Question as to inconsistent OAL on loads

[WTNUT]

Trying to up my reloading game. On my 338 RUM, I use a reddding full size die with bushing from Short Action Customs. My recollection I am loading to a diameter that is .002 or .003 bullet diameter. My steps are knock out the primer, clean pocket, anneal, tumble, resize, then use expanding mandrel, prime, powder and seat bullet.

I am using ADG brass and Barnes LRX bullets.

When I seat the bullets I am getting up to .005 difference in an overall length. I think this is due to differences in components. Like last night I am sure when I switched to a new box of bullets it changed the overall length and I adjusted the seating die.

My question: is that normal? And, am I being anal as to .005 or .007 difference in OAL?

As always thanks for feedback.


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[gman82001]

Just basic cartridge overall length or base to ogive length? Many bullets differ on the over all length but good bullets should be pretty consistent on the ogive measurement. But even then .005-.007 is pretty minuscule and really shouldn’t affect much.

 

[FB Trout]

I see variation of COAL length in line with what you are seeing, that is cartridge overall length. Base to ogive length, is usually much less variable, but as noted, can vary with bullet manufacturer. Lapua and Berger bullets, in my experience, have the least variability, but Hornady is usually within 0.002-0.005 variation on base to ogive length for a given load. The Barnes 127 LRX I have loaded in 6.5 Creedmoor or 6.5 x 55 has been right in line with your observations.

 

[Dixie]

Had the same issue loading 270 eldx in My .338 ultra... found out my primers on a few were not seated correctly

 

[Vern400]

Trying to up my reloading game. On my 338 RUM, I use a reddding full size die with bushing from Short Action Customs. My recollection I am loading to a diameter that is .002 or .003 bullet diameter. My steps are knock out the primer, clean pocket, anneal, tumble, resize, then use expanding mandrel, prime, powder and seat bullet.

I am using ADG brass and Barnes LRX bullets.

When I seat the bullets I am getting up to .005 difference in an overall length. I think this is due to differences in components. Like last night I am sure when I switched to a new box of bullets it changed the overall length and I adjusted the seating die.

My question: is that normal? And, am I being anal as to .005 or .007 difference in OAL?

As always thanks for feedback.


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In the manufacturing process, the base of the bullet is always pressing against the bottom of the die pocket. That's true for forming the jacket from a copper pellet. It's true for inserting the lead. It's true for forming the outside shape and closing the jacket. So the base of the bullet is the datum. It's the origin or home position. In the manufacturing process the dimensional variation ends up at the tip of the bullet. It's normal

Then the freaky thing is that your seating die presses in a DIFFERENT place that's NOT the ogive (where the bullet reaches full diameter).

The location of the tip of the bullet from the ogive will affect your BC a little bit. It can affect the fit of your cartridges if you're close to mag length.

The location of the Ogive to the cartridge base effects loading, and the distance to the rifling. That affects pressure characteristics and perhaps accuracy depending on your chamber and which bullet you're using.

So even though overall length is kind of important, the base to ogive length is more important.

I typically see +/-0.003 on OAL and possibly as much as +/-0.005. but if your cartridge base to ogive is consistent that's the best chance of changing a lot number of bullets without changing POI or accuracy.

 

[WTNUT]

Just basic cartridge overall length or base to ogive length? Many bullets differ on the over all length but good bullets should be pretty consistent on the ogive measurement. But even then .005-.007 is pretty minuscule and really shouldn’t affect much.

Good question my bad. I use a short action customs comparator to measure from bullet to base of the case.


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[Mag_7s]

Just another thought here: Are you using a vld style seating stem? If not, there could be some contact on the meplat causing some variation.

 

[WTNUT]

Just another thought here: Are you using a vld style seating stem? If not, there could be some contact on the meplat causing some variation.

I am using whatever came with the Redding Full Length Type S die.


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[WTNUT]

In the manufacturing process, the base of the bullet is always pressing against the bottom of the die pocket. That's true for forming the jacket from a copper pellet. It's true for inserting the lead. It's true for forming the outside shape and closing the jacket. So the base of the bullet is the datum. It's the origin or home position. In the manufacturing process the dimensional variation ends up at the tip of the bullet. It's normal

Then the freaky thing is that your seating die presses in a DIFFERENT place that's NOT the ogive (where the bullet reaches full diameter).

The location of the tip of the bullet from the ogive will affect your BC a little bit. It can affect the fit of your cartridges if you're close to mag length.

The location of the Ogive to the cartridge base effects loading, and the distance to the rifling. That affects pressure characteristics and perhaps accuracy depending on your chamber and which bullet you're using.

So even though overall length is kind of important, the base to ogive length is more important.

