Can case cleanliness affect accuracy?

[handofcod]

Just like the title says, if I have 100 beautifully clean cases, and 100 slightly dirty ones, eg not full of crud but not exactly sparkling either, and all other things are equal, can I expect better consistency / accuracy from the cleaner cases?

Of in other words, would you put case cleanliness down to more than simple appearance? How much does case appearance factor into your reloading?

[tom604]

short answer,,,no long answer,,,,slightly dirty= no full of crud= maybe, you have to take into account that you have to clean your brass a bit before you can reuse them

[handofcod]

I clean them in a sonic cleaner but some come out cleaner than others. I was wondering if they all had the same level of cleanliness they would be more consistent.

[Chronos]

Removing some or all of the carbon from inside the case necks is believed to affect neck tension or friction on bullet release. I've even heard if people adding graphite to clean case necks with a bore brush to replace this carbon.

Bare in mine the tightest groups youll ever see shot at 100 and 209y are shot from cases just deprived, primed, charged and seated.

I think for most of us there are probably 30 things that would improve out accurate before worrying about how clean a case is.

Chronos

[handofcod]

Cheers, good to know.

[Lamijo]

Clean case are safer to use as it is eaiser to see any flaws in the case. I will take safety over accuracy any day

[Tiiger]

It's arguable there could be some impact.

But what level of accuracy are you chasing? Fun? Hunting? Match?

For all but the most serious target shooter I'd say there is no difference.

[Lorgar]

How much does case appearance factor into your reloading?

Not at all really.

I lube then size mine before tumbling them. The outside is quite shiny, but the inside of the necks have a fine layer of 'dust' from the tumbler media.

As would the inside of the cases but I've never really got in there and looked.

I don't bother to clean the inside of the necks, just seat the bullet into it.

I haven't done any comprehensive testing, but I noticed no difference between this and loading new brass which was sized, but not tumbled so still perfectly clean.

[Carter]

I clean them in a sonic cleaner but some come out cleaner than others. I was wondering if they all had the same level of cleanliness they would be more consistent.

When you say some come out cleaner, the "dirty" ones we're just talking about discolouration or tarnishing, right? Not a layer of grime obviously.

If you're just talking about surface tarnishing and discolouring I wouldn't think it would make any difference whatsoever.

That tarnishing would be soooooooooo thin you couldn't tell. IMO.

[handofcod]

No in my case I have some come out perfect inside and out, some may be a little discoloured, but others still have some visible grime inside. This happens mostly with 223s for some reason.

I was debating the virtue of upgrading to a better case cleaner but thought it might not be causing and issues with shooting in the first place.

[Korkt]

On paper...

A layer of grime inside the case would change case pressure by some degree. As discussed though, whether or not it matters or is even noticeable is another thing.

I see you've got a Tikka sporter and Ruger Scout there. Neither are meant for ultra-accurate (not knocking them, just saying what kind of rifle they are, you get it...) so I guess the focus is on your R5.

What sort of ranges are you covering with that?

[handofcod]

Just 100m for the time being. I'll step up to 200m once I'm confident I can produce repeatably accurate ammo from batch to batch.

[Korkt]

At 100m I seriously doubt you'd see any decisive difference.

As Chronos said "I think for most of us there are probably 30 things that would improve out accurate before worrying about how clean a case is. "

Unless you're already batching projectiles by weight, and cases by capacity, and turning necks, and meplat uniforming and doing all the other top-end practices, and you're a very consistent shot, I say no difference.

My 2c.