Difference in brass question

[bayjoe]

I was shooting my Remington VS in 308 today.
I had 5 rounds of 168 grain Hornady A-Max over 42.5 grains of IMR-4064 using twice fired federal brass
Then I had 5 rounds of 168 grain Hornady A -Max over 42.5 grains of IMR-4064 using twice fired PPU brass
OAL was identical
When I shot the rounds with federal brass I shot just under 1/2 inch
When I shot the rounds with PPU brass I shot almost a 2 inch group
With all things being identical except the brass, why such a difference???
FYI - I shot a fowler round and then had a 20 minute break between groups so the barrel was cool.

 

[midnightmalloy]

Brass is very important. I find it WAY EASIER to find a good load with very good brass and very good bullets vs trying to use cheaper components. My example is using lapua brass and Berger bullets. Both are well known for extreme consistency. This makes issues easier to diagnose. Use known temp stable powder such as hogdon extreme powders and a great load is much easier to accomplish!

 

[Dosh]

Case capacity can vary between brands of brass causing pressure differential.

 

[WalksLikeADeer]

I was shooting my Remington VS in 308 today.
I had 5 rounds of 168 grain Hornady A-Max over 42.5 grains of IMR-4064 using twice fired federal brass
Then I had 5 rounds of 168 grain Hornady A -Max over 42.5 grains of IMR-4064 using twice fired PPU brass
OAL was identical
When I shot the rounds with federal brass I shot just under 1/2 inch
When I shot the rounds with PPU brass I shot almost a 2 inch group
With all things being identical except the brass, why such a difference???
FYI - I shot a fowler round and then had a 20 minute break between groups so the barrel was cool.

bayjoe, I would be curious to know the neck thickness of the PPU brass compared to the Federal? I'm having simalar accuracy issues with PPU brass in a 7mm Rem Mag. The PPU brass seems very thin walled at the neck and leaves .011" clearance between a loaded round and the chamber wall at the neck. I don't know if this is what is causing my accuracy issue, but it is one of the components in suspect.

 

[Jnms73]

What is PPU?

 

[WalksLikeADeer]

PPU PRVI Partizan Rifle Brass made in Serbia.

 

[Jnms73]

ty

 

[J E Custom]

I was shooting my Remington VS in 308 today.
I had 5 rounds of 168 grain Hornady A-Max over 42.5 grains of IMR-4064 using twice fired federal brass
Then I had 5 rounds of 168 grain Hornady A -Max over 42.5 grains of IMR-4064 using twice fired PPU brass
OAL was identical
When I shot the rounds with federal brass I shot just under 1/2 inch
When I shot the rounds with PPU brass I shot almost a 2 inch group
With all things being identical except the brass, why such a difference???
FYI - I shot a fowler round and then had a 20 minute break between groups so the barrel was cool.

It is most likely the case volume difference.

Check the volume difference in the Hornady brass and get the average and then do the same to the PPU and that will tell you which one is the most consistent.

I don't recommend using different case brands when working up loads
for this reason. Even though the PPU did not shoot as well, it could out perform the Hornady with the right load if it is more consistent.

So far I have had very good luck with the PPU ammo and brass in certain cartridges.

J E CUSTOM

 

[blumboss33]

its because of the thickness.