Gunsmithing 4R rifling?
- Thread starter jzerfoss
- Start date
Shilen has one called ratchet rifling. Google some images, but it also only 4 lands.
There are many ways to spin a cat, err, bullet.
There are many ways to spin a cat, err, bullet.
We've made 4R style rifling. Doesn't shoot any better. Even have made them for top F Class teams and they tested them to the 5R etc...again cannot see a difference.
For the most part and this has been beaten to death....the style and number of grooves accuracy and barrel life wise don't mean a thing.
There are a couple/few exceptions to this rule but again for the most part no difference.
Later, Frank
Bartlein Barrels
For the most part and this has been beaten to death....the style and number of grooves accuracy and barrel life wise don't mean a thing.
There are a couple/few exceptions to this rule but again for the most part no difference.
Later, Frank
Bartlein Barrels
Hart pretty much told me the same thing when they asked what groove i wanted and i asked if it made a difference.
Glad to hear it from 2 respectable places now.
I will say this....the short 65-68gr bullets that are shot in 6PPC benchguns don't like the 5R rifling. I tell guys the best it will shoot is upper .2xx's to a flat .3xx". Those guys are going for the perfect one hole group keep in mind. Now conventional 5 groove rifling....the gun is a hammer.
Also I do believe in the 5R rifling does help fight bullet failure.
Also from just some recent testing by a bullet maker/ammo maker a few months ago is they do believe that they found that the 5R rifling helps the flight of the bullet in the transonic range vs a 4 groove barrel that was also being tested the bullet had a disturbance in the transonic range.
Later, Frank
Bartlein Barrels
So if short bearing surface is a factor in that would that hold true for a 224 bore with 65-80gr bullets? Or the bore to bearing surface ratio is more close to say a 6mm shooting 107s and a typical bearing surface?
Also interesting you mention the 5r and transonic. Ive been reading up on polygon (and all the other marketing names it goes by) and one of the theories is it handles that transition very well since theres less stress on the bullet from the bore. Not sure going from 5r to polygon there would be any noticeable difference but im far away from being knowledgeable on groove design.
Hi,
That relates back to the original cheytac days....It was proven at Yuma that the 8 groove Lawton barrels performed better in transonic realm than the 6 groove Lawton barrels.
Sincerely,
Theis
I have a 3R AR10 barrel in 338 Federal that works really well. After reading this, I’m sure the bullet will tumble if it goes trans-sonic, but I’m not going to shoot it that far. I will say it cleans very easily. I don’t know if that has anything to do with the rifling.
From what I understand when I did limited research on Shilen's ratchet rifling (like a 4R) is it helps in cleaning. Which makes sense because there is less surface area to get fouled.
Was there any mention to the bullet tested/twist rate? Just wondering if there is a relationship between a faster twist for caliber vs deeper grooves and jacket disturbance from the 4 groove rifling.
Short range BR guys shooting the 6PPC and 68 gr bullets are almost universally shooting 14 twists.
Sorry I should have specified my question was referencing the transonic disturbance Frank mentioned and not the short range BR info.
