[faceplant]

I have a Colt H-BAR with carry handle. I will be changing out the upper reciever for a flat top keeping the 20in barrel. I have ordered an upper assembly with parts but no bcg as I will be using the colt bcg. Do I need to check the chamber or will it be adjusted already?
Thanks

[Constructor]

If you keep the same bolt and barrel combination the headspace will not change so you are good to go.

[faceplant]

So your saying that if I get an extra BCG say from Bravo Company that I would not be able to use it in different ARs without worrying about headspace?

[Constructor]

Most bolts are close and will not pose a problem but CMT/Stag are known to be on the large side, LMTs are known to be on the small side. If you use a Stag bolt in a LMT barrel most will be tight headspace, use a LMT bolt in a Stag/CMT barrel and there will more than likely be too much headspace. I have no idea who BCM buys their bolts and carriers from.
Also swapping back and forth is not a good idea because the lugs of the bolt get mated to the lugs of the extension, they should be flat but nothing is perfect. I would buy a bolt for each barrel and keep them together.

[faceplant]

Thanks

[faceplant]

I changed out the upper reciever. The gas tube was big pain in the backside. I had to use a set of pliers to grip it and bang that with a hammer. Any tips for the next one?

[Constructor]

installing the gas tube in the gas block, including the roll pin?
They make a GB jig, little plastic tray but, I just lay the GB in the vise align the hole and use a roll pin starter. It looks like a long punch but has a hole in the end to hold the roll pin. Then slide the assembly over the barrel and through the hole in the receiver.

[faceplant]

Getting it out of the front site post while taking it apart.

[Constructor]

If I have to pull them apart I clamp the tube in a vise and pull the f-sight base or gas block off.