January 19th, 2019

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 3 Comments »
January 19th, 2019

New PRS Production Class Rifle from MasterPiece Arms

MPA production facotry class PRS competition rifle 6.5 Creedmoor 6mm curtis action mag feed

There’s a formidable new option for PRS Production Class. MasterPiece Arms (MPA) is bringing out a new tactical/practicalcompetition rig, officially called the MPA BA PMR Competition Rifle. This new rifle has a $1999.99 price tag, making it suitable for Production Class. It will be offered with Curtis Action fitted to an X-Caliber, hand-lapped 26″ match barrel. Three chamberings will be available: 6mm Creedmoor, 6.5 Creedmoor and .308 Winchester.

MPA production facotry class PRS competition rifle 6.5 Creedmoor 6mm curtis action mag feed

This rifle is designed specifically for the Production Class requirements of the Precision Rifle Series (PRS) and has been approved for use within this division. It includes many competition-related features while staying under the $2,000 price limit for this class. It is available in either a Black or Tungsten Cerakote® finish. Accuracy is helped with a very good barrel — an X-Caliber, hand-lapped 416R Stainless premium barrel with a polished finish. The chamber is indicated within 0.0001” or less to the bore of the rifle.

The MPA BA PMR Competition Rifle utilizes the MPA BA Ultra Lite Chassis, CNC-machined from 6061 aluminum. The V-bedding system provides additional clearance for glass bedding action and straight section of the barrel. The chassis also includes a built-in inclinometer, thumb notch, lower mounted Picatinny Rail, 20 MOA Scope Rail, A2 Style Pistol Grip and is R.A.T. System compatible. The MPA Buttstock comes with an adjustable cheek riser and length of pull that are locked in position with a series of set screws that are embedded into the buttstock body. This is the same system MPA uses on its Standard BA Chassis, but without the thumb wheels.

MPA production facotry class PRS competition rifle 6.5 Creedmoor 6mm curtis action mag feed

Permalink Competition, New Product, News, Tactical 4 Comments »