I have a "no dash" S&W 586 with a 6" barrel. The rifling in it appears to have parallel sided walls into the grooves. It shoots just fine.

I was considered a 4" version, and have been looking around for a "no-dash" to a 586-4 version, with 4" barrel for some time. Prices seem high.

For a giggle, I looked a new, current production, S&W 586 with a 4" barrel. The rifling in it just looks "different" from my 1980ish "no dash". The current rifling doesn't seem to have parallel-sided grooves. They look more "roundish" or perhaps "slanted" or "trapezoidal" in wall shape.

Am I seeing things? The young clerk didn't have a clue when I asked him.

Does the "new" 586 have some new-named/designed rifling compared to the "old days" of 1980?

I don't buy new Smiths so I haven't looked at the rifling in any, but your description makes me think they might be button rifled now, when the previous method is what is called broaching. Google both for pics and explanations.

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Yes, it is different...

Firearms History, Technology & Development: Rifling: Manufacturing: Electro Chemical Machining

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Pisgah

Short answer - Yes they are different
Old 586 - Broach cut rifling
New 586 - ECM rifling

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NRA Benefactor Member

Never heard of this before. Very interesting, Thanks.