Why can't i reload exact cartridges?

[RockyMtnMT]

There is not a single point on the nose that defines the location of the ogive. I think many believe the point that the nose reaches bore dia is considered the ogive. This is not true. As stated by others earlier, the entire nose is the ogive. The ogive is defined by the shape of the nose.

That is my best definition of ogive.

 

[kburdic1]

If you measure your ogive tool, you will see that it is not measuring to 0.264", and the seating stem in your die is touching a completely different spot on the bullet. So any variations in the bullet batch will introduce this variance, compounded by powder compression in the case if you are filling the case. However, great news! There is about a 0.015" window of accuracy in your chamber in regards to seating depth. So unless your rounds are more than 0.005" off your measurement, it's not going to matter or change your POI. I have a seating depth target system that proves this, if you're interested.

As the Title suggests, I find it almost impossible to load cartridges that are all exact. I understand there are so many variables it is impossible, but something has been bothering me for years. Let me see if I can explain what I'm trying to say here, and it has to do with the measurement of a loaded round, namely, off the Ogive.

A few specifics, this caliber is 6,5 x 55 but applies to any. Bullet is 130gr the Nosler Accubond. My press is a Foerster Co-Ax, and the Die is RCBS Comp Micrometer Bullet Seater. I am using a Stoney Point Comparator (now Hornady LnL), with the 6.5 insert.

Here is what I'm looking for:

Many do measure exactly 2.530, however I always get a few off, mostly under, and I have learned when all adjustments are set, not to touch and play with adjustments, because that seems to make it worse. If one measures simply to the point of the bullet, you will have variances. But how can it vary measuring to the Ogive?

Ok, close enough, or is there some reason I just can't get 100% of my loads to measure exactly the same? I have not touched anything, how can the measurement possibly be different? This has had me stumped for years, as I have no logical explanation how the measurement can be different.

 

[woodnut]

The one variable no one has touched on is the human error. A good friend of mine showed me that if you apply a differing pressure to the dial, it WILL give you differing results! Your loads may be exact but your ever so slight pressure to the gauge can give you that difference. Try it and see for yourself.

 

[HOT TUNA]

I use a Redding Instant Indicator with a bushing that is the exact groove diameter of the caliber I am loading for to establish seating depth. I set up the indicator with a inert master case that I have seated to length for the jump to the lands I want in the rifle I'm loading for. The Redding Instant Indicator paired with a Redding T7 Press and a Redding Competition Seating Die allows me to seat with near dead nuts consistency. Usually within +/- .0005" or under. In my opinion most comparators are useless because they are kind of random to what the inside diameter of the inserts are. They are usually never a diameter that is useful for consistency which is groove diameter. I know there are a few machinists out there that can make custom comparators where you can specify the exact diameter of the hole you need. If I was to ever buy a comparator that is the route I would take. When you measure from the base of the cartridge to the point on the ogive where it is the exact diameter of the grooves of the bore... every single bullet you load will have the exact same jump to the lands. I've found when I seat this way and closely manage my charge weights I almost always end up with loads with single digit ES and SD with very little effort in load development.

 

[hunter0528]

As the Title suggests, I find it almost impossible to load cartridges that are all exact. I understand there are so many variables it is impossible, but something has been bothering me for years. Let me see if I can explain what I'm trying to say here, and it has to do with the measurement of a loaded round, namely, off the Ogive.

A few specifics, this caliber is 6,5 x 55 but applies to any. Bullet is 130gr the Nosler Accubond. My press is a Foerster Co-Ax, and the Die is RCBS Comp Micrometer Bullet Seater. I am using a Stoney Point Comparator (now Hornady LnL), with the 6.5 insert.

Here is what I'm looking for:

Many do measure exactly 2.530, however I always get a few off, mostly under, and I have learned when all adjustments are set, not to touch and play with adjustments, because that seems to make it worse. If one measures simply to the point of the bullet, you will have variances. But how can it vary measuring to the Ogive?

Ok, close enough, or is there some reason I just can't get 100% of my loads to measure exactly the same? I have not touched anything, how can the measurement possibly be different? This has had me stumped for years, as I have no logical explanation how the measurement can be different.

