Getting pretty frustrated with inconsistent bullet seating depth.

J

Jim K III

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Aug 27, 2019
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I'm reloading several hundred rounds of LC-66 that I've had stored for years. Primer pockets have been swaged/reamed and primers seated just fine. Cases have been trimmed to between 2.484" and 2.490.

Here is my load data:
Bullets: Nosler .308 168gr HPBT
Powder: IMR-4895 - 45gr
OAL per Lyman 49th Edition: 3.300"

I'm using a Lee Classic Turret Press, but only one stage at a time; decap/resize everything, then seat everything - no back and forth.

The problem is when I'm seating the bullets (using 2-die RCBS set) I get inconsistent seating depths. Most depths are ~ 3.295 to 3.300". But around 20% have an OAL greater than 3.300" with some as short as 3.280". I just set those aside and fix them when I'm done with a batch.

In the photo are three examples from one batch of 60 rounds.
Bullet on the left OAL = 3.280"
Bullet in the middle OAL = 3.300"
Bullet on the right OAL = 3.310"

Of the 60 rounds I reloaded today:

45 were between 3.295" and 3.300"
13 had an OAL over 3.300"
2 were short around 3.280"

Overall, the OAL range for this batch of 60 rounds was 3.280" to 3.310".

Is that normal? How close to the OAL in the book is acceptable? If it needs to be spot on, how does one insure consistent seating depth?

Oh, and I measured a random sample of the Nosler 168gr bullets and they ranged from 1.198" to 1.214"

Thanks!

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Your seating stem is partally hollow in the middle. If it is plugged with crap your bullets are going to seat at different lengths. Also it is supposed to contact the bullet on the ogive not the tip of the bullet. I take a 25 caliber rifle brass and put it over the pointed part of the bullet. Then measure headstamp to headstamp and your length will be a lot closer on each finished round as that measurement is closer to the ogive to base of your loaded round. Small variations on OAL probably will not be noticed as long as you are not loading a max load at the time.
Your bullets are from several swaging dies and they are not all the same length just as they are not all the same weight. Still they are good enough to make accurate ammo for 100YD shooting.
 
I'll check out the seating stem and measure base to olgive as suggested.

I just shoot for fun at a local range. No hunting or competition shooting.
 
take a sized case and slip the mouth over the bullet of the loaded round. measure the length of that combo. subtract the sized case length from the combo length. that is your base-to-ogive measurement. make sure you use the same sized case for all your bto measurements. hint:write the case length on the side of the case with a sharpie.

luck,

murf
 
Lots of good stuff already posted.

Another thing, seat the bullets with approximately the same force and speed.

If you seat the bullet to final position with several light strokes vs a single heavy stroke, the COL will vary alot.

Consistent operation of the press is important.
 
cfullgraf said:
Lots of good stuff already posted.
Click to expand...

cfullgraf said:
Another thing, seat the bullets with approximately the same force and speed.

If you seat the bullet to final position with several light strokes vs a single heavy stroke, the COL will vary alot.

Consistent operation of the press is important.
Click to expand...
This is kind of off topic and purely rhetorical so ignore if you wish:)

I have read this many times over the years and wonder if it’s really accurate…in particular on a SS press how can pace or consistency of movement alter the depth of seating?

Provided the full range of travel of the ram is completed either in one consistent motion or in a multiple of limited motions, the ram and [case] bullet are mechanically pushed to the same place each time—the bullet into a stationary [relative to the ram] case.

When the ram stops the [case] bullet stops—it is not carried further by momentum.

Edit: yes I know I screwed up description of what moves and what doesn’t such as case isn’t stationary but it doesn’t move independent of the ram is what I meant. My point remains same and accurate.
 
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CQB45ACP said:
This is kind of off topic and purely rhetorical so ignore if you wish:)

I have read this many times over the years and wonder if it’s really accurate…in particular on a SS press how can pace or consistency of movement alter the depth of seating?

Provided the full range of travel of the ram is completed either in one consistent motion or in a multiple of limited motions, the ram and [case] bullet are mechanically pushed to the same place each time—the bullet into a stationary [relative to the ram] case.

When the ram stops the [case] bullet stops—it is not carried further by momentum.

Edit: yes I know I screwed up description of what moves and what doesn’t such as case isn’t stationary but it doesn’t move independent of the ram is what I meant. My point remains same and accurate.
Click to expand...
When I set up the COL for a new bullet, I set the seating stem, seat the bullet then measure. I usually set things long. I make adjustments, push the bullet deeper, then measure again. After I get the COL I want, I seat a bullet in a new case and the COL is different, outside the range of normal variations.

