Barrel to receiver problem

[cutt1100]

I have a Wilson Combat barrel that measures 1.00 at the barrel extension. I have a Cross Machine Tool upper receiver that measures .990 at the barrel opening. Any suggestions. My first build. cutt1100 Thomson GA

[alamo5000]

Not sure where you are measuring from or which specific dimensions but putting up pictures might also help.

[Fathom_Arms]

So is the barrel extension sticking out inside the upper receiver? It should be flush. As stated, pictures would help.

[BoilerUp]

I presume you are talking about diameter dimensions. Use a heat gun to apply heat to the upper receiver. It will expand and let you slide the barrel right in.

[UWone77]

I presume you are talking about diameter dimensions. Use a heat gun to apply heat to the upper receiver. It will expand and let you slide the barrel right in.

This.

Or throw the barrel into the freezer.

Using a rubber mallet to help you tap it into the receiver is useful as well.

[DutyUse]

And don't forget to add a little grease to the barrel extension

[cutt1100]

Nothing wrong with Cross Machine Tool receiver. I measured it wrong (old eyes). With a little grease it slipped right in. Nicest looking upper and lower I have.