Seating depth inconsistency

[DShortt]

I agree with this. Most comparator inserts don’t contact the bullet anywhere of significance. They don’t actually touch where the bullet actually contacts the rifling. For my 7mm bullets, I found that a 6mm insert is close to where my seating stem contacts. That’s a measurement that actually has some meaning. I also get more consistent measurements here. The 7mm insert has absolutely no importance. I check bullets for total length and base to seating stem contacts

And that's my point.

*IF* we're going to be concerned about seating depth, why measure at some arbitrary point as opposed to the contact point, or as near as possible.

Yes, I'll be making a comparator insert also. For myself.

Will it make any difference? I dunno. Haven't tried this yet.

 

[Bob3700]

Ok,
Had to mess with ya guys today.
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(That's actually my setup to trim meplats)
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Ya got me there. Well played!

 

[JFrank]

Ok,
Had to mess with ya guys today.
-------------------------------------
(That's actually my setup to trim meplats)
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I use a bench grinder to trim meplats.

 

[Asumner]

And that's my point.

*IF* we're going to be concerned about seating depth, why measure at some arbitrary point as opposed to the contact point, or as near as possible.

Yes, I'll be making a comparator insert also. For myself.

Will it make any difference? I dunno. Haven't tried this yet.

I thought the short action customs comparator was designed to measure the ojive based on when it hit the rifling like your wanting or at least that’s what I understood

 

[DShortt]

I thought the short action customs comparator was designed to measure the ojive based on when it hit the rifling like your wanting or at least that’s what I understood

That may be correct. I just plan to make a comparator bushing for the tool I already have.

 

[Webster]

I am getting inconsistent seating depth ranging sometimes 5 to 6 thou out. The powder charge is the same but they do sometimes feel more compressed. I assume this is causing my bullet to have different seats. I get them all to the same length but it is annoying. All of the brass has been prepped exactly the same way as well. I am using Hornady brass but I am considering using alpha or Peterson brass thinking it may fix the issue but as I am new to reloading I do not want to be hasty.

My groups have been fine it seems but I have noticed every once in a while I get a spiked velo round. I marked every single bullet that I had a seat issue to see if that shot spiked in velocity and will find that out today.

You said the groups are great. Why are you concerned about details that are not a problem?

 

[wkdickinson]

I started a thread about my aggravation with the design of all the seating stems/inserts I've examined. They contact the bullet somewhere in the upper 30% of the tip. Some are worse than others.
When time allows, I have a plan to move that to the lower 30%, very near the ogive.
I believe this will prove to be much more consistent, but right now, it's just a theory.

Truly, I think a comparator insert closer to the actual rifling engagement diameter would be best. But then you would also need a seating stem of that same diameter - not sure that is possible.

 

[DShortt]

Truly, I think a comparator insert closer to the actual rifling engagement diameter would be best. But then you would also need a seating stem of that same diameter - not sure that is possible.

It is if you make it yourself. Which is what I plan to do if and when I get the opportunity to do so.

 

[wkdickinson]

It is if you make it yourself. Which is what I plan to do if and when I get the opportunity to do so.

I was referencing the actual diameter required, if there is enough material in the seating stem to make it work.

 

[DShortt]

I was referencing the actual diameter required, if there is enough material in the seating stem to make it work.

I'll make an entire new stem to test it if that's what I discover I have to do.

With a Redding, that appears to be the requirement.

 

[Asumner]

You said the groups are great. Why are you concerned about details that are not a problem?

Because I check every bullet to keep them in my node but if I didn’t I would be all over the place

 

[ELR LVR]

so when you find the difference in bto and sort them do you still put them at the same length as you found your node? What’s the common practice? I ask because the bullet would still be deeper in the case.

This is a good question, that I think got skipped over.
And something I haven't really considered .....so good thinking on your part
I have been seating them all at the same length base to ogive
But also have found my seating depoth windows are approx .005"-.010" before I notice accuracy change
I am thinking now after you pose this question it would be a very good idea to seat the bases all the same depth then test and compare.
Same case depth may actually be a better idea, in theory anyway.
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BTW, this is 3/10th of a grain of brass in the powder pan as a comparison
I don't even think I take this much off the meplats

 

[ricco1949]

Using Bushing dies, as Bullet seaters

I've been using neck bushing dies to do a final bullet seat . Yesterday, I used my 17 Fireball, Neck bushing die, with the appropriate bushing, to do a final seat on my 204 R ammo. What I like about this method, is, the base to ogive of my reloads, is very accurate. I can use this same set...

benchrest.com

The attached BR Central thread addresses the ogive/seater differential using a neck bushing die with the appropriate size bushing as a bullet seater.

