Hornady o.a.l.gauge

[josebd]

With the modified case for 6.5prc it’s .006 shorter for the headspace than a fired round.
Will this effect the measurement for the c.o.a.l.?

 

[338 dude]

With the modified case for 6.5prc it’s .006 shorter for the headspace than a fired round.
Will this effect the measurement for the c.o.a.l.?

Yes I believe it will ,some people have a modified case made from there once or twice fired brass for better results

 

[josebd]

What would be the difference?+ or - .006?

 

[josebd]

I’m kind of in a hurry,don’t have time to wait for one

 

[338 dude]

In theory only because I can’t say what happens first but I assume the case would expand first when fired filling the chamber thus pushing the bullet forward .006 until the shoulder made contact with the chamber then the bullet would release so in theory when firing the round it would grow .006 before the bullet was released from the case

 

[338 dude]

Take a spent case that has been fired in your rifle seat a bullet long color it with a black sharpie now load it into your rifle close the bolt open the bolt remove the round look for Marks where your bullet contacted the rifling seat the bullet .001 deeper re-coat the bullet with your black sharpie and repeat the process until you see no marks from the rifling then add .001of an inch and that will be your distance to touch

 

[josebd]

In theory only because I can’t say what happens first but I assume the case would expand first when fired filling the chamber thus pushing the bullet forward .006 until the shoulder made contact with the chamber then the bullet would release so in theory when firing the round it would grow .006 before the bullet was released from the case

So I should go ahead and measure c.o.a.l then substract .006?

 

[338 dude]

So I should go ahead and measure c.o.a.l then substract .006?

Yes if you’re using the brass that you already know is .006 shorter than your fire brass. I’m not saying this will be your most accurate load or anything like that but it is stopping you from possibly jamming the bullet .006 into the rifling and raising pressures

 

[Gargoyle]

@josebd

My favorite method is to remove the bolt from the gun, seat a bullet a bit long in the once fired and sized case, and with a finger, press the round into the chamber. Seat .002" until the round falls free when you point the barrel upwards. Use a cleaning rod from the muzzle end to pop the round free when the bullet sticks in the rifling. Essentially you are finding the point where the bullet is just off the rifling when it falls free. Prior to that the bullet is being retained by the rifling.

You are also better off measuring CBTO instead of COAL for this. The Hornady bullet comparator is handy for this.

 

[338 dude]

With that being said I have a rifle that shoots best jammed .010

 

[338 dude]

With that being said I have a rifle that shoots best jammed .010

Vld bullets

 

[josebd]

Yes if you’re using the brass that you already know is .006 shorter than your fire brass. I’m not saying this will be your most accurate load or anything like that but it is stopping you from possibly jamming the bullet .006 into the rifling and raising pressures

It’s the modified case from hornady I measured with that’s .006 shorter on headspace

 

[SVT_Tactical]

If you have once fired brass in that gun then the tap and drill bits to make your own modified case are on amazon with prime shipping.

 

[Gargoyle]

In theory only because I can’t say what happens first but I assume the case would expand first when fired filling the chamber thus pushing the bullet forward .006 until the shoulder made contact with the chamber then the bullet would release so in theory when firing the round it would grow .006 before the bullet was released from the case

Exactly

 

[338 dude]

It’s the modified case from hornady I measured with that’s .006 shorter on headspace

I got that twisted then If it’s retained on the bolt face it wouldn’t change your overall length then it’ll only change the length of bolt face to your shoulder(chamber)?

 

[dellet]

The distance from the contact point of the shoulder in the chamber and the bullet to the lands will be the same for both cases. This is actually what you are measuring.

The modified case, if measured correctly will be .006” shorter in the body, and .006” longer in the neck. If they were the same length to begin with.

You should be fine by simply increasing the COAL by .006”. But check it by inserting an assembled dummy round into the chamber and make sure it does not jam.

The problem is when the modified case is longer from base to shoulder than the loaded round. Then if the COAL is the same, you headspace off the bullet in stead of the shoulder.

 

[josebd]

I’ll just make one from a fired case and get the measurement then and compare it to the original modified case from Hornady and see what the difference is

 

[K22]

The simplest way I found to measure COL (cartridge overall length) is to use the Frankfort Arsenal tool, or in my case, a homemade version of it.

If you want to make your own all you need is a cleaning rod, two nylon spacers w/ nylon screws and a standard caliper. If you want instructions on how to make and use this tool, PM me.

This method does not require the use of a case. This method measures the distance from the bolt face to the bullet ogive in the lands for the bullet you intend to use which may and often does vary when you change bullets.

I usually take at least three bullet measurements per lot of bullets since the ogives vary somewhat, even in quality bullets like Nosler and Sierra. I average the readings to obtain the "working" maximum COL.

I then start load development by backing off at least .010" to allow for ogive variations and to avoid pushing the bullet into the lands. I many need to back off further to insert at least one bullet diameter into the neck to provide for adequate bullet tension.

 

[Dave M.]

Take a spent case that has been fired in your rifle seat a bullet long color it with a black sharpie now load it into your rifle close the bolt open the bolt remove the round look for Marks where your bullet contacted the rifling seat the bullet .001 deeper re-coat the bullet with your black sharpie and repeat the process until you see no marks from the rifling then add .001of an inch and that will be your distance to touch

NO POWDER, NO PRIMER AND FIRING PIN REMOVED.

 

[Gargoyle]

NO POWDER, NO PRIMER AND FIRING PIN REMOVED.

"TAKE A SPENT CASE" - 338 dude