Fitting 10-22 barrel

[bruceflinch]

[H8Mud]

Don't force it you can crack the reciever or gall the barrel. I like to throw the barrel in the freezer for a couple hours. It will shrink the shank up a bit. Then right before install I heat up the receiver a bit with a heat gun or hair dryer. They will slip right together.

[ar15barrels]

Warm up the reciever.
It will expand.

Aluminum expands more than twice as much as steel with the same change in temperature.
That means that warming up a reciever by just 120 degrees will get you 4x the change in part size than chilling a barrel by 70 degrees in the freezer.

[ar15barrels]

I like to throw the barrel in the freezer for a couple hours.
It will shrink the shank up a bit.
Then right before install I heat up the receiver a bit with a heat gun or hair dryer.
They will slip right together.

The heating of the reciever is doing all the work.
The freezer is not shrinking the barrel appreciably.
Going forward, you can skip the freezer and just heat up the reciever.
Your results will be the same as if you had chilled the barrel, but your barrel will not get rusted from the condensation you cause by chilling it and letting it come back to room temperature.

[H8Mud]

The heating of the reciever is doing all the work.
The freezer is not shrinking the barrel appreciably.
Going forward, you can skip the freezer and just heat up the reciever.
Your results will be the same as if you had chilled the barrel, but your barrel will not get rusted from the condensation you cause by chilling it and letting it come back to room temperature.

Good to know, thank you.

[bruceflinch]

Warm up the reciever.
It will expand.

Aluminum expands more than twice as much as steel with the same change in temperature.
That means that warming up a reciever by just 120 degrees will get you 4x the change in part size than chilling a barrel by 70 degrees in the freezer.

[ar15barrels]

Have something handy on the barrel to ALIGN the barrel with while the reciever is hot because the receiver will shrink on the barrel in just a few seconds and then it won't be as easy to turn to correct the alignment.
If you heat up BOTH the barrel and the reciever, they will stay loose longer.
If you freeze the barrel, the barrel will quickly cool the reciever and that will make them shrink together even faster than if the barrel is left at room temperature and the receiver heated up.

[Scota4570]

Measure the new barrel with a micrometer, and compare it to the old ones that fit. I bet the new one is too fat. The new one should be machined to fit properly. It is probably a very minor adjustment. It does need to be done in a lathe.

IF you heat, chill and wack, you will have an unitized barrel and receiver. They will probably not be aligned properly when the temperatures equalized.
At that point you have a serious mess.

[Canucky]

Remember the extractor groove alignment. Nice to see you around Bruce. Short Shorts.

[ar15barrels]

Measure the new barrel with a micrometer, and compare it to the old ones that fit. I bet the new one is too fat. The new one should be machined to fit properly. It is probably a very minor adjustment. It does need to be done in a lathe.

IF you heat, chill and wack, you will have an unitized barrel and receiver. They will probably not be aligned properly when the temperatures equalized.
At that point you have a serious mess.

A shrink-fit receiver/barrel junction is more accurate.
That's WHY barrels are being made slightly larger than a factory barrel and why aftermarket 10-22 receivers have a slightly smaller barrel bore than factory 10-22 receivers.
This is all done on purpose to make them more accurate.
No need to undo all that work.
Just shrink fit them...

[ar15barrels]

Remember the extractor groove alignment.

Hence why I said to make sure you have something to align the barrel before the receiver shrinks!
You can always warm the reciever back up and turn the barrel into alignment after the reciever has shrunk.