Why does ammo (quality) make a difference in accuracy

[fredridge]

I am talking same caliber.....shouldn't it just be an explosion that sends it down the opening and the barrel determines accuracy?

I mean if bullets are the same shape and all, why is there difference?

[Beetle Bailey]

Ammo quality is about, among other things, consistancy. You want brass to be as uniform as possible, powder charge to be the same from round to round, consistant primers to ignite the powder charge, and cartridge overall length to be the same.

Bullets also have to be consistant. The box says each bullet weights 168 grains but depending on manufacturing techniques, the individual bullet weights may vary. You want them all to weight the same. And it's not just weight, the ogives must also be the same, as well as the bearing surface.

The more consistant the ammunition, the more repeatable the results you get.

BTW smokeless powder does not explode, it simply burns at a fast rate and the result is expanding gases that push the bullet down the barrel and out of the muzzle. It's internal combustion, just like in your car's engine.

[Biigg50]

Ammo quality is about, among other things, consistancy. You want brass to be as uniform as possible, powder charge to be the same from round to round, consistant primers to ignite the powder charge, and cartridge overall length to be the same.

Bullets also have to be consistant. The box says each bullet weights 168 grains but depending on manufacturing techniques, the individual bullet weights may vary. You want them all to weight the same. And it's not just weight, the ogives must also be the same, as well as the bearing surface.

The more consistant the ammunition, the more repeatable the results you get.

BTW smokeless powder does not explode, it simply burns at a fast rate and the result is expanding gases that push the bullet down the barrel and out of the muzzle. It's internal combustion, just like in your car's engine.

Exactly! When I was shooting BR matches, I weighed everything and sorted bullets, brass and primers by weight. Then measured my powder very carefully and assembled each round with great care. Each gun will like something different so a load has to be worked up for each firearm.
Quality is everything when it comes to accuracy!

[SanPedroShooter]

The key to precision is consistency. Accuracy too. They are two different concepts, but they both depend on being able to repeat or control the same factors everytime.

There is a lot more going on in rifle chamber than just an 'explosion'. Its actually not an explosion, it a rapid deflagration. There is a difference there too.

[bubbapug1]

The most important parts of good ammo are consistent powder charges (velocity) and a bullet which leaves the barrel straight. The bullet also needs to be concentric weight wise around the axis of rotation, and not have separation between the lead and the jacket.

Makers of bullets like Sierra, Nosler, and Berger spend a lot of time and money on uniform jackets and equipment needed to maintain that consistency while making the bullet.

Primers must also need to ignite the powder consistently with no or little variance between each shot.

It also helps if the bullet is chambered parallel with the bore, and to do so the brass should be as larger as possible to the chamber...as in fire formed.

It has been proven loads using a powder which fills the case completely produce less variance in velocity from shot to shot.

To get the best ammo, you need to reload.

[ddindetroit]

Beetle

Ammo quality is about, among other things, consistancy. You want brass to be as uniform as possible, powder charge to be the same from round to round, consistant primers to ignite the powder charge, and cartridge overall length to be the same.

Bullets also have to be consistant. The box says each bullet weights 168 grains but depending on manufacturing techniques, the individual bullet weights may vary. You want them all to weight the same. And it's not just weight, the ogives must also be the same, as well as the bearing surface.

The more consistant the ammunition, the more repeatable the results you get.

BTW smokeless powder does not explode, it simply burns at a fast rate and the result is expanding gases that push the bullet down the barrel and out of the muzzle. It's internal combustion, just like in your car's engine.

Beetle is correct. Except this is how you spell consistent.

Let me comment and say the bullet is extremely important. Hence Sierra bullets (the benchmark boolit) commands a good price.

Berger boolits made in Fullerton, Kalif is hand swaged and this is very very consistent because the operator can visually inspect and 'feel' every boolit when it comes out. That's why it commands prices at double Sierra prices which are machine swaged.

I grab Bergers when they come on sale.

DD

[ar15barrels]

I mean if bullets are the same shape and all, why is there difference?

The bullets are NOT all the same shape.

Cheaper bullets do not have jackets that are as consistent as match bullets.
Match bullets are more consistent and therefore more accurate, but add a lot to the cost of the ammo.