Hornady Lock-N-Load Neck Wall Thickness Gauge
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- Last updated: 01/07/2019
I tested the Hornady Bullet alignment/ concentricity tool recently and it’s proving to be a valuable asset on my reloading table. It’s a great piece of kit and has the added benefit that you can use additional attachments for other operations.
I purchased the neck wall thickness gauge, as this is a very handy add-on that fits directly to the concentricity gauge chassis, which allows an accurate measurement of the neck wall thickness and uniformity of the neck itself. This can be really handy in segregating brass with irregular, lop sided or differing wall thicknesses, which will affect bullet seating, neck tension and ultimately accuracy.
It’s nicely packaged and comes with all the kit you need to get started and has clear and concise instructions. It consists of three components; dial indicator, calibre pilots and pilot spindle. The new indicator offers better accuracy, as it has a measurement capacity to 0.0005”; in old money, that’s half a thousandth of an inch, which is pretty damn precise and all you need for the neck measuring operations. The pilot spindle holds the pilots that support the neck and you have a good selection of ten provided covering the major calibres; .22, 6mm, .25, 6.5mm, .270, 7mm, .30, .338, .35 and .45. Additional sizes can be ordered.
You need to fit the spindle and pilot first, by unscrewing the large rubber ball knob on the gauge and removing the bullet spindle. Keep the spring and collar and inset the new pilot spindle in its place. Select the correct calibre pilot for your case to be measured and insert into the head of the new spindle and tighten in place with the grub screw and Allen key provided. Replace the rubber ball to the new spindle and check it all moves freely.
Replace the old dial (0.001”) for the 0.0005” unit, which is retained by the large thumbwheel tightener on top of the cradle. Position the cradle by loosening the thumbwheel that slackens the dovetail rail, so that the indicator spindle is touching the straight part/surface of the pilot. It’s important that the dial indicator spindle is not fouling the pilot spindle face, otherwise a false reading will occur. Finally, remove or slacken off the bullet straightening nylon tipped probe on the cradle, as it’s not needed here and set the O-rings on the dial indicator to the body of the dial so that when a case is inserted it does not foul it.
To position the case, loosen the case head spindle lock to the left of the tool, so that the case can be inserted and then slid forward. This will position the neck over the calibre-specific pilot, but just so it passes the undercut and not touching the actual spindle face. Lock off the case head spindle and now cases can be inserted and removed by just pulling on the black rubber sprung knob of the pilot spindle.
With a case in place and the indicator dial spindle resting on the neck, rotate only the case. The actual calibre-specific pilot must not move. So, it is advisable to have the pilot’s grub screw facing upwards, so that you can see it and if it moves. Any rotation will cause a false reading.
Rotate the case until you get the lowest reading on the dial and set it to zero by loosening its face lock and rotate the face until it indicates zero. Now, rotate the case again and the maximum reading will be the runout of the neck wall but hold the black rubber knob to stop the pilot rotating. You can therefore separate cases by the amount of run-out on each neck. From the results, 0.001 to 0.002” is fine, above this I would put to one side.
For measuring neck wall thicknesses, set the dial indicator spindle on the calibrespecific pilot without a case and then zero the dial. Place a case onto the pilot and the measurement is the neck thickness, which can be measured around the neck by rotating the case, but again keep the pilot stationary. It takes far longer to explain it in words than actually do and it’s really simple or intuitive to use.
I ran differing brands of cases over the gauge and checked for runout and thick wall thickness/variation.
As you can see, the cases from Hornady and Lapua were, as expected, very consistent with very little run-out of only 1 to 1.5 thousandths of an inch, which is really good. Although the case neck wall thicknesses did vary between the calibres quite a lot, which I found interesting, very consistent but different.
You need to get a feel for the tool and hold the case at the rear end by the case head spindle and rotate the case. If not and you hold the case higher up near the shoulder, you have the tendency to cant/tilt it when rotating and this will give a false or enlarged reading. Also, with the other hand, keep the pilot spindle stationary for the same reason. Other than that, a really good bit of kit that can be fitted and refitted as an when you need it. Next time, I will try out the neck turning tool.
This is a very neat little attachment tool to help the reloader get the best from their handloads. It is easy to set up and use and can instantly tell you if your cases are uniform and true, as well as if your neck turning has been successful or not. You have to follow the instructions correctly to get the best results and make sure you rotate evenly and not with a slight angled pressure otherwise the neck can sit askew on the pilot. Practice and excellent results will be your reward.