Bullet Seating Deapth Issues

[Amithus]

So My last batch of .223 was being seated at the 2.250" mark. However I would get variences from 2.250 to 2.255. Not a lot, most were at 2.250 however about 1 in 6 were longer. Now I'm measuring from tip to tail and not from the ogive. Using a bench mounted Redding T7 with hornady dies. I am using the same motion every time and try to repeat the same movements in all stages of reloading.

Is there a way to tighten this up so they are closer? I have the die tightened down and the lock ring locked.

[mmcnx2]

Most likely your die is seating based on diameter at a specific place on the bullet, not the tip. Thus the variation might be the lenght from that place on the bullet to the tip. While the OL is important for magazine fit, for accuracy the free bore measurement is more critical and in most cases that number varies less given the bullet seating die works basically the same way.

[rugersol]

So My last batch of .223 was being seated at the 2.250" mark. However I would get variences from 2.250 to 2.255. Not a lot, most were at 2.250 however about 1 in 6 were longer. Now I'm measuring from tip to tail and not from the ogive. Using a bench mounted Redding T7 with hornady dies. I am using the same motion every time and try to repeat the same movements in all stages of reloading.

Is there a way to tighten this up so they are closer? I have the die tightened down and the lock ring locked.

Off the top of my head, maybe weigh each bullet, and sort 'em by the 0.1gr? ... try a batch of the same within 0.1gr? ... see if that makes a difference?

[Shipyard]

what kind of bullets? it's not uncommon to have some variation in OAL of the bullet itself.

still, +/- 0.003 is a pretty darn good result in most things machanical, especially with a human factor involved

[RAGGED]

So My last batch of .223 was being seated at the 2.250" mark. However I would get variences from 2.250 to 2.255. Not a lot, most were at 2.250 however about 1 in 6 were longer. Now I'm measuring from tip to tail and not from the ogive. Using a bench mounted Redding T7 with hornady dies. I am using the same motion every time and try to repeat the same movements in all stages of reloading.

Is there a way to tighten this up so they are closer? I have the die tightened down and the lock ring locked.

You want to measure from the ogive, going from the tips your numbers look completely normal and nothing to worry about, like others said your die is indexing off the ogive, not the tip, so they will likely be more constant when you measure from the same place the die is indexing from.

[Amithus]

Rockin' thanks again everyone. I figured it may be a manufacturing flaw with the tips of the bullets as when you look at em they all are a bit different and .001 to .004 is pretty small however being new to this, I trust you guys more than my "I thinks".

[JJ]

You could always measure the bullets themselves and see how much variation you are getting from base to tip.

[hammAR]

You could always measure the bullets themselves and see how much variation you are getting from base to tip.

Not really, you want from the point on the ogive where the lands of the barrel would begin contact with the bullet. The ogive is more consistent than the actual tip on most bullets. Therefore, you can verify the Overall length (OAL) of your handloads more accurately by measuring back from the ogive to the base. Your chamber pressure and accuracy is affected a great deal more by the positioning of the bullet ogive than by the actual bullet tip. When inspecting and measuring the OAL of a handload, measure back from the bullet ogive.

When I examine my handloads, they vary in length - considerably. I make all on the same press, using the same seating die, with the same depth setting, and the same bullets. So, why do they still measure different lengths when I measured them from their ogive to the base?

These were identical 175 gr. match grade bullets, from different lots and their length differ by .005" when measuring them to the bullet tip to base. However, after measuring these bullets from the ogive to base, some of them actually measured .012" different from the others. This shows that it's also possible to get serious variations in bullet shape. I've seen this happen with other brands of bullets that came from the same box. This inconsistency can be found by first comparing individual bullets from the ogive back to the base.

I'm sure that by now, someone out there is wondering "Wait a minute . . . . if your bullets are seated from contact at the ogive, how can you find a different OAL when measuring those handloads from the ogive to the base?" The answer surprised me at first, but it's simple. I was taking the final length measurement from a much lower part of the bullet ogive. This shows that the curved shape of a bullet (the ogive) can vary. This lower part of the bullet ogive is much more significant, because it initially contacts the rifling. An inconsistent bullet ogive can also affect the distance that your bullet travels to the rifling. This is an important item to look at when you're trying to shoot tight groups.

To sort bullets for loading, besides weighing, I compare my long range match bullets (right out of the box) from the lowest part of the ogive to the base - before loading them. This comparing of the ogive uniformity can improve the quality of your bullets before reloading. By the way, with a little patience this can reduce your (5 shot) 100 yard groups by as much as 25%.

But than again this is only worth what you paid for it................

[JJ]

hammAR I get exactly what you are saying. He mentioned earlier that he was awared that base to ogive would be more accurate.

However I would get variences from 2.250 to 2.255. Not a lot, most were at 2.250 however about 1 in 6 were longer. Now I'm measuring from tip to tail and not from the ogive.

I was just referencing checking his variation to the tip. If he was seeing .005 variance in the loaded round I would be willing to bet he would see similar variation measuring just the bullets.

Measuring to the ogive is the only accurate measurement that matters.

Of course in most of my bolt guns I work up loads that are jam fit to the rifling, which is a whole nother conversation.

[hammAR]

[gyrfalcon]

Most likely your die is seating based on diameter at a specific place on the bullet, not the tip. Thus the variation might be the lenght from that place on the bullet to the tip. While the OL is important for magazine fit, for accuracy the free bore measurement is more critical and in most cases that number varies less given the bullet seating die works basically the same way.

+1

You might want to take out the seating plug out the die and measure a bunch of bullets with it to see how much the ogive varies.

[nosualc]

Bullets vary in overall length, especially to the tips. Depending on your bullet, measuring to the tips, 5 thous really isn't that bad.

Note that your bullet seater does not seat from the tip, rather from the ogive. Measuring from the tips is going to indicate more variance than you're really getting. You can improve your results by measuring to the ogive instead of the tip. Look into bullet comparators. Hornady makes a fairly inexpensive one.

You can also improve your results by buying match bullets. Berger, Sierra MKs, Laupua Scenars, JLKs, etc. are going to have less variance from bullet to bullet than non match (eg hunting or plinking) bullets. You'll pay extra for this consistency.

If you really want to get hardcore, you can also sort your bullets by base to ogive length and/or use a meplat trimmer to make your bullet tips more consistent.

The last couple of steps are for the truly obsessive (or competitive).

-nosualc

[gman1868]

Gotta get you one of these:

http://www.sinclairintl.com/.aspx/sid=66673/pid=34262/Product/SINCLAIR_BULLET_COMPARATOR__1



Bullet Comparator. You'll see that it measures at the ogive and from there you should get consistent measurements.

[xd ED]

Reading the most recent posts suggesting measuring from a specific point on the bullet's ogive has me wondering about the technique and instruments used to do so. I gather one end point of the measurement is at the diameter of the bullet that will contact the lands. How does one accurately locate, and measure from this point?
Thanks in advance for satisfying my curiosity.
ETA: I guess I was typing when gman1868's post arrived. It answers my question.(That's pretty good: getting an answer before you ask)

[nosualc]

Here is the Sinclair comparator pictured above in action



This is a picture of the hornady comparator



-nosualc