Excessive Buffer Wear

ericoak · Jun 18, 2016

I just got an H3 buffer and put four 30 round of magazines of full auto through it.

I was inspecting the buffer afterwards and noticed the following circular wear on the buffer. I have read conflicting reports online whether that is normal or something isn't in spec. See pictures.

I recently switched out my A1 stock for a collapsible stock and the buffer detente was actually damaged and would not easily come out. I had to pull it out with a pair of pliers. I no longer use that detente. See pictures

I checked to make sure that my bolt was pushing the buffer back so that it didn't slam into the detente each time and it appears to push it back just slightly. I tried to get a picture of this but it is kind of difficult. It is a very small amount, but doesn't appear to be contacting as I close it up. Not sure how far it is supposed to go to be honest.

Dowtom · Jun 18, 2016

The buffer is normal. It's from the buffer contacting the bcg and detent

clandestine · Jun 19, 2016

This is common, but NOT ok on a RR M16.

If one breaks a title 1 lower, its no big deal. Break a RR M16 and its a deadlined lower, or a VERY expensive repair.

Let me explain. If the gun is in spec, the buffer should NEVER touch the retainer when the upper is installed with a bolt group. The carrier should push the buffer conpletely off of the retainer.

If you continue to allow this to happen, it can break the retainer, but in the worst case it can break your lower. Ill dig up some pics to show you how.

There are there are many variable on why this is happening. It could he the upper receiver, bolt carrier, or the lower can be slightly out of spec (buffer retainer hole drilled to far forward).

There are 2 things that will fix it.

One is a tubb carrier weight system. It has an insert that goes into the carrier tail that will oush the buffer bask more. I prefer this mod as it drops in. You dont jave to ise the weights, just the insert.

The other is a Leitner Wise Buffer Retainer. It may need to be fit so it fits beteen the valley in the bolt tail without binding.

Stop shooting the gun until you put one of these remedies in place.

StantonCree · Jun 19, 2016

clandestine said:
This is common, but NOT ok on a RR M16.

If one breaks a title 1 lower, its no big deal. Break a RR M1y and its a deadlined lower or a VERY expensive repair.

Let me explain. If the gun is in spec, the buffer should NEVER touch the retainer when the upper is installed with a bolt group. The carrier should push the buffer conpletely off of the retainer.

If you continue to allow this to happen, it can break the retainer, but in the worst case it can break your lower. Ill dig up some pics to show you how.

There are there are many variable on why this is happening. It could he the upper receiver, bolt carrier, or the lower can be slightly out of spec (buffer retainer hole drilled to far forward).

There are 2 things that will fix it.

One is a tubb carrier weight system. It has an insert that goes into the carrier tail that will oush the buffer bask more.

The other is a Leitner Wise Buffer Retainer.

Stop shooting the gun until you put one of these remedies in place.

Should we just call you Omar cuz that was Gangsta!!!!!

clandestine · Jun 19, 2016

mpdc4511 said:
Should we just call you Omar cuz that was Gangsta!!!!!

I had to look who that person is.

ericoak · Jun 19, 2016

clandestine said:
This is common, but NOT ok on a RR M16.

If one breaks a title 1 lower, its no big deal. Break a RR M16 and its a deadlined lower, or a VERY expensive repair.

Let me explain. If the gun is in spec, the buffer should NEVER touch the retainer when the upper is installed with a bolt group. The carrier should push the buffer conpletely off of the retainer.

If you continue to allow this to happen, it can break the retainer, but in the worst case it can break your lower. Ill dig up some pics to show you how.

There are there are many variable on why this is happening. It could he the upper receiver, bolt carrier, or the lower can be slightly out of spec (buffer retainer hole drilled to far forward).

There are 2 things that will fix it.

One is a tubb carrier weight system. It has an insert that goes into the carrier tail that will oush the buffer bask more. I prefer this mod as it drops in. You dont jave to ise the weights, just the insert.

The other is a Leitner Wise Buffer Retainer. It may need to be fit so it fits beteen the valley in the bolt tail without binding.

Stop shooting the gun until you put one of these remedies in place.

Definitely going to hold off shooting until I get this figured out.

The tubbs looks like it would work well, probably would have to go with a lighter buffer since it adds weight?

How does the Leitner Wise Buffer Work? It looks like it has a larger square top.

Had a couple more questions:

1. So the small amount of movement of the buffer rearwards isn't enough? I was naively thinking a small amount is all it would take. It's hard to see in my photo, but right when I'm closing it up it seems like it is off the buffer retainer. Are the marks a dead give away that it is not?

Do you happen to have a picture of what normal looks like?

2. How does the buffer retainer make that circular mark? In my head I wasn't picturing the buffer spinning, I would think it would leave a mark in the same area creating one small spot. It must spin a lot to make that mark in only 120 shots?

3. I have a friend who has an out of spec Sendra conversion and the buffer hole isn't drilled correctly. Would your suggestions work equally well there?

clandestine · Jun 19, 2016

The tubbs insert is aluminum and should not be a concern about added weight.

The L.W. Retainer allows the buffer to come forward just a little bit more, but not as much as the Tubb pushes the buffer back which does the same thing. The LW retainer is much wider than a standard retainer and fills the slot ofbthe carrier tail completely, which means it may need some fitting.

