I've put couple of hundred factory rounds through my SAKO TRG 42 in .338 Lapua Magnum over the years. It liked best Lapua ammo and worst PPU ammo.
Then after playing with VN570 powder and HNDY AMAX bullets to various degrees of success I decided to try a new combination: H1000 + Scenar 250.
I went to Hodgdon's on-line calculator which gave me a 88.0 - 98.0 grain range on the powder for 250 gr bullets. Seemed high. I opted for 94.5 - 96.5 range in 0.5 increments: 5 loads, 3 rounds each. I'm using an RCBS charge master.
I used PPU brass once fired in same chamber, trimmed and neck re-sized with a Lee collet die with standard mandrel at 0.3355" diameter (which is too big for Lapua brass I intended to use due to its larger wall thickness).
From past experience (VN570 powder and HNDY AMAX), rifle liked a CBTO of 2.900" so I started with that using a Redding competition seating die.
Included are entire target + best (95.0 grain load) and worst (95.5 grain load) measured groups at 100 yards. The worst group is worst probably because of me considering all others, before and after, are better.
A few salient points:
1. MVs are up there. However, I've noticed no over-pressure signs of ANY sort.
2. My worst ESs are in 30+ so I need better uniformity with my charges, brass/bullet weight, CBTO, neck tension...etc.
Interesting observations:
1. Velocities and especially vertical POIs vary very little with powder load - the last 2 points show MV/height inversion although the MV difference is much less than the ES/std_dev within each group - which makes me think this is the nice, flat, sweet spot - or range as it were - for the load.
2. Horizontal POIs seem to slowly move rightwards with load increase - no luck finding a load-invariant load in terms of horizontal harmonics yet.
What I'd like to try next:
1. Try to re-create this to check reproducibility.
2. Try lower charges in the hopes I can get a horizontal harmonic load-invariant node.
3. Open up the groups at longer distances.
4. Play with CBTO.
Then after playing with VN570 powder and HNDY AMAX bullets to various degrees of success I decided to try a new combination: H1000 + Scenar 250.
I went to Hodgdon's on-line calculator which gave me a 88.0 - 98.0 grain range on the powder for 250 gr bullets. Seemed high. I opted for 94.5 - 96.5 range in 0.5 increments: 5 loads, 3 rounds each. I'm using an RCBS charge master.
I used PPU brass once fired in same chamber, trimmed and neck re-sized with a Lee collet die with standard mandrel at 0.3355" diameter (which is too big for Lapua brass I intended to use due to its larger wall thickness).
From past experience (VN570 powder and HNDY AMAX), rifle liked a CBTO of 2.900" so I started with that using a Redding competition seating die.
Included are entire target + best (95.0 grain load) and worst (95.5 grain load) measured groups at 100 yards. The worst group is worst probably because of me considering all others, before and after, are better.
A few salient points:
1. MVs are up there. However, I've noticed no over-pressure signs of ANY sort.
2. My worst ESs are in 30+ so I need better uniformity with my charges, brass/bullet weight, CBTO, neck tension...etc.
Interesting observations:
1. Velocities and especially vertical POIs vary very little with powder load - the last 2 points show MV/height inversion although the MV difference is much less than the ES/std_dev within each group - which makes me think this is the nice, flat, sweet spot - or range as it were - for the load.
2. Horizontal POIs seem to slowly move rightwards with load increase - no luck finding a load-invariant load in terms of horizontal harmonics yet.
What I'd like to try next:
1. Try to re-create this to check reproducibility.
2. Try lower charges in the hopes I can get a horizontal harmonic load-invariant node.
3. Open up the groups at longer distances.
4. Play with CBTO.
