Just obtained Sinclairs bump gauge insets with the intent of minimally resizing my brass for my AR rifles. In .223 the difference betweem fired and full length resized cases is.005" in .223, and in 6.8 SPC the difference is .003". I consider these measurements to be acceptable minimum shoulder set back for my rifles. I had thought that the shoulders would be moved back more than this and had expected to need to adjust my dies to obtain the amounts I am getting with with the die body contacting the shell holder. I am interested in hearing of others experiences when checking shoulder set back when full length resizing. Thanks.
Sinclair bump gauge
- Thread starter 4306
- Start date
Ron H.
US Veteran
Sir, I've not used the gauge you mention, but I suspect it would be more appropriate to a bolt gun than an AR. When I was loading for the AR for high power competition, it seemed like case body expansion was a bigger issue than shoulder movement. I checked my brass with a Wilson case gauge, and fired brass always stopped on the body long before reaching the shoulder. This was in a match upper built by John Holliger, BTW, so it wasn't some sloppy parts gun.
Hope this helps, and Semper Fi.
Ron H.
Hope this helps, and Semper Fi.
Ron H.
