September 25th, 2017

Stub Gauges — Cool Tools That Perform Important Functions

Barrel Stub Gauge

Next time you have a barrel fitted, consider having your gunsmith create a “stub gauge” from a left-over piece of barrel steel (ideally taken from your new barrel blank). The outside diameter isn’t important — the key thing is that the stub gauge is created with the same reamer used to chamber your current barrel, and the stub must have the same bore diameter, with the same land/groove configuration, as the barrel on your rifle. When properly made, a stub gauge gives you an accurate three-dimensional model of the upper section of your chamber and throat. This comes in handy when you need to bump your case shoulders. Just slide a fired case (with spent primer removed) in the stub gauge and measure from base of case to the end of the gauge. Then, after bumping, re-measure to confirm how much you’ve moved the shoulder.

Barrel Stub Gauge

In addition, the stub gauge lets you measure the original length to lands and freebore when your barrel was new. This gives you a baseline to accurately assess how far your throat erodes with use. Of course, as the throat wears, to get true length-to-lands dimension, you need take your measurement using your actual barrel. The barrel stub gauge helps you set the initial bullet seating depth. Seating depth is then adjusted accordingly, based on observed throat erosion, or your preferred seating depth.

To learn more about stub gauges, read this AccurateShooter Forum Thread.

Forum member RussT explains: “My gunsmith [makes a stub gauge] for me on every barrel now. I order a barrel an inch longer and that gives him enough material when he cuts off the end to give me a nice case gauge. Though I don’t have him cut that nice-looking window in the side (as shown in photos). That’s a neat option. You can tell how much throat erosion you are getting from when it was new as well. For measuring initial seating depths, this is the most useful item on my loading bench next to calipers. Everyone should have a case gauge made by their smith if you have a new barrel put on.”

Forum member Lawrence H. has stub gauges made with his chamber reamers for each new barrel He has his smith cut a port in the stub steel so Lawrence can actually see how the bullet engages the rifling in a newly-cut chamber. With this “view port”, one can also see how the case-neck fits in the chamber. Lawrence tells us: “My stub gauges are made from my barrels and cut with my chamber reamers. With them I can measure where my bullets are ‘touching the lands’ and shoulder bump dimensions. This is a very simple tool that provides accurate information.” The photos in this article show the stub gauges made for Lawrence by his gunsmith.

Permalink Gear Review, Gunsmithing, Reloading 1 Comment »
August 19th, 2016

Smart Tool Tip: Make Your Own Length-to-Lands Gauge

Here’s a tip we feature every year or so, because it is something that costs nothing, yet can be very useful in the reloading process. With a simple, easy modification to a fired case, you can determine the length to lands in your rifle barrel. As long as you set the tension right, the measurements should be repeatable, and you’ve just saved yourself $31 — the price of a commercial OAL gauge.

To achieve best accuracy with a rifle, you must control bullet seating depth very precisely, so all bullets end up in the same place relative to the entrance of the lands, every time. There may be multiple cartridge OALs which prove accurate. However, with each, you first need to determine a “zero” point — a reliable, and repeatable OAL where the bullet is “just touching” the lands.

There are tools, such as the Hornady (formerly Stoney Point) OAL Gauge, that will help you find a seating OAL just touching the lands. However, the tool requires that you use a special modified case for each cartridge you shoot. And, while we find that the Hornady OAL Gauge is repeatable, it does take some practice to get in right.

Make Your Own Length-to-Lands Gauge with a Dremel
Here’s an inexpensive alternative to the Hornady OAL tool — a slotted case. Forum member Andris Silins explais how to create a slotted case to measure length to the lands in your rifle:

“Here’s what I did to find length to lands for seating my bullets. I made four cuts into the neck of fire-formed brass. Then I pressed the bullet in lightly and chambered the entire gauge. As the cartridge chambers, the bullet slides back into the case to give you length to lands. It took less than five minutes to get it cut and working. A little light oil in the barrel just past the chamber helps ensure the bullet does not get stuck in the lands. It works great and is very accurate.

case OAL gauge home made

I made the cuts using a Dremel with a cut-off wheel. You can adjust tension two ways. First, you can make the cuts longer or shorter. Longer cuts = less tension. If you used only three cuts insted of four you would get more tension. The trick is to be gentle when you open and close the bolt. If you ram the bolt closed you may wedge the bullet into the lands. When you open the bolt it helps to keep a finger or two near by to guide the case out straight because the ejector wants to push it sideways.”

Permalink Bullets, Brass, Ammo, Reloading 7 Comments »