Seating depth inconsistency

[Asumner]

Enough to mean the difference between compacting the powder and crushing it if you’re on the edge.

Exactly and wish I would have looked earlier

 

[Asumner]

gonna have to chuck 'em in a drill and sand the ogives down until they're all the same
finish up with steel wool

lol is this really a thing?

 

[ELR LVR]

lol is this really a thing?

yep, heres my setup

 

[Bob3700]

That is quite the setup u have there.
Let me see if I understand this process.
First, I measure my box of bullets and then establish the bullet that has the shortest base to ogive.
Next, I chuck my bullets into a collet or drill and with sandpaper reduce the ogive dimension till the BTO measurement matches the shortest bullet in the box.
Finally, I polish the sanded bullets to remove the scratches the sandpaper created.
Now the bullets are ready to shoot,
Is that the procedure?

 

[Asumner]

yep, heres my setup

Nice, I don’t currently have a lathe but I definitely could make a lighter one or something to hold a collet in a drill for sure

 

[ELR LVR]

Ok,
Had to mess with ya guys today.
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(That's actually my setup to trim meplats)
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[Asumner]

Look it could still work lol

 

[Asumner]

Ok,
Had to mess with ya guys today.
-------------------------------------
(That's actually my setup to trim meplats)
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How often to you trim them? I have noticed inconsistencies in them but I figured it was down the pipe so why mess with it lol

 

[ELR LVR]

How often to you trim them? I have noticed inconsistencies in them but I figured it was down the pipe so why mess with it lol

Actually I haven't trimmed meplats until just recently,
I still need to test them and haven't had a chance to do that yet due to weather
The OAL is all over the place so I am going to equalize several different brands
Lapua, Berger, Sierra etc and see if it takes out any vertical at all
_-------------------
I am figuring I am not going to gain much just because 6mm Meplats are already small to begin with
But if it helps even 1/2" vertically at 600 yds then thats a decent gain.
--------------------
We'll see

 

[Ruger15151]

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.

Inconsistent eating an be caused by a few things.

1 Work hardened necks.
How many firings do you have on your rounds have. Are you annealing?

2. Incorrect bullet seating stem.
Make sure the seating stem is sitting on the ogive of the bullet and not resting on the tip.

3. Sizing die incorrectly set up.
Make sure your sizing die is set up so the press cams over slightly at the top of the stroke.

4. Inconsistent neck tension.
Remove the expander ball on your sizing die, Use a expander mandrel to set consistent neck tension.

5. Too much neck tension
Depending n the caliber you should only need .02 - .003 thousand of neck tension.

6. Not chamfering the inside of the neck.
You need to chamfer the inside of the necks prior to every loading even if you are not trimming the brass because any burr on the inside of the neck will drag on the bullet jacket and cause inconsistent seating depths.

Good luck. Hope this helps!

 

[DShortt]

Inconsistent ogive form. Bullet seating stem contacts bullet way further forward than a bullet competitor. I bet if you made a comparator insert the same size as your seating stem, you would find your loaded rounds are very consistant. Ask me how I know .

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.

 

[Asumner]

Actually I haven't trimmed meplats until just recently,
I still need to test them and haven't had a chance to do that yet due to weather
The OAL is all over the place so I am going to equalize several different brands
Lapua, Berger, Sierra etc and see if it takes out any vertical at all
_-------------------
I am figuring I am not going to gain much just because 6mm Meplats are already small to begin with
But if it helps even 1/2" vertically at 600 yds then thats a decent gain.
--------------------
We'll see

I wonder when trimming how much weight you lose, not saying it would be a grain but I guess it could because like you said some of these bullets oal is way different than the others.

 

[Asumner]

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.

 

[Straightshooter1]

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.

Is the idea about getting the distance to the lands more consistent? Or do you just think it's better for concentricity?

If it's about more consistent jump, I've thought about that some time ago and don't really see where it'd really make any difference since distance to the lands isn't really all that important when seating off the lands. I came to this conclusion from reports from top end shooters and my own testing with how throat erosion hasn't been much of a big factor (and why it's typically recommended that one doesn't "chase the lands"). But consistent seating depth (how far the base of the bullet is into the case along with the lengths of the bearing surfaces) is far more important than jump. So, the way I see it, whether you're seating stem is making contact at the upper 30% of the ogive or the lower 30%, it really doesn't matter.

 

[DShortt]

Is the idea about getting the distance to the lands more consistent? Or do you just think it's better for concentricity?

If it's about more consistent jump, I've thought about that some time ago and don't really see where it'd really make any difference since distance to the lands isn't really all that important when seating off the lands. I came to this conclusion from reports from top end shooters and my own testing with how throat erosion hasn't been much a big factor (and why it's typically recommended that one doesn't "chase the lands"). But consistent seating depth (how far the base of the bullet is into the case along with the lengths of the bearing surfaces) is far more important than jump. So, the way I see it, whether your seating stem is making contact at the upper 30% of the ogive or the lower 30%, it really doesn't matter.

I understand your point, and I don't dispute that.

I have also read multiple reports here that concentricity isn't anything to obsess over either, at least not up to a point.

In my particular circumstance, I'm attempting to achieve a consistent seating depth as the primary objective. I'd like to think that if I get this right, run-out will at worst not be worse, remain unchanged or at best reduced.

I may discover that it's a wild goose chase. But until I try, I'll never know.

Ultimately, I'm looking for consistency.

 

[ELR LVR]

I wonder when trimming how much weight you lose, not saying it would be a grain but I guess it could because like you said some of these bullets oal is way different than the others.

Not very much, I'm only shaving maybe .005" off the nose so perhaps 3/10th grain

 

[Asumner]

Not very much, I'm only shaving maybe .005" off the nose so perhaps 3/10th grain

Ahh ok.

 

[Asumner]

I just measured the last 200 or so bullets I have in my lot and around 50 were of a different dimension. They usually were around 3 thou different. I should be able to shoot some this weekend so I will know if I can see a difference I. The loading process and the groups as well the sd. I will wait for my new funnel with a longer tube plus I will feed the powder slowly vs dumping it and see what I get.

 

[Fire Dog]

yep, heres my setup

That setup rather reminds me of Erik Cortina’s April 1st video of him increasing the accuracy of bullets by chucking them in a lathe and counter sinking the base…
He also recommended using a Harbour Freight lathe….

 

[Ringostar]

Is the idea about getting the distance to the lands more consistent? Or do you just think it's better for concentricity?

If it's about more consistent jump, I've thought about that some time ago and don't really see where it'd really make any difference since distance to the lands isn't really all that important when seating off the lands. I came to this conclusion from reports from top end shooters and my own testing with how throat erosion hasn't been much a big factor (and why it's typically recommended that one doesn't "chase the lands"). But consistent seating depth (how far the base of the bullet is into the case along with the lengths of the bearing surfaces) is far more important than jump. So, the way I see it, whether your seating stem is making contact at the upper 30% of the ogive or the lower 30%, it really doesn't matter.

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