could bullet corrosion build-up affect ballistics?

[Dannavyret]

I was watching "Sniper" last night and got to the point in the movie where Tom Berrenger was putting a small rat tail file to one of his rounds. "Sometimes these bullets get burrs on them, affects the performance."

So I went to my cabinet out of curiosity and pulled out a box of 30-06 Greek M2 1977 lot and looked at the rounds. No burrs but the rounds were a very dark brown. So I grabbed a can of Brasso, dipped the tips and started cleaning em. Sure enough I removed a thick cake of black oxide deposit from each round. I'd be curious to see just how much I removed.

The question is, can such deposits affect the round's in flight performance and can cleaning them cause improvement?

 

[30Cal]

Put down the tools, turn off the TV and step away from your ammo.

 

[Dannavyret]

Your stupid flippant comments shouldn't be tollerated.

 

[Owen]

it was flippant, but he's right.

 

[fletcher]

I doubt that it will affect the performance to any measurable degree.

 

[Red Tornado]

I'd be surprised if anybody has ever tested this, but you can experiment and report the results to us. I'd keep the file away from it though. Has there ever been a sniper that wasn't in a movie that filed his ammo?!?

 

[Zak Smith]

Alright, let's settle down a bit.

I would expect surface defects to make most difference in two places: 1. the base of the bullet (covered in this case), and 2. the bearing surface where it would affect friction with the barrel (also covered in this case, almost certainly). At supersonic speeds, there is not normal flow over the bullet surface, but more the supersonic shock waves produced by leading surface features.

I would be more concerned with using abrasives and ammonia on the bullet, since it may leave some in the bore. The last thing I want in my hand lapped match barrels is an abrasive compound.

As for "burrs", some long-range match shooters are uniforming meplats with a special trimmer-- this is supposed to make the BC values more uniform. However, at closer ranges, you can get away with pretty gross nose defects without a big affect on accuracy.

In short, I wouldn't worry about it.

-z

 

[30Cal]

The M2 bullet does all it's work at supersonic speeds. Skin cleanliness may make a difference on fuel consumption of a jet travelling cross-country, but not on a bullet travelling behind a shockwave with an effective time of flight of 0.5 seconds. There would be no practical benefit.

A downside would be the introduction (albeit in small amounts) of abrasives to your bore.

Ty