Types of rifling

[ohiohillbilly]

Im looking at getting a marlin 336 and i have a question about the differenteffects of the microgroove and ballardrifling on bullet performance.

From what i understand the low spin/turn(not sure of the term) rate of the microgroove is ideal for flat nosed bullets. Then on the other handthe faster turn/spin rate produced by the ballard rifling is ideal for pointed bullets.

So my question is, which type of rifling has less of a negativeeffect on the performance of a less than ideal round?In other words,is it better to have a flat nosed bullet spinning too fast or a pointed bullet spinning too slow?

[Ridge Runner]

its the length of the bullet that determines what rifleing you need, micro-groove and ballard are different types but its the rate of twist that stabilizes a bullet.
for example 223's are available in rifleing rates of 1in12, 1in10, 1in9, 1in8, and 1in 7 being the most common ones. now the #'s 1-7 mean that to make 1 revolution the bullet must travel 7" down the barrel. 1-12 means it has to travel 12" to make one revolution. the longer a bullet is the faster you have to spin it to make it stabil in flight so in a 223 if you wanna shoot 35-50 gr bullets you use a 1-12, 45-60 gr you use a 1-10, 55 to 68 gr a 1-9, 60-75 a 1-8, and for the 70 gr on up a 1-7. However its hard to overstabilize a bullet so a fast twist 223 say a 1-8, may very well shoot 50 gr bullets just as well as a given 10 or 12 twist, you never know, but if a bullet is understabilized, it'll be clear with just a few shots.
you might have a broached barrel (rifleing cut with a small cutter head) or a buttoned rifled barrel (rifleing more or less ironed into the steel buy pulling a hard slightly oversized button through the barrel) but lets say its a .284 barrel for a 7mm Rem Mag, as long as its a 1-9 you can shoot bullets of 100-180 gr with good accuracy but probably the bullets from 140-180 will shoot the best through any of the rifleling (button, broached, or 5c {5 degree canted lands}). so as long as you have the right amount of spin on the bullet the type of rifleing really won't matter at all.
RR

You don't want microgroove. my 45-70 is microgroove and doens't handle cast at higher speeds. It's really made for copper coated bullets.

You can get microgroove to shoot cast but have to slug your barrel and get little oversized bullets from places that will do that for you.