it first.

 

[MarkR]

I intend to and this is not my first AR. Just reading some of the reviews and one suggestion was to change the buffer, just not sure if really needed.
I know I'm going to change the charging handle to a BCM Mod 4, at some point the BUIS to a Troy and then save some pennies for an Aimpoint.
Also, the sling swivel is at the 6 o'clock position under the front sight, so I need one of the sling mounts that fits the Magpul hand guard.

 

[Roost426]

Will that help the gun hold flatter against your body? I also have a 400 enhanced with a vtac sling attached to that front swivel and a QD swivel into the mount point on the receiver.

 

[dukalmighty]

Will that help the gun hold flatter against your body?

Not if you have a middle aged protruding belly like mine

 

[MarkR]

Roost426 - I think it will. The sling mount should fit any of the slots on the hand guard. I was thinking of mounting it more towards the mag well on the lower. How is the QD swivel on the receiver working for you? I'm debating using that or using one of the attachment points on the stock. I have a VCAS padded sling, if that makes a difference.

 

[Roost426]

Its working good for me so far have not had any issues of the swivel disengaging on its own, but attaching the sling to the stock is more failsafe it seems. Would you just route it through the slot on bottom side of the stock?

 

[MarkR]

I'd put it through the slot on the top of the stock. I also found a mount that you can add to the stock for the QD swivel. It goes in the vertical slot at the end of the stock. If interested check out this web site Impact Weapons Components
They have some good stuff.

As a suggestion for using the front swivel, you could put a HK or Mash hook on the sling and it may lay flatter also.

 

[jonconsiglio]

Its working good for me so far have not had any issues of the swivel disengaging on its own, but attaching the sling to the stock is more failsafe it seems. Would you just route it through the slot on bottom side of the stock?

You can hang from a quality QD socket. I have them on all my rifles with BlueForce Gear VCAS slings, and none have ever failed in any way. Actually, I'd prefer they did break at a certain weight just in case I got in some bad spot, that way it wouldn't choke me out or jam me up.

On the SCARs, I didn't use QD sockets. Sadly, I have parted with both of them.... I'm right handed. Notice I attach near the barrel nut on the left side and to the stock on the right side. This pulls the sling in tighter when hanging and keeps it off of my neck when shooting, especially when switching shoulders.

I use the Daniel Defense QD attachment for my hand guards. There are some new ones on the market that are nice, but these work for me.

 

[jonconsiglio]

As MarkR pointed out, IWC is the way to go when you need mounts for lights or slings for tubular or MOE hand guards. Also, I'd strongly suggest at least an H buffer. I'd possibly go to an H2 since it's a carbine gassed 16", but that's if I'm running 5.56 ammo and not 223 the majority of the time. An H buffer should be fine.

A carbine buffer will work obviously, but it's best with 223 ammo. If you run hot ammo, you increase the risk of extraction failures due to early extraction as the buffer is not delaying it enough. This may eventually result in broken case lips or complete failed extraction due to the bullet not completely returning to normal size after expansion in the chamber.

Honestly, I see no reason to not use an H buffer. I'd buy an H2 then open both the carbine and H2 buffers and make an H1. Then, make it an H2 to see how it performs. This way, you buy two buffers and have three available weights (you end up with 4 steel weights and 2 tungsten). You could even get an H3 to have all four weights available, but I don't see any use in that. This is just me, though.

 

[MarkR]

Thank you, I'm going to order an H2 and experiment as you suggested.