The UK's Finest Independent Forum for Shooters and Gun Owners. Est 2010.

Have bought a new to me Rossi 92 16" .44 mag, I did a little internet research before it came.

I decided it would need a .430 cast boolit just as the internet said should be a good fit.

The rifle would only group at 2 to 3" at 25m. At 50m it's like a shotgun including tumblers.

I slugged the barrel last night...... .432. Pants, I have around 2000 cast boolits that will go back into the pot. Lesson number one, slug the barrel

Bullet fit is king and you will get that when you know your specific firearms dimensions.

You need to get a better job that keeps you occupied in the darkness of the night so that you don't waste your life wading through fables, myths, legends, old wives tales and down right lies and misinformation on the internet trying to learn about shooting and guns.

What exactly is slugging? Is it getting the exact bore measurement?
How is this done?

The "easy" way is to push a tight fitting lead ball through the barrel so that it fills the grooves. After that, your problems start: most rifles have an odd number of grooves, so that the imprint of land and groove on the slug are opposite each other. I have encountered many claims of people rotating the slug in the jaws of a micrometer and getting an accurate dimension. It just does not work. The technique that I came up with is to chuck up a bit of scrap steel in the lathe and drill a hole slightly smaller than the nominal bore diameter. Then, using a good sharp boring bar, gradually open up the hole until the slug will just slide into it. You now have a groove diameter hole which can easliy be measured.
Fred

Thanks Fred

dromia wrote:Bullet fit is king and you will get that when you know your specific firearms dimensions.

You need to get a better job that keeps you occupied in the darkness of the night so that you don't waste your life wading through fables, myths, legends, old wives tales and down right lies and misinformation on the internet trying to learn about shooting and guns.

You could work for the Samaritans.......

I use "V" blocks for measuring odd groove number rifling.

Not being a lathe owning type of person.

Dahonis wrote:

dromia wrote:Bullet fit is king and you will get that when you know your specific firearms dimensions.

You need to get a better job that keeps you occupied in the darkness of the night so that you don't waste your life wading through fables, myths, legends, old wives tales and down right lies and misinformation on the internet trying to learn about shooting and guns.

You could work for the Samaritans.......

No I am far too sensitive for stuff like that.

The method I use to measure a bore slug that has an odd number of grooves, is to wrap a piece of copy paper tightly once around the slug, take a measurement then subtract twice the paper thickness.

ukrifleman