Hornady Modified Cases

[Curmudgeon]

I have been using modified cases to measure case and bullet length to lands. I have a 6.5x47 case made by Hornady before it was a product regularly made. This case is on the numbers with my formed cases. I use a .308 and 30-06 case also. A friend at the range said his 6br case was short in head space. Approx .015, this made his bullets short of lands when he thought they were just in. With minimum neck tension it's hard to feel touch. I measured head space on my not custom cases and they were .005 short of my formed cases therefore my cartridges were short of lands. Where does Hornady get cases for there over the counter sales? Have I been negligent in not measuring head space on modified cases? Does Hornady mention this question anywhere? Who else has noticed this? If we have a max load we think is in the lands and it's not we might load a long one and have pressure spikes. Anyway it's something I haven't dealt with before. Thanks for the look.

 

[Judd]

I think I understand what you are asking and if I don't them tell me to shut up ;D

I expected the case to be a bit short to make sure it will fit in all chambers. The goal is to get the OAL so from the case rim to the Ogive or bullet tip...I don't think it matters where the head space is as long as the case seats all the way in and you can push the bullet into the lands I think that is all that matters.

Please do correct me if I am wrong, I would consider myself admittedly a rookie.

 

[Curmudgeon]

With a modified case tool it isn't the bolt face that pushes case in so if the shoulder is not correct case goes in chamber further. When that measurement is used with a case for live round length from back of case to ogive measurement it would result in shorter overall length. That's a minus x distance from lands. Am I looking at this wrong.

 

[NorCalMikie]

It makes no difference how long the case is. All you're after is how long to set your bullets in the neck to reach the lands.
The case is inserted into the chamber on the case holder and the bullet is pushed to the lands. That's the measurement you're after.

 

[Justin1098]

I agree with you Curmudgeon. Having a test case that has the shoulder pushed further back will make your coal shorter than your resized cases. I had this concern too but I just let it go because its only .004 in for me and I jump my bullets. The other thing that throws off the measurement is that your caliper is offset on the case head in the gauge and that adds .0015ish.

The shoulder is what indexes the case in your chamber not the case head, unless its a belted magnum. When you measure the coal of the hornady coal gauge and bullet, you are measuring from the case head, not the shoulder.

 

[BoydAllen]

Fellows,

This is way too easy. If you measure any new ammo or cases they are quite a bit short of minimum chamber headspace.

The answer as to how to properly deal with this is right in front of you. Measure a case that has been fired, neck sized, till it is tight, and the Hornady case, If the Hornady case is .006 shorter, add that much to the measurement that you obtain using it, and you will be right on the money. End of problem. Just remember to take good notes, and keep them where you can find them.

 

[DennisH]

It makes no difference how long the case is. All you're after is how long to set your bullets in the neck to reach the lands.
The case is inserted into the chamber on the case holder and the bullet is pushed to the lands. That's the measurement you're after.

I agree with the above. With the Hornady COAL tool, no matter how long the neck is, you push the bullet until it touches the lands, then tighten the set screw on the COAL tool.

Therefore you have your "exact" distance to the lands. Neck lenght just needs to be consistant. Example, a 6br and 6brx case, necks are definetly different, but you determine the distance to the lands using the method above.

CORRECT ?

 

[Curmudgeon]

Thanks, I understand how to correct the problem, I will measure all modified cases now since I don't soft seat my bullets into the lands. I just read how concerned shooters are about seating depth but have never seen reference to the length of modified cases and how that can change cartridge length and seating depth. thanks to all. There is no offset with the knurled knob of comparator body pointing toward you and the caliper can be zeroed also.

 

[jcampbellsmith]

..The answer as to how to properly deal with this is right in front of you. Measure a case that has been fired, neck sized, till it is tight, and the Hornady case, If the Hornady case is .006 shorter, add that much to the measurement that you obtain using it, and you will be right on the money. End of problem. Just remember to take good notes, and keep them where you can find them.

Agree, if we don't correct or our own chamber lengths, we are getting a relative measurement, not an absolute measurement. Much of what we do in reloading is based on relative measurements from our own kit and rifles and 99% of the time that is all that is necessary.

On bullet seating my objective is to consistently get the bullet to the same place +-1 thou every time. I'm not overly bothered exactly where that is relative to the lands.

One thing that the reloading world is crying out for is a good book on how to make key reloading measurements and understand the statistics (especially Standard Deviation) that support the measurements.

Regards JCS

 

[DennisH]

reference to the length of modified cases and how that can change cartridge length and seating depth

Unless I am missing something, case lenght has no bearing on bullet seating depth. After measuring you have your measurement to the lands. With any case your loading, set the bullet to any depth you want with your reference measurement to the lands.

If your measurement to the lands is 2.043, then add or subtrac from this number to determine if you want to be in the lands, or off the lands.

