Like I said, my experiences in 3vs4 groove are only in 223 but having burned up many barrels in both grooves and knowing almost all our state team shooters having some of each going over the last 3-4 years the gain available is appx 75 fps.
That being said it may well have a lot to do with factors other than just groove numbers. It may be barrel size also. And cut vs button rifling. But I do know that in 223 and in 6.5 twist when you compare 4 groove Krieger vs 3 groove Pac Nor the accuracy is equal, barrel life leans well towards Krieger and velocity leans 75 fps to the Pac Nor.
BTW I'm not disputing anyone at all here as my experience in larger calibers is much more limited, but simply am posting this as a FWIW
Get as close as you can, but utilize your skills as needed.
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:
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.
Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.
Thanks fifty I really appreciate you taking the time to answer my questions that in depth. I think I will go with a 3 groove Lilja from what you are saying. If you can get those kinda groups at that distance thats pretty impresssive. Thanks again.
Thats the reason i didnt have you to build me .257 stw Fiftydriver. I was afraid with the lighter bullets 115gr 100gr 85gr that the 257 stw wouldnt be much faster than a
30 inch barreled .257 weatherby. As i have
a stash of ultra strong .257 weatherby brass. This stuff is alot stronger than norma or weatherby's .257 brass! I wasnt interested in the heavier .257 bullets as
i have bigger bores for the 500 yard + shots. I didnt get a .257 weatherby either.
For now i just but a .257 on the back burner for now.. I am very interested though about those .3380 300gr bullets you are getting made. I cant wait to see how they work out. Id like to try them also.
I would like to have a heavy .308 bullet also but it would need to work in my 1-10 twist barrel.
I wonder if H870 or wc872 would work good in
your .257 AM. I wish you would test some lighter bullets just for kicks to see how much speed you could get out of them. I know this wildcat was built for the heavy bullets but it would be interesting to see
how fast it would shoot 85gr or 100gr bullets if using the proper powder.
This is some really good info thanks guys. Fifty you say the Lilja barrels are slower because of a tight bore. I have been told that they are supposed to be a fast barrel? I am not doubting you I would just like to hear what barrels you have found to be overal faster then a Lilja because it sounds like you have a lot of experiance in this area. If you can't tell already I want the fastest and most accurate barrel I can get. [img]images/icons/grin.gif[/img]