Home Forums Hunting & Shooting AR and Tactical Rifles AR-10 Light Primer Strikes

First let me start out saying that i know very little about AR's so bare with me. I went out yesterday to shoot a new to me Palmetto state AR-10 in 6.5 creedmoor that I recently traded a buddy for. As far as I know he had no issues with it previously. After I got it I made a few changes to it before shooting it. I switched out the stock trigger with a rise armament trigger ( https://www.midwayusa.com/product/102163288?pid=887715 ). I also changed the collapsible stock for a Luth-AR MBA-1 stock ( https://ar15discounts.com/products/...10-rifle-length-a2-a1-buffer-tube-black/ ) and the buffer tube, spring, and buffer for a NBS A2 mil spec one (https://ar15discounts.com/products/nbs-ar-10-308-a2-style-milspec-buffer-kit/ ).

I was using hornady american whitetail ammo and loaded a couple in the mag and proceeded to fire the first round with no issues. When i went to fire the second round all I got was "click". Extracted the round and it had a very faint primer strike. Tried the next round that was in the chamber after extracting the previous one and it went "click". Once again light primer strike.

For the next couple rounds i left the empty mag in the gun and loaded it by pushing the cartridge into the chamber and then release the bolt with the bolt release and it would fire each time with no issues. Each time it would fire the case was ejected and the bolt would lock open.

What do you think is causing my issues? Is it the buffer or buffer spring or the trigger, or do I need an adjustable gas block? Any help would be greatly appriciated.

My guess is your bolt isn't fully closing on the live rounds. In an AR, if the bolt doesn't lock up all the way, the carrier is held back out of battery slightly, and that will cause light strikes or prevent firing pin contact alltogether. You can verify this by looking at the position of the bolt carrier through the ejection port; look at it with the bolt closed on an empty chamber, then compare it's position when you get a light strike. Causes can be a dirty chamber, tight chamber, out of spec ammo, too strong extractor spring, just to name a few.
If you verify this is correct, first thing I'd do is inspect the chamber and locking lug area for excessive fouling and debris, second thing is to try different ammo, like whatever your friend used.

Also, since you're new to ARs you may not know this: when you chamber a round (on a correctly functioning rifle) the firing pin makes light contact with the primer due to inertia. If you eject a chambered round, you'll probably see a light firing pin strike on the primer (very small, way too light to set it off). This is normal.

I doubt it's the Rise trigger. I only have a couple but they seem to be good to go. The fact that you can fire the gun by dropping the bolt on a round in the chamber indicates the trigger group is working fine.

It is possible you assembled something wrong with the buffer tube and internals. Hard to say without knowing what you did.

I don't see any indication here of needing an adjustable gas block, other than that it's an AR10 and they pretty much all benefit from one. However that's a separate issue from what you're describing.