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Whats Most Important: Weight Variations or Nose Profile
- Thread starter The Old Salt
- Start date
The Old Salt
New member
O-give to Head specs
In each shot group I picked a bullet that was representative of the groups average NP. Take group 1B. It has 2 bullets w NP of 0.6610 "& 3 w 0.6615". So I selected 1B3 as the bullet that represents the group.
That rd is shown in yellow backround in the "O-give to Head w bullet on rifling" column on the pdf. The number shown was arrived at by taking that bullet, putting it in my "Sacrifice Case" ( a case with a slot cut down the neck & 2/3 of the sholder) and chambered letting the rifling seat the bullet. Remove and measure. Repeat 5 more times. Throw out the obvious out lier and average the rest. You now have a O-give to Case Head spec for that particular group of 5 rds.
The number below the group representative bullet, in Black underlined, is the average variation in NP to lands actually achieved when I assembled those 5 rds. My intent was to achieve a 0.0100" off lands gap. 1. By gradually adjusting the bullet seating deeper to get there. 2. But not pulling any bullet that got seated deeper than desired. Thereby not disturbing the neck tension.
This barrel can shoot groups much smaller than these. Even though I struggle to achieve that. That said, the goal here is to demonstraight that NP has a place in the reloading world because in does impact micro variations in the loaded rd. Using a "sacrifice Case" to determine that specific bullets NP, O-give to Head spec, "In Your Chamber!!!" allows loaded rds with matching NPs to have a very consistant gap to lands.
Those of you who have the micrometer dies should try this process. I'm happy to sent the spread sheet and explaination of how to use it. Perfectly matched bullets result in prefectly uniform gap to lands, consistant IVs, very tight ES, and groupings.
My shooting skills are not good enought to prove all the above, but it cries out for investigation by those who have better reloading equipment that I do, and superior shooting skills.
I believe group size is partially controlled by IV. Using NP helps load rds w more consistant IVs. NOTE! The test components here are NOT match grade components: Used Win brass with std necks, WLR primers, factory second bullets, H4895, a good powder but maybe not the best for producing small ES, and an old guy with vision issues. And substancial resluts were achieved. Immagine what they could be if good eyes were paired up with truly top notch components.
Thoughts?
In each shot group I picked a bullet that was representative of the groups average NP. Take group 1B. It has 2 bullets w NP of 0.6610 "& 3 w 0.6615". So I selected 1B3 as the bullet that represents the group.
That rd is shown in yellow backround in the "O-give to Head w bullet on rifling" column on the pdf. The number shown was arrived at by taking that bullet, putting it in my "Sacrifice Case" ( a case with a slot cut down the neck & 2/3 of the sholder) and chambered letting the rifling seat the bullet. Remove and measure. Repeat 5 more times. Throw out the obvious out lier and average the rest. You now have a O-give to Case Head spec for that particular group of 5 rds.
The number below the group representative bullet, in Black underlined, is the average variation in NP to lands actually achieved when I assembled those 5 rds. My intent was to achieve a 0.0100" off lands gap. 1. By gradually adjusting the bullet seating deeper to get there. 2. But not pulling any bullet that got seated deeper than desired. Thereby not disturbing the neck tension.
This barrel can shoot groups much smaller than these. Even though I struggle to achieve that. That said, the goal here is to demonstraight that NP has a place in the reloading world because in does impact micro variations in the loaded rd. Using a "sacrifice Case" to determine that specific bullets NP, O-give to Head spec, "In Your Chamber!!!" allows loaded rds with matching NPs to have a very consistant gap to lands.
Those of you who have the micrometer dies should try this process. I'm happy to sent the spread sheet and explaination of how to use it. Perfectly matched bullets result in prefectly uniform gap to lands, consistant IVs, very tight ES, and groupings.
My shooting skills are not good enought to prove all the above, but it cries out for investigation by those who have better reloading equipment that I do, and superior shooting skills.
I believe group size is partially controlled by IV. Using NP helps load rds w more consistant IVs. NOTE! The test components here are NOT match grade components: Used Win brass with std necks, WLR primers, factory second bullets, H4895, a good powder but maybe not the best for producing small ES, and an old guy with vision issues. And substancial resluts were achieved. Immagine what they could be if good eyes were paired up with truly top notch components.
Thoughts?
Last edited:
The Old Salt
New member
In my last post I forgot to add that my RCBS $125 electronic scale has a .1g accuracy. Trickle technique is important. Those of you with scales in the $400 range will get much more consistancy in your charge wts. Also the brass was weighed and I selected a wt of 158.5g +/- 5.0g.
Weighed bullets & brass, consistant case prep, inter group consistant NP, controlled bullet seating as best I could w my equipment, documented every step. Did I overlook anything?
Weighed bullets & brass, consistant case prep, inter group consistant NP, controlled bullet seating as best I could w my equipment, documented every step. Did I overlook anything?