5-r rifling expectation

[brokenharley711]

I have a buddy i'm helping build a custom rifle, probably a .260 or 6.5-.284, and am looking at krieger barrels to do the work as they absolutely NAILED my .260. (barrel and gunsmithing) question is, is the 5-r rifling worth it? Just what kind of muzzle velocity increase can i expect and how much better BC? (i've just read up on this and understand the radiused impressions from the rifling on the bullet jacket MAY increase the BC). anyone with relavant knowledge that has feedback is greatly appreciated.

 

[BountyHunter]

The 5R will not raise BC. BC is related to the bullet and has zero to do with the bullet BC.

What most people using the 5R see is less pressure with a given charge and less drag on the bullet going down the barrel and ability to push a little more powder for same pressure but increased MV.

BH

 

[brokenharley711]

talked to one of the tech guys at Krieger and he says the jury is still out on the change in muzzle velocity from the 5r. he said he expected it to go down with decreased bullet to barrel resistance. he said he would wait until they got feedback as they had only been making them for a little over a month.

as to the article on increased MV, i can't remember where i read it but i'll try and find it. i believe the point they were making was the increased continuity of the jacket due to less deformation from rifling decreasrd drag. although for all i know the rifling marks could have provided a laminar boundary layer, much like golf ball dimples.

 

[royinidaho]

talked to one of the tech guys at Krieger and he says the jury is still out on the change in muzzle velocity from the 5r. he said he expected it to go down with decreased bullet to barrel resistance.

I got into one heck of an argument with a Canadian scientist about friction reduction decreasing velocity with the same powder charge. (See bold text above).

I used his company's magic juju juice which is a friction reducer and achieved the same result as Krieger expected.

The Phd said I was flat out wrong. I gave him the chrono reading.

I really like the stuff they make. Its a friction reducer additive for gas/diesel engines.

I use it to lube everything that needs lubing in my bullet making and reloading process including what little lube I put on recoil lugs and the last swab through the bore.

 

[brokenharley711]

i'm sure the philosophy is that without a certain amount of resistance adequate pressure will not build before the bullet exits the barrel. like voltage, resistance is needed in order for pressure to develop. anyway, the techs take was the advantage was barrel cleanliness and accuracy.