Re: 5R Rifling -Yes or No?
For the additional work that has to be done to the tooling in order to make a 5r rifling profile, £6 surcharge is a bargain.
Geoff and I have probably made somewhere around 40K match grade barrels between us. Most of them rifled one-two hours at a time. Gives us time to think things thru..
The '5r project' came about in a conversation prior to the 2002 Imperial Meeting at Camp Bisley. There were some american shooters who had inquired if we made such a thing, which at that time we hadn't. Geoff and I started asking around to see if there was indeed a market for 5r in this part of the world. There was. Problem was, we didn't have any 5r's lying about to reference..So we humbly requested the permission and guidance of Boots Obermeyer, as he is the guru, which he in turn graciously assisted us in setting up the toolmaking facility, and offered his invaluable experience and expertise.
After months and months of 'smoothing out' the toolmaking process and gathering the proper inspection and gaging tools, we felt we could then generate the proper 5r form while maintaining a concentric groove radius..So we initiated production.
Believe you me, we were just as or more curious to see how the 5r's would perform. Big risk for a place who is well known for making accurate barrels, to replicate a rifling form which was made popular by another very well known accurate barrelmaker...We'd researched the potential, worked it out on paper and ticked all the boxes, but until you send a bullet down the pipe, you just don't know, do ya..Haven't looked back..
I don't make gimmicks. Don't have the time. But to emphasize 'if' they work, every employee that shoots here including Geoff shoots with a 5r barrel. Match rifles, stalking rifles, and varmint rifles..If they weren't working, I wouldn't hear the end of it eh...
The percent of increase of orders for 5r vs 4 and 6 groove over the past few years has been almost overwhelming. I would say 50% of our customer centrefire barrels made by cut rifling are now in the 5r profile due to customer demand. I have a Swiss customer who alone orders 80 plus barrel blanks at a whack, and all in 5r.
What we've seen firsthand:
Velocity potential. Our Dennis and Lee are using 32" 6.5 x 284 Norma 8.46 twist 5r's for F-Class, 139 lapuas, and driving them at 3200+ fps with ES in the low teens to single digits over a 20 shot string. Lee was previously using a 29" 6 groove barrel with velocities around 2880fps and highish pressures with the same cartridge.(as a side note, his 24" 22-250 5r was getting velocities over 4000 fps with the 52's, we've since backed it down to 3880.)
Life. The same said 6 groove fag mag'shot out' at less than 900 rounds. Throat has seen better days, looks typical of what I would generally expect out of the fag mag. The faster 5rs are still going strong at 1300 rds..Bit of firecracking(which I think is due to the N170 used at the start), but the throat hasn't moved much atall..I'm not sure why this is, surprised really, but it's a plus nonetheless. Perhaps it's because the land that wears out, and this particular profile is more wear-efficient due to it's shape, land's a bit wider at the bottom than the top.
And they clean up well.
Anyway guys, the point I'm trying to make is we didn't approach this method blindly, we are constantly evaluating the performance on our rifles. I wouldn't say our 5r is more accurate for group than our 4 and 6 groove barrels, but is definitely not less..They all shoot well..
What I can guarantee is in the next month either Geoff, Dennis, or Lee will be asking 'when you making 5r's again?'(they know I'm tooling up for mine) hah...