Hornady OAL Guage ?

[statjunk]

Hello All,

I recently purchased an RCBS Precision Mic because I've been having issues getting a consistent measure with the Hornady OAL guage. The OAL tool that comes with the Mic is garbage so back to the Hornady OAL guage.

My issue isn't so much in it's use as it is getting the measurement from the tool. Here is what I'm talking about. Since I have the screw in piece of brass attached to the tool and there is a bullet in the brass, I cannot simply use a comparitor to get at the oal. So I have to measure from the back of the brass where there is a notch out in the tool to the tip of the bullet. Then use that exact bullet, because of variance in ogive to tip measures between bullets to figure out where to set the seater die. Only then can I get at the OAL, once the first cartridge is assembled. However, there is so much inherent error in the measurements that it's likely to be very wrong.

The problem is I cannot get a consistent measure of cartridge length using this method. I use my calipers, mitituyo's, to measure and each time I re-measure the Hornady case and bullet I get a different result. Within .01 but still not close enough for loading close to the lands.

To make matters worse once I go to load the first round with the exact bullet I used for measuring the chamber now there is the issue of placing the caliper in the exact orientation as it was in while it was on the Hornady OAL guage. Any variance there will result in error.

To anyone that understands what I'm going through, please let me know if you have a trick to make this a more precise proceedure.

Thanks

Tom

 

[MTBULLET]

you also need the comparator device to take measurements from the ogive of your bullet.

 

[freebird63]

I too have the OAL Guage and the comparator and for the life of me I can't seem to figure it out either, I know I am no rocket scientist here and I don't remember reading that you needed to be one to use it. With the comparator it says to put the traveling blade of your caliper and zero out your caliper, so when the comparator is in the caliper its at zero, then you put your bullet or your loaded round in and measure, but that only gives your the measurment from the base of the shell to the Ogive, that comes out way shorter then the OAL, which is 3.600 for my 300RUM. I am confused.

 

[statjunk]

Freebird,

That does give you the oal as long as you have a comparitor attached to your caliper. The problem is it's impossible to measure accuratly and impossible to transfer that measure to another round given that your caliper is essentially at an angle when measured. So you'd have to be able to repeat that exact angle to measure oal.

This has been my argument the whole time.

Does anyone else have a solution to this problem?

Thanks

Tom

 

[MTBULLET]

I too have the OAL Guage and the comparator and for the life of me I can't seem to figure it out either, I know I am no rocket scientist here and I don't remember reading that you needed to be one to use it. With the comparator it says to put the traveling blade of your caliper and zero out your caliper, so when the comparator is in the caliper its at zero, then you put your bullet or your loaded round in and measure, but that only gives your the measurment from the base of the shell to the Ogive, that comes out way shorter then the OAL, which is 3.600 for my 300RUM. I am confused.

what measurement are you getting ?

 

[freebird63]

Ok will try and put all this info down so its understandable.
Rifle-Remington Sendero 300 Ultra Mag
OAL-3.600
Bullets being used-Berger 185gr
Published OAL of Berger bullet-1.378
The lenght of bullet from my caliper-1.360
With Hornady OAL Gauge-3.824
With comparator on the OAL guage-3.140
With my caliper I have found that my magazine will only allow for a OAL of 3.610, after that it becomes a single shot rifle.
So with all these numbers can anyone tell me what I am doing wrong here???
I also know that with the RCBS dies and Lee dies the tips of my bullets were bottoming out in the seater therefore damaging the tips of the bullets. I have only found two dies companies that make a seater for VLD bullets and that is Redding and Forster.
Thank you in advance for any insight anyone can give me as to what I am doing wrong, I have followed the instructions to the best of my ability, I am just an old dumb scooby mule deer hunter.

 

[cedarswamp1]

You aren't doing anything wrong, but you need to decide whether you want a repeater or to be set .010 off the lands. I've never measured a factory Remington that would allow both.

Also once you're measuring to the lands, you can pretty much forget OAL, it only tells you how much bullet is hanging out in front of the lands, your critical measurement is to the ogive.

Don't worry about getting perfect results with your comparator. Take 10 reading and see which number keeps popping up the most and figure that as your
"ogive OAL"

Your going to drive yourself nuts, if you are trying for the same exact number for each round, too many places where that could go wrong.

