I bought a 30-06 headspace field gauge to check my newly acquired Winchester M1917 in order to see if it was safe to shoot. I also bought a Winchester bolt last week on eBay to replace the Eddystone bolt that came with the rifle so I had two bolts to test. The Eddystone bolt passed and the Winchester bolt failed. The eBay seller agreed to take the Winchester bolt back and refund my payment. The $29 I spent for the headspace field gauge was probably the best investment I've made in a while. It also points out the fact that excessive headspace isn't always caused by a worn barrel.