Two other items that can make a difference is the primer (measure the length of the primed case) .003 could be the difference in the primer seating. Do you clean each primer pocket? (I've been using a ultrasonic case cleaner for about 1 hr before proceeding)
Another is are these compressed loads? As mentioned the case neck tension if that varies and it is a compressed load it can shift the bullet or if the cases have different volumes the powder will take more or less space.

 

[Bigaldepr]

You can't because it is impossible. All processes are subject to random errors or deviations as well as actual failures. What you can do is to use statistical process control to determine which of the member's recommendations actually improve your process and detect when you have a problem. It really isn't very complicated and a Control Chart can be easily created with an Excel spreadsheet. The control chart is useful:

• When controlling ongoing processes by finding and correcting problems as they occur.
• When predicting the expected range of outcomes from a process.
• When determining whether a process is stable (in statistical control).
• When analyzing patterns of process variation from special causes (non-routine events) or common causes (built into the process).
• When determining whether your quality improvement project should aim to prevent specific problems or to make fundamental changes to the process.

https://asq.org/quality-resources/control-chart

 

[SMK1000plus]

As the Title suggests, I find it almost impossible to load cartridges that are all exact. I understand there are so many variables it is impossible, but something has been bothering me for years. Let me see if I can explain what I'm trying to say here, and it has to do with the measurement of a loaded round, namely, off the Ogive.

A few specifics, this caliber is 6,5 x 55 but applies to any. Bullet is 130gr the Nosler Accubond. My press is a Foerster Co-Ax, and the Die is RCBS Comp Micrometer Bullet Seater. I am using a Stoney Point Comparator (now Hornady LnL), with the 6.5 insert.

Here is what I'm looking for:

Many do measure exactly 2.530, however I always get a few off, mostly under, and I have learned when all adjustments are set, not to touch and play with adjustments, because that seems to make it worse. If one measures simply to the point of the bullet, you will have variances. But how can it vary measuring to the Ogive?

Ok, close enough, or is there some reason I just can't get 100% of my loads to measure exactly the same? I have not touched anything, how can the measurement possibly be different? This has had me stumped for years, as I have no logical explanation how the measurement can be different.

What I've found with my loads Dom, particularly with 95% full case charges, or especially heavily compressed powder charges, and with heavy for caliber VLD style or ELD style bullets, is reloading press flex... Yes even my Rockchucker! I have even set dial indicators on the press frame, mount base and ram. I have noted from .001" to as much as .004" flex, depending on the % of case fill and how well the powder packs into the case, even with long drop tubes! I have also often noticed minor ogive deformation, when loading charges and bullets as noted above, even thought my seater plugs are casts of the exact type of bullets I'm loading and I drill the tip out of the seat with a 1/8" bit, to garuantee that the tip can't bottom out.

Try this; seat a bullet in a sized but unprimed case. Check the BTO and COAL length of that weight charge, loaded cartridge. Next charge a case with the same powder charge that causes your BOT measurement inconsistency but, do not seat a bullet yet. Next take something that vibrates strongly, like an electric toothbrush or as I use, an old electric engraver, cover the neck of the cartridge so that no powder granules bounce out, and vibrate the cartridge while lightly tapping it, until the powder granules compact/seat. Now seat your bullet as usual. Try 10 rounds like this. How consistent are your cartridge's BTO measurements now?

 

[NEMTHunter]

Looks like we need to define ogive.

There is not a single point on the nose that defines the location of the ogive. I think many believe the point that the nose reaches bore dia is considered the ogive. This is not true. As stated by others earlier, the entire nose is the ogive. The ogive is defined by the shape of the nose.

That is my best definition of ogive.

And it cant get any more simple than that Steve.

