I was looking at the muzzle of my VZ-24 recently, and noticed the bore/rifling is squarish, not round. Four lands, four grooves, it appears to me, but is it supposed to obviously squarish? I figured a bore is supposed to be round...
As of today, it a toss up if I'll retain this barrel, and just do a re-barrel job, so this may be a moot concern, but offer up a few words if you please. ~~~Suluuq

Sharp and deep rifling sometimes has a squarish look to it. I expect the barrel is just fine and maybe has seen very little use.

What Stans said, It's just an optical conclusion.

In these the rifling is very deep and the grooves appear to have a radius at the bottom that is smallr than the groove diameter. One shooter was showing a sectioned bullet that showed that there can be some major jacket distortion from this type of rifling. Since therifle was very accurate though the question has to be, "Who cares?"!
Anyway your rifle is just fine.Regards, Bill.

After shortening and re-crowning my first milsurp, I observed exactly this....Its not very noticable on a blued barrel, especially with a "sporting" crown (not sure the correct term0. But on "raw"

After shortening and re-crowning my first milsurp, I observed exactly this....Its not very noticable on a blued barrel, especially with a "sporting" crown (not sure the correct term0. But on "raw" metal, and I was using 11 degree "target" crown, the bore looks VERY much square. Thought maybe this was because of type of rifling (Mosin-Nagent), but ones I've done after more or less same result. These were all .30 or 8mm, probably less noticibale in a larger caliber. Anyway, i found it interesting, as well.

Ok, here's another Mauser rifling question. I noticed the rifling (lands) tapers down near the chamber -- on old military 98's, I thought this was due to erosion. Then I noticed it on a brand-new but old Mauser-made 7x57 barrel, THEN on my new Lothar Walther barrel. How does this differ from American barrels where the lands are full height all the way back to the throat? Is there any functional difference?

Todd

Actually, all barrels have an area just beyond the chamber where the rifling is tapered. This allows the bullet to be gently engraved by the rifling without stripping the bullet material. Some barrels are made with a longer lead than others.

what I consider to be a typical American style throat is a short paralell section close to bullet diameter (sometimes this is wishful thinking) with a lead angle of 1.5 degrees per side or 3 degrees included. There has been a shift in recent years to a 1.5 degree included angle (.75 to a side) but this year I'm seeing some return to the 3degree lead.
In what I've come to think of as the typical European throat, the throat is a long taper commencing at the mouth of the case and often considerably greater than bullet diameter. This taper is often less than 1 degree included.
Both systems work quite well. One of the most accurate hunting rifles I ever had was a Euro-throated 30/06. The European style throats seem to shoot best with around.075-.050 jump.
BR shooters and gunsmiths settled on the paralell style of throat years ago and the only real changes have been in experimenting with the lead taper. Regards, Bill.

Thanks for the info. Anyhoo, I've decided to re-barrel. I'm already drawing up a set of plans for this project. Thanks. ~~~Suluuq