Different types of rifling and there uses.

[Pdvdh]

Some gain seems like a good idea, to my way of analysis. Tim_w posts like an engineer, and I agree with the theoretical benefits expressed.

Primary reason I didn't go gain twist was additional cost. That and I wasn't pushing the limits of
jacketed bullet integrity, so didn't feel the need. Might be a good idea above ~3500fps?

 

[tim_w]

Some gain seems like a good idea, to my way of analysis. Tim_w posts like an engineer, and I agree with the theoretical benefits expressed.

Primary reason I didn't go gain twist was additional cost. That and I wasn't pushing the limits of
jacketed bullet integrity, so didn't feel the need. Might be a good idea above ~3500fps?

I agree I think its lost if you have no need either for the super fast twist and or combined with jacket tearing vel.

 

[Deleted member 46119]

I am a fewer groove/lands than more. I don't always specify. Most times it's the manufacturers "normal".

The 338s are either Benchmark or Weatherby factory Krieger.

The Pac-Nors are all their 3 groove.

There are lots of others.

I shoot a lot of lead free so I have no separation issues for most things.

I think my Pac-Nor 3 groove are fast but a little heat up. No coppering issues.

This thread makes me want to look at the grooves/lands and profile of each barrel.

 

[J E Custom]

Interesting point, the extreme cartridges may have different needs than the more moderate cartridges.

They certainly do !!!

The times that I have built "Extreme" rifle/cartridge combinations, groove design along with twist rate was a major consideration.

I have found that Bullets are the limiting factor if the wrong grove design is picked Irregardless of the twist rate and also the other way around for extreme cartridges.

I have had good results with the 3 grove design as long as I used strong or bonded jackets. Example: One such rifle with a 3 grove in 223 WSSM has exceeded 4600 ft/sec (Still not maxed out)with very good accuracy with good bullets. twist rate is 1 in 15 and at or around 4400 ft/sec It culled most jacketed bullets. I did not try Mono metal bullets because I wanted to see the effects of this combination.

I have found that in the middle of the diameter range and velocity cartridges that almost any grove design will work If the optimum twist rate is picked.

I also consider the truly big bores to have special needs like 8 grove barrels with slower twist rates because of the bullet mass and the starting inertia that causes the jacket to be separated from the core.
also as stated the land height is important. Most dangerous game bullets have heavy jackets and the multiple lands (8 or more) engrave well. This is what I would consider the perfect place for the gain twist
along with an 8 grove design.

Barrel manufactures will recommend grove designs and twist rates based on you needs but sometimes you have to think outside the box and choose what is best for your use.

Choose grove design and twist rate wisely and the outcome will be good. Choose poorly, and you will have a disaster in the making.
like most people that experiment have found including my self, mistakes are inevitable.

More to come

J E CUSTOM

 

[Alex Wheeler]

Far more important than the rifling style is the area of the bore. You can do all sorts of things with the size and shape of the lands and if the area is good it will shoot. Aside from a few exceptions I prefer conventional lands and grooves. In competition I am firmly in the 4 groove camp, enough that I will call a customer if they send me a 5r barrel to chamber in a Benchrest caliber. The 7mm and 30 cals seem to tolerate the 5r style much better. Some 5r barrels have shot well in Br but if I think of the % of the barrels that did not shoot well, the 5r barrels are far higher. For hunting applications I think its irreverent.

 

[Greyfox]

Over the past dozen+ years I have owned 4 Remington Mil specs(3-308,1-300WM) with the 5R rifling. I used them for factory class competition 200-300 yard Egg Shoots and hunting. All of them shot better then .3MOA, 5 shot groups, would hold accuracy to at least 200 rounds between cleaning, and would clean fast and return to zero within 5-6 fouling shots. With heavy/hot use I would get about 2500 rounds before would experience loss of accuracy(308's) They would hold accuracy shot hot or cold. My new Ruger Precision rifle in 6.5CM with 5R performs similarly. This surely leads me to being a believer in the stated qualities of the 5R design and their use in the M24 Sniper rifles. I will say that I have had excellent performance with my customs that have used a variety of button and cut rifleing designs. I have used Hart, Bartlien, and Wilson match barrels with good success, but I am partial to the Kreiger 4 groove cut rifled barrels and have more recently settled on them for my custom/competition rifles. They are very accurate and demonstrate qualities similar to the R5 barrels mentioned above.