After determining the seating depth of 200 gr Accubonds for my 300 win, Do I need to change the die for Partitions? Is it the bullet tip or the ogive that RCBS dies are calibrated from? Thanks

Chain

Usually the seater plug contacts a datum point on the ogive, often indicated by a shined up ring around point of contact, I doubt the Accuubond will have the same ogive profile as the Partition but cannot say for sure, the best test is to use a stoney point OAL and seating gauge and work out point of contact with the lands for each bullet type, and then by loading each type of bullet into an empty unprimed case so as to make a dummy round for each you will find where each bullet type comes into best accuracy seating position for your rifle and then by working backwards by carefully trying each in the seating die and screwing down the seater plug onto each loaded sample case you will find if there is any difference in seater plug position.

Hope you are able to follow this thread from the explanation.

Jonathon's advice is "spot on" as they tend to say on his side of the Pond.

However, I've always regarded the Stoney Point tool as a solution looking for a problem. I simply seat my bullet a little long, chamber (or attempt to chamer) the round, and progressively seat it deeper until the land marks disapper from the bullet. Smoking the bullet with a candle allows you to see even the slightest land contact clearly.

As Jonathon says, it is doubtful that the datum point for the two bullets is identical. In the end, it is the relationship of the bullet's ogive to the lands of your barrel that you are concerned about; that is providing cartridge with a bullet seated to it's maximum length will still fit in the magazine.

quote:

Originally posted by Stonecreek:
However, I've always regarded the Stoney Point tool as a solution looking for a problem. I simply seat my bullet a little long, chamber (or attempt to chamer) the round, and progressively seat it deeper until the land marks disapper from the bullet. Smoking the bullet with a candle allows you to see even the slightest land contact clearly.

roger

Thanks I will give that a try. A dummy round for each bullet seems like a sound idea.

I don't think you need to go the dummy round route unless you are switching back and forth a lot. Just carefully note your optimal OAL for each bullet and leave yourself a note in the die box telling you what you last loaded so you know what it is set for. It only takes seconds to check OAL with a vernier and reset your seater.

I just take a fired case and pinch the neck enough to hold a bullet. I take a flat based bullet and seat it backwards long enough that the lands will push it in. Close the bolt and you have the distance to the lands.

Lyle

I will try that. I didn't have any luck with the smoke. Thanks

quote:

Originally posted by Versifier:
I don't think you need to go the dummy round route unless you are switching back and forth a lot. Just carefully note your optimal OAL for each bullet and leave yourself a note in the die box telling you what you last loaded so you know what it is set for. It only takes seconds to check OAL with a vernier and reset your seater.

Hey Versifier, How do you compensate for the "length variation" of the bullets found in the same box?

For you folks doing the Split Case or Pinched Neck on a Fired Case, do you concern yourself with the Bullet "slipping" slightly into the case each time you set-up the Seater?

Use a magic marker to "smoke" your bullet. Then rotate it under a bright light and any land marks will jump out at you.

quote:

For you folks doing the Split Case or Pinched Neck on a Fired Case, do you concern yourself with the Bullet "slipping" slightly into the case each time you set-up the Seater?

Hot Core
Put a little thin CA glue on it and it will never move.

quote:

Originally posted by Hot Core:

Hey Versifier, How do you compensate for the "length variation" of the bullets found in the same box?[/QUOTE]

I load Sierras and I don't worry about it. I have never noticed any variation in their lengths. Even if it exists and there is a minor enlargement of group size in my .30 cal loadings, you can't prove it by the dead deer in the freezer.
I also load Sierras in my .22-250. I've never noticed a "length variation" problem there with either hunting or match bullets, both stay easily below 1/2MOA out to 400yds.
What kind of bullets are you shooting that you encounter this trouble with?

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What kind of bullets are you shooting that you encounter this trouble with?

Hey Versifier, Basically all of the different brands - including Sierra, but to less of a degree.

Try sitting down with a box of the Sierra bullets and a 0.001" capable Caliper at the table. Measure them from Base to Tip and place them in front of you so the shortest ones are on the Left. As they increase in size, start another row to the right.

You should see a Bell Shaped Curve forming before your eyes as the Bullets of the same length are added to the proper row.
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If you have the Seating Die set-up for those Sierras in say the 22-250 and "do not" change the Seating Stem Length then it won't matter. That is because the distance from the Point-on-the-Ogive that will make initial contact with the Lands will remain the same.

As long as you are getting good accuracy at that setting and Sierra does not change the Profile, the accuracy should remain fine until the Throat begins to recede. Either can change the "Distance Off-the-lands" and goof up your accuracy Load.
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Had an old buddy call me in a panic one day. After he had loaded some BarnesX bullets, he happened to pick up his Calipers and measured the Overall Cartridge Length. They were all different, by a lot.

So, he pulled the bullets, dumped the Powder, pulled the Deprimer, resized the cases and reloaded them. Same thing - again!

If he had just not measured the OCL, everything would have been fine. But he thought the Seating Operation was somehow goofed up. It was simply the different overall bullet lengths.

That is why I recommend that people convert to the "Overall Die Length" and write it on the Box of Bullets. And it needs to be remeasured each time a new box of bullets is opened. That way you can catch changes the manufacturer eventually makes to the Profile as well as the Throat Recession.

Best of luck to you.

Originally posted by GSP7:
And yes a partition will have a different c.o.l. than a Accubond/Balistic tip

Also take any brand box of lead tip bullets and measure about 5 with your calipers. There will be a variation in length depending on the lead tip . They get smashed, deformed, or not perfectly the same . Usualy around .005 +++ Variation on some.