The cartridge I used to make the small changes in COL during adjustment had several light movements of the bullet while the single seating was one seating at the time.

I figure the loading on the press at the time of seating can affect the full amount of the tolerances take up. Hence the seating depth becomes variable if you do not cycle the press the same at each seating operation. A slow, light cycling of the press during seating may not take up all the looseness in the ram on the press.

Except for the variations I’ve found during the seating adjustment phase, I’ve not done any data gathering during a reloading run.

Generally, once I get the seating stem set, I cycle the press about the same way for every round.

But, based on my knowledge and experience, I do feel if one gets sloppy and does not cycle the press about the same way every time, COL could have an increase in variability.

I keep getting amazed by mechanics. Things can happen that one thinks is impossible. I race sports cars. I recently had a transmission failure on my car. Upon disassembly, we found the crankshaft in the engine broken in two and the engine would still run and move the car. The crank broke at the right spot where things still functioned but it was telling us there was a problem.
 
I like this method, but buying one of these may be easier ….

www.hornady.com

Lock-N-Load® Bullet Comparator - Hornady Manufacturing, Inc

Lock-N-Load® Bullet Comparator & Inserts...
www.hornady.com www.hornady.com
murf said:
take a sized case and slip the mouth over the bullet of the loaded round. measure the length of that combo. subtract the sized case length from the combo length. that is your base-to-ogive measurement. make sure you use the same sized case for all your bto measurements. hint:write the case length on the side of the case with a sharpie.

luck,

murf
Click to expand...
 
Are you using fresh or fairly fresh 1x fired brass? I have seen old brass that turns hard and brittle. Even with a full length resize, the brass will return to out of spec diameter width, and bullet seating will not be consistent. This happened to me with military .30-06 brass.
 
cfullgraf said:
When I set up the COL for a new bullet, I set the seating stem, seat the bullet then measure. I usually set things long. I make adjustments, push the bullet deeper, then measure again. After I get the COL I want, I seat a bullet in a new case and the COL is different, outside the range of normal variations.

The cartridge I used to make the small changes in COL during adjustment had several light movements of the bullet while the single seating was one seating at the time.

I figure the loading on the press at the time of seating can affect the full amount of the tolerances take up. Hence the seating depth becomes variable if you do not cycle the press the same at each seating operation. A slow, light cycling of the press during seating may not take up all the looseness in the ram on the press.

Except for the variations I’ve found during the seating adjustment phase, I’ve not done any data gathering during a reloading run.

Generally, once I get the seating stem set, I cycle the press about the same way for every round.

But, based on my knowledge and experience, I do feel if one gets sloppy and does not cycle the press about the same way every time, COL could have an increase in variability.

I keep getting amazed by mechanics. Things can happen that one thinks is impossible. I race sports cars. I recently had a transmission failure on my car. Upon disassembly, we found the crankshaft in the engine broken in two and the engine would still run and move the car. The crank broke at the right spot where things still functioned but it was telling us there was a problem.
Click to expand...
I understand the concept/theory and have experienced it first hand with a Uniflow. Same long motions with clunks at beginning and end result in consistent powder throws. Alter that and inconsistency creeps in.

If it wasn’t such a pain pulling bullets, I’d load a bunch of dummy rounds testing the issue on my T-7 with Redding competition seating dies. In the meantime I’m just going to remain a polite skeptic.

Gotta love race car stories. I wanted to race SCCA years ago (early 1970s) in my MG but couldn’t afford it. So I just hung out at Group 44s shop near me and dreamt of things that could’ve been.
 
CQB45ACP said:
I understand the concept/theory and have experienced it first hand with a Uniflow. Same long motions with clunks at beginning and end result in consistent powder throws. Alter that and inconsistency creeps in.

If it wasn’t such a pain pulling bullets, I’d load a bunch of dummy rounds testing the issue on my T-7 with Redding competition seating dies. In the meantime I’m just going to remain a polite skeptic.

