grooves and lands/ rifeling question

[outlawkyote]

Its common for many people to have specific groove barrels that they claim is best. I happen to like 3 groove barrels but dont have one at the moment. Im wanting to order a three groove barrel but I want to know some specifics first.

On a 3 groove barrel, are the grooves and lands equal in size? Here is a picture of what Im talking about.
http://i5.photobucket.com/albums/y15...relgrooves.jpg

The bore on the left has very robust rifeling while the bore on the right has thin rifeling.

Will robust rifeling create more pressure?
Someone give me some 101 on the toppic please.

[BrentWin]

Based on nothing other than my own sense of logic, I would say that the rifling on the left would create higher chamber pressure. Since its rifling has a larger total surface area, it will displace more jacketing marterial. This would, it seems to me anyway, create more resistance and thus higher chamber pressure.

I have also always wondered if the difference in various rifling configurations engraved in the bullet makes any aerodynamic difference in the bullets. ie do more grooves create more resistance or is it minimized by the major shock wave that comes off the nose of the bullet, as in the picture below.



Surely surely some of the engineering types on this sight could help provide answers.

I have no scientific backround, but I did stay in a Holiday Inn Express a couple of weeks ago.

[outlawkyote]

Theoreticly, the more robust rifling will be more wear resistant too.

How do the manufactures cut their bores? thick rifling or thin? Do I have the option of ordering thicker rifling or do I just have to accept what I get? Do all manufacturers use a specific rifling specification? Would I be getting in over my head if I was to order thicker rifling or is it just a preferance thing?

Not too many responces so far

[Apache]

My PacNor 22-6mmAI is a 3 groove (equal size lands and grooves) barrel specifically for it's (supposed) ability to resist throat errosion as much as normal rifling......in this chambering, I don't think it's gonna make a lot of difference though.

I have around 150ish rounds down the tube and throat wear is starting to show up...although not a lot of it. Had to decrease setting depth .005 to continue touching the lands the same as when loads were first developed. It is still an extremely accurate barrel.

[Fjold]

I like any odd number of lands and grooves, 3 groove, 5 groove, etc.

There is less objuration of the bullet because every land is opposite a groove so bullets get compressed less as they go down the tube.

[stevec]

I talked to Dan Lilja a few years ago about the 3 groove barrels and he said that yu could expect a little more barrel life with it because of the wider lands. I bought one and chambered it in 6-284. never tried that cal in a 6 groove so I have nothing to campare to but, it didnt live long, about 900 rounds till the first set-back.

Steve

[johndoe3]

Like Apache, I have a 3-groove Pac-Nor barrel and the lands and grooves are equal size. Mine is 338 Federal with 1 in 7 twist to mainly shoot 300gr subsonic bullets. However, it shoots full power loads great too. I would want the lands and grooves to be equal size and not narrow lands. If it had narrow lands, then I'd prefer a 5 groove barrel.

[Ring31]

easier to clean as well..

[teebirdhyzer]

Holy Old Thread, Batman!