SBR malfunction

[JD Williams]

I would read this first and then come back with some additional info.

https://www.m4carbine.net/showthread...leshooting-101

When I clicked the link there were only two posts that did not have a complete list. Looks like it was cut off at 4 and prior listings.


Sent from my iPhone using Tapatalk

[Iraqgunz]

Everything in my original post is showing up for me.

When I clicked the link there were only two posts that did not have a complete list. Looks like it was cut off at 4 and prior listings.


Sent from my iPhone using Tapatalk

[JD Williams]

Everything in my original post is showing up for me.

Must be my equipment. Thanks.


Sent from my iPhone using Tapatalk

[Tnemt]

1. The buffer is unmarked
2. The bolt will lock open after last round
3. The gas key is mounted solid
4. Buffer spring is correct length

So......would I be better off buying a lower weight spring or buffer? Or a heavier weight spring??

[tb-av]

For $4 I would replace the ejector spring with the copper colored Colt version.

Colt copper colored spring, no black O-ring.

At least that would eliminate that potential aspect that several of us have experienced.

[markm]

1. The buffer is unmarked

That's the first, and most obvious problem. It's likely a carbine buffer, which is a good solution for NO AR15 that I'm aware of. H2 is what should be in any carbine system that's close to being correctly gassed.

A carbine buffer will give you WAY TOO MUCH bolt speed and cause lots of problems.

[P2000]

What kind of ammo were you shooting? Who is the barrel manufacturer?
So far it sounds like you need a heavier buffer like an h2.

Sent from my XT1565 using Tapatalk

[Tnemt]

Windham 10.5 inch barrel. I was shooting a mix of ammo. UMC 55 grain fmj, hornady 55g, xm193, some handloads, all with the same outcome. It typically only happens when the gun gets hot or I fire at a faster rate.

Why would it begin after the fir initial 400-500 rounds? Up until then it ran like a top.

[markm]

Probably the bolt carrier group is broken in, rings, etc. And now that excessive bolt speed is causing the gun to run too fast. I'm sure Windam likely has a port on the larger end. An H2 should make that thing run a TON better.

[Tnemt]

So h2 instead of h1