seating compressed loads.. inconsistent ogive 2 base measurements… need assistance

[dcnyli]

Fellas, I'm having some issues with getting my 175g VLD's to seat consistently into Federal brass(once fired, vibratory tumbled, neck sized "338" bushing) with my forster ultra die. I am only in the dang testing phases and when increasing my powder charges the depths somewhat increase over a series of rounds. If I load 5 of a charge, but the time i get to #5, the ogive to base measurement creeps from 2.085 to 2.1 and sometimes worse

These are moderately compressed, my chamber is super super tight/kinda national match .308 style(quantico gunsmith)

what can i do to get my consistency? It's literally driving me insane, I am having in depth negotiations and arguments with my press and die. I even removed my "lock n load" bushing setups to see if that made a difference…

 

[mdmp5]

I think we were talking about this via PM the other day, but I cannot remember if I answered your question. Try seating the bullet, take a measurement, then seating it again without turning the micrometer, and check again. If it is longer than you want it to be, adjust the mic to the necessary adjustment and seat it again and check. I made this video earlier this month on seating. Pay attention to around 6 minutes in.

<iframe width="480" height="360" src="//www.youtube.com/embed/ZAgAnIIxqHA" frameborder="0" allowfullscreen></iframe>

 

[dcnyli]

never did hear back on the PMs but this makes sense, although with a single stage press it's a huge PITA to keep adjusting and not what I ever envisioned this to be… My seating stem was just adjusted at forster cause it was grabbing the bullets….

the increase on measurement is linear too, not all janky, i can't wrap my newbie head around it.

what type of seater doesn't function like this?

 

[mdmp5]

never did hear back on the PMs but this makes sense, although with a single stage press it's a huge PITA to keep adjusting and not what I ever envisioned this to be… My seating stem was just adjusted at forster cause it was grabbing the bullets….

the increase on measurement is linear too, not all janky, i can't wrap my newbie head around it.

what type of seater doesn't function like this?

On a single stage press, you can do what I am doing in the video, just that your measurements will most likely be taken with calipers. You are likely dealing with 2 factors:

1. the variance in each bullet shape where the seating stem makes contact with the bullet. Remember, we are dealing with thousandths of an inch here, and although tolerances in equipment and components are tight, there are variances, but are not so critical that it would cause anything to completely fail. You may get one case here and there, but I think it is safe to say that the true recalls are less than 0.1% of the outstanding product on the market.

2. upward pressure from the powder on the bullet base from a compressed load. There can likely be enough resistance that may cause the bullet to unseat very slightly. That's why I suggested running it through for another pass.

This is all assuming that your micrometer is tracking correctly in accordance with the scaled graduations. My 308 comp seater tracks perfectly. My 300 win mag comp seater is sometimes a little off, but I haven't found the root of this yet. It may be because I am using 210 SMKs, which are VLDs, and they might be wedging a bit. So far, the variance I have been experiencing with that caliber has usually been under .001, so I haven't bothered conducting a thorough investigation as of yet.

 

[dcnyli]

gotcha. I do seat, pull out rotate and reseat, i can give it another shot…

i had to throw in the towel for the day, wife thinks i'm insane.

 

[mdmp5]

You are insane, but then again, so are most of us. We are going bananas over measurements that can barely be discerned with the naked eye that may or may not lend to change in performance. Reloading is not hard. Reloading to the nearest .001 for everything is nearly impossible. We can come close, but the amount of work increases dramatically. I have worked to maximize my results with as little work as possible. And that is why I use the equipment shown in the video.

 

[mdmp5]

gotcha. I do seat, pull out rotate and reseat, i can give it another shot…

i had to throw in the towel for the day, wife thinks i'm insane.

Measure before you reseat to see if anything is happening on the 2nd seating.

 

[dcnyli]

this is my OCD's favorite hobby yet…

 

[bjay]

I think that 338 bushing litle to loose specialy on fed brass.. if your neck not griping right it will make bullet jump in and out

 

[KYpatriot]

Clarify your question. Are you saying that you seat a round, measure it, then come back to it later and measure it again and it is longer? If that is the case then insufficient and/or inconsistent neck tension and a compressed load are causing it. You mention having the seater polished but if it is still sticking at all this will also cause it.

On the other hand, if you are getting inconsistent seating depths as you load right out of the die, then that is because of the variations in the bullets. For instance with my 308 and 175smk I see my base too ogive measures vary by about .005, so I set my micrometer die to seat .005 long, in my case 2.815 since I want 2.810. I seat the round, then measure using the comparator. Usually it will be a little long as I expect, but because of manufacturing tolerances in bullets it may not be exactly .005 long, it might be only .003 long for example. This is the beauty of a micrometer die because I can then crank it .003 down, reseat and then it will measure perfect. I like the the Sinclair comparator inserts because they are very consistent and apparently are machined to mimic a chamber throat.

If you do not have a micrometer die you will have to accept the variance in oal that the manufacturing tolerance of the bullets will give you, or sort the bullets into lots if the ogive length is important enough to you. Personally for me when producing precision ammo a micrometer die is well worth the money for the aggravation it saves.

 

[dcnyli]

its in the seating depths out of the die unfortunately, I am starting to think that this part of the seating process is the one people don't really mention… it's all quick and clean on youtube…

 

[noylj]

Have you simply tried SHOOTING and seeing if this slight difference is really as important as you making it out to be?
Targets don't lie.
Are you verifying that all the bullets have the exact same ogive curvature and the datum hits every bullet at the exact same spot compared to bullet tip and base? There are variations in bullet geometry coming from the same swage die.
Are the case bases all exactly flat, perpendicular to the case axis, and smooth so all measurements taken around a case are exactly the same?
Unless you know the precision and consistency of EVERYTHING, you may just be chasing your tail.

 

[Assault116]

One thing I've found that works fairly well is getting the powder to settle in the case a little better before seating. A drop tube is one way to do that, and I do it pretty routinely. However if getting a little more aggressive is needed, here's one that I've found that works well.

I charge all of my cases or a group of them and place them in a loading block/case holder to hold them all nice and happy. Then I use a vibratory engraver to vibrate the cases and allow the powder to settle. Normally all it takes is a couple seconds of touching the engraving tip to the block and you can watch the powder settle. Then seat your bullets. Obviously this is really only for stick powders, in lightly compressed loads, but it does make things pretty easy.

 

[KYpatriot]

If you are shooting a tangent ogive bullet like the SMK then as long as you aren't loading to the edge of your magazine clearance a little seating depth variation is probably not going to be noticeable on target. Smks don't mind jumping a long ways...a few extra thousandths won't do much.

 

[bruddah]

I think we were talking about this via PM the other day, but I cannot remember if I answered your question. Try seating the bullet, take a measurement, then seating it again without turning the micrometer, and check again. If it is longer than you want it to be, adjust the mic to the necessary adjustment and seat it again and check. I made this video earlier this month on seating. Pay attention to around 6 minutes in.

<iframe width="480" height="360" src="//www.youtube.com/embed/ZAgAnIIxqHA" frameborder="0" allowfullscreen></iframe>

Well that explains why I get variance even with my Forrester comp seating die....

 

[Sonic Crack]

its because your seating into compressed loads. your just going to have to re seat the rounds. I have also seen this kinda of variation based on the amount of neck tension of the cases.

 

[MitchAlsup]

Just a side note: I double seat my compressed loads.
In 308W I first <pre>sat to 3.000 OAL and then come back and seat for 0.015 from the lands.