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Pulling my hair out over inconsistent seating

Ratbert

Ratbert

Gunny Sergeant
Full Member
Minuteman
Jul 18, 2007
2,341
1
48
Concord, NC
#1
I'm running out of ideas here, so I'm hoping someone can give me a fresh prospective...

Since moving this summer I've been struggling with very inconsistent seating depth. I've seen it vary as much as 0.020" from cart to cart with no apparent source. At first I thought it was my new Hornady LnL progressive, but it is also occurring with my Forrester. Previously I'd loaded 1500rds or so of 308 (and another 1500 or more of 223) on this Forrester with no apparent problems (random spot checking had never indicated anything like this and I'd never had a stuck bullet or hard to chamber cart.) So far I've tried:

Measuring 3 different ways (RCBS mic, COAL w/ calipers, and Sinclair Ogieve tool w/ calipers) and the 3 seem consistent.

A Lee seating die (what I used previously) as well as a Redding seater and a Redding comp/mic seater

Both the Hornady and Forrester presses.

These problems have been with the final few hundred rounds from a 1000box of Lapua 155 Scenars. I hadn't noticed any problems with the first few hundred. The problems have been both with virgin Lapua brass and a mix of previously fired/sized stuff.

Any ideas?
 
#4
Re: Pulling my hair out over inconsistent seating

Disassemble and Clean your die and shell holder, maybe there is something messing with your seating. Also when you are seating your bullet...seat like normal, then rotate the cartridge (while still in the shell holder) 120 degrees and re-seat, repeat, then check your OAL.
 
#6
Re: Pulling my hair out over inconsistent seating

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Ratbert</div><div class="ubbcode-body">I'm running out of ideas here, so I'm hoping someone can give me a fresh prospective...

Since moving this summer I've been struggling with very inconsistent seating depth. I've seen it vary as much as 0.020" from cart to cart with no apparent source. At first I thought it was my new Hornady LnL progressive, but it is also occurring with my Forrester. Previously I'd loaded 1500rds or so of 308 (and another 1500 or more of 223) on this Forrester with no apparent problems (random spot checking had never indicated anything like this and I'd never had a stuck bullet or hard to chamber cart.) So far I've tried:

Measuring 3 different ways (RCBS mic, COAL w/ calipers, and Sinclair Ogieve tool w/ calipers) and the 3 seem consistent.

A Lee seating die (what I used previously) as well as a Redding seater and a Redding comp/mic seater

Both the Hornady and Forrester presses.

These problems have been with the final few hundred rounds from a 1000box of Lapua 155 Scenars. I hadn't noticed any problems with the first few hundred. The problems have been both with virgin Lapua brass and a mix of previously fired/sized stuff.

Any ideas? </div></div>

Generally, measuring from the tip to the base (COAL) you'll get the variance you seem to be getting, as (as Victor tells us) most of the imperfections in bullet manufacture occur in the top third of the bullet.

Measuring from the bullet's ogive, OAL, (once again, as Victor tells us--O-jive), you'll get a more consistent measurement from loaded round to loaded round.

Depending on the bullets you seat and how much care has gone into keeping their tolerances tight, you'll get more or less variance at the ogive point on the bullet.

I use the Stoney Point/Hornady bullet comparators and on my last batch of 155 Lapua Scenars and older 155gr Sierra Palma MKs, my variance was roughly .002" for the two loaded cartridges, 25 and 25 each. I'm using a Hornady New Dimension inline seater with micro seating stem, for reference, on a Dillon 550b.

Chris
 
#8
Re: Pulling my hair out over inconsistent seating

as others have alluded to here, your issue is bullet inconsistency. try sorting them by base to ogive then by overall length. this should give you some consistent "batches" but may have to adjust seat for each varying sorted batch type.
 
#9
Re: Pulling my hair out over inconsistent seating

Just since several folks have mentioned it, 2 out of 3 of my measuring techniques (including my primary method) measure from the ogeive. I'll process some of these other suggestions tonight.
 
#10
Re: Pulling my hair out over inconsistent seating

In order of what I would check:

1 inspect the bullets
2 is the powder charge compressing?
3 clean the die
4 neck tension OK?

These would be the first few things I would suspect. There may be other reasons for the problems you mentioned. But these are the most obvious.

Good luck.
 