I plan to try this with a 20 VT neck bushing die in my next loading session.

 

[DShortt]

I've a similar plan in mind. I'm curious what results I see on the range.

 

[Asumner]

This is a good question, that I think got skipped over.
And something I haven't really considered .....so good thinking on your part
I have been seating them all at the same length base to ogive
But also have found my seating depoth windows are approx .005"-.010" before I notice accuracy change
I am thinking now after you pose this question it would be a very good idea to seat the bases all the same depth then test and compare.
Same case depth may actually be a better idea, in theory anyway.
--------------------
BTW, this is 3/10th of a grain of brass in the powder pan as a comparison
I don't even think I take this much off the meplats

Oh dang nice, well I definitely can find out but my bullets seem to be able to stay in my node based on the direction in size they are different. I plan to shoot this weekend so hopefully I can have a small sample test

 

[Ringostar]

I am thinking now after you pose this question it would be a very good idea to seat the bases all the same depth then test and compare.
Same case depth may actually be a better idea, in theory anyway.
--------------------

This is why I measure base to seating stem contact. It will put base of bullet at same point inside the case, which should keep case volume consistent. It might be crazy theory, but I see no point at all in measuring to a place on a bullet that really has no bearing! Yes, that’s meant as a joke!

 

[Asumner]

I will say that in my case, pouring slower seemed to help tremendously or it could be the area 419 funnel I bought either way it has seemed to help. I did set 5 rounds at a different base height due to change in length of bullet so we shall see if I see a major change. It’s still in my node though so it won’t be a be an obvious one if there is some sort of jump.

 

[dellet]

so when you find the difference in bto and sort them do you still put them at the same length as you found your node? What’s the common practice? I ask because the bullet would still be deeper in the case.

.

This is a good question, that I think got skipped over.
And something I haven't really considered .....so good thinking on your part
I have been seating them all at the same length base to ogive
But also have found my seating depoth windows are approx .005"-.010" before I notice accuracy change
I am thinking now after you pose this question it would be a very good idea to seat the bases all the same depth then test and compare.
Same case depth may actually be a better idea, in theory anyway.
--------------------
BTW, this is 3/10th of a grain of brass in the powder pan as a comparison
I don't even think I take this much off the meplats

I theory nothing would change from what you did before, except you went to great lengths to even out the base to ogive measurement.

What should happen is that if you sorted you bullets into 4 groups, then as long as you drop your powder the same, and your brass prep is the same and you work the press the same, then you should have exactly the same 4 groups when loaded. In a perfect world, one of the four groups will be the same as your original length. The other three will be plus or minus the same as you sorted the bullets.

 

[ELR LVR]

.


I theory nothing would change from what you did before, except you went to great lengths to even out the base to ogive measurement.

What should happen is that if you sorted you bullets into 4 groups, then as long as you drop your powder the same, and your brass prep is the same and you work the press the same, then you should have exactly the same 4 groups when loaded. In a perfect world, one of the four groups will be the same as your original length. The other three will be plus or minus the same as you sorted the bullets.

The theory with having the base to the same depth
As opposed to the ogive being the same depth
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1. Is the flame front will act on the base of the bullet the same way each shot (importance of seating depth)
2. The bullets base will exit the muzzle (importance of seating depth) at the same time each shot / as opposed to the ogive meeting the muzzle at the same time each shot - which really don't mean squat
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We don't know yet, some others may know but are not telling us
Seating the bullet depth according strictly to the Ogive is one of those
"well thats just how we've always done it" kind of things

 

[JFrank]

Over the years I’ve sorted hundreds of non custom bullets, I’ve also shared this information before but I can’t seem to find it now so I’ll just summarize if ya’ll don’t mind.
The Wilson seater stem makes contact around the .174 mark so for simplicity I ordered a .17 caliber comparator insert to sort bullets base to seater stem in .001-.002 batches .
Then I use the appropriate caliber ( .24) for 6mm to sort the previous sorted batch’s base to ogive, so when I move the seater .001 the relationship to the lands moves the same amount, so now I know the nose geometry on each sorted batch is as close as I can get them and my seating node remains the same.
How much of the bullet base is in the case is IMO irrelevant.
The seater recognizes its contact point, the lands recognizes the ogive and LR target is effected by BC so I sort the best of the best by OAL for long range record rounds.
The odd ball bullets that fall outside the parameters get used for shorter range shooting or testing.
Now days I just buy Vapor Trail Bullets and skip all the extra sorting.