Posted by Michael Bell on Dec 08, 2018; 7:01am
URL: http://oldforum.flyshooter.com.au/6mm-Grendel-Improved-6mm-ProCal-tp5709226p5710252.html

G'day Shaun & Joe,
As it turns out I do have a bit more to offer on the performance of this case.
I was so encouraged by the results with my PPC converted to Procal that I decided to have a barrel chambered for my light Fly rifle which I have run as a BRX for a number of years.
I was curious to understand how it would perform over the length of a season in the variety of conditions we experience & at the different ranges.
There were quite a few unknowns like case life & barrel life etc, etc, so I committed to shoot the Procal in the light rifle category for the entire season for better or worse.
With this slightly longer, heavier barrel I worked up a load of 2206H (Joe, this is H 4895 in the US) which was very close in performance to the rem var barrel on my PPC platform. I used 103 copperheads for every match but did experiment with other projectiles during practise.  In my view the 103's suit this case best ( of the projy's I tested)  in an 8 twist barrel.
The season started pretty well with good results in the first 3 matches. Then I stumbled a little with a few poor performances upon which I couldn't blame the rifle.
Turning up crook (self induced) on the odd occasion, bad calls on some targets mid match both contributed to some self doubt through the seasons middle.
Then...a chance phone call from Will Greer, a very talented short range benchrest shooter from Gladstone who was interested in discussing this case. He had an 8 twist barrel chambered for his PPC & was interested in shooting longer range.
The discussion went something like this.....What bullet are you using Will?..(.he told me). What powder & charge are you using?  I'm using BM2 & up to 31 grains!   Are you Molly coating your bullets with these loads?... No! .... Holy Crap! What do your cases look like after shooting an uncoated 105 with 31 grains of BM2??   Well...I blew a few primers out with the max load but it shot OK!.......Why did you use BM2? ... Well, I'm a short range shooter & I've got heaps of it!

At this point I should say I was using 30.7 grains of 2206H with "molly" coated 103's so I was way behind Will on the pressure curve as 2206H is a slower burning powder than BM2 & "molly" coating takes the equivalent of up to a full grain of pressure off the charge!

All this said I was (in the back of my mind) having a think about trying 8208 (faster than 06H) in my rifle & this conversation with Will provided an arse kick causing me to immediately purchase some 8208 & test it against BM2 (which I already had some of) and 06H.

Out I went early one morning with enough loaded ammo to do a good comparison. I really had no idea what to expect so I very tentatively pulled the trigger on the 1st BM2 load & was quite surprised at the result.
Without going into all the nuts & bolts I can say that all 3 powders, in the 6 Procal case with 103 copperheads, are a lot closer in burn rate than I had anticipated. BM2 is the fastest & 06H is the slowest but only about half a grain seperate the three, and BM2 is only faster than 8208 by about .1-.2 of a grain.
I also think that both the faster powders shot with less verticle than 06H.

I decided to finish the season with the faster powders & went to Brisbane with a load of  BM2 delivering very close to 3000 fps.
I was very happy with the way it shot so I went to Melbourne with the same load & again it performed very well in typical Little River weather.

By the time I got around to testing these faster powders my barrel had about 850 rounds on it. The cases had been fired probably about 10 times each and were just starting to get a little "clicky" at the back end. Whether the faster powders contributed to this or whether my custom die doesn't quite size the case base sufficiently I can't say.
What I can say is that my 850 round barrel shot like a new one  with the faster powders &, as yet, I haven't lost a single case to split necks nor to I have any loose primer pockets.
As I type this out I have another barrel being chambered by Luke Easter from Procal so that I can find out how a "new" barrel will go with either BM2 or 8208.
Can't wait for next year!!

Regards,
Belly