Dakor,
Well, from what I have actually seen in rifles I have built is that the fastest barrel I have personally used was a Kreiger 4 groove that I used for a customers 6mm-06.
It was 28.5" long and shot the 55 gr Ballsitic tips to a full 4400 fps easily. 70 gr Ballistic Tips went 4100 fps with no problem at all and the big 105 gr A-Max bullets were hitting a very comfortable 3500 fps.
This last bullet is what got me interested in studying the 3 groove vs other designs for use in the fast twist barrels shooting VLD style bullets to high velocity.
My 6mm-284 is a 30" Lilja 3 groove and would shoot the 105 gr A-Max into 1/5 moa groups at 500 yards until velocity hit 3240 fps, almost exactly. If the velocity hit 3250 or above groups opened to the 1 moa range which is quite a jump telling me that the jacket/core integrity was compromised.
Same with the Berger 105 gr VLD's.
This 6mm-06 with the Kreiger barrel was a 1-9 twist with the 4 groove system and obviously was easier on the A-Max bullets with its slightly slower twist and 4 groove system as it prints in the .3's at 100 yards at 3500 fps.
Comparing velocity, my 30" 6mm-284 drives the 107 gr SMK to 3500 fps compared to the same velocity with the 105 gr A-Max out of the 6mm-06 with 1 1/2" shorter barrel.
Now this is really comparing apples to oranges, there are to many variations to come to a clear conclusion that the Kreiger is an honestly faster barrel then the Lilja.
One thing for sure, the Lilja barrels are built to very tight BR specs, all of them. They are built for accuracy first and formost and they flat are accurate.
Just tested a 22-6mm AI in one of my Barrel Bedding V-Block rifles for a customer just a few minutes ago using the 80 gr Berger.
I do not know the velocity of this load as it is only 30 degrees here and the chrony gets cranky in those temps.
This rifle used a 30" 3 groove barrel and I just shot four groups at 500 yards that measured an average of .977" ctc in a 15 mph quartering wind.
I suspect these loads are in the 3400-3500 fps range but do not know for sure.
TO be honest, I have heard alot of good things about the Rock Barrels being pretty quick but I have no first hand experience.
The fastest velocity possible will have as much to do with your throat design as it will your barrel to be honest.
If I had a customer come in wanting the fastest round possible in a certain caliber, I would still use a Lilja because of the results I have had with them as far as accuracy and then either find or design a round that would get the customer the velocity they wanted.
One final example of what I have found with velocity in the Lilja barrels.
The 257 STW is a hell of a hot round. It is widely advertised to get 4100 fps with a 100 gr bullet out of a 28" barrel.
Personally I find this a sales ploy as I have yet to see one actually hit this mark. In fact I tested three different 257 STWs this summer that I built for customers.
THe barrel lengths were 27", 28" and 30".
With top loads using Rl-25 the velocities were as follows:
27"---------3900 fps
28"---------3940 fps
30"---------4010 fps
Anything much over this was starting to loosen primer pockets. I believe the 4100 fps claim alot of smiths are throwing around is simply a sales trick but if they are getting that velocity with a 28" barrel, the Lilja 3 groove barrels are about 150 fps short of that mark.
Again, I do not think Lilja barrels are that much slower, in fact I would say it is more like 30 to 50 fps at the most in any case and agian, I would say that the chamber and throat design has much more to do with velocity potential then the barrels really do.
As long as they shoot little groups and have glass smooth bores, thats all I really care about as a rifle builder. I can find a round to produce the horsepower needed to reach a velocity goal.
Good Shooting!!
Kirby Allen(50)