The Hornady LNL gauge (formally Stoney Point) combined with a BRT Custom modified case is a great tool to measure the lands touch point of certain bullets in your rifle.
To use this device accurately you need a special modified case made from your fired cases’
We do not supply the Hornady branded modified cases. This because they are generic and have not been fired in any chamber let alone in your rifle. They will give reasonable, general, approximate results but not precise results for the chamber in your specific rifle. Basically those Hornady modified cases are virgin brass and the headspace measurements of those will not match case fired in any chamber. This is why the best, most accurate way if to modify a case which has been fired in your rifle to match the actual headspace and therefore give you results which are true.
We offer a service to modify your cases that have been fired in your rifle.
To do that we need you to send us two (2) cases fired from your own rifle – one case correctly full length sized (see below) and the other case unsized (simply a fired case with spent primer still in).
Send 2 cases well wrapped in a piece of thick cardboard or a container and then place them in a small PADDED mailing bag (not an envelope or they will get here crushed). Your Name, address and contact details inside also.
Post to BRT, PO Box 1124, Springwood. QLD. 4127.
The benefit of this is that only then will you get accurate measurements because you will be using a case which has already been fired in your chamber (fireformed)
We drill and tap the thread in the head of a case using a proper lathe. The thread is an unusual type. The inside of the neck needs to be reamed also to allow the bullets to slide.
IMPORTANT: We can”t stress this enough. Please read and understand the following because 50% of the time we receive cases here which are over or under resized and a good result therefore cannot happen. This situation also tells us that many reloaders are not correctly using the proper tools (cartridge headspace measuring tools) to setup their resizing dies correctly. This is a reloading fundamental.
The full length resized case which you will send us needs to be correctly resized so that the headspace measurement (shoulder bump) equals that of the fired case which is not resized. In other words what this means is “zero shoulder bump”. The second case, just a fired case is for reference purposes mostly. This case you can leave the spent primer in if you wish.
It is important that you understand this otherwise the modified case cannot not give precise results for you. I can modify most standard cartridges but if the FL sized case you send me is not correct the result is no good really. This would be as bad as buying a standard Hornady brand Modified case which is an unfired case and doesn”t match your chamber. So to match your chamber we simply need a FL or Body resized case set to ”zero shoulder bump”.
When reloading you generally try to achieve – 0.002″ (0.05mm) shoulder bump (compression) of your FL resized cases . That means, for a rimless cartridge, the shoulder is compressed this very small amount. So you always need the right gear to measure and achieve this die setup anyway.
But for this modified case to work properly, use the same equipment but adjust the die to achieve this ”zero shoulder bump”. Not longer, not shorter, equal to the measured fired cases!
Tip: when taking a cartridge headspace reading on a fired case, remove a spent primer first because any small cratering of the firing pin hit can give you a false reading of what the real cartridge headspace happens to be. You are measuring down to the case head and if the caliper blade cannot fully contact across the case head because of a cratered primer, the result therefore, will be false.
If you do not already own and are using the proper tools for Cartridge Headspace measuring, you will really need to consider these. This is essential reloading practice for correct die setup of all types and style of Full Length, Body and/or shoulder bump type resizing dies in a reloading press.
Examples of 4 types and brands of these tools which we sell to achieve these jobs are: