357 mag bore diameter?

[bluesman423]

I thought I saw my question answered but now cannot find it.

I do not have the ability to measure my rifle bore.

Can somebody please tell me the most common bore diameter for a Rossi 357 magnum rifle?

[Gunny268]

According to SAAMI Specs. Bore Dia is .346. Groove Dia is .355. But I don't think they (Rossi in So. America) ever held their work to SAAMI Specs.
Best to "cerrosafe" cast your chamber and about 1" of the bore ahead of the chamber (or slug the barrel) to get the actual dimensions.
Example is my 45 Colt M92 has a groove diameter of .4548 (SAAMI spec is .450). Have to use .455 cast bullets or .454 jacketed to get good accuracy.

[cavelamb]

There is no such thing as a common dimension in firearms.
There are the design specifications, and manufacturing tolerances.

So your barrel size depends a lot on how worn (or new?) the reamer was.

Slugging the barrel is not hard.
Cerrosafe is the simplest and best way.
For slugging, use a dead soft lead pellet.
There are Youtube vids on how to do it.

[Sarge]

I can only tell you my last one, an early Taurus R92, loved Hornady XTPs and shot really well (2 MOA to 200 yards) with them.

[golfish]

(2 MOA to 200 yards)

Oh my!

[cavelamb]

Might be time to reexamine what MOA actually means?

MOA stands for "Minute Of Angle," which is a unit of angular measurement. When the accuracy of a gun is given in minutes of angle, it is possible for a person to know approximately what size groups the gun shoots within its effective range.

There are 360 degrees in a circle, and 60 minutes of arc in each degree, totaling 21,600 minutes of angle in a complete circle. Imagine the shooter is at the center of a circle, and that the target is on the edge of that circle. The distance, or range, from the shooter to the target is also the radius [R] of the circle. For any given range or radius [R], one minute is equal to (2) x (Π) x (R) / (21,600).

If the range is 100 yards, that distance is equal to 3,600 inches. When we plug 3,600 in for R in our formula, the result is (2) x (3.1416) x (3,600) / (21,600) = 1.0472 inches. Therefore, at 100 yards, one MOA is equal to 1.0472 inches. The formula works for any range. If the range is 500 yards, one MOA equals 5.2360 inches.

Many shooters equate one MOA to one inch at 100 yards, 2 inches at 200 yards, and so on. Often, they will call a gun that shoots one-inch groups at 100 yards a "one-MOA gun." Since targets are usually on an inch grid, and sight adjustments in fractions of an inch, the difference between "true" minutes of angle and "shooters'" minutes of angle is academic at close range.

Rifle Shooter Magazine