Remington 700, Chambering

Here is the final stage of barrel fitting, chambering.  This barrel has previously been threaded and breach cut to fit a Remington 700 Titanium, as can be seen here.  This barrel will be chambered in .270 Weatherby.  These are the tools required:

In this case a JGS ground .270 Weatherby reamer, PTG Belted Magnum gage set, and a dummy cartridge.  The dummy cartridge is not normally necessary.  In this case I am building a new rifle to hopefully be compatible with ammo loaded for another and a dummy cartridge will allow me to correct any fit issues right away.

The previously prepared breach again coated in Dykem.  This time so I can easily see when the belt portion of the reamer makes contact.  This will be when I first check headspace.

Making chips.  It is interesting the difference cartridge design and proportion make for to the feel of chambering.  The .270 Weatherby is fairly large body diameter in relation to the bore size, a lot of metal has to be removed to clear the chamber.  An example of the opposite proportion is the .300-221 Fireball, very little metal to remove in either diameter or length of the case.  The first one I cut I nearly blew past the headspace the chamber cut so quickly.

This shows the beautifully formed double radius should of the Weatherby cartridge, just have to move it another 2″ forward now.

As soon as the belt portion of the reamer hits the breach, I clean off all the chips and test fit to get a measurement for final headspace.  You see the action, with bolt closed, screwed down tight against the GO gage.  The gap between the barrel shoulder and recoil lug is just about .060″.

So I set up for the final cut, and use a dial indicator to cut .055″ deeper into the barrel.

And here is the result, the chamber nearly done, about .005″ shy of closing on a GO gage, I will ream to headspace once the barrel is installed on the receiver.

One last cut to make with the lathe, a 45 degree chamber on the chamber mouth.

Here the barrel is torqued to the receiver and I use a reamer extension to carefully cut the chamber until it will close on the GO gage with light drag.

After the bolt closes on the GO gage, and in this case the dummy cartridge which needed a bit more then zero headspace to fit, I check with the NOGO gage to ensure I am still with in the tolerance of the belted magnum cartridges.  And this barrel is now chambered, next will be fitting the barreled action to a stock.

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