Shilen barrel rifling-4 groove ratchet vs traditional

[Kroberts]

This summer I plan to order a 284 win 8 twist barrel for my savage and am wondering how much difference the rifling will make in the long range performance of heavy weight bullets. I'm not worried so much about the ease of cleaning aspect between the two rifling forms as much as accuracy and which one will give the higher BC with the heavy bullets. So for those that have used both styles of rifling which one provides the better ballistic performance at extended ranges? My typical distance I will shoot is going to be about 1000 yards but will play around up to 1 mile if the accuracy, stability, and my skills are up to it. At those ranges will one make a difference over the other? I've been looking and can only come up with people taking about the difference between the ease of cleaning and velocity, but not on the effects on the BC of the bullets and extended range stability. If the rifling style has much effect of stability.

Thanks for advice,
Kyle

 

[barnesuser28]

According to Mr. Bryan Litz in his book "Applied Ballistics for Long-Range Shooting", the smoother and shallower the engraving of the rifling is, the greater gyroscopic stability will be at extended long range. It doesnt make a huge difference but the difference between a 10% +- roll dampening coefficient results in a 4% difference in gyroscopic stability once the bullet reaches transonic speed. The lesser the roll dampening coefficient (less and shallower the engraving of the bullet), the greater stability is once it reaches transonic speed. Btw, i think you will like your 284 win, i shot mine at 1512 yards today, it did well considering the bullet was going subsonic about 20 yards before the target.

 

[Kroberts]

So if the ratchet rifling is set up so that the bullet is turning into the angled edge, it should make for smoother airflow around the bullet. So if my thinking is correct the 4 groove should produce the ballistically superior bullet, even if very slight. And could possible handle the sonic transition better since there would be a little less resistance to the bullets turning. Does this sound about right? If not please correct me. I want to understand the physics of the projectile in flight the best I can. Especially since when I get the confidence to, I plan to play in to subsonic range. I have found that my current setup doesn't handle the sonic transition too well. 243win 58gr zmax.

Kyle

 

[barnesuser28]

Correct, and any of the 5R or 5C canted rifling options from other barrel manufacturers would also be ballistically superior (slightly) than the regular land and groove configurations.

 

[Jud96]

So if the ratchet rifling is set up so that the bullet is turning into the angled edge, it should make for smoother airflow around the bullet. So if my thinking is correct the 4 groove should produce the ballistically superior bullet, even if very slight. And could possible handle the sonic transition better since there would be a little less resistance to the bullets turning. Does this sound about right? If not please correct me. I want to understand the physics of the projectile in flight the best I can. Especially since when I get the confidence to, I plan to play in to subsonic range. I have found that my current setup doesn't handle the sonic transition too well. 243win 58gr zmax.

Kyle

You would have a lot better ballistics if you shot a better suited bullet for the .243 Winchester. My Remington 700 Varmint .243 loves 87gr V-MAXs and shoots them under 1/2 MOA at 100yds and continues under MOA out to 700yds. This bullet performs well on varmints and coyotes, its low .400 G1 BC actually handles pretty well in the wind. Wanting to try out some 105gr A-MAXs with a BC of .500 for those longer shots to buck wind better and for whitetail at long range.

 

[Kroberts]

Made it out shooting the other day at 850 yards and was able to keep appox. a 1 moa grouping across 9 shots withe the 58gr zmax. But I picked up 300 95 gr SMK to try and with their .48 BC should do much better at that distance if I can find a good load.

Kyle