View Full Version : SIG M400

Sweet Shooter
October 22, 2012, 10:47 AM
So I don't know why it happened but I finally got into the AR platform. It may be just to annoy the emotional folks that don't "approve". However I am downright blown away with this remarkable piece of sporting engineering.


1. Is it really worth following any kind of break-in procedure with this chrome-lined bbl?

2. I cleaned it and oiled it a bit but didn't do a deep clean... should I bother before I shoot it?

3. Any accurizing tips to the bone stock M400?

4. Deer hunting okay?

It's got A2 handle/sights which I like from a traditional standpoint.


October 22, 2012, 02:21 PM
1: No
2: Just clean it, lube it and shoot it. Mine was pretty dry out of the box.
3: No. Just sight it in. However, the M400 has an upper/lower tensioning device in the lower receiver. You will see it sticking up in the void behind the trigger, where the rear upper lug fits into the lower receiver. It keeps upward pressure on the upper receiver rear lug which reduces wobble/play. Mine came adjusted from the factory and my rifle has no upper/lower play at all. To adjust it you have to remove the grip and adjust it from the bottom with an allen wrench. Close the upper and lower and push in the rear pin. Then tighten the device until its snug and any upper/lower wobble is gone. Upper/lower play doesn't really affect accuracy, but it does effect consistency and getting rid of the play makes for a more solid feeling rifle, and reduces the cumulative effects of wear from upper/lower play.
4: IMO, it's not an optimal deer caliber. But a good bonded bullet should do the job if you do your part.

October 22, 2012, 02:23 PM
The following are my opions/experiecnce with similar ARs. Your mileage my vary:

1. Is it really worth following any kind of break-in procedure with this chrome-lined bbl? No.

2. I cleaned it and oiled it a bit but didn't do a deep clean... should I bother before I shoot it? I clean all new firearms well prior to shooting. An AR is pretty easy to break down for cleaning. At least clean the barrel, clean and lubricate the bolt carrier group, and clean the inside of the upper reciever. A good wiping out and light oiling of the fire control group in the lower receiver should be sufficient.

3. Any accurizing tips to the bone stock M400? The AR platform is inherently pretty accurate. I'd shoot it first before doing anything. Get a good sling.

4. Deer hunting okay? In my opinion, .223/5.56mm is insufficient for deer hunting (especially when it comes to providing a good blood trail), and there are better calibers available in the AR platform for this. I'm sure there are many who will disagree. Check your local laws regarding the legality of this round for hunting.

Sweet Shooter
October 22, 2012, 02:58 PM
Yes it is legal here for deer. I don't know what answer I was looking for with that question.

I know lots of folk do use the cartridge for deer... I guess I was wondering if the rifle would excel in any way as a hunting rifle. It's not actually why I got it.

Okay here's another question... I have AN AWFUL LOT of .223 40gr v-max/b-tips. Do we think these will be too light for the 1 x 7?


October 22, 2012, 03:20 PM
No break in, just shoot and clean. No problem as a deer round if you use bullets designed for deer hunting. Most who advise against it have only seen the results from varmit bullets which are not adequate. The 40 gr bullets are not deer hunting bullets and are probably too light to shoot well. But I'd try them, just not on deer. Sometimes stuff works even though it is not supposed to.

As to accuracy, I'd be surprised if it needs anything other than playing around with some different bullets to see what it likes best. My 1:7 guns shoot best with 60 gr and heavier bullets. I've used bullets as light as 50 gr with acceptable results, but nothing lighter.

There are only 6 states where rifles are legal and 223 is not at the last count I had. Several others have recently changed their laws or are considring such. There are a few other states that are shotgun only so all rifles are illegal, including 223. The laws prohibiting 223 were written years before it existed specifically to outlaw the 22 Hornet. With good bullets the 223 is a very effective deer round.

October 22, 2012, 03:43 PM
I have AN AWFUL LOT of .223 40gr v-max/b-tips. Do we think these will be too light for the 1 x 7?

You might be pushing it. The 1 in 7 barrels seem to prefer the 55gr and heavier. The only way to be certain, however, is to try it out. See if accuracy is decent.