Again, am I missing something?

 

[seanhagerty]

I'm with Dennis on this one. Shoulder set back should have nothing to do with length to lands.

 

[NorCalMikie]

What makes this discussion difficult is the fact that we're talking about three different things at once and not concentrating on the one thing. Distance to the lands. That has nothing to do with COAL or headspace.
Set the bullet to touch the lands and WRITE that measurement down.
Change bullets and you'll get a different measurement.
WRITE it down also.
Short case length will change your COAL measurement. That won't change how far the bullet is out of the neck to reach the lands.
The shoulder of the case is bottomed out in the chamber. That doesn't change. The bullet still goes to the lands to set the jam.
One other thing to consider is the "actual" chamber length. If the neck is longer than the chamber, you won't be able to bottom out the case shoulder in the chamber. Make sure your case isn't too long, bottoming out and keeping you from getting a "correct" measurement.
WRITE EVERYTHING DOWN!!
Accurate notes will save you a bunch of trouble and keep you from chasing your tail.

 

[SmokinJoe]

Y'all are getting each other confused by talking about different reference points. The OP was asking about the use of the Hornady/Stoney Point tool. Boyd Allen's response is the correct approach because this tool measures from the case head to the point of interference with the bullet & the caliber specific gage, therefore headspace issues are very important to getting accurate information. My personal preference is to own the reamer, so all chambers are as close to each other as the smith can make them, then use a modified case made from brass fired in that chamber. By doing this, I'm taking most of the variables out of the picture. Modified cases are easy to make, so the generic ones from Hornady are not the only economical source. All you need is someone with the correct tap & a small lathe.

 

[XTR]

... then use a modified case made from brass fired in that chamber. By doing this, I'm taking most of the variables out of the picture. Modified cases are easy to make, ...

Actually a drill and a tap will work. Which bit and which tap?

 

[BoydAllen]

The whole point of the Hornady (formerly Stoney Point) tool is to come up with an accurate measurement from the head of the case to some point on the ogive of the bullet to use as a reference for setting up a seating die so that the bullet is at the desired relationship to the rifling, jumping, just touching, or a specified distance into the rifling. While it is true that you can start your experiments with seating depth at any repeatable point, without really knowing exactly where it is relative to the rifling, I prefer to use the rifling as a reference, either jam, for my benchrest rifles, or touch on my field rifles. For the latter, I have generally used the Sinclair gauge, that only requires an unmodified piece of fired brass, from the rifle being loaded for, and the bullet being loaded. I also have one of the gauges that was made by Stoney Point that uses a new case that has had its head drilled and tapped. In order to use this gauge to accurately determine the distance from the bolt face to some point on the ogive, comparing the the case that was ordered for the tool, that is unfired, to a fired case that has attained the maximum attainable dimension from shoulder to head is necessarry, unless a case that has been fired in the chamber is used. I find that taking one measurement each from a case fired in that barrel, and the furnished case is the easiest method, and adding the difference to the measurement obtained using the furnished. Of course the measurements obtained do not give the headspace of the chamber (Brass does not have headspace as the word is properly used. I put the word in quotation marks to denote the difference when referring to a measurement from some point on the shoulder to the head of the case to iindicate the non standard use of the term.) As long as the same tool is used to take all measurements for setting up a die, and what tool was used is recorded for future reference, that is all that is necessary. It is the difference in these measurements that is the useful information, not their absolute value.

 

[284driver]

Personally I believe the Sinclair comparator that clamps on a cleaning rod. (The two rings that lock in place when the rod tip touches the bolt face then again when the tip touches the bullet tip when it is pushed through the chamber to engage the rifling. Take calipers and measure outside to outside and subtract the thickness of one of the rings .) Hope that makes sense. The hornady cases index off the shoulder not the bolt face. That small difference will make a difference, albeit miniscule.

 

[DennisH]

... then use a modified case made from brass fired in that chamber. By doing this, I'm taking most of the variables out of the picture. Modified cases are easy to make, ...

Actually a drill and a tap will work. Which bit and which tap?

5/16 X 36 and use a 19/64 drill bit to drill out the primer

 

[Killshot]

... then use a modified case made from brass fired in that chamber. By doing this, I'm taking most of the variables out of the picture. Modified cases are easy to make, ...

Actually a drill and a tap will work. Which bit and which tap?

5/16 X 36 and use a 19/64 drill bit to drill out the primer

Speaking from experience, it's best to have a drill press and a jig to hold the case so it doesn't crush. The drill/vise/caseholder combo leaves much to be desired. (I also had Curmudgeon's thought about the case differences)

That said, Hornady will make you one from your fired case for a pittance.

 

[nfhjr62]

I use my wood lathe (can do lite medal work) for the drilling and taping of the cases i want to modify