#11
Re: Pulling my hair out over inconsistent seating

I had the same problem with some cheap SS109 bullets I bought. I measure OAL from base to tip since I don't have anything to measure off the ogive, and I was getting big inconsistencies.

I had the cannelure as a reference too and I could tell none of the bullets were seating at the same spot just by that.

I'm sure it's inconsistencies in the ogive of the bullet since that's what the die seats from.
 
#12
Re: Pulling my hair out over inconsistent seating

Alright, spent an hour or so with the puller and a few cart's. Here's what I've determined...

1) The charge is not compressed and the variance exists with or without powder.

2) A cart will always seat consistently for itself. if it seats 0.020 long once then it will be that way (+/- 0.001) no matter how many times you press it, even if you pull the bullet out and reseat

3) Neck tension is consistent at ~0.0025-0.003 but does not seem to effect the outcome even as it loosens up when having the bullet seated/pulled repeatedlyu

4) Bullets all measure 1.623 (+/- 0.002) from base to ogieve using sinclair tool.

5) headspace on all tested carts was consistent within +/- 0.001, one cart was long by 0.004 and all tests were run at that length and then resized to be perfectly 0.000 with no change in outcome (bullet seated same length regardless)

6) seating variance appears to be tied directly to the case. I swapped bullets around between various cases and each time the seating variance remained consistent for the case (didn't matter which bullet I used, a case always seated it a particular length)



The one thing I DID discover was that I had some virgin Lapua brass that hadn't been trimmed (measured 2.002) and that was what was seating 0.020 longer than other once-fired cases that measured 1.992. Putting it in the Giruad trimmer cut it down to 1.995 and with that change I ended up seated only 0.006 long. Additionally, once I resized the previously long-headspaced fired case and trimmed it, it ALSO measured 1.995 and ALSO produced 0.006 seating.

So, the variance appears to correlate closely to approx twice the variance in case overall length, specifically the neck length as the shoulders all headspace equally. However I have not yet figured out WHY this is occurring because I've checked and the seater stem does not come anywhere close to contacting the case mouth, which would seem the only obvious reason why neck length would effect seating depth that is indexing off the shell plate.
 
#13
Re: Pulling my hair out over inconsistent seating

It's coming from the different neck varitions/viscosities from case to case. Virgin, once fired, trimmed, not trimmed, etc. The cases need to be the same to seat the same. Consistancy is the key, and the brass necks are all over the place. Pick one and run with it. When you mix it all up, you get mixed results. If you take a nylon brush with a slight dab of mica on it and run it inside the case neck, it will help on the virgin brass.
 
#14
Re: Pulling my hair out over inconsistent seating

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChadTRG42</div><div class="ubbcode-body">It's coming from the different neck varitions/viscosities from case to case. Virgin, once fired, trimmed, not trimmed, etc. The cases need to be the same to seat the same. Consistancy is the key, and the brass necks are all over the place. Pick one and run with it. When you mix it all up, you get mixed results. If you take a nylon brush with a slight dab of mica on it and run it inside the case neck, it will help on the virgin brass. </div></div>

I can understand that, but what I find odd is that if I take a neck and trim 0.003 off of it there seems to be a correlating change in the seating dept of 0.006. Trim 0.005 and I get a change of 0.010, etc. This occurred both with virgin and fired brass and within my (obviously small sample so far) testing neck length became the primary characteristic for predicting seating depth. I just don't understand why because I cannot see how neck length is at all in play when the bullet is being seated or measured.
 
#16
Re: Pulling my hair out over inconsistent seating

All of the fired brass had been tumbled, I saw the same variation correlation to neck length with that as well as the virgin. Obviously the virgin was just more because it was longer (until trimmed.) Once trimmed the virgin produced the same results as the once fired of the same length.

I'll give the nylon brush a try tomorrow.
 
#17
Re: Pulling my hair out over inconsistent seating

Are you using a crimp? If not make sure that the longer cases are not trying to start into the crimp area of the die and causing some sort of inconsistency.
 
#18
Re: Pulling my hair out over inconsistent seating

Hmm, I was not intentionally using a crimp, but now that you mention that it occurs to me that the Redding IS supposed to have a crimp built in. Let me try backing the die out so it isn't touching the shell plate and see what happens...
 
