OAL length ?

[Nube]

I splurged and bought a Hornady OAL Gauge, a Modified Case, and a Bullet comparator. I have measured my 223 Savage FV and my 223 Ruger Predator with a 1:9 and 1:8 twist respectively. Both with a 50 gn Hornady VMax. They both measured approximately 1.809 inches with the comparator, however I have some “factory” Fiocchi with a 50 gn Hornady VMax in them and they measure approximately 1.843 inches. This is a difference of 0.034 inches IN THE WRONG WAY! Is it possible that they are "Jamming" into the rifling with the factory loads. I expected a difference but this is not what I expected. Just to make sure I have measured multiple times and always came up with the approximately the same measurements, even if I pressed fairly hard on the OAL Guage. Your thoughts on this are appreciated or am I doing something wrong?

Thanks for the replies!!

[Bart B.]

That happens when two different ogive shaped bullets are seated with the same die settings.

If one bullet touches the rifling when its round is chambered, seat it .005" deeper.

[T. O'Heir]

Fiocchi ammo is made to CIP Spec, not SAAMI. Savage and Ruger chambers are made to SAAMI spec. SAAMI Max OAL for .223 is 2.260" measured from the pointy bit to the flat bit with no ogives involved. Minimum OAL is 2.125". Where are you measuring to get 1.anything?
"...Is it possible that they are "Jamming" into the rifling..." Not likely. You'd know that by the bullets being pulled out upon extraction.
Do not press hard on any gauge.

[Nube]

Bart B
Ok, so if I understand correctly it is not only rifle specific, it is comparator insert, and die size (or manufacturer) specific, for the OAL? This is due to manufacturing tolerances? My measurements were not off, just a different set of "tools" to measure?

T. O'Heir
Where are you measuring to get 1.anything? Measuring from the base of the cartridge to the point on the ogive of the bullet where the comparator sits, not the complete overall length of the cartridge.

[Bart B.]

Bullet seating comparator gauging diameter has to be the same the barrel throat rifling diameter it touches the bullet ogive. Typically about 2 to 3 thousandths smaller than bullet diameter.

Otherwise bullet to rifling distance can be hard to manage,

[cw308]

Different bullets have different tapers , you can seat one bullet to touch the rifling and seat a different bullet with more of a taper will be further out before it hits the rifling . If your seating to the ogive both measurements will be the same but your OAL will be different . Ogive measurements are more accurate if loading one round at a time I wouldn't be concerned with OAL , but loading from a magazine you have to be careful your not seating too long to the point they won't fit in the mag. Even with different lots of the same brand of bullets you could have a slight difference in taper not .034 but .002 or 3 . Measure your reload ogive measurement to the factory ogive measurement not OAL , what is the difference . Only way to tell if it's a jam or jump from the ogive measurement . Hope I Helped .

Chris

[RC20]

newb:

You are measuring on the Curve of the bullet (Ogive)

Each bullet from any mfg has its own Shape (curve).

Bullets between mfg of course also have their own shape.

There is a lot of variability in bullets due to blunter hunting types vs the ELD types.

Also each bullet behind the Ogive has its own length and shape and taper to the back be it boatail or flat base.

That affects what an mfg goes for on Ogive as well as the bullet weight (heavier bullets in a caliber will have longer length)

All the data is an attempt to give a re-loader a safe bullet distance off the lands. Mostly its right even if sometimes way short, but I have seen a couple that stick in the lands going by the book data.

The best way to actually find out when a bullet is hitting the lands is to use a dummy round (no powder or primer) deliberately long and close the bolt gently.

You will feel resistance and you pull back. Sometimes the bullet (particularly the sharper ELD type) will stick and you tap the bolt handle with a plastic handle (screwdriver works nicely)

As long as you did not force it the dummy round will come out.

You make sure you have its measurement going in.

You want to measure it again at that point as it is possible it pulls the bullet out a bit.

If its way out form closing, you can set it in .020. Repeat until its does not stick.

At that point a second dummy and close it and see if there are any marks on the tip. You can get marks without a stick. You can use a sharpie to darken but the marks are there.

No marks you know you are close.

You may be .020 off, you may be .010 off, you may be .005 off.

If you want to confirm then seat another dummy .015 out from your last unmarked dummy. Marks or stick you know it needs to be at least .005 shorter. If not you know you are really really close.

Sharpie works at that point if you want to check further but that pretty much good enough for anyone other than a bench rest professional.

You need to do that with each mfg type of bullet you use and bullet types that are the same weight but different style from a mfg.

A caveat here is I have seen some Hornady (mostly all I am using right now) that have a nutty Ogive different from the rest and have had to move those .020 back to stop sticking. I just set those aside. They are one in 100 or more maybe.

I am in the habit of closing the bolt and then opening it if I am less than .010 from the lands to avoid a lack of bullet jump. You can get some real serious pressure spikes if you are in the lands and those are best avoided.

[Bart B.]

Over All Length is case head to bullet tip; per SAAMI glossary.

There is no standard definition for case head to throat contact point on bullet.

RC20, great post well written. Should be included with every bullet seating die sold.

Remember the ogive touch point on the rifling lands erodes further down the bore about .001 inch every X dozen rounds. X = ~3 for 308 Win, ~2 for 260 Rem, ~1 for 264 Win Mag.

