.303 Throat Gauges
Posted: Tue Mar 31, 2020 4:17 pm
We all know someone with a .303 rifle, or own one ourselves. In fact I believe all new FAC holders should get out and shoot one at some point, just because. I have a modest collection of .303 Sporting and military rifles, including Lee Speed and postwar No1Mk3 commercial examples here in the armoury along with later ones such as the 1920 Lithgow below.
One thing I can usually say about the .303 rifle is it will have been shot, usually shot a lot and accuracy does suffer after a while. Now accuracy is not always a good reason to buy a rifle and I have rifles here that will not shoot a hand span group at a 100 yet they are keepers, equally I have worked with rifles capable of shooting tiny groups at extremely long distances that have left me cold.
For me, the majority of .303s are usually very special rifles and to find one that shoots is even better, so how to determine if the rifle in your hands is going to shoot? Well range time is the simple answer, however you can also check a few areas before taking the rifle out and bore and throat erosion are always good places to start. A careful peer up a barrel tells you a lot however a shiny bore is not always a good bore and if the throat has disappeared 3/4" up the barrel you are always going to chase accuracy. So I made some throat gauges for just this reason and here is a prototype and an early version.
Use is very simple, just remove the bolt and drop the gauge into the chamber. The amount of the relieved section visible gives an instant indication of throat erosion. This is not an absolute measurement and just because the throat has gone does not mean the rifle should be put back in the rack, however if you gauge two identical looking rifles and one swallows the gauge you know which one to shoot first.
So there you go, one small area to check when considering a .303 purchase. I should probably sit down and write a book of such tips however not all of them are going to interest people.
....so why am I telling you this? Because you need to know.
One thing I can usually say about the .303 rifle is it will have been shot, usually shot a lot and accuracy does suffer after a while. Now accuracy is not always a good reason to buy a rifle and I have rifles here that will not shoot a hand span group at a 100 yet they are keepers, equally I have worked with rifles capable of shooting tiny groups at extremely long distances that have left me cold.
For me, the majority of .303s are usually very special rifles and to find one that shoots is even better, so how to determine if the rifle in your hands is going to shoot? Well range time is the simple answer, however you can also check a few areas before taking the rifle out and bore and throat erosion are always good places to start. A careful peer up a barrel tells you a lot however a shiny bore is not always a good bore and if the throat has disappeared 3/4" up the barrel you are always going to chase accuracy. So I made some throat gauges for just this reason and here is a prototype and an early version.
Use is very simple, just remove the bolt and drop the gauge into the chamber. The amount of the relieved section visible gives an instant indication of throat erosion. This is not an absolute measurement and just because the throat has gone does not mean the rifle should be put back in the rack, however if you gauge two identical looking rifles and one swallows the gauge you know which one to shoot first.
So there you go, one small area to check when considering a .303 purchase. I should probably sit down and write a book of such tips however not all of them are going to interest people.
....so why am I telling you this? Because you need to know.