Heavy Buffers

[Mnukedude]

Apparantly there is an H2, and an H3 buffer. How is this different than the H buffer and what would it give me that normal weight buffers won't?

[boraxis]

They're a little heavier so they reduce felt recoil. They can be good if your AR is over-gassed or for whatever reason cycles harder than necessary. Mostly they're for short carbine or pistol length gas systems. If your AR cycles perfectly the way it is, then a heavier buffer could in theory make it less reliable. For example if you're shooting <55 gr .223 loads in a 5.56 20" rifle.

[Mnukedude]

Originally posted by boraxis
They're a little heavier so they reduce felt recoil. They can be good if your AR is over-gassed or for whatever reason cycles harder than necessary. Mostly they're for short carbine or pistol length gas systems. If your AR cycles perfectly the way it is, then a heavier buffer could in theory make it less reliable. For example if you're shooting <55 gr .223 loads in a 5.56 20" rifle.

I have one AR that fails to lock back on the last round, but only if using hot ammo AKA 5.56

[GixxerSixxer]

A heavier buffer can also help reduce bolt bounce. That's more applicable for the FA AR's or those who like to bump fire a lot.

From what I've seen it's pretty rare to have an Upper that doesn't like the H2 buffer. There are some people that run a 9mm buffer which is even heavier.

I use an H2 buffer with an ISMI spring and have no problems even when I shoot Wolf or my economy reloads.

[Mnukedude]

Originally posted by GixxerSixxer
A heavier buffer can also help reduce bolt bounce. That's more applicable for the FA AR's or those who like to bump fire a lot.

From what I've seen it's pretty rare to have an Upper that doesn't like the H2 buffer. There are some people that run a 9mm buffer which is even heavier.

I use an H2 buffer with an ISMI spring and have no problems even when I shoot Wolf or my economy reloads.

What is bolt bounce? How do I know if my rifle is doing it?

[GixxerSixxer]

It's when the bolt is cycling so fast that as it is returned to battery it has enough force to bounce off of the barrel extension when it's closing and locking.

If you're pulling the trigger and nothing is happening even with a chambered round, good springs, and intact firing pin then bolt bounce is suspected. This is because the bolt has "bounced" back a small amount.

This applies to FA and bump firing more, less so in simple semi-auto use. If you're target shooting or plinking then the chances of bolt bounce giving you problems are slim.

For your problem with the bolt not locking back with hot ammo I'd suggest you lube your bolt catch pivot points. See if it's rubbing or binding slightly anywhere. How old is the rifle, and about how many rounds have been through it?

[Gary G23]

I use H buffers in my midlengths and a H2 buffer in my carbine.

You just have to tailor the buffer to your gun and the loads that you use.

A shorter gas system will require a heavier buffer. Hotter loads will require a heavier buffer.

[Mnukedude]

Originally posted by GixxerSixxer
It's when the bolt is cycling so fast that as it is returned to battery it has enough force to bounce off of the barrel extension when it's closing and locking.

If you're pulling the trigger and nothing is happening even with a chambered round, good springs, and intact firing pin then bolt bounce is suspected. This is because the bolt has "bounced" back a small amount.

This applies to FA and bump firing more, less so in simple semi-auto use. If you're target shooting or plinking then the chances of bolt bounce giving you problems are slim.

For your problem with the bolt not locking back with hot ammo I'd suggest you lube your bolt catch pivot points. See if it's rubbing or binding slightly anywhere. How old is the rifle, and about how many rounds have been through it?

The weapon in question has about 5500 rounds through it. Lubing the bolt catch helps but doesn't eliminate the problem. No evident binding of the catch.

So far I just recently went to Magpul followers and I will install the heavy buffer. I'll have to see what that does. Most of the time I shoot standard .223 ammo, but the SHTF stash is 5.56, and this only happens with that stuff.

[RENEA]

I run H2 buffers as standard in all of my 16" carbines and over here an H3 buffer in my issued piece for increased reliability/increased dwell time.

[DT]

Originally posted by Mnukedude
[Most of the time I shoot standard .223 ammo, but the SHTF stash is 5.56, and this only happens with that stuff. [/B]

Are you sure your 5.56 loads are hotter ? They might not be.
It sounds like you might have a short cycling problem with the bolt failing to lock back. A heavier buffer will make this problem worse. Have you tried a standard buffer to see if the problem goes away ? Also are you using an extra power buffer spring ? If you are I would go back to a standard spring. If you are using the standard CAR buffer spring and buffer and still have the same problem you may have a gas leak somewhere. I would check the carrier key on the bolt carrier to make sure it is not loose. Some bolt carrier keys get loose after a while if they have not been staked on properly.

[Mnukedude]

Originally posted by DT
Are you sure your 5.56 loads are hotter ? They might not be.
It sounds like you might have a short cycling problem with the bolt failing to lock back. A heavier buffer will make this problem worse. Have you tried a standard buffer to see if the problem goes away ? Also are you using an extra power buffer spring ? If you are I would go back to a standard spring. If you are using the standard CAR buffer spring and buffer and still have the same problem you may have a gas leak somewhere. I would check the carrier key on the bolt carrier to make sure it is not loose. Some bolt carrier keys get loose after a while if they have not been staked on properly.

The 5.56 loads are definitely hotter. At 100 yards they reliably land an inch or so above the other loads, and in both cases we are talking about a 55gr bullet.

Currently I am running a standard spring and buffer. Replacing the buffer spring with a new one had no effect. Lighter powered .223 loads do not create this problem, and if a gas leak were the culprit, I would expect a lighter load (that generates less gas) would be worse.

[Stickman]

I run heavy buffers in most of my carbines, including my duty weapons. Running a standard H, versus running a heavier buffer gives a noticeable difference.

