Thanks, I double checked and it is the go gauge. I will reclean everything again and then test the go gauge. If still no luck. I will start adding the tape to the snap cap as you suggested.The most reliable measurement is with the go gauge (you are sure it is not a no-go gauge?). Snap caps are made smallish so that they fit any 8x57 out there. But to get an idea, add layers of tape to the base of a snap cap until you start feeling it get tight to chamber. That will give you some idea of the chambers headspace. Compare that to your go gauge headspace and to SAAMI specs.
It is very strange that you can not close the bolt on a go gauge. The chamber and bolt might need a good cleaning. I would want to fully understand why the go gauge does not pass even if you can resize brass to fit a short chamber.
Yes, I am using a Forster. A photo is attachedWhat is the dimension stamped on your gauge? A Forster 8x57 go gauge 1.874". No go gauge is 1.880".
Tom
All the responses are correct, but this adds a significant detail. Brass is nearly self-lubricating; hardened, unpolished tool steel is not. Any tool marks on front of extractor multiply this, especially that both are formed radially and near identical size. Though small, they can engage almost like gears, it just takes one. It is not common, but does occur.Place the gauge in the bolt head first, instead of relying on the extractor to snap over the rim on the gauge. Snapping over the rim of a gauge is sometimes harder than over a cartridge.
The most reliable measurement is with the go gauge (you are sure it is not a no-go gauge?). Snap caps are made smallish so that they fit any 8x57 out there. But to get an idea, add layers of tape to the base of a snap cap until you start feeling it get tight to chamber. That will give you some idea of the chambers headspace. Compare that to your go gauge headspace and to SAAMI specs.
It is very strange that you can not close the bolt on a go gauge. The chamber and bolt might need a good cleaning. I would want to fully understand why the go gauge does not pass even if you can resize brass to fit a short chamber.