Headspace question

[STexhunter]

As I understand it most most new rifle barrel chambers are cut a little short needing final reaming when you put them on your action to insure proper headspace.  My question is, if you get a take off barrel from, lets say a Remington, and put it on a Remington action and using a Remington recoil lug, do you still need to do any finish reaming?

[Luckyducker]

Let me first say I am not a gunsmith.  I have heard from the gurus that build custom rifles that installing a manufacturers barrel on another action is harder to set the headspace than installing a barrel makers barrel on this action and setting headspace.  I don't think the chamber would have to be finished reamed, but I really don't know.

[trotterlg]

If you put a Remington take off barrel on a Remington action of the same type using a factory recoil lug you will probably be close, but not perfect.  Easiest thing to do is change out the recoil lug to a thicker or thinner one to get the proper headspace.  Savage solves this problem by using a barrel nut, then you set the headspace by scerewing in the barrel and and tighten down the nut when it is right.  You should not have to ream the chamber on a factory barrel.  Larry

[gunnut69]

Standard practice when using a takeoff barrel is to cut one thread off and move the shoulder on the barrel back a like amount. The barrel is then installed and finish reamed to the proper head space. Most prethreaded after market barrels are sold this way and it's called a 'short chambered' barrel. A long chambered barrel is set so the chamber is reamed too deep. The head space is then set by turning the correct amount off the barrel end and the shoulder.

[wtroger]

There are several things to take into consideration when head spacing a barrel. The barrel shoulder to the end breech of the barrel needs to the correct length for the action being used. If it is a Mauser then it needs to come tight against the inner shoulder on Rugers, Remintons and non claw extractor Winchesters you need to insure the breach is as close to the bolt face as possible but not interfering. You want to insure that you do not have a lot of unsupported case when the bolt is at battery. And no you cannot assume anything when fitting a barrel to an action even if they came from the same manufacture and model. Always head space. If a  bolt won't close easily on a go gauge then finish ream by hand until it will (I like to just feel mine come against the gauge when the bolt is at the end of its travel.) It the bolt closes on a no-go gauge then take off the need amount from the shoulder and/or the breech face as needed. I like the rifles I build to be close to minimum head space they seem to be more accurate and easier on brass.