Gotta love race car stories. I wanted to race SCCA years ago (early 1970s) in my MG but couldn’t afford it. So I just hung out at Group 44s shop near me and dreamt of things that could’ve been.
Click to expand...
My auto-sport was Thundercar at Smyrna. Lots of fun and I made enough purses to pay for the weekly damage but that was it. Also ran 1/4 mile drag on two wheels at Bithlo. Lost a couple of good bikes but again it was all good fun.
With rifle seating in particular you have to concern yourself with yaw and spring back. With rifle, you should be expanding the neck with the bullet for consistent tension. Not resting the press at the top of the run allows the brass to spring back and push the bullet back out a little. How much? Depends. Maybe less than can be measured accurately and maybe enough to make you scratch your head and wonder what the Sam Hill’s going on. The other thing, yaw, is from crooked seating. Leave it crooked and you get one number. Straighten it with a second, slightly shifted run of the press and you’ll get a new number.
But I don’t think either one of those are the issues here. It’s how the OP is taking the measurements. That’s all.
 
In HS we’d race on the Dulles Airport access road because it wasn’t patrolled at night—wasn’t a state or county highway and airport security had jurisdiction only at airport—great government planning—and only a couple guys worked at night in those days.

No prize money but bragging rights across many different county high schools was better than a little dough. In many respects though it was a test of “whose dad had the fastest car.”

Today, while I can’t condone nor excuse the people taking over city intersections drifting or packs of bikes blocking traffic on an interstate or ATVs marauding on the Mall in monuments’ shadows, I can understand it. Completely.

For RN pistol bullet measuring I’m amused at all the seating stem ogive this and ogive that and then we measure at the tip.
 
An issue I have experienced is if the press is not set up to cam over or if handle pull does not go completely through the cam over part of the stroke inconsistent OAL will result. Utilizing the cam over feature of the press ensures that the ram travels to the exact same point on every stroke.
Cam over is the point that the ram reaches full extension, we can call it top dead center, and if you move the arm a little further the ram actually drops down a little bit.
This ensures that you are utilizing full extension of the ram and greatly increases repeatability.
Along with this making sure that the press bushings at the fulcrum points are not worn or sloppy is a good idea.
 
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Atavar said:
An issue I have experienced is if the press is not set up to cam over or if handle pull does not go completely through the cam over part of the stroke inconsistent OAL will result. Utilizing the cam over feature of the press ensures that the ram travels to the exact same point on every stroke.
Cam over is the point that the ram reaches full extension, we can call it top dead center, and if you move the arm a little further the ram actually drops down a little bit.
This ensures that you are utilizing full extension of the ram and greatly increases repeatability.
Along with this making sure that the press bushings at the fulcrum points are not worn or sloppy is a good idea.
Click to expand...
On my three SS presses, once the shell holder contacts the die that’s it. The bullet & case are done. Any additional cramming, ramming, or jamming are a waste of time, effort, and damaging to equipment.

Edit: Just for grins I just looked at my T-7 and don’t think there is a snowball’s chance in anywhere one could adjust it to do more than it does. But I won’t swear to it.
The arm on my Lee whatever it’s called would bend or break before the linkage would cam over.
Both have linkages which seem finite in their movement range.
 
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CQB45ACP said:
On my three SS presses, once the shell holder contacts the die that’s it. The bullet & case are done. Any additional cramming, ramming, or jamming are a waste of time, effort, and damaging to equipment.

Edit: Just for grins I just looked at my T-7 and don’t think there is a snowball’s chance in anywhere one could adjust it to do more than it does. But I won’t swear to it.
The arm on my Lee whatever it’s called would bend or break before the linkage would cam over.
Both have linkages which seem finite in their movement range.
Click to expand...
Which rifles are you loading for? Pistol is stupid easy - the tip is rounded or flat - but with rifle it’s pointy, very pointy, extremely pointy, sorta pointy, not real pointy or rounded. With pistol bullets you can see where the shank ends - with rifle you can’t tell by looking right where the ogive ends or where the shank narrows. That’s why how you measure can make a difference.
 
A whole bunch of suggestions far all over the spectrum. I'll just add a few odd things from my experience. I once had a heck of a time getting a consistent OAL on some 30-06 handloads. Tried a lot of the above methods. It turned out some of me cases had been hitting the Op Rod hump on their way out and dinging the case head/rim enough go to throw off a consistent measurement. Another time was reloading some 9mm and getting t wide variations. Turns out the bases weren't flat and affected primer seating causing a poor measurement surface. Earlier in my reloading, before I went to ram priming, an occasional primer would seat a bit crooked one side would sit a bit high.

Being a life long machinist/mechanic I don't give much thought/credence to cam over, or over top dead center for a reloading press. A dead stop adjusted and used properly, is as accurate and consistent as possible, not only on a reloading press, but in machine work too
 
Of course all this is just my opinion and a bit of experience.

Go slow. Double check everything. Most important, have fun...

I hate my cell phone!! I was trying to edit my previous post...
 
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