 

[woods]

I use the Hornady OAL tool and another tool called the C.O.L. E-Z Check from R-P Products 318-424-7867. Here they are shown together

The R-P is much better but your question is about the Hornady. Sometimes it is difficult to get consistant measurements and there is a learning curve. But it is pretty straghtforward. First you zero the calipers with the comparator attached

then seat the modified case in the chamber and push the bullet to the lands

lock the gray rod and retract. Measure with the comparator attached

or measure for OAL with no comparator

The measurements will be different and the comparator body itself will take up 1.00" after zeroing. There will also be a slight difference because of the difference in the headspace of the modified case and the headspace on your loaded case (if any).

But I don't understand why you think that there would be an error induced in the measurement because of the angle of the caliper being different from the tool and loaded round. Both measure close to the center of the case head and there should not be any differences because of that.

 

[freebird63]

So I need to take the time to measure from the base to the ogive and figure out what lenght will fit in the magazine. I wonder if any gunsmiths have ever or can install a longer magazine on these rifles??? But then I need to see what is going to shoot the best for my rifle. I have read that for hunting purposes you can get by with being ten thousandths off the lands. But then I have also read that you want the tip of the bullet to be right on the lands. I first have to get my die situation fixed, I have went through 4 sets of dies, none of them work with the VLD bullets, Redding is suppose to be sending me a seater that will work with the berger bullets. I have also gotten in contact with Redding and Forster and found out that their competition seater die comes with a seater that works with VLD bullets. All these little gagets sure do add up "money".

 

[Moman]

Statjunk, a little hard to follow this post, but a couple of things I can think of that may help.

1. Make sure your chamber area is completely clean. This includes the throat area. Any fouling or grime in these areas will give you erratic readings.

2. The comparator is drilled and tapped on both sides. I always set mine up with the screw on the back side of the caliper blade. You can see there is a difference in the two sides, one is offset, the other is straight on. Set the comparator up so it is offset when measuring your dummy round off of your lands. Then rotate the tool 180 degrees, and thread the screw into the backside of comparator for taking measurements of loaded rounds. It will be dead on straight when in this position.

3. Each time you move the comparator from side to side, re zero it on you calipers.

Freebird, I wouldn't worry too much about your freebore situation at this time. I have a couple of factory Remingtons that have quite a bit of freebore and they are tack drivers. I think it's much more important that the action, chamber, barrel and ammo are concentric. My 308 jumps .135, my Sendero jumps .126, both are capable of quarter inch groups.

As was mentioned, you will probably load to mag length, but it's still nice to know what the amount of jump is. When you get the hang of the Hornady tool, measure the freebore with one bullet and record the reading. Keep this bullet seperate with the notations. In the future, you can re measure with this bullet to keep an eye on throat erosion. Hope this helps.

 

[woods]

Like Moman and cedarswamp have said, it would be unusual for you to be able to load close to the lands and still fit the magazine. Especially with a 300RUM and a Remington rifle. Those are all made with a lot of jump.

Best thing for you to do is seat as long as your magazine will allow and forget about seating close to the lands. Find a load at an OAL that is .025" to .050" shorter than your mag and work on your seating depth consistancy, bullet grip and velocity to get the most accuracy.

A competition seater from Redding or Forster will definitely help but they are not cheap. A good seating die will help with seating depth consistancy and will not introduce additional runout. Won't cure any runout you have, but won't add any.

 

[nfhjr62]

Receved the new Sinclar catlog today in the mail (2010-A) on Pg. 40 is upper rt. of page is the Davidson seating depth checkers have been thinking of purchasing one of these to go with Hornady gauges as i see it would keep same angle when checking cases or OAL of loaded rounds.

 

[statjunk]

Woods and Moman,

Thanks for answering my question.

Specifically for Moman. So what you're telling me is the Hornady Comparator, specifically this one:

Bullet Comparators - Hornady LNL Comparator Set - 22 6mm 25 270 7mm 30 cal

Is offset on one side so that it lines up perfectly with the tool? Then can be squared back up to the caliper by placing the screw in the other side and reattaching it to the tool?

From the picture I can't see the offset. It that were the case it would get me much closer to the right answer but still not control for the placement of the caliper blade on a live round. I have a davidson comparitor but it can't be used with the Hornady OAL tool because it provides a base.

Woods, any chance you could provide a picture of the top of the comparator where it attaches to the caliper, to show the offset?

I would really appreciate it as this has been burning my biscuits for quite some time.

Thanks for pulling my thread back to address the issue I've been having and your detailed post.

Thanks to all

Tom

 

[cockcroft]

The amount of pressure you use to push the bullet into the lands will make a big difference in your measurements. Come up with a method that is repeatable and uses the same amount of force to push the bullet into the lands. I just use one finger and very light pressure to just feel the bullet touch.