[infotech]

Hello,
On my ongoing AR15 build the complete upper I purchased came with a stock BCG. I purchased one of the custom M16 BCGs from Spikes Tactical and it seems to function just fine -but- I'm reading I need to pull the extractor and check the rifle with a set of go / no go headspace gauges now.

Is this true? Is it something that has to be done every time you replace part of or the entire BCG?

[Dillinger]

Is it absolutely necessary? No. With this day and age of CNC Machining and tighter tolerances, you are PROBABLY fine.

That said, in our shop, we do a Go/No Go headspace check for free - it takes about 2 minutes and then you know you are good to go.

Safety first is always the best practice in my mind.

Some have suggested using a dummy round from a previous batch of ammo you had successfully fired. Actually, someone suggested first using a live round, then later a dummy round. You can do that, it's not for me personally - but I suppose it would work in a pinch. I don't believe you have any old ammo that you successfully fired through the weapon, since it's a new build, so a headspace guage would be worth the limited investment if you like to tinker and perhaps build a few more yourself.

You can get the basic one from Brownells for about $20 shipped to your door.

Or you can get the set, which is about $40 to $50 depending on where you shop. If you are going to build/tinker one or two rifles, and leave them alone, it's probably not worth the money. However, if you plan on doing some major kind of work, or building a gun for someone else, it might be worth it to you.

I would own one as part of my standard range kit, but we have them in the shop that I can use for free.

JD

[stalkingbear]

If you don't have access to headspace gauges and it shoots fine, continue to shoot & have fun. Ars are designed to accept all same standard dimentions bolt carrier/bolt interchangability, and do not require timing. If it's radically different or different sized, then it would be good idea to check headspace.