[cw308]

When checking with a stripped bolt for a better feel your base to ogive setting is on the bolt lift without any resistance . You can check out the video on line Wheeler Method of chasing the lands . Very simple and accurate. You can do the same for headspace only the feel or slight resistance is on bolt closure . Hope I Helped .

Chris

[Unclenick]

Nube,

You are comparing the same bullet to the same bullet, so there shouldn't be much difference, even though, occasionally, you run into a problem where the tooling for a particular lot of bullets did vary from the norm. But that is unlikely to be the problem here.

Nor is the problem the CIP specification vs. SAAMI. For cartridge overall length (COL) they are within two-tenths of a thousandth of and inch of one another after you make the metric conversions (divide any of CIP's millimeter numbers by 25.4; it's an exact conversion factor by definition and with no unaccounted for digits afterward).

That said, I suggest you redo the measurements. I have noticed repeatedly with my match AR that the comparator insert is loose enough that the bullet hangs up on the way into the throat giving me a short measurement similar to what you are getting. The way to check this is simple. After you get the bullet comparator number, remove the adapter, zero the caliper, then make a COL measurement from the base to the tip of the bullet. Hornady recommends a COL of 2.25" for this bullet. If you get a result shorter than that, unless your chamber is defective (also unlikely) something is going wrong with the measurement as happens to me.

What I had to do to get the measurement right took two steps. One is I painted a bullet with Magic Marker and looked at where the chamber marked it. It was a line on the ogive below where a comparator contacts it. If the bullet is really all the way into contact with the throat, you should see rifling land's marks evenly spaced all around it. I had none.

When I figured out I was not getting contact, I wanted to know why? It turns out the gauge case being loose in the chamber plus the bullet being loose in the gauge adapter case is a combination that allows the bullet to tip too much and sit too far off-center to seat cleanly. It catches on the step at the end of the chamber's neck space.

To avoid that, set the gauge in the barrel and seat it as before. Pull it out. Using your caliper and an example of the Fiocchi load, set the rod in the gauge forward until you have the same COL in your gauge the Fiocchi does. Now hold the gun muzzle-up with your weak hand and slowly move the gauge in while you wiggle it around until you feel it slip in past the sticking point (it stops, but then goes in deeper). Then hold the gauge in place as you lay it down and then loosen the rod again and gently press the bullet in the rest of the way. I've gotten close to 1/4 inch more COL doing that with some bullets. Now you should see the rifling marks on your test bullet, too. Now you have a good measurement.

[jmr40]

OAL just isn't that important as long as the cartridge will fit in the magazine and chamber without the bullet jammng into the lands. Bullet shape is the key. A RN bullet of the same weight will have a much shorter length.

[Unclenick]

But his measurement is telling him the bullet WILL jam into the lands at a normal COL, even though I suspect the measurement to have been fooled. He does need at least to prove he's not jamming anything.

[Nube]

Thanks all who responded esp Unclenick I tried his method and got it within 0.001 to 0.002 inch. I guess I was just a little too timid in inserting the projectile, all I read was just to go till you feel any resistance. Now I can go ahead and load some up and see how they preform (while feeling good about it). Thanks again, it seems the more I know the less I know! (Guess you never stop learning)

[F. Guffey]

OAL, over all length, and then there is case length, my cases do not have head space, I understand that drives many reloaders to the curb but my cases have two lengths because SAAMI published their case drawings with a datum.

My cases have a length from the datum to the case head and from the datum to the end of the neck. This information is helpful when using a case gage. And then there is the diameter of the rifling, that is something that is difficult for a reloader to get a grip on.

And then there is the Sinclair/Hornady comparator.

F. Guffey

[RC20]

That said, I suggest you redo the measurements. I have noticed repeatedly with my match AR that the comparator insert is loose enough that the bullet hangs up on the way into the throat giving me a short measurement similar to what you are getting. The way to check this is simple. After you get the bullet comparator number, remove the adapter, zero the caliper, then make a COL measurement from the base to the tip of the bullet. Hornady recommends a COL of 2.25" for this bullet. If you get a result shorter than that, unless your chamber is defective (also unlikely) something is going wrong with the measurement as happens to me.

My brother made me a metal one and while its better, it still comes up short.

You really have to tap hard on the back of the device to get it to emulate the same affect a bolt closing has.

[cw308]

nino
I to tried the Hornady OAL gauge , it will get you in the ballpark but no way for me being accurate . It now sits in the cabinet never to be used . The Idea is good but there are better , guess we go through them all .

[RC20]

I use the inserts that come with the set and the piece that clamps on the micrometer for Ogive seating depth for reloading seating (and at the range to play with) and shoulder setback so not wasted (I just took one of the inserts and bored it out to a 30 caliber shoulder size)

[hounddawg]

take a Sharpie and completely cover the bullet on the Fiocchi round, chamber the the round, then extract. If the bullet is hitting the lands the you will see a ring where the bullet touched the lands

[F. Guffey]

I have TRIED TO CONVINSE reloaders it was possible to determine 'off the lands' without chambering the round. And now? They have convinced me they can not check 'off the lands' without chambering the round.

I want to know the distance from the lands to the bolt face.

F. Guffey

[Bart B.]

Originally Posted by F. Guffey

I have TRIED TO CONVINSE reloaders it was possible to determine 'off the lands' without chambering the round.

Maybe you will convince them if you explain how it's done.

[cw308]

That would be nice for a change.