5-R,5C rifling ?

[Deleted]

I have noticed on custom barrel sites about 5-R rifling and 5C rifling. Any thoughts about these in ml application? Could this be the next step or just for centerfires only?
2much time on my hands,
Greenhorn

[Richard]

It would seem to me we want a barrel with sharp rifling on both sides of the groves.............Those barrels will not do it! For a rifle with bullets that get squeezed down via a "throat", the 5-C will work. I doubt it in a ML
Richard

[rossman40]

With most MLs you have 8 lands and when shooting sabots it works great to provide better centering of the "projectile" (bullet and sabot) and when you properly align or index the sabot you end up with 2 lands on each petal of a 4 petal sabot.

5R or 5C rifling has 5 lands so the bullet is not squeezed between two lands directly opposite each other. The sides of the lands are canted so less stress on the jacket trying to make a 90° so you end up with less friction which means less fouling, better gas seal, less wear on the rifling and more velocity. It is nothing new, the old Enfields had the same style but when everyone went to button rifling it was better to use a 6 groove button, again to keep things centered. With the switch to hammer forged barrels western makers (HK) went with polygon rifling because it was easier to remove the mandrel at the end of the process. The Russians went with the canted or angled lands for the hammer forged barrels for the AK family. Since most of their ammo has copper washed steel jackets it really cut down the friction and prolonged barrel life. Here in the states you had "Boots" Obermeyer called it 5R (the "R" stands for russian) and then Broughton Barrels came out with their version, they called it 5C ("C" for canted). While similar there is minor differences in the cant and top of the land plus Obermeyer's 5R were cut rifled and Broughtons 5C is button rifled.

As far as canted lands for a ML with sabots,, Homey don't think so. The cant would let the sabot perhaps slip in the rifling by not providing a edge for the sabot to grip. Now sabotless is another matter...

[Deleted]

Thanks again for the lesson guys,if there was promise in these rifling I would want to try it out ml wise. I am shooting sabots now and have not stepped into the sabotless world yet. I'll keep reading about it though. Maybe one of those guys would try out a barrel 5r or 5c and see. Who knows as for now thanks for saving me some time and money.
Greenhorn

[rossman40]

The hottest thing in rifling now is a progressive or gain twist with variable width and depth lands which the German company Rheinmetal (one of their products is the tank guns on just about every western tank including the M60 and M1) is producing. The round starts out with slow twist and narrow and short lands and as it makes the trip down the barrel the twist increases as do the width and height of the lands. While giving big performance gains it is easy to do on big guns like 30-155mm. But would be tough to do on say a .223. While several makers have tried progressive/gain twist it is tough to get right. The only barrel maker in the US playing with progressive/gain twist and variable width lands that I know of is Schueman Barrels which makes 1911 barrels. Only doing a 6" .45 barrel is easy. This would not work for a ML.

One of Broughton's secrets is they put a slight taper in their barrels so it is tighter at the muzzle end. I think one of the benefits is that as the bullet is squeezed the resistance goes up and the chamber/bore pressure curve stays higher on the backside permitting a more complete burn of slower powders. Again this wouldn't work for a ML.

Boots big thing was barrels for the SR-25 that Knight Armament (not Knight MLs) made. If you every get a chance to shoot one of these $5000 rifles, "it's like butter". His apprentice, Mike Rock, went out on his own and was making barrels for Remington. You would find his cut rifled 5R barrels on some of the early Remington 700 PSS (police sniper) models and his barrels were on the early M24s. Now Remington hammer forges their high end 5R barrels and button rifles the lower end ones.

[Richard]

Krieger and Bartlein are making gain twist barrels also but I am not aware that they are changing the width and depth of the rifling. Some have shot them in various BR configurations (Dashers, BRX's etc.). None have really proven to shoot better than straight twist rates. I.E.-----------6mm 8.5" vs. 8.7 to 8.3 gain twist. Here again, when shooting at 600 yards, there are too many variables to decipher which is shooting better
Richard

[GMB54-120]

Ive always wanted to try a gain twist in a ML. Similar to what a few companies use with the 460S&W or was it the 50S&W. It sounds like it would have a chance for good sabot performance but im only guessing.

[Richard]

Now your talking! Take a PN .45 and start it at around 28 and run it up to 18 or 16! Although I don't think PN can do it? I has to be done with a machine that cuts the rifling and PN button rifles their barrels. With CNC mechinery, you just program the rate of twist and BINGO, it done. This could be done on the old ML's where rifling was actually carved in a duplicator. As the rod with the cutter was pulled thru the bore, it mimic's the pattern on the duplicator.
Richard