The biggest problem with heavy buffers is when people expect that they will work the same for weak 223 ammo as it will for standard loads. Make sure you try it with the ammo you are going to carry or use for defensive purposes.

[Mnukedude]

Originally posted by Stickman
I run heavy buffers in most of my carbines, including my duty weapons. Running a standard H, versus running a heavier buffer gives a noticeable difference.

The biggest problem with heavy buffers is when people expect that they will work the same for weak 223 ammo as it will for standard loads. Make sure you try it with the ammo you are going to carry or use for defensive purposes.

FWIW, the buffer I intend to install says "H" on it's face, where the one it is replacing is unmarked. Will this be helpful with the lockback problem?

[DT]

I think the H buffer will make the problem worse. What brand of ammo are you using ?

[RMTactical]

2 of my AR's run heavy buffers. They work great with a variety of .223 and 5.56.

[DT]

I use an MGI, 9mm, H2, and H buffer with the standard carbine spring in a 16 inch upper. They all work fine. The only problem I had was with the MGI buffer and a Tubbs extra power spring which caused short stroking. I like the MGI the best but it costs 5x as much as the other buffers. It is not 5x better.

[Critter]

It actaully sounds like the action could be outrunning the magazines. Are the magazines new/good quality? Another thought is the bolt carrier. Is it full shrouded or not? If not, have you measured the rear 'flange' on the firing pin? If your carrier is not shrouded, it certainly needs to be at .330 or it could get caught up on the safety hook on your hammer.

I have actually had carbines, with standard springs, outrun the next round in the magazine and have it cause all of your symptoms and some other interesting ones. The H buffer may help, I run one in my 7.5" rifle, but I also only use new DSG magazines. I've never had a failure due to this, even with my reloads. Same goes for my carbines since I switched all of my magazines.

[Mnukedude]

Originally posted by DT
I think the H buffer will make the problem worse. What brand of ammo are you using ?

The problem ammo is Federal XM193, (not the "PD" load) Russian M193 brass case also does this.

[Mnukedude]

Originally posted by Critter
It actaully sounds like the action could be outrunning the magazines. Are the magazines new/good quality? Another thought is the bolt carrier. Is it full shrouded or not? If not, have you measured the rear 'flange' on the firing pin? If your carrier is not shrouded, it certainly needs to be at .330 or it could get caught up on the safety hook on your hammer.

I have actually had carbines, with standard springs, outrun the next round in the magazine and have it cause all of your symptoms and some other interesting ones. The H buffer may help, I run one in my 7.5" rifle, but I also only use new DSG magazines. I've never had a failure due to this, even with my reloads. Same goes for my carbines since I switched all of my magazines.

I kinda thought so too, that the action was outrunning the magazines. I did try a new one, but that didn't help. I have since replaced the followers with magpuls, will install the H buffer, and will give the bolt catch a little extra oil. The bolt carrier fully shrouds the firing pin. We'll have to see what happens next time I go to the range with it.

On an unrelated matter, I also have a problem with my buffer's finish getting beat up by what I suspect is a burr on the rear of the bolt carrier. To grind this off, would a sharpening stone such as what I might use for a knife be a good choice?

[Mnukedude]

Range Update: I took the rifle to the range this week with the heavy buffer installed. I didn't have a lot of time to really get the rifle dirty, but I had enough time to fire about 40 rounds through it, using either the Russian M193 or the Federal XM193 loads where the problem was previously seen. Magazines were almost always loaded with one round only, to maximize the opportunity for lockback failure. The weapon was reloaded 35 times during this range session.

There were NO lockback failures

There was, however a double feed or two, which I believe was caused by a couple of tired magazines, which on close inspection, had feed lips bent slightly further apart then the spec calls for. I think discarding these magazines will solve that problem.



Any ideas on the bolt carrier issue? Is my idea to use a sharpening stone a valid one?

[halfmoonclip]

A stone should work just fine. Don't go crazy; keep the bolt carrier square to the stone.
Some light marking of the buffer face by the carrier is normal.
Moon

[Panzerfaust]

I recently purchased a regulated gas tube for my CAR-15A2. It is quite a nice thing to have....

[Washington,D.C.]

Originally posted by GixxerSixxer
A heavier buffer can also help reduce bolt bounce. That's more applicable for the FA AR's or those who like to bump fire a lot.

From what I've seen it's pretty rare to have an Upper that doesn't like the H2 buffer. There are some people that run a 9mm buffer which is even heavier.

I use an H2 buffer with an ISMI spring and have no problems even when I shoot Wolf or my economy reloads.

In semi auto the heavy buffer is rearely if ever needed or required. As for using a 9mm buffer in 223 this will only work reliably with the early two piece 9mm buffer. The later and curent Colt one piece 9mm buffer can cause reliablity problems in 223. The heavy buffer used to be marked with an "H" but I think it has now become the standard carbine buffer and not just the M-4 buffer and may no longer be marked. The 9mm buffer is all black on the metal.

[halfmoonclip]

Originally posted by Panzerfaust
I recently purchased a regulated gas tube for my CAR-15A2. It is quite a nice thing to have....

'faust, tell us some more about this tube; how it works, how you install it, was there a reliability issue you were solving, or just makes a more pleasant shooter?

Saw a 6520 of recent production with the H-marked buffer.

Moon

[Mnukedude]

Yes, I'm curious about this gas tube as well. Do tell.

[GixxerSixxer]

I think he's talking about an adjustable gas block like is found in the FAL.

You can adjust how much gas goes through and get it to the point that it just barely cycles the action. 3-gunners use the adjustbale a lot since there is softer feeling recoil and reduced muzzle rise after the shot.

JP has a lot of info on adjustable gas blocks. The 3-gun forum at Brianenos.com will also have guys there that can share a lot of info on the system.