The Buffer can clock (rotate) when it goes completely forward, thus the marks all around the surface.

There marks look to be in the place where the buffer retainer is. If they were more towards the center it would be burrs on the tail of the carrier causing the marks on the buffer case.

There are 2 other factors as well, one being the buffer glface being machined untrue, which means the face isnt square to the body. This might cause contact on half of face so I dont think thats the issue at hand.

The buffer springs coiled ends on standard springs have unground ends that can also force the buffer to be off axis. Springs like the tubb dont have this issue as much because of the springs design. I dont think this is the case.

In the end, you are looking for the right things. You observed the buffer being pushed off, which is corre t, but sometimes its just not enough. When the bolt goes into battery it allows the buffer to come forward "just" a small amount too much. Its a small amount like .010. Sometimes the carrier tail can be cut forward just a tad too much.

A normally functioning buffer should have no marks on it, it any they would be scrapes across the face as the upper is pivoted down and the carrier scratches it as it closes. This is remedied by deburring the bottome of the bolt carrier tail.

paperwork351 · Jun 19, 2016

The tubb site is out of stock and midwayusa has discontinued the carrier weight system.

clandestine · Jun 19, 2016

If tubb stopped making them its s not hard to have something like that machined if one has access to a lathe.

The other fix is to have the barrel setback in the upper, as this will push the carrier rearward when in battery. That is much more involved though.

Here is one that will work too.
http://commonbullets.com/wp/archives/1727

ericoak · Jun 19, 2016

I'm going to get my tripod and take a video later tonight of all the parts, it should give a better view of everything. I'm going to compare it another BCG as well. Might just be the PSA BCG is slightly too short. The back end of the BCG is defiitely not smooth though, it concaves in from the outside towards the middle, so it seems like only a very small part of the BCG is actually touching the buffer. Again, not sure if that is normal or not.

clandestine · Jun 19, 2016

ericoak said:
I'm going to get my tripod and take a video later tonight of all the parts, it should give a better view of everything. I'm going to compare it another BCG as well. Might just be the PSA BCG is slightly too short. The back end of the BCG is defiitely not smooth though, it concaves in from the outside towards the middle, so it seems like only a very small part of the BCG is actually touching the buffer.

That is very much a possibility. The barrel and upper allowing the barrel to set too far forward can cause it too.

This is a very fixable problem. Kudos to you for noticing it.

ericoak · Jun 19, 2016

I went back to the range today and borrowed a BCG and buffer from my friends AR that has maybe 50 or so rounds through it. Not my first choice, but it was all I had to compare mine too.

I first tried out my BCG and his buffer (which was basically unmarked as shown in pic 1).

After 20 rounds, additional wear was noted but it appeared to occur around 12 O'clock as the buffer was rotating counter clock wise (pic 2).

I then tried 20 rounds with the new BCG and the new buffer. No new wear was noticed (pic 3).

This was repeated two more time with 30 and 40 rounds, with no new wear occuring (pic 4 and 5).

I then took out my buffer detente and spring and put my BCG back in. I fired another 40 rounds and additional wear was noted (pic 6). It could not have been caused by the detente (very relieved, the whole point of getting a Colt is to get an in-spec receiver), so I think I have it narrowed down to a burr on the back of the BCG around 10-12 O'Clock.

What do you think Chad?

outrider58 · Jun 19, 2016

I've been wanting to see the tail of your BC since your OP... You got?

clandestine · Jun 19, 2016

Very good troubleshooting. At this point I think its likely the carrier. Hard to say if the carrier too short or if it has a real bad burr causing the damage.

Your lower is probably not the issue, other gactors in the upper receiver can cause this. You didnt make a bad choice.

The damage will sometimes only clock on some areas of the buffer unless you fire a large amount of ammo.

BradMacc82 · Jun 19, 2016

Burr on the tail, I'd be willing to bet on it. A burr small enough to hardly see, can create the 'ring of havoc' on a buffer face.

BTDT.

Check the tail closely, I'll bet you find the burr(s).

ericoak · Jun 19, 2016

Well I can kind of see a small mark on the corresponding part of my BCG, but I was expecting more. I certainly can't feel anything when I touch it.

clandestine · Jun 19, 2016

That could be causing the marks but its often the 2 sharp areas at the bottom.

BradMacc82 · Jun 20, 2016

I can say from first-hand experience, burrs small enough to barely even catch your fingernail - will chew the f out of a buffer face in short order, less than 100 rounds.

Pics from one of my own experiences:

Brand new BCG and buffer, had under 100 rounds thru the rifle. And I popped it open to find that nice surprise.

De-burred and polished tail of the BCG (hit the exposed metal with a few coats of cold-blue just to keep corrosion at bay), cleaned up the buffer face (simply because I didn't have any spares on hand), and tested.

Haven't had any issues since. There were 3 (IIRC) burrs on the tail of my BCG that had to be addressed.

Hawkeye · Jun 20, 2016

This is a fantastic thread - thanks to the OP and to Chad.
Stuff like this that's informative and well documented is a fantastic part of this forum.

clandestine · Jun 20, 2016

Brad is spot on with dressing the bolt tail. I used to do that as part of my reliability package.

What has me concerned is why the retainer was jacked up if it was a carrier burr.

Excessive Buffer Wear

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