Re: 6mm 115 grn vld
In all the 6-284s I have built I have learned a few things. First off, if you want a fast twist 6-284 you will need to build the rifle very specifically to get it to perform well.
First off, conventional wisdom will tell you you need a 1-8 twist for the heavy bullets. That may well be for the velocities that all these types of bullets were designed to be used at, that being 2600-2800 fps for the most part, especially the Berger J-4 based bullets.
What I have found however is that with the 6-284 you actually have more gun them most of these bullets can handle in a traditional wisdom 1-8 twist. Some will work, some will tear bullets apart.
For the 105-107 gr bullets, I have long ago learned that the best twist range is a 1-9 and even more importantly for getting max velocity especially with the 105 gr Berger and Hornady A-Max is to use a rifling design with as thin a land as possible. 6 groove Liljas work great in my experience and that is what I use.
A 3 groove Lilja on the other hand will be very hard on thes two 105 gr pills because the lands are so wide in these barrels. Great for long barrel life, very bad for high velocity, heavy for caliber bullets in fast twist barrels.
For example. In a 30" Lilja 1-8 3 groove, you can get around 3250 fps with the 105 gr Hornady A-Max or Berger and thats about it before accuracy really drops off and in many cases you have complete bullet failure.
The 107 gr SMK on the other hand can be drive to much higher velocities because of its thicker jacket. I have driven them to +3550 fps in a 1-8 3 groove Lilja with fine accuracy. This is a hotter load then you should be using, I was just attempting to make this bullet fail in the 1-8 3 groove barrel.
Switching to a 1-9, 6 groove barrel, the 105 gr Hornady A-Max and Berger can easily be driven to 3450 fps which in my opinion is about the max the 6-284 should be loaded to in a 30" barrel.
With the 115 gr pills, I would stress that you will need a rifling design that is very gentle to the bullet. The thinner the land and shallower the groove the better to a point anyway.
I would go with the Sierra(D-Tac) 115 over the Berger.
Problem is that the 6-284 is simply more round then the current batch of bullets are designed for. When you take a bullet designed for the 6mm BR class of velocity and drive it out of a much larger 6-284, special considerations need to be taken to get the rifle to shoot well.
If you want to load to fullpressure loads, I personally would recommend building the rifle to shoot the 107 gr SMK and if you want more BC, jump up to a larger caliber that will be more user friendly as far as consistancy is concerned.
Just my opinion,
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