Bore condition

[Russ]

I know the "bullet test" is not scientific but I find it pretty accurate of the barrel wear on milsurp's.
Here's a 1903 springfield with a new barrel.

And here is a M1 garand with the same bullet.

Seeing this how would you rate the bore on the M1?

Russ...

 

[Imperial luger]

would you be talking about the complete bore ,chamber to muzzle or just the muzzle area, have seen many a rifle with cut down barrels because of crown and muzzle damage that shot just fine afterward.

 

[Russ]

Just a rating based on the bullet test....Not being able to test it for group. Excellent, Very Good, Good, Fair, Poor, Tomato stake.

Russ...

 

[purple]

Well the M1903 barrel looks new. The M1 barrel is approaching .303 at the muzzle, but it still may shoot OK depending on concentricity of the crown. The best test is always to shoot the rifle, but I'd be anticipating a barrel swap for the M1.

 

[Russ]

Which of the 6 descriptions would best describe the bore based on what you see in the picture.
I can add more of a description of the bore based on looking down it with a light but lets just go by the picture right now.

 

[Snider shooter]

Visual bore inspection and bullet test are my first two then see how it shoots. I have rifles here that I thought were canidates for rebarrelling and they shot quite well. It can surprise you.

 

[purple]

Rifling is eroded by propellant gases and friction from bullets and/or improper cleaning techniques. Rifling begins to erode in the throat nearest to the chamber and then moves progressively forward down the bore.

The best say to determine rifling erosion is to use tapered gauges of known dimensions which are inserted in the breech and muzzle. A plug gauge of known diameter can also be passed through the bore to gauge overall wear. As an example, the military throat gauge for the M1903 will show wear from .300 to the reject point of .308. The muzzle gauge will show wear from .300 to the .303 reject point. There are various plug gauges of differing diameters which were used in Lee Enfield bores to establish wear/erosion based on whether or not specific gauges could be passeed through the bore.

In addition to mechanical wear, bore condition is also affected by accumulations of metal fouling and corrosion/pitting from improper/inadequate cleaning techniques. I've spent a lot of time gauging barrels in M1 Garands and M1903 Springfields and find tgat a visual inspection for fouling and corrosion as well as use of muzzle and throat erosion gauges is the best way to do this. Gauges don't lie on rifling erosion/bore wear and they do beat a Mk1 eyeball. Thats why armorers and gunsmiths use them.

 

[weimajack]

MY OPINION IS:

If the end of the barrel is very flush with rifling, bullet test give a good idea.

But, if rifling is not flush the end of the barrel, and is inside a 0.010 - 0.015 or 0.020 in. recess at the end of the barrel, it's will be a false reading.

The only real way to determine rifling erosion is to use an erosion gauge.

When you see inside a barrel from the chamber very strong square scharp rifling, you have a pretty good idea this barrel is top shape.

 

[purple]

A barrel that is otherwise sound and serviceable, but shows excessive muzzle wear from poor cleaning techniques, can often be restored to usable condition by counter-boring at the muzzle. This was done by various foreign militaries and was done by the US military in the case of M1 Carbines. Counter-boring is described and illustrated in the M1 Carbine Technical Manual.

 

[Russ]

On a bolt rifle you can pull the bolt out and look down the bore from the chamber end. on a M1 garand you either pull the barrel off or use a mirror to see from the chamber end. I agree the only true way to give an accurate description of a barrel is with the proper bore/throat gauges. in the end Opinions are like azzholes...everbody has one and not one is alike.

 

[BlackPowderBurner]

I think the bullet test is a poor indicator of bore condition, different bullets have different bearing surface sizes so what may look like a "fail" could in reality be just fine.
What does the bullet test really tell you about accuracy anyway? In my experience not much.

 

[Russ]

But if you use the same bullet in a known new barrel.....as I did...and it drops deeper in another barrel would this not tell you one has more wear than the other.
You can't always test fire a rifle before you buy it. I'm not asking for accuracy, I'm asking for a proper description of the bore condition. Based only on the picture
does this appear to be a new barrel or a well used barrel. In the end this does not matter...Gauge the barrel with proper tools and you have your answer.

Russ...