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6brx 70gr NBT - seating depth??

Loaded up some test loads in .3gr increments from 33.7gr to 34.9gr with Imr8208xbr powder in lapua brass (neck sized with .268 bushing, primer pocket uniformed, trimmed to length etc) with CCIBR4 primers & 70gr Nosler ballistic tips seated to just touch the rifling. At the range all the loads shot very average (around 1 moa @ 100yds) and reached sticky bolt lift & ejector marks on the cases at 34.9gr for an average of 3,470fps from my 1-8" 24" barrel. Interestingly all the groups were nice & triangular apart from what I'd call the max safe load at 34.6gr -this group was horizontally strung with no vertical. I'm guessing this would be the load to investigate further with different seating depths to see if accuracy improves. Do the noslers liked to be jumped or jammed or am I just wasting my time with these projectiles and should be trying something else?
 
Try a different powder. I use 35.5 gr Vit. N-135 in my Dasher and it is
fantastic with the 70 gr Nos BT. My favorite Prarie Dog bullet. More
accurate than the 65 V-Max. I got a PD once at 914 yds. with this bullet.
Your BRX should use a similar load, start a little lower. I had no luck with
the 8208.
 
VV-133 works as well, but the 70's are about max weight to push with it in my Dasher.
 
In my 6mmBR that bullet shoots poorly w/ H322 powder regardless of the seating depth. With N133 it will shoot consistently right at 1/3 an inch .005 into or off the lands. Varget yields groups between these two powders.

The bullet should work. I would change powders before you bother to adjust seating depth or give up on the bullet.
 
Varget works well for me in 70 and 80 grain bullets. I like to see the case full to the neck or even a little compressed. You may want to give the 80 grain Bergers a try as well in that fast twist barrel. So far all bullets have shot best for me with a 0.010" jam, but testing has been kind of limited.
 
A friend had some n135 left over so I have loaded up some more test rounds and hopefully get to the range in the next day or two. Does n135 differ a lot between lots as if this works well will need to purchase some? Also how temperature tolerant is this powder?
 
I believe the VV stuff is quite temperature sensitive compared to the Hodgdon Extreme line of powders like Varget.
 
N135 is a good choice to try. Because it is more expensive I'm sure your gun will shoot great with it. At least that is how it always works out for me.

With a 70 grain Sierra match bullet and Fed 205m primers, I find that my N133 load is more accurate for me in warmer temps and the N135 load is more accurate in colder temps, with all other factors such as brass, neck tension and seating depth the same. Not sure if that is suppose to be the way it works, but so far the results have proven that in my 6mmBR.

As for the temperture insensitive Hodgdon powders, I've found it to be more marketing hype than reality. At least those have been my results.
 
Thanks for all the usefull information guys. It's strange that the IMR8208 proved to be so inconsistent in the 6BRX with lighter projectiles. It has been nothing short of a relevation in a freinds .223 & 308 with average ES hovering around 5fps. We came up with "the load" for his 308 FTR rifle that shoot's in the two's with an ES of 2fps (checked over 2 different chronograhs) & way more speed than his previous Varget load. 155grainers are being safely driven at 3150fps from his 32" barreled Barnard rifle. I persevered more than I should have with it trying different combinations hoping for the magic that never came. Hopefully N135 proves to be a worthwhile trial in my rifle. I will try to keep everyone posted.
 
Finally got round to trying out the N135 Loads. It turns out that I were a bit on the optimistic side & started at 34.6gr with the 70gr NBT & this load gave heavy bolt lift & plunger marks on the case head with 3,400fps so stopped right there. At least the group size was an improvement at about 1/2" at 100yds. I'm going to try 34.2 & 34.4gr pick the best then play round with seating depths. One thing I did like with the N135 is that it healthily fills the case & looks to be very, very clean burning.
 

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