Seating Depth First Test of 105 Gungnir in 6 BRA, Thoughts?

[Buttstock-TX]

In the recent testing I did with my PPC trying to get my powder sorted out, I found that lighter loads and light neck tension made my SD's go up dramatically when the bullet was out of the lands. With those corrected, it's now the same. I also abandoned doing a powder workup at 100yds and went to 300 instead. My rifle shoots so much better now, it feels like somebody swapped the barrel for a Dasher.

I have also found that more neck tension on jumped loads results in less vertical at 550 yards. My test was comparing 2.5/1000 and 4.5/1000 in long strings of fire.

 

[Clancy]

I do agree and plan to test the best jump load also.

But, since the subject of ES has come up several times in this conversation, I should explain my motivation. I used the Berger ballistic calculator and computed the elevation change at 500 yards for a 105 VLD on my home range at 500 yards. The ~23 fps extreme spread of the -14 group is 0.89" on the target. I would prefer not to build in that kind of elevation change if I can avoid it, since I am trying to shoot as many X's as possible. ;^)

That’s what the charge weight testing is for. Should definitely leave the chronograph at home- and do your powder work up at 500 yards. A true, traditional impact ladder’s results are worth a million chrono readings.

 

[Buttstock-TX]

That’s what the charge weight testing is for. Should definitely leave the chronograph at home- and do your powder work up at 500 yards. A true, traditional impact ladder’s results are worth a million chrono readings.

I'm learning here; How much would you vary charge weight on the -14/1000 seating depth load at 550 yards? What increments of powder charge?

I would offer that of the six different bullets (108 to103 grains) I've tested to date, both in and out of the lands, the best load, after testing large charge weight spreads, has ended up between 31.3 and 31.6 grains.

I heretofore would not have tested that many bullets but, since the 6 BRA was new for me, I have sought to understand characteristics of well-regarded bullets.

 

[Clancy]

I'm learning here; How much would you vary charge weight on the -14/1000 seating depth load at 550 yards? What increments of powder charge?

I would offer that of the six different bullets (108 to103 grains) I've tested to date, both in and out of the lands, the best load, after testing large charge weight spreads, has ended up between 31.3 and 31.6 grains.

I heretofore would not have tested that many bullets but, since the 6 BRA was new for me, I have sought to understand characteristics of well-regarded bullets.

I’d test in .1 grain increments for sure. I’d look below and (if safe to do so) above and document all temperatures along with velocities as Varget is a little temp sensitive. I’m an N135 or H4895 guy so I don’t know normal charge weights with Varget in a BRA.

Testing six bullets in one barrel sounds like a lot of work. Please share anything cool you found while doing it!

 

[Buttstock-TX]

OK, I went out and shot the distance tests today and was pleasantly surprised. I had a fishtailing wind and problematic mirage but, that is the general rule on this range in the Texas Hill Country. It keeps you from shooting small groups but, that said, there were some small groups and a couple horizontal 9's too. I've boiled it down to vertical spread only. Bottom line, I love the Bart's Gungnir bullet. It can shoot either in the lands +15/1000 or jumped -14/1000 in my rifle. I think the ~14/1000 jumped might be the easiest for F class, as there seems to be a wide window in charge weight there.

Thank You all for the feedback. I don't think I would have tried this approach without some coaching.

 

[Clancy]

@Buttstock-TX you’ve discovered why seating depth first is the way. Trust the depth and you get a wide tuning window. With powder first, you often get a one trick pony.

Enjoy the rifle.

What’s bullet number 7 haha?

 

[Buttstock-TX]

I'm done testing bullets! I've worn myself out but identified a couple that will easily hammer the X ring. It's now time to practice and improve my wind calling.

 

[JFrank]

I'm done testing bullets! I've worn myself out but identified a couple that will easily hammer the X ring. It's now time to practice and improve my wind calling.

What’s your round count after all that testing ?

 

[Buttstock-TX]

What’s your round count after all that testing ?

Between practices, initial load development, bullet testing and 3-4 matches I am about 850 now.

 

[Clancy]

Between practices, initial load development, bullet testing and 3-4 matches I am about 850 now.

You’ll get to where you can head to a match with 40 rounds on a barrel. I used to tinker with everything too. Pick a favorite and stick with it. Order a full haz of powder and primers from the same lot. 10,000 bullets at a time. Stuff like that….

 

[JFrank]

When I send extra rounds tuning, I end up wishing I had that barrel life back in the end.