Should I Jump Into The Arbor Press World? (To Improve Seating Depth Consistency)

[CarlGeorge]

I'll go ahead and predict that you'll find no meaningful difference.

And......you were right. Shot some tests today. All grouped basically identically. I expected to get some better seating depth results (I did) but didn't see a result on paper.

I ordered the Arbor and bullet seater last night. I'm gonna venture into the world of checking seating pressures.

Thanks all!

 

[dannyjbiggs]

I ordered the Arbor and bullet seater last night. I'm gonna venture into the world of checking seating pressures.

Thanks all!

You will soon realize that you are embarking on a technique of sorting your just-seated cartridges by bullet "neck tension"...the reason behind seating by "feel" that several have mentioned, and best done with an arbor press.

Dan

 

[EdHarley]

All you need is a barrel stub and reamer and you can measure exactly where itll hit

How is that different than the BTO they are discussing? I would like to just measure one thing when I sort.

 

[EdHarley]

Correct. Put a bullet nose down in on collimator and note the reading. Swap collimators and measure again. You'll get a reading like 50-72. Those all go into one bin, as do the 51-72s and 50-73s.

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All of the bullets in a particular grouping will have the same contact point on the seater stem and thus--assuming all the other parts of your seating process are consistent, will seat the same. Additionally, all these bullets CO will be the same distance from the rifling. This ensures maximum seating and jump/jam consistency.

If I am describing this correctly.......With 50 being the CO and 72 being the SO, a 50-72 will seat .001" differently than a 50-73, and the chamber contact will be .001" different. A 51-72 will seat the same as a 50-72, but the chamber contact will be .001" different. A 51-71 should seat the same as a 50-72 with the same chamber contact point, though the ogive is shaped different.

Good custom bullets will sort into 4-5 groupings. Berger's will have 11-13ish.

SO/CO vs BTO only matters with a LR BR rifle shooting in good to excellent conditions.

Maybe I understood your process wrong. You swap the metal piece that holds the bullet not the comparator with the dial correct?

 

[Dusty Stevens]

How is that different than the BTO they are discussing? I would like to just measure one thing when I sort.

It takes into account the different ojive shape overall like front and back just how it would hit your exact barrel. Gets the whole picture

 

[JFrank]

So if a bullet needs to be sorted 5 different ways, does that mean I need 5 different tunes ?
Couldn't I just buy better bullets?

 

[INTJ]

Maybe I understood your process wrong. You swap the metal piece that holds the bullet not the comparator with the dial correct?

Correct.

 

[INTJ]

So if a bullet needs to be sorted 5 different ways, does that mean I need 5 different tunes ?
Couldn't I just buy better bullets?

No, the tune doesn't change. It's just a matter of sorting all the bullets in a way that will allow them the best chance of shooting together. Even the best bullets have inconsistencies, though custom bullets are a LOT more consistent than Bergers or Sierras.

With Barts I'll get 3-4 sorts. With Bergers it can be a dozen or more. If I am tuned for .015 jump or more, then all the Barts will be shot together. There will be less sortings needed for Bergers with such a jump, but still 3-4.

Most of the time sorting good custom bullets doesn't help a lot. IIRC, out of a couple thousand plus Barts bullets I found ONE bullet that was significantly different than all the rest. I suspect I could have just loaded and shot them and did nearly as well.

However, if that ONE bullet had been loaded and shot in a record group it may well have dispersed significantly........and that is why I check every bullet. Even though most of the time it may not matter, I never know when I'll get the excellent conditions where it will matter.

 

[Ccrider]

All you need is a barrel stub and reamer and you can measure exactly where itll hit

For a season. The. Your lands wear.

 

[Dusty Stevens]

For a season. The. Your lands wear.

Actually the diameter gets bigger because with each expansion (shot) the barrel doesnt contract to its original diameter so the bullet has to go farther to hit the same spot. Just adjust your zero accordingly

 

[EdHarley]

It takes into account the different ojive shape overall like front and back just how it would hit your exact barrel. Gets the whole picture

Makes sense. So do you measure bearing surface as well or sort by the bto measurement using your barrel stub only?

 

[Dusty Stevens]

Makes sense. So do you measure bearing surface as well or sort by the bto measurement using your barrel stub only?

I use good bullets. They only need to be checked for OAL if you dont have anything else to do