I'm a big fan of Redding reloading products, so when Midway put Redding's case neck gauge on sale a few months ago, I decided to buy one. This morning I used it for the first time and measured the deviation (runout) of the neck wall thickness of 89 W-W Super .300 Win Mag cases. I've used the cases four times and neck sized only after each firing. When I first bought the cases and weighed each one, the ES was 4.2gr with a SD of 0.64gr. The lightest case was 236.8gr and the heaviest case was 241.0gr.
The theory behind measuring case neck wall thickness is that the cases are formed by drawing the brass into the desired case shape. If the neck thickness isn't uniform, then there's a good chance that the rest of the case wall isn't uniform either ... that's the theory anyway. Inconsistent case wall thickness can adversely affect accuracy. Redding recommends "discarding" cases that have a runout greater than 0.0015" and no, that's not a typo!! This is how the 89 cases measured up.
0.0000" to 0.0005" (13)
0.0006" to 0.0010" (32)
0.0011" to 0.0015" (8)
0.0016" to 0.0035" (36)
So I'll be using 53 of the 89 cases for matches and the rest ... well, maybe hunting or something. I have 100 new Norma cases so I'll measure those necks soon and report back. Here are a couple of photos showing one of the best cases and THE worst case. As you probably figured out, the needle in the dial indicator is shown at either end of the measurement range for that particular case.
I'm very impressed with the Redding case neck gauge. I only had one issue and that was the thumb screw that engages the shaft of the dial indicator to lock it in place. The thumb screw is too short i.e. it doesn't contact the dial indicator shaft so I used a stainless steel set screw (allen head) of the appropriate size. I sent Redding an email so hopefully they'll send me a longer thumb screw. Eventually I'll make up a nice base of aluminum or something, but for now I simply mounted the gauge to a piece of 3/4" thick nylon and clamped it to the bench.
I'll be sending 22 (or more) .300 Win Mag bullets downrange tomorrow during the 600 yard stage of a match so it'll be interesting to see if this effort pays off.
The theory behind measuring case neck wall thickness is that the cases are formed by drawing the brass into the desired case shape. If the neck thickness isn't uniform, then there's a good chance that the rest of the case wall isn't uniform either ... that's the theory anyway. Inconsistent case wall thickness can adversely affect accuracy. Redding recommends "discarding" cases that have a runout greater than 0.0015" and no, that's not a typo!! This is how the 89 cases measured up.
0.0000" to 0.0005" (13)
0.0006" to 0.0010" (32)
0.0011" to 0.0015" (8)
0.0016" to 0.0035" (36)
So I'll be using 53 of the 89 cases for matches and the rest ... well, maybe hunting or something. I have 100 new Norma cases so I'll measure those necks soon and report back. Here are a couple of photos showing one of the best cases and THE worst case. As you probably figured out, the needle in the dial indicator is shown at either end of the measurement range for that particular case.
I'm very impressed with the Redding case neck gauge. I only had one issue and that was the thumb screw that engages the shaft of the dial indicator to lock it in place. The thumb screw is too short i.e. it doesn't contact the dial indicator shaft so I used a stainless steel set screw (allen head) of the appropriate size. I sent Redding an email so hopefully they'll send me a longer thumb screw. Eventually I'll make up a nice base of aluminum or something, but for now I simply mounted the gauge to a piece of 3/4" thick nylon and clamped it to the bench.
I'll be sending 22 (or more) .300 Win Mag bullets downrange tomorrow during the 600 yard stage of a match so it'll be interesting to see if this effort pays off.
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