I've been firing IMI 5.56 ammo out of my sport ll. The ejected brass is hitting the brass deflector so hard that the deflector is actually a brass color when I'm done shooting. This is my first civilian AR. I've fired a lot of AR's but they've all been the A2's the army gave me. I don't remember this happening with any of them. Would a heavier buffer and/or spring fix the problem? Do I have a problem in the first place? I'm not really looking to reduce recoil or muzzle rise I just want wear and tear on the rifle kept to a minimum.

Just to be clear, you are concerned that your brass deflector is deflecting brass?...

You don't have a problem. The brass markings clean off. The edge of your deflector is going to wear and show bare aluminum if you shoot it...

The commercial carbines are overgassed. This is so that they will reliably feed just about any off the shelf ammo available, from 5.56mm NATO to weak .223 steel cased imports. If you are only going to fire hot stuff like IMI, then you can change the buffer to a heavier buffer and this may change how the brass is deflected... However, you may affect reliability with weaker ammo.

A heavier buffer may help with the symptoms of over gassing, but will not fix the problem. It's the gas drive that opens the carrier, but it's the spring that closes it. If the buffer is heavy enough to slow an over gassed carrier to the right opening speeds, it's too heavy for the spring closing it.

Brass marks on the deflector are normal and not an indicator of over gassing.

If your AR has a carbine (unmarked) buffer, replace it with an H or H2 buffer. Carbine buffers (3.0 oz) are too light. A H buffer (3.8 oz) is good and an H2 buffer (4.6 oz) is best when using a carbine RE assembly. While recoil with a properly gassed AR and a 3.0 oz buffer isn't excessive, it's a bit sharper. The recoil with an H is softer and softer and flatter still with the the H2.

No sir. The brass on the deflector leads me to believe the bolt carrier is coming back harder than it should which may or may not result in increased wear. I've shot plenty of A2's. Don't recall seeing that before.

OK, the A2 has a rifle buffer and rifle recoil spring. The M4 has a H2 buffer to control BCG bounce and reduce the cyclic rate during full auto fire and a carbine recoil spring. Both of those will produce a slightly slower BCG velocity during ejection than a semi-auto carbine with a standard carbine buffer and recoil spring will.

Now, there is only one rifle and one carbine length recoil spring. Since the semi-auto carbine has no full auto, and no need to reduce bolt bounce or reduce the cyclic rate, it has a standard semi auto carbine weight buffer. The operation you're seeing is normal-you don't have a problem: it feeds, fires, extracts and repeats. That said, if you're unduly disturbed by that, H or H2 buffers are available. They'll slightly slow the BCG-in both directions. Which may cause cyclic issues. You can, if you wish, experiment. Good buffers are fairly cheap. Try an H first if you're going this direction.

Over/under gassing: the perfect gas operated firearm would use exactly "enough gas" to function. But, under adverse conditions it would need more. Some designers dealt with this by adjustable gas systems. Being wary of giving the troops something to screw with, the US has nearly always used non-adjustable gas systems. This means they've always been a wee bit more energetic than absolutely necessary.

The ejection pattern/bolt velocity of all gas operated firearms is affected by the pressure at the gas port. The weight of bullet and burning rate of the powder pretty much control this.

Or, you could have bought a mid-length and eased the problem that way

Buffer weights, spring rates and gas port locations do nothing to solve the problems that come with over gassing. The only way to solve over gassing is either to change to the right gas port diameter or use an adjustable gas block.

Experimenting with gas drive and buffer weight has shown me that the carbine buffer is too light, the H buffer is good and the H2 buffer is better.

A rifle or A5 RE with a buffer of about 5.3 oz is even better than the H2, but that's a different discussion.

An AR that's gassed to operate in adverse conditions with 5.56 spec ammo isn't really over gassed. But far too many AR makers use gas port much larger than needed.

Pic? Brass marks are normal but the empty cases painting the deflector ain't so normal. What do the cases look look like after you police your brass? Pics 2?

Right--how dented up is the brass?

I didn't bother to take any pics but "painting" is exactly the way I'd describe it. I don't think the brass was dented any more than what I'm used to seeing. By that I mean it looked normal with an occasional case having a dent in the body. I'll try the H buffer and see if that helps. Thank you all for the advice.

The original M16 and its successor the M16A1 didn't have a shell deflector. It was added on the M16A2 model. All subsequent models have had it. It was added because the ejection is not always consistent.

Look at my AR:


As you can see, there is a little brass on the deflector. This is the life of an AR. I also have several thousand rounds through this one.

I know some guys that put a small piece of electrical tape on the deflector to protect it from the occasional brass mark. Do that if you like. Adjust the gas system if you like. I suspect that if you futz with it enough, you'll get ejections that won't hit the deflector.

Meh, I don't care. I would never modify a reliable firearm because of a cosmetic issue. But that's me. I'm a function over form kind of guy. I take very good care of my firearms, but don't worry about marks that come about through use.

I was at the range once and another shooter was admiring the gun I was shooting. I asked him if he wanted to shoot it. He replied that he didn't want to because he didn't want to damage my (according to him) expensive rifle. I told him that if he could damage it, I didn't want it. It's a battle rifle, a self-defense tool. If used properly, trained with properly, practiced with properly, marks are going to happen.

Attached Images

Brass on Deflector.jpg (49.8 KB, 118 views)

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