 

[TheLongRanger83702]

For me accuracy is a matter of relativity. Given the +/- variables with each reloading component one should accept the averaged average outcome and move on. Especially with these smaller calibers. From information I've read the 6.5's have a barrel life of @ 1000 to 1200 rounds before accuracy begins to degrade just from barrel wear alone. You're going to beat your head against the concrete wall of "perfection" over case capacity differences, primer variances, powder charge, bullet length variances added TO the barrel wear???...lol. And these are only firearm/cartridge variables. Add to this list of foibles of the shooter. Add to this list as well environmental variables: temperature, air pressure, altitude, etc. affecting the accuracy outcome. Good luck...lol.
If you really dont mind torchuring yourself with the process, start with a standard action length .30 cal cartridge at a minimum so at least the barrel life issue is lessened. Thats why I chose the 308 Winchester. I read many many articles stating barrelife BEFORE accuracy degrades is @ 5000 rounds, NOT 1200 like the 6.5's. I'd probably go more with the .338 cal. myself. But then I'm happy using standard procedures and getting 0.30 MOA groupings with my .308 Winchester AR-10 WILSON COMBAT SS.

 

[NEMTHunter]

I don't care wether the bullet is a tangent or secant ogive bullet. I'm talking about the start of the ogive. Reguardless of bullet design the ogive starts at the same diameter per that caliber of bullet. I should have been more clear. The type of ogive is of no consequence in reguards to seating.

Now that changes things a little. Or should I say a lot. You are right The type of Ogive has no bearing on seating. But it did serve the purpose of defining what the Ogive is. The whole length of the nose. The Ogive is the curve of the nose.

Thanks for stating were ON the Ogive you were talking about. That will help other understand what was being said. Me included! What you were talking about was the mating of the bearing surface to Ogive.

That's the thing was the E-net. If we would have been face to face it would have been hashed out a lot quicker with less running around.

Have a good day!

 

[Jason Lott]

As the Title suggests, I find it almost impossible to load cartridges that are all exact. I understand there are so many variables it is impossible, but something has been bothering me for years. Let me see if I can explain what I'm trying to say here, and it has to do with the measurement of a loaded round, namely, off the Ogive.

A few specifics, this caliber is 6,5 x 55 but applies to any. Bullet is 130gr the Nosler Accubond. My press is a Foerster Co-Ax, and the Die is RCBS Comp Micrometer Bullet Seater. I am using a Stoney Point Comparator (now Hornady LnL), with the 6.5 insert.

Here is what I'm looking for:

Many do measure exactly 2.530, however I always get a few off, mostly under, and I have learned when all adjustments are set, not to touch and play with adjustments, because that seems to make it worse. If one measures simply to the point of the bullet, you will have variances. But how can it vary measuring to the Ogive?

Ok, close enough, or is there some reason I just can't get 100% of my loads to measure exactly the same? I have not touched anything, how can the measurement possibly be different? This has had me stumped for years, as I have no logical explanation how the measurement can be different.

If using a shell holder (SH)? The Redding comp seater is allowed to ligntly touch the SH on seating. Acts as a stop. Removing any slop from press linkage. (Not that yours has slop) Just saying.

The Lee dead length bullet seater also uses the SH as a stop.

More likely a difference in bullets?

It is only 1.5 thousandths of an inch. I admit that I'm not sure if this is enough difference to matter for your intended application. I have a background as an engine machinist and I can tell you that the variance you are seeing could be caused by one or more of the following: tolerance of your measuring device, amount of pressure used when closing caliper, or even temperature of the various cartridges. Or, they could be varying that much due to a build-up of tolerances in your sizing and press equipment. Most likely it is a combination of everything I mentioned. You may be able to get it dialed to half a thousandth or less. I still give myself .0002-3" just due to myself with everything set up as well as I can on engine parts.

 

[Zen Archery]

What's that book called, "Don't Sweat The Small Things?"

 

[jshepherd61]

Is it possible some of the bullets tips are hitting the "wall" on the inside of the red comparator? If so, can you loosen the allen set screw and pull the 6.5mm bushing out a little, retighten, and then try measuring again to see if you get the same results?

If you measure all your Bullets base to ogave you will find that they are all a few thousands different! Even the high priced solid copper turned Bullets! That's with all stamped or high volume manufacturing. That's why you see SD (standard deviation) in all you data!

 

[Philward]

Press flex or inconsistencies between strokes or even a piece of dirt on the base where the case sits when seating the bullet could cause that small of an error. I just checked out the press and lots of moving parts and slip fit items like dies and shell holders. I don;t think you have enough variation to cause issues. Use calipers that only measure to 0.001" and not 0.0001" and you probably won't have any concerns.