[El Bucho]

On a bolt action rifle, what does it mean to "True up the aciton??"

Thanks in advance.

[dfariswheel]

It's a method of accurizing a rifle.

Also known as 'Blueprinting", it means to insure that everything is actually in perfect alignment with the bore per the blueprints.

For instance, the blueprints for a rifle action specify that the front face of the receiver be EXACTLY at 90 degrees to the bore, and the front face be perfectly flat, with no high spots.

When "blueprinting" or "truing up" the action, the front face of the receiver is trimmed with a lathe or milling machine to be SURE it actually IS at 90 degrees to the bore and perfectly flat.

Another check is the front face of the bolt.
It too must be at 90 degrees to the bore, so it too is turned on a lathe to insure it's right.

According to blueprints, both locking lugs in the action should be in equal contact with the locking lugs on the bolt.
Many rifles have one lug that makes slightly less contact than the other.
This causes flexing of the receiver and bolt, and the rifle won't be as accurate.

So the lugs are checked, and if necessary lapped to equal contact on both lugs.

In short, everything about the action is checked or re-machined to be certain it's in perfect agreement with the blueprints.

[USSR]

Basically, it's correcting all the dimensions that cannot be met in a mass produced rifle. The time to do this is when you are replacing the barrel.

Don

[rockstar.esq]

It is also a way to make a $500.00 rifle cost $2000.00 through a great deal of custom work. Course you could just buy a better rifle in the first place...