How to fix "nicks" on extractor rims?

[PolarFBear]

A final note on my case head aggravation: Stopped in to a Bass Pro, had a Xmas gift card to burn, and picked up a Lyman case gage. This is the model that does six calibers. Tried some of my Speer Lawman reloads. They "passed" on the Lyman gage but "failed" on the Dillon. I guess SAAMI specs are different at the two companies. I trust both firms as a Gold Standard but now I am curious.

[jmorris]

They "passed" on the Lyman gage but "failed" on the Dillon.

It's called tolerance, every machine part has it. Some are large and others small but every blue print has a +\- specification. Worst case would be having a gauge at the + end and a chamber at the - end. I would use the tighter case gauge, myself.

[ShootistPRS]

Even SAAMI lists a range of dimensions for the case and the chamber for every cartridge they show specs for.

[Reloadron]

PolarFBear:

A final note on my case head aggravation: Stopped in to a Bass Pro, had a Xmas gift card to burn, and picked up a Lyman case gage. This is the model that does six calibers. Tried some of my Speer Lawman reloads. They "passed" on the Lyman gage but "failed" on the Dillon. I guess SAAMI specs are different at the two companies. I trust both firms as a Gold Standard but now I am curious.

Which Lyman case gauge? There are a few things to consider when using a case gauge, starting with which dimensions it actually looks at. For example most case gauges like these:

Lyman
Wilson
Dillon

Look at a few case features but for example ignore case diameter(s). I only used Lyman and Wilson as examples as there are other similar gauges. The manufacturers do explain their gauges and what dimensions they measure. There are a few newer case gauges out there like:

Sheridan Engineering

These gauges are cut to chamber specifications including diameter. Likely the best gauge available is your own chamber. Resize a case, trim as necessary and see if the sized case chambers in your rifle(s). Most off the shelf case gauges are really little more than a Go/NoGo gauge as they really don't provide a numeric value. They can be used with a good straight edge (steel pocket rule) and some good feeler gauges to get a numeric value as long as the case gauge manufacturer tells you what their gauge is and the step values but this will always go back to your chamber.

Ron

[jmorris]

It's not uncommon for folks that barrel a rifle to make a case gauge using one of the drop off the barrel blank and the reamer used to chamber it.