Sweet Shooter
October 22, 2012, 03:58 PM

There are only 6 states where rifles are legal and 223 is not at the last count I had...

It is legal here in Utah for sure... source=DNR. At least has been for the last 3 or 4 years.

I was thinking of the 60gr Partition for deer.

October 23, 2012, 08:06 AM
4. re: deer hunting with 5.56/223.

I have no problem with the results that can be achieved in the hands of a cool shot who waits for the proper presentation. Who carries a .223 and thinks of it as a precision tool. There are modern bullets out there that can do amazing things. And shot placement is always number one, just number one "even more" in a smaller cartridge. I've used it myself on two occasions, once without planning and because I had to, and once as a normal deer stand rifle. In both cases, the deer went right down.

The problem I have is with just a blanket recommendation that ".223 is suitable for deer hunting." Like a general purpose, general use, just as effective as a .243 Win deer cartridge. I'm not comfortable doing that.

> The first reason is the obvious one, the bullet isn't very big. Ballistics are a step down from .243. Then the .223 gets even more of a problem in this same area by virtue of available factory ammo. If you could specify .223 with only the best premium bullets... I might be comfortable making it a general recommendation. But the public will bite you on this one every time. They will go into the gun store and buy a twenty round box of the cheapest soft points they have. They would pay the premium price for the great bullets for their 7mm Magnum but they just can't resist all the much cheaper ammo in 5.56 and .223.

> And the second reason one is actually the one I've noticed "in the field" personally. When they made .223 legal here and raised legal mag capacities, that sounded fine to me since I wouldn't have to try to find some kind of blocked mags or something. I could put a 15 round mag in my 6.8 AR even if I only loaded 5 rounds. But apparently Joe Average doesn't believe in carrying around all that "empty space" in his magazine. So you get the guys with Ruger Mini 14's and factory iron sights and fully loaded 30 round magazines. And .223 AK's. And lots of AR's. Which still should be ok.....

But in reality, how much time does Joe Average spend in the woods every year with a loaded rifle? Not talking about all you serious hunters. Not talking about people like me that live on our own property and hunt our own woods. But visit the public hunting areas that ring the major metro areas. I haven't done it in years and I'm not planning to go back. There are just too many city people that are overly excited about finally getting to carry their new rifle into the woods. But then get bored in no time at all when no deer conveniently show up. These are the guys who start shooting trees after a while just so they can enjoy shooting that rifle.

You put that type of hunter out in the woods by the thousands with .223 rifles and big mags and a whole lot of them end up shooting a whole string of fast shots at a running deer. Either missing it or actually injuring it but then it keeps going. These are the injured or dead deer I sometimes find on my property the first few days of deer season. Sure it's just anecdotal but these deer always seem to have _small_ holes in them. I never seem to find an injured a hiding deer and later find it has a 30/06 bullet somewhere in the body. It's always little holes that look like icepick stab wounds. One little deer had three of them and he still got away and hid on my land. Poor guy was trying hard to get away on three legs until I put a 5.56mm square into his brain and he died instantly.

Sorry, I rambled on and on. But if you are going to hunt with a .223... use the right bullet. And just because your magazine holds 20 or 30 rounds.... load it up with a lot less. And PLAN to only shoot one of them!! Don't be aiming that first shot and already prepping yourself inside for how fast you can get off your second or third shot!

I'm done!


Sweet Shooter
October 23, 2012, 12:00 PM
tulsamal 4. re: deer hunting with 5.56/223.

Thank you Greg, for your input. You're mainly talking about ethics here, and preaching to the choir.

I've seen those guys who start shooting stumps at the end of the day and they **** me off. I just came back from a fruitless two week Elk hunk and chambered a round only once (in a bolt gun) and then it was because of bear showing up. None of us pulled the trigger on that hunt. I don't need to shoot trees (or bears).

I have shot .223 for a looooong time and I know it's capabilities. Here's food for thought also for your comparison with .243—

A bullet of a given weight often fails because of being driven too fast re: "Proportionally" a .223-60gr PSP/Partition driven at ~2700 fps (likely for that cartridge and from a 16"barrel) is no more or less likely to fail than a .243-115gr PSP/Partition driven at 3000 fps.