I'm having a problem setting up the A&B barrel in 416 Taylor. With a piece of belted brass in the chamber I close the bolt and screw down the barrel until I am out of threads and the bolt still opens an closes easily implying that I still have a fair amount of space between the bolt face and cartridge head. Can I fireform with a light load of Unique, cereal and wax plug and just headspace off the shoulder of the formed case? The barrel lock nut is out as far as it can go. What gives?????

Get some headspace gauges (at least a go gauge) so that you know the headspace is right before you fire that rifle!

Be very careful. Depending on your Savage action it sounds like your barrel doesn't have enough threads on it. Get a real live .300 win magnum set of go/no go headspace guages( same as 458win guages) and use Them. With the extractor and trigger group removed from the bolt. Screw the barrel( with the go guage in place) into the action with the bolt closed until it stops and you can feel major resistance on the closed bolt. Open the bolt and close it and you should feel some resistance as it closes completely. Then tighten down the barrel nut. Try the no go guage and the bolt should not close on it. If you can close the bolt on the no go guage repeat as above till you can't. If you set the headspace wrong you risk hurting yourself severely.-Rob

[ 03-13-2003, 08:06: Message edited by: Robgunbuilder ]

You're right, of course. I have been reading of guys doing the Savage barrel swap setting headspace off a piece of brass and was just wondering if forming brass with a light, fast load w/o a bullet would form brass which makes the belt location a non-issue. The true gunsmiths here are likely squirming at that thought but I'm trying to do this one with a minimum of tools and fuss. Probably not possible. Thanks for the warning.

Always, always, always chamber and headspace correctly, you never know who will have the rifle in the future that will not know what is "special" about the chamber. Headspacing off the belt, where fire forming is needed to fit the shoulder to what is a long chamber, is a sure way to obtain case head seperation. AND you really do not know how far that case head is sticking out of the chamber, might be far enough to get into thin brass just above the belt and you will have a ruptured case.

There is no substitution for proper headspace guages, a good depth micrometer, and the correct method of measurement when chambering barrels, or installing pre chambered barrels.

Search the gunsmithing room, we had a discussion on headspacing belted cases a week or so ago. Think it was concerning the 416 Taylor, but applies to all belted cases. Might be in the big bore room, can't remember.

If you are out of threads on the barrel, take the rifle to a gun plumber that knows how to pick up threads and continue, and knows how to headspace correctly.

When one gets into the world of special chambers, neck turned brass, and all those crazy things benchrest and 1000 yard shooters do, it is extremely important to engrave the specifics on the barrel along with the caliber designation, like:

6.5-284 Lapua, 0.290" Neck

This lets future owners know what is required for that special chamber.

Here is the post, saw your questions on it also.
http://www.serveroptions.com/cgi-bin/ubbcgi/ultimatebb.cgi?ubb=get_topic;f=16;t=002993

[ 03-13-2003, 08:56: Message edited by: John Ricks ]