Erratic Ejection Angle + Bolt Locked behind Live Round

[VIPER 237]

First take out that ST-T2 buffer and throw in a real H2. I have seen that POS make perfectly reliable carbines an instant jam-o-matic, and many have experienced the same issue that you are describing.

[velocity2006]

I would try to try a few different brands of factory quality brass cased ammo before pulling any parts off of the rifle. Is it possible to find out of the re-man ammo was made with a full length or small base sizer? When I load for my ar's I specifically use small base dies, using FL dies can cause the issue your are experiencing.

[gatordev]

First take out that ST-T2 buffer and throw in a real H2. I have seen that POS make perfectly reliable carbines an instant jam-o-matic, and many have experienced the same issue that you are describing.

I'm curious, what makes the ST-T2 specifically unreliable? My understanding is that it's just a buffer with a weight in between a H and H2 buffer. If something doesn't work with it, wouldn't it be more about an incorrectly ported barrel for the length and/or ammo? By the same logic, I've heard of people not being able to cycle a round after using a H2 buffer, but again, you can't really blame the type of buffer itself for the failure, just that it's too heavy for the setup.

Please understand, I have no emotional tie to the T2 (I do own one as my first lower was a factory Spike's from years ago) and I run mostly H2s with a few Hs, I'm just curious about the reasoning.

[SINNER]

I have heard the e-myths about the ST-T2 causing issues but have never seen it myself. Usually it's just too heavy of a buffer for the use and most people not having a clue to the effect of changing buffer weights. IE changing out a carbine buffer with a Spikes heavy that will not run and then blaming the buffer. I have asked and asked to be shown where a gun will run a H buffer but not the Spikes and NEVER saw an example. The fact that the ST-T2 is actually slightly heavier than a standard heavy buffer likely has not helped the uneducated who assume it's identical to a normal H buffer.

[Scout Actual]

I'll be taking a variety of ammo and a couple rifles to the range soon to compare & contrast. After that I may swap out Buffers if it makes sense.

[VIPER 237]

The reciprocating mass of a standard buffer design (3 weights separated by rubber pads) helps reduce bolt bounce. The Spikes ST-T2 has been shown to increase bolt bounce over a standard buffer design. I have personally seen carbines run with an H or H2 buffer that would not run reliably with a ST-T2. It is more prevalent in a Full Auto as you have more carryover forces from one shot to another but the concept is true for semi's as well. I have found on many occasions that when a person is having problems similar to what the OP is stated, they are solved by switching to a standard buffer design.

I stole this off of Arfcom as it is one of the best explanations I've found.

'Bolt bounce is reduced by the buffering motion of the internal weights in the buffer (that's why it's called a "buffer"). In a standard carbine length buffer there are three internal weights separated by rubber pads. The successive movement of the weights creates a long duration "push" on the bolt carrier as it closes in order to prevent or limit its "bounce" and hold it against the barrel extension. An often overlooked function is that the same process works at the back of the function cycle, when the buffer and BCG reach the back of the buffer tube. At that point, the buffer tries to hold the BCG at the back of the tube momentarily instead of it bouncing forward... this gives more time for the ejected case to clear the ejection port, the ammo stack to rise and settle in the magazine, the bolt catch to rise on the last round, etc.

It also buffers the opening and unlocking sequence of the BCG to smooth that process out and reduce impulse loading on the bolt and cam pin.

All of those work in concert, since if the last two functions are "buffered" this reduces the BCG velocity and the cyclic rate, so there is less bolt bounce on closing that needs to be controlled.

The Spike's buffer is different in that is just has a mass of small pellets as moving internal weight instead of the individual weights and rubber spacers. This design means that there is just one delayed spike (no pun intended) of force from the buffer instead of the long duration push of the multiple weights from a standard buffer.'

[gatordev]

Ahh, okay, so it's a different design and not just weight. Gotcha. Thanks. I thought I remembered there was something "different," but didn't realize it was a different take on what would initially appear to be the same idea.

[SINNER]

My limited knowledge of physics tells me that those weights in a buffer will act as a single weight at the velocities experienced during firing. As will the powder to a lesser extent only because the powder lacks a hard face to impact the buffer internally. The clearance in the buffer that allows the weight to travel a short distance from end to end provides the deadening affect. Just like a dead low hammer that is filled to capacity is no longer a dead blow hammer, if you remove the open space it will no longer provide any dampening.

I have no reason to say the Spikes is better or worse. To the contrary I have found NO difference in the function of a rifle with or without the spikes buffer installed when you match the weights. I see the Spikes buffer as a invented fix for a non-existent problem honestly.

[alamo5000]

It will be at least 2 weeks until I can get outdoors to shoot I can probably get to an indoor range this week. Hopefully I will be able to do the comparison effectively in the little booth. FYI I own two different brands of remanufactured ammo and I will buy some factory ammo and compare all 3 ejection patterns.

I can also try the remanufactured ammo in another rifle with a new DD barrel and another with a 1000 round DD barrel.

I feel your pain. I haven't been able to shoot for a while now. We had a family member pass away and have been housing a few people and planning a funeral. It's been a house full of people from all over for a week. Tomorrow is the ceremony. (FWIW It was my grandmother and she was like 93 years old so it's not like it was unexpected)... but everyone is doing fine if anyone is wondering.

Not that we know that ammo is the problem---but to me it's a real contender...but do you mind telling us what kind of ammo you were running? Or was it just some home spun local kind?

In the process of my reloading I got a bunch of random brass that I was resizing and trimming for a while there. I was actually surprised at just how deformed the brass can get. If the brass is of a very soft variety and it was fired in a slightly larger chamber it's likely that that ammo might not even seat well in a standard chamber. And the length of the brass was also very instructive. The brass was very stretched out length wise in some cases.

I would be curious as to what you figure out so please keep us updated.

[GOST]

Hate to hear that about your grandmother.

[SINNER]

Hate to hear that about your grandmother.

X2 Sorry for your loss.

And I do not suspect ammo as the cause if in fact the extractor was not capturing the rim. Even if the case sticks halfway into the chamber the extractor should still engage the case.