wkdickinson
Gold $$ Contributor
OK, I just purchased a box or 500 Berger 6mm 105 Hybrids. How should I sort them - by weight, by bearing surface length, by both, does it matter?
Bullet Sorting?
- Thread starter wkdickinson
- Start date
dcali
Bullet Maker
Define "matter". I wouldn't bother with anything other than OAL sorting. The weights are all going to be pretty much the same. Same with base to ogive. Boattail lengths are very consistent too. It's the nose that varies - sorting can help even out the BC variation.
I don't sort any of my 600 yard F TR bullets at all. I do ok.
I don't sort any of my 600 yard F TR bullets at all. I do ok.
Bto will not all be the same. Hybrids I’ve measured vary 5k or so between extremes. I believe this matters more than oal. You’ll quickly find if you ask 5 people their opinion on sorting you’ll have 5 answers.
On a separate note: I loaded up 100 rounds of Berger 140's 2 weeks ago and never checked the ogive bearing area ( it was from a different lot #) my mistake. After I loaded 85 of them I thought wow I never checked my seating depth and on a Wilson arbor press it doesn't change but guess what on this lot of bullets I was .006 off of my go to load. I ran that load on a Saturday morning in open F class and shot a 599, would all that measuring helped ..... I doubt it. Just makes you wonder how much it's worth.
Darrin
Darrin
How do you measure, COAL or base to ogive?
I sort Base to ogive and over all bullet length. If you don't sort Bullet over all length prior to seating you will find a large variation in coal. I sort bullet over all length just for piece of mind. Can you see it on paper, probably not.
Darrin
She's all good. I wondered what could be achieved if you sorted COAL only or COAL first.
Ever thought of doing a base to ogive sort first, then meplat trimming each batch and then measuring to see if there's any discernible difference in COAL?
Nope too much time in what I'm doing now and it works excellent for me.She's all good. I wondered what could be achieved if you sorted COAL only or COAL first.
Ever thought of doing a base to ogive sort first, then meplat trimming each batch and then measuring to see if there's any discernible difference in COAL?
Darrin
ckaberna
Gold $$ Contributor
This is the link to what some of the posts are talking about http://forum.accurateshooter.com/threads/bbto-or-bearing-surface.3966113/
Why is it so popular to use the case head as the reference to any measurement to some point on the bullet?
Case heads are typically not against the bolt face when the round fires. A few to several thousandths clearance is the norm.
The case shoulder is against the chamber shoulder when the round fires so it's a much better reference, in my opinion. Unless all the cases' headspace is the same.
Case heads are typically not against the bolt face when the round fires. A few to several thousandths clearance is the norm.
The case shoulder is against the chamber shoulder when the round fires so it's a much better reference, in my opinion. Unless all the cases' headspace is the same.
Because it's the bottom of the cartridge and one needs a place to start all measurements from.
So if all shoulders are set to standard length
Measured from case head to shoulder, then it's safe to assume all measurements will be equal if bullets are sorted by base to ogive
Giving one a very consistent cartridge to cartridge measurement.
Now do cartridges have headspace or do chambers?
My understanding as per the teachings of
Sir F Guffy, the chamber does.
Ned Ludd
Silver $$ Contributor
The base-to-ogive (BTO) length of the bullet doesn't necessarily have much to do with cartridge base-to-ogive (CBTO) measurement. The seating die stem pushes bullets from a specific contact point on the ogive slightly below the meplat down to whatever setting the die mic has dialed in; it doesn't "know" that the bullet has BTO variance below the contact point. For that reason, unsorted bullets with significant BTO variance can easily be seated to very consistent CBTO, but you will likely end up with significant variance in the amount of bullet shank/boattail down in the neck/case.
The best approach to achieve uniform seating depth is to sort bullets using something like Bob Green's Comparator tool, which sorts bullets based on length of the region between the point on the ogive just above the bearing surface where the bullet first contacts the rifling, and farther out on the ogive where the seater die stem contact point is located.
As a more general observation, bullet sorting should largely depend on what type of shooting you intend to do. For example, many BR shooters swear by sorting bullets at a minimum by BTO, and sometimes several other methods as well. As an F-TR shooter, I don't find BTO sorting to be very useful based on my precision requirements, which are not the same as BR shooters. I sort bullets by OAL largely for the purpose of pointing them, which slightly improves BC and is useful for the changing wind conditions often observed during the long (20+ shots) strings of fire in F-Class. So match your bullet sorting approach to the type of shooting you intend to do. Talking with experienced shooters in your chosen discipline will be the best way to find out what approaches they are using successfully.
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All of this would be mitigated if seater stems touched bullets at their diameter where the chamber throat's rifling does. That place is typically a couple thousandths less than bullet diameter.
Only if the bullet's ogive reference diameter is where it touches the rifling. And all cases headspacing on their shoulders have the same headspace.
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