Misfire Issues - Mid-Length AR build

[Extremehunter]

I tried to search for an answer on this but didn't find anything.

I recently built a Mid-Length AR with Spikes Tactical Lower, PSA buffer and spring. Spikes tactical 1:7 5.56 barrel. The upper is an aero precision with a no name BCG and a BCM low profile gas block.

I took my new toy out last weekend and when I was shooting slow (not in rapid succession) the rifle was doing fine. However, when I started to rapid fire I would get a misfire. When inspecting the fire vs. unfired rounds the dimple in the unfired round was not as pronounced. I then re-chambered the unfired round and pulled the trigger, it fired then.

The rifle was clean. I'm wondering if this could be the buffer and spring not being strong enough for a mid-length? The buffer and spring came from a carbine length rifle. Or if this is an issue with the BCG?

I'm new to building AR's and any help would be greatly appreciated.

Please let me know if there is more information needed.

Thanks,

Brett

[Khackee]

Have you double checked your assembly of your hammer springs?

[mike94yj]

I would try a heavier buffer first. I am assuming the carbine buffer is a standard weight. I had a cycling issue, went with a heavier buffer, took care of the problem. With a H3 and standard buffer you can mix and match until you get the best weight.

[LewP]

Have you double checked your assembly of your hammer springs?

This ^^^^

If you're getting light primer strikes then there's either something wrong with the trigger assembly or the firing pin/bolt/carrier. Too heavy buffer/spring combinations usually show symptoms of not cycling, weird ejection, or not locking back on empty mags.

[Endur]

I would double check the hammer springs. You can install them where it seems to function normal but is incorrectly installed. Which can result in light strikes. Make sure the hammer spring legs are on top of the trigger pin, not under.

[Iraqgunz]

First thing I would do is ditch that "no name" BCG since the BCG and barrel are two of the most important components. You should also be looking at the FCG as mentioned. You should also be using an H buffer.

[constructor]

I tried to search for an answer on this but didn't find anything.

I recently built a Mid-Length AR with Spikes Tactical Lower, PSA buffer and spring. Spikes tactical 1:7 5.56 barrel. The upper is an aero precision with a no name BCG and a BCM low profile gas block.

I took my new toy out last weekend and when I was shooting slow (not in rapid succession) the rifle was doing fine. However, when I started to rapid fire I would get a misfire. When inspecting the fire vs. unfired rounds the dimple in the unfired round was not as pronounced. I then re-chambered the unfired round and pulled the trigger, it fired then.

The rifle was clean. I'm wondering if this could be the buffer and spring not being strong enough for a mid-length? The buffer and spring came from a carbine length rifle. Or if this is an issue with the BCG?

I'm new to building AR's and any help would be greatly appreciated.

Please let me know if there is more information needed.

Thanks,

Brett

Check the disconnector and spring under it too. The hammer could be following the carrier and pushing the firing pin home instead of striking it. Along with checking your hammer spring like everyone else said. The tails of the hammer spring should rest on top of the trigger pin not under it.
This is not a buffer and spring problem IMO it is a control group problem.

[Eric]

[Extremehunter]

Thank you all very much. This is a huge help. I'll check everything. Re-test and report back.

Again, thank you! I'm getting addicted to this stuff

Alright, just checked the hammer spring and it is installed incorrectly. I'm going to fix and re-test.

Boy am I glad I asked the question before I started spending a bunch of money

[Extremehunter]

This picture helped immensely! Thank you!