Here is a target using 43.7 4064 ( an accurcy load that shoots all 175 and 168 bullets from this rifle under an inch) sorted with 'shorts' on top and 'longs' on the bottom .. seated 2.172 which is 2.86ish COAL in lapua 2x winds were light at 4-6 kts and you can see the vertical and horizontal issues with this load. velocity was ~2680 based off of magneto groups fired prevously with this powder load. these groups were with magneto off since the magnetto throws my rounds .9 mil higher on target.. yeah.. 4" at 100 ..
the barel profile is modified MTU 24" scheider with a .91 at the muzzle.
shot on the same day as foulers were a load of 43.2 4064 berger 168 and grouped .4 for 8x then fired these 2 groups.
dgheriani well it sounds promising however I have yet to get this schnieder barrel to eat them
so to be clear.. you are setting up the seating for the bullets to 2.175 adj the seater for the shorter bullets..? basically seating them twice to get the same CBTO
What I have found (see below) is that the 'long' bullets touch my rifling with much greater varance CBTO than the shorts...
what kind of jump are you looking at and what chamber is your benchmark cut for. What is your powder of choice with these?
2750 is moving out even for a 26" barrel .. I dont get 2750 ish in this tight, fast, schneider (shoots 175GMM factory 100+FPS higher than book ~2760 magnetto) until I get to 44.9g of 4064. It was about 50F that day and while no pressure signs in lapua on that day, not sure what it will look like in aug in 100+ heat. usually once I get above 44+ g of 4064 its usually better for me to move to varget, which I have yet to try but perhaps 45 of varget will get me the same velocity node and do so with slightly less pressure which has been the norm loading with thise 2 differrent powders.
so, to be clear you are not seeing 2 distinctly different groups at 980? are you even shooting for groups at that distance or just banging a 2+ moa plate at that range?
again I was planning on using the same bullet for F as I do for PRS, and so far, this bullet isnt it. its back to sierra or berger until nosler can figure out their issues with the 175RDF..
as an asside here are more technical details.. detailing 3x of each 'shape' found in the 3 different lots that I have... one lot has these mixed, one lot is all 'long' and another lot is all short. So after I sent this info to nosler last year ( and never heard back) or shooters pro shop not willing to take these "COSMETIC ONLY' bullets back leaving me with $500 in scrap metal...but given that in later lots they are segregating them leads me to believe they know they HAVE A PROBLEM and are SCREWING US THE CUSTOMER....
here it is...
starting from tip to base using various diameter comparitors working down the hybrid curve of the bullet jacket ending at the .28 measurement.
Comp dia used diff of the 'short' bullet using the long as ref distance
.22 ---- -.008 +/- .001
.24 ----- -.008
.25 ----- -.010
.27 ----- -.007 +/- .004
.28 ----- -.006
.30 ----- +/- .002
CBTO seated into my chamber variance (cartridge base to ogive)
‘short’ ‘Long’
2.208 2.220
2.207 2.197
2.208 2.210
So I was going off the belief that the 'long' ogive bullets were the ref, but its clear their is far less variance on the 'short' seating near identical COAL with the hornady tool were the 'long' has a variance of over .023 that 23 thou in the 'sorted' long bullets.. this is because the ojive isnt touching the rifling first but the tangent/secant nose curve of the bullet.
Weight ES .4 grain
Bullet BTO with a .25 comparator which is just about where the land engraving surface is for comparison
'short' 'long'
.870 .879
.870 .8795
.8705 .8775
ES .0005 .0015 so 3x more ES
So I was going off the belief that the 'long' ogive bullets were the ref, but its clear their is far less variance on the 'short' seating near identical COAL with the hornady tool were the 'long' has a variance of over .023 that 23 thou in the 'sorted' long bullets.. this is because the ojive isnt touching the rifling first but the tangent/secant nose curve of the bullet.
So clearly.. its more likely that the 'short' are the more uniform and likely the designed shape for the bullet die, and that the 'long' rounds are the bullets coming out of the flawed die or machine that is not forming them completely. Its possible that its the company providing the jackets vs the swaging operation but either way.. its shit.
this would be alot more definitive if I were still in the service. I would just take them over to the NDI shop and have a couple dozen run under the laser comparitor
but its clear with these measurements that getting any consistency with loads using these bullets is just pure luck or a very 'forgiving' rifle that just has a super wide node for this particular load
seating these anywhere near the lands is impossible as the CBTO for touch varies between 2.197 to 2.220 .. and that is just with 6 bullets.. if I opened up the sample size it would get worse not better. 23 thou is a huge varience when a 5 thou seating depth change can take you out of a sweet spot even with a berger hybrid.
I cant get this editor to hold my formatting of data so just bear with it...