FTRB issue with a 11.5 BCM

[17K]

I’d do a good PM cleaning and inspection on the trainer and make it the primary, put the primary into the training role and see what happens.

[Patrin]

I’d do a good PM cleaning and inspection on the trainer and make it the primary, put the primary into the training role and see what happens.

Yep, we're on the same page there. Primary is the trainer for the duration till I'm satisfied with performance.

[Patrin]

Sorry for the late update gents, wanted to get a couple training sessions in before updating.

150rds per sesh, no FTRB or malfunctions of any kind.

After exhausting the list Stickman put forth over the course of time, the only change made to address this issue, now, was changing to a Sprinco 'GREEN' spring from the standard COLT rifle spring.

Will update again after a few more outings.

[17K]

Not surprising.

[MistWolf]

I get the feeling the Colt rifle spring doesn't have enough strength (it's a new spring). It's my understanding the green Sprinco has a bit more punch, and is on the way.

I don't think the green spring has more "punch" but I do believe it's more consistent.

[17K]

I’m thinking that the A5 reliability window may not as big as we thought it was as finicky as they are about springs.

[MistWolf]

I’m thinking that the A5 reliability window may not as big as we thought it was as finicky as they are about springs.

If a spring is bad, it’s bad.

Green springs have the same spring rate as a standard rifle spring.

[georgeib]

If a spring is bad, it’s bad.

Green springs have the same spring rate as a standard rifle spring.

Could there be other, less obvious factors? Such as friction inside the receiver extension being higher with one spring vs the other, for example.

[MistWolf]

Could there be other, less obvious factors? Such as friction inside the receiver extension being higher with one spring vs the other, for example.

It's possible there could be quality control issues or some part being out of spec.

The A5 was thoroughly tested- by the Marine Corps, I believe. They found it more reliable than the rifle RE assembly which is pretty damn reliable.

The AR is a very reliable, durable and mature design. When everything is right, when everything is in spec, it works every time. If it doesn't work, something is out of spec.

If an AR with an A5 RE assembly has a narrower span of operation than normal using a properly assembled A5 buffer, the problem is likely to be an out of spec spring. That doesn't mean the A5 assembly is spring sensitive as much as it means the AR is spring sensitive. It needs springs made to spec.

Look at the following malfunctions and the cause-
-Extraction malfunctions are caused by out of spec extractor springs
-Weak ejection is caused by out of spec extractor springs and/or out of spec ejector springs
-Incomplete return to battery is caused by out of spec action springs
-Weak ignition and light primer strikes are caused by out of spec hammer springs
-Feed issues can be caused by out of spec mag springs
-Trigger malfunctions can be caused by out of spec trigger return and/or semi-auto block spring

Without springs any firearm becomes useless. Too many AR owners downplay the importance of spring specifications and quality. When ARs have about a thousand rounds through them, especially when several hundred rounds are fired in a day, springs that aren't up to snuff start making themselves known. I found that out first hand and it wasn't my Colt or Sprinco springs that were failing. It was the generic springs.

Once I have an AR upper properly sorted out, that is the gas drive is right (correct gas port, all leaks fixed) and extraction & ejection problems eliminated (Colt extractor spring, ejector checked for proper function) I find it works with any lower with any in spec buffer & spring (carbine RE with standard Colt spring and H2 buffer, rifle RE assembly with quality rifle spring and rifle buffer and A5 RE assembly with A5H2 buffer & Sprinco green spring).

Uppers include a 20 inch, 16 inch middy, 16 inch carbine, 14.5 inch carbine and 11.5 carbine with and without suppressor. The shorty uppers are set up to be always shot suppressed, or always shot unsuppressed. I shoot mostly XM193 except in the precision ARs.

With one exception, I've never had to adjust the gas on any of my Colt uppers. The exception is a 6933 set up as a suppressor host.

[17K]

^I’ve long held an idea that maybe, on a semi-auto, the buffer almost doesn’t matter as long as the upper is good to go.

But there sure has always been a lot of chatter about buffers. Maybe it’s because they’re so easy to change.