Bullet Ogives Change with Lot Numbers

[LRNut]

Lately I am a bit frustrated that bullets have fairly large lot-to-lot dimensional differences with respect to ogive location. This past weekend I was loading .338 Lapua and the box of 285 ELDMs was empty and the last of that lot. I grabbed another box and without measuring the bullet ogive, proceeded to seat a bullet - the ogive OAL (the term I use to measure OAL) was 40 thou different! Before you criticize Hornady, I saw the same thing with a box of Berger 300 .338s - in fact, I can't even use them unless I drill out the Stoney Point holder because the bullet bottoms out on this before the ogive tangent point is engaged.

Anyone else frustrated? I don't understand how manufacturers can't control something like this better - it is pretty critical.

What do the rest of you do? Do you adjust the seating die so the ogive OAL is the same as the previous lot?

 

[xsn10s]

Hmm I'm not saying that you measured incorrectly but I agree that is a large variance. I've been out of the bullet manufacturing game for awhile but the tolerances were far closer than that. Last time I was involved dies for bullet forming were finished by hand. So some variance was to be expected, nothing like you are describing. We used optical comparators for ogive location as well as other measurements. That was almost twenty years ago.

 

[Petey308]

It boils down to cost cutting. They run dies and tooling a bit longer than maybe they should, so they wear will differ when changed out for new. They also don't have dedicated machines for each product line, so when dies/tooling get swapped out, your get done variance there as well.

It sucks, and I wish it wasn't like that, but it always has been, that's why it's always been a thing to try to buy in big lots if you can, or just measure and adjust as necessary when changing lots. Usually it doesn't take much.

I sort bullets. I sort them base to ogive. I keep batches in big bins based on the measurements. By doing this, I can order a new lot number and when I sort them, they all end up in batches that are the same. By doing this, I create just a few lots and if I need to switch from one to another, I just adjust things as required and I'm good to go.

 

[xsn10s]

Forty thou is a big variance. Running dies too long is one thing but there is a liability issue with a forty thou seating difference. I am suspicious of this due to the possible pressure issues that could come from this large a variance. For larger manufacturers there are at least three quality control checks: operator, QC and the ballistics lab. I'd check the OP's seating stem for a polymer tip that broke off and got stuck. The OP might be having this issue for real, but I haven't seen this large a variance before.

 

[CaptDru]

I see a difference with 6.5 156 Bergers. Not that much variance as you, usually about 5-10 thou between different lot numbers. Within the lot it's pretty consistent. I just measure before when I use a different lot number.

 

[Huntsman66]

I have noticed the same issue… not to the extent you did, but still surprised me a little. Had a box of Nosler bullets and grabbed the next in line and they were 14 thou different from the previous box. But correct me if I'm wrong, but if you are measuring to the Ogive thats the first contact point for the lands. So the relationship between the BTO and touching the lands of the barrel should remain the same even if the over all length of the bullet changes a slight amount. Thats why you dont use COAL when setting your jump, because of those variables…

 

[Petey308]

Forty thou is a big variance. Running dies too long is one thing but there is a liability issue with a forty thou seating difference. I am suspicious of this due to the possible pressure issues that could come from this large a variance. For larger manufacturers there are at least three quality control checks: operator, QC and the ballistics lab. I'd check the OP's seating stem for a polymer tip that broke off and got stuck. The OP might be having this issue for real, but I haven't seen this large a variance before.

I missed that the variance was that much. I agree that wouldn't be from simple wear and swapping of dies, unless the operator messed up and the subsequent QC messed up as well.

I agree there might have been a mistake by the reloader in this instance, or he was the victim of a quality control gap at the factory. It does happen from time to time, unfortunately.

 

[Petey308]

Another question to the OP:

Did you measure just the bullets (base to ogive), or were you measure loaded rounds?

If loaded rounds, I'd ensure things like compressed powder loads, insufficient case mouth chamfer, too much neck tension, insufficient/incorrect contact with the bullet seating stem to the bullet, etc aren't messing with the end result. Also, if measuring loaded rounds, ensure your primers are seated just below flush. I've seen guys complain about OAL variance and the cause was primers protruding and by an inconsistent amount. Seems obvious, but it happens to the best of us.

 

[WapitiBob]

Just measured my Berger 195's, .020" difference between lots. The 500 I bought a few weeks ago are the longer ones.

 

[LRNut]

I have noticed the same issue… not to the extent you did, but still surprised me a little. Had a box of Nosler bullets and grabbed the next in line and they were 14 thou different from the previous box. But correct me if I'm wrong, but if you are measuring to the Ogive thats the first contact point for the lands. So the relationship between the BTO and touching the lands of the barrel should remain the same even if the over all length of the bullet changes a slight amount. Thats why you dont use COAL when setting your jump, because of those variables…

I am measuring the OAL with respect to the bullet comparator, i.e., not the actual OAL. So if I keep that comparator OAL consistent, then the jump to the lands should be consistent as well. If I didn't adjust the seating die, then my jump would change if the bullet ogive tangent to base changed.

 

[xsn10s]

Anything is possible but I'd expect a pretty large variance in diameter if there was that large a variance in length, whether it was ogive location or overall length. That would cause a pretty significant pressure change. If there was that large a change in ogive location then I's expect a BC change too. But hey anything is possible.

 

[LRNut]

Another question to the OP:

Did you measure just the bullets (base to ogive), or were you measure loaded rounds?

If loaded rounds, I'd ensure things like compressed powder loads, insufficient case mouth chamfer, too much neck tension, insufficient/incorrect contact with the bullet seating stem to the bullet, etc aren't messing with the end result. Also, if measuring loaded rounds, ensure your primers are seated just below flush. I've seen guys complain about OAL variance and the cause was primers protruding and by an inconsistent amount. Seems obvious, but it happens to the best of us.

Both; the bullet ogive tangent to base was different and translated directly to the difference in OAL using the comparator.

You are correct about primer seating - seen that before as well.

 

[Huntsman66]

I am measuring the OAL with respect to the bullet comparator, i.e., not the actual OAL. So if I keep that comparator OAL consistent, then the jump to the lands should be consistent as well. If I didn't adjust the seating die, then my jump would change if the bullet ogive tangent to base changed.

I agree that you would need to adjust the die, but the load will be fine as long as you maintain the BTO number. Thats all I was saying.

 

[Petey308]

Both; the bullet ogive tangent to base was different and translated directly to the difference in OAL using the comparator.

You are correct about primer seating - seen that before as well.

And you confirmed there's nothing interfering with your measurements? It's 100% just an actual variance in the dimensions of the bullet?

Not trying to be a jerk, just trying to confirm the actual problem.