#19
Re: Pulling my hair out over inconsistent seating

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: marduk185</div><div class="ubbcode-body">as others have alluded to here, your issue is bullet inconsistency. try sorting them by base to ogive then by overall length. this should give you some consistent "batches" but may have to adjust seat for each varying sorted batch type. </div></div>

Another vote here. I have some Berger 185VLDs on my bench that vary .030" base to ogive from bullet to bullet in the same box. Most mass produced bullets come from two or more assembly lines and then are collected into a single packaging area. Bullet production dies are hard to make and live hard lives, so between differences between die specs and wear on each individual die, these irregularities show up. The bullets at the bottom of your box likely came from a different production line than those at the time. About the only thing you can do now is measure each bullet from base to ogive and segregate them accordingly, or send them back and ask that they be exchanged.

Regards,


Wes
 
#20
Re: Pulling my hair out over inconsistent seating

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: dmg264</div><div class="ubbcode-body">Are you using a crimp? If not make sure that the longer cases are not trying to start into the crimp area of the die and causing some sort of inconsistency. </div></div>

Ding ding ding! We have a winner!

When I moved and got the LnL I set all the dies up for the new press and forgot about the crimp. Then when I was moving dies back and forth between the two (requiring new setup each time) I STILL forgot about the crimp. Backing the die off of the shell plate a few turns solved the problem. There is now a +/- 0.001" variance regardless of neck length with the Redding seater.

Separately the LnL has a ~0.008" variance depending on which stations have cases in them when seating (specifically the Lee neck sizing die in particular.) I think this is what was throwing me off with the Lee more than anything else (that and the Lee was never better than +/- 0.002" anyway and tended to walk away from the initial setting over time.)

I believe the plan from now on will be to use the Lee die to seat about 0.035" long in the LnL then do a final seating to length with the Forester/Redding combo.


Life is good again...
 
#21
Re: Pulling my hair out over inconsistent seating

Glad I could help Ratbert.

Did I win a prize?
laugh.gif
 
#23
Re: Pulling my hair out over inconsistent seating

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: dmg264</div><div class="ubbcode-body">Glad I could help Ratbert.

Did I win a prize?
laugh.gif
</div></div>

You may now spend 10 minutes alone with the Hot GF thread and no one will judge you.
 
#25
Re: Pulling my hair out over inconsistent seating

Who knows, didn't get this figured out until 8 last night and I probably won't get to the range again until next week when the inlaws/nephews/et all go home. But I imagine now that they measure out the same they will shoot as well as they ever did, which is to say better than FGMM but nothing to write home about.
 
#26
Re: Pulling my hair out over inconsistent seating

I had the same problem as you with inconsistent seating, unless you presort your bullets there is no way I have found to have consistent base to tip lengths. Even measuring from the ogive isn't always consistent because the ogive to bullet base may vary, and the ogive to tip definetly varies. You can either measure each round and adjust by seating the bullet a little longer then reseat each one until it's right. Or seat the bullet a little more than you need say 2.250 vs 2.260 for .223 AR rounds so you know they will fit in the mag.
 
#27
Re: Pulling my hair out over inconsistent seating

The issue here wasn't a problem with inconsistent COAL, the problem was inconsistent ogeive to lands relationship caused by a inconsistent ogeive to casehead relationship in the finished cartridge. With a seater pressing on the bullet ogeive and indexing off of the shellplate, bullet base to ogeieve distances and ogeive to tip distances are mostly irrelevant. Feeding from an AW mag, my chamber is the limiting factor for COAL. So I really could care less about COAL, so long as the ogeive to lands relationship is consistent.
 
#28
Re: Pulling my hair out over inconsistent seating

Mate if you have Bergers that vary that much they are faulty in some way. I make bullets and it would be very difficult to get that much variation on the same press.
However you could be right about them being made on different presses.
Either way you should send them back as they are not target quality with that kind of variation.
Target bullet makers usually do not mix batches but I guess it does happen.
What I am thinking is that someone has been sorting Bergers and taking the perfect ones and sold you the junk.
Never buy target bullets in open packs always check the package seals and if the seal is broken or looks as if its been tampered with reject them. Also check that the box can not be opened or the bullets tiped out without breaking the seals. If thats the case then complain bitterly to the manufacturer and demand better sealed packaging.
 
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