AlNyhus
Silver $$ Contributor
skeetlee said:what are most of you fellas trimming your 30BR brass back to? I have been trimming at 1.515. Should i go on back to 1.500, or does it make much difference? Thanks Lee
Lee: A true 'Robinett' spec 30BR reamer will have 1.520 chamber length. On both my 30BR's, I trim to 1.500 and leave it at that. Reamer mfgs. work to tolerances and unless you know exactly how long the reamer cuts the neck length, running to within .005 can cause some fliers that will be hard to track down. There's no upside to running them that close...only downsides. I do take a bit of care to make sure no hard powder fouling gets built up in the gap between the end of the neck and the end of the chamber neck area....a bit of Shooters Choice Black Powder Gel on a brush and a few twists in that area once in a while does the trick.
I've run them to within .005 doing some testing and have never found any advantage. When Stan Ware chambers a barrel for me using a reamer we've never used before, he runs the reamer into a piece of round aluminum and then does a cut-away of it. This is a great tool for a visual check on how the case neck length fits the chamber neck length and allows me to know exactly how long the neck can be w/o running into the end of the chamber neck area. This is a crappy pic, but you'll get the idea.
By the way, the late Shelley Davidson had very good success with Benchmark in his 30BR. There's nothing at all wrong with great accuracy from these cases in the 2850-2950 range, that's for sure.