I typically see +/-0.003 on OAL and possibly as much as +/-0.005. but if your cartridge base to ogive is consistent that's the best chance of changing a lot number of bullets without changing POI or accuracy.

If I am reading this right I am measuring length from base to Ogive or darn close to it when measuring with comparator. I loaded 91 rounds last night 64 ended right at 3.965. The remainder were in the 3.960 to 3.958 range with a couple going 3.955. The rounds outside the 3.965 were set aside because I expect their poi to differ.


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[MTtrout]

Good question on measurable differences in variation. I wonder that with certain measurements myself. Measuring to ogive with Barnes and Hornady bullets have always been close, like within .001. I take measurement to polymer tip on few for my notes. This is separate loads for each bullet type. I have not compared notes for different bullets to see if they are the same.

 

[Tahoe1305]

I have been loading a ton of 143 eldxs without adjusting anything I’m within .001” (+/-) base to ogive on 9 of 10. The ones that aren’t are typically a tad long and I adjust the micrometer a bit to make them within .001”. If one ends up a tad short I don’t mess with it.

Ogive should be what matters though. Not OAL (except for mag length restrictions).

It sounds like you are measuring right though. OAL will have more variation as mentioned but isn’t as important if a metric.

I have also found having a “base” on the caliper really helps with measuring consistency. I have a habit of gently wiggling the case around till it seats well and shows the smallest measurement. I “feel” I can do this consistently each measurement. Without the base the thin caliper on the case bottom gave more erroneous readings.

This base should work with your comparator if it doesn’t have one.

https://www.amazon.com/Hornady-AB1-Lock-N-Load-Anvil-Base/dp/B005CMMIM4

 

[A382DWDZQ]

Variables I didn’t see addressed yet:

1. Tumbling wet or dry?
2. Are the cases themselves consistent lengths?
3. Dry lube inside neck?
4. Neck chamfered?
5. Seating stem clean?

 

[AT79]

Just another thought here: Are you using a vld style seating stem? If not, there could be some contact on the meplat causing some variation.

This ^^^^. I had issues before buying and using a vld seating stem.

 

[WTNUT]

Variables I didn’t see addressed yet:

1. Tumbling wet or dry?
2. Are the cases themselves consistent lengths?
3. Dry lube inside neck?
4. Neck chamfered?
5. Seating stem clean?

Here you go:

Tumble dry
I trimmed the cases to consistent length and measured each.
No dry lube in neck
Yes, Neck chamfered.
Yes seating stem clean.


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[pbroski]

If I am reading this right I am measuring length from base to Ogive or darn close to it when measuring with comparator. I loaded 91 rounds last night 64 ended right at 3.965. The remainder were in the 3.960 to 3.958 range with a couple going 3.955. The rounds outside the 3.965 were set aside because I expect their poi to differ.


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If the CBTO is 3.965", what is the cartridge OAL? They seem to be kind of long. Do you mean 2.965"?

 

[Tahoe1305]

May not have ability to zero the calipers.

 

[WKR]

If 5 thousandths more/less of jump is effecting your load and poi than id search for a wider node. And tune a load that can accept 10 thousandths plus or minus either way without a significant change in poi.

Atleast thats how I like to develop loads.

 

[EdP]

I can generally keep CBTO to +or - .001. Make sure primers are well seated and measure every loaded round. Mechanical tolerances in the press ram mechanism seems to be the cause. When a round is long, cycle it again with a bit more force and it will come out a bit shorter.

I don't know what effect a larger + or - in CBTO makes down range, but I try to be as consistent as possible.

I think there are situations where handloaders chase tolerances that are inconsequental, but we don't know what ones they are. I wish I knew more about which ones to chase and which to let go and why. I also think it might be different for different rifles. For example, I have a .270 Rem with some throat errosion that likes a long jump (.05) but shoots consistently sub MOA. Then I have a .25-06 that shoots sub MOA only when loaded very close to the lands. My thought is that the .25-06 is likely more sensitive to CBTO length.

 

[Shortschaf]

Just another thought here: Are you using a vld style seating stem? If not, there could be some contact on the meplat causing some variation.

This ^^^^. I had issues before buying and using a vld seating stem.

^^ this again. In 3/3 instances with your symptoms, this was the problem. (one instance was mine, others were friends)

Take the stem out and make sure the tip of the bullet isnt bottoming out. The stem should contact some part of the ogive.

think I drilled out the bottom of the stem with an 1/8" drill bit to remedy

 

[Quicksilver]

I have the feeling OP is getting his coal and OAL from ogive mixed up. Most any bullet is going to have that much variance coal especially an open tip style like a Berger.