OAL length guage errors

[jaybray]

I thought I would post this though embarrassing, as maybe it would help other reloader's like myself with far less experience than most people that frequent this awesome site. I came across a post entitled 6 dasher .020 jump on this site and read a reply from the forumboss on page two regarding the proper way to use the hornady oal guage to find the lands. I have been doing it wrong. When I use it to find the lands I very gently pushed the rod forward until the bullet made the slightest contact with the rifling, like JUST touching and called it good and made my measurement. In the Forumboss's reply he states to do what I did and then lightly tap the rod 2 or 3 times which I did not. Well what I came up with as the lands doing it my way was not the lands and I did what he explained and with both my 6br's what I thought was touching in both rifles was 25 thou off the lands!! I hate to say it but in 3 years I have never fired a round even touching the lands let alone in them : What I thought was 10 ITL was actually 20 thou off!! CRIPES!! I think this explains why I could never get the 105 bergers to shoot. Always a jump. I just got lucky with the 107 match king which shoots good at what I thought was 10 ITL but was a 20 thou jump. Anyways maybe this will help other noobs when finding the lands. Im pretty sure how he explains it is the proper way with the hornady tool.

 

[Dusty Stevens]

Using a ready case with the bullet seated long closing the bolt yields the correct results everytime.

 

[deadwooddick]

Using a ready case with the bullet seated long closing the bolt yields the correct results everytime.

Unless the bullet sticks (even slightly).

 

[Webster]

Sounds like you were just touching the rifling and a couple taps pushed it forward into the lands another 0.020" Because of the bullet ogove it's easy to push the bullet in a little farther than just touch. No problem just different interpretations of touch and jam. I use the light neck tension method a lot. I record what the COAL was when the bullet stuck in the bore when I extract the case. I use this number as a length I don't want to exceed so I don't dump powder in the action (varmint hunting rifle). I make the COAl 0.005" shorter than this length so I don't end up with a rifle I cannot shoot in the field.

 

[Erik Cortina]

Using a ready case with the bullet seated long closing the bolt yields the correct results everytime.

Unless the bullet sticks (even slightly).

Use die wax on bullet ogive and lift bolt handle fast, then extract round. Bullet will not stick using above procedure.

 

[Webster]

I want to know when it sticks in the bore when I determine COAL.

 

[Joe R]

jaybraysaid: I thought I would post this though embarrassing, as maybe it would help other reloader's like myself with far less experience than most people that frequent this awesome site. I came across a post entitled 6 dasher .020 jump on this site and read a reply from the forumboss on page two regarding the proper way to use the hornady oal guage to find the lands. I have been doing it wrong. When I use it to find the lands I very gently pushed the rod forward until the bullet made the slightest contact with the rifling, like JUST touching and called it good and made my measurement.

That's the way I've been doing it. I've been sitting here dumb and happy letting real accuracy slip through my fingers.

Forumboss's reply he states to do what I did and then lightly tap the rod 2 or 3 times

This is a great help. It is much appreciated. You shouldn't be embarrassed, on the contrary it actually shows great courage, integrity and kindness to admit a mistake and then put it out there so that others (me and...) may benefit from your experience. People like you and Forumboss are what makes this such an exceptional forum.

Kindest regards,

Joe

 

[jaybray]

Well one of my 6brs just never would shoot consistent no matter what bullet or powder type ,charge or seating depth i used. My old touching the lands measurement with the 107 matchkings in this rifle was 1.673 which i got consistantly. With the new measurement tapping lightly three times is 1.700 touching the lands consistently also. So the new measurement 10 ITL is 1.710. I loaded up 20 rounds at 1.710 with 30.6 grains of varget and with the old measurement of 1.683 10 ITL i was looking at around 1 inch or larger 5 shot groups at 200 yards. Now it is much better. The largest 5 shot group was 3/4 inch and 2 different groups measured .390 and .400 and the last 2 were half inch or a little better. What ever way you look at it, this new measurement improved the accuracy of this rifle in a big way. My other rifle I used the very soft touch when finding the lands and it shoots very well for me. From now on this will be the way i will find the lands on my rifles.

 

[rjnallie]

Using a ready case with the bullet seated long closing the bolt yields the correct results everytime.

Unless the bullet sticks (even slightly).

Use die wax on bullet ogive and lift bolt handle fast, then extract round. Bullet will not stick using above procedure.

Eric, Using your method, does it leave a rifling mark on the bullet? If it does, how long?

 

[Erik Cortina]

Using a ready case with the bullet seated long closing the bolt yields the correct results everytime.

Unless the bullet sticks (even slightly).

Use die wax on bullet ogive and lift bolt handle fast, then extract round. Bullet will not stick using above procedure.

Erik, Using your method, does it leave a rifling mark on the bullet? If it does, how long?

Yes. I don't know how long, I have never measured them.

 

['Freak]

If you’ll saying zero is where the projectile ends up after being shoved deeper into the neck on closing the bolt so already beyond the point of initial contact, where or what is zero when talking a -.015” jump to the lands?

 

[Dusty Stevens]

when you pull it out then seat it deeper until its .015 shorter

 

[SFGUY]

this one item in reloading gets more people in trouble - or thinking their rifles are not performing well. First consideration is your load and the pressure you currently have. if you touch or push into the lands your pressure will increase tremendously. start low and work your way up. Just because you saw that load on the internet or your best friend uses it, does not mean it is right for you. I use a coated cleaning rod (with a male end) to lightly tap out the projectile. in my kit for each caliber i have an example of each bullet i might load in that caliber. i use a fine tipped marker to write on them for ID. I keep them in old style 35mm film cans. I mark the lids as to make and weight.
You can use a felt marker to color in the bullet on the ogive and then look for score marks when it is extracted. Recolor as needed.

since not all projectiles are the same and different manufacturers of the same caliber and weight do not touch the same, you will have to gauge the length for every bullet you use. Do that in every rifle, for every different bullet.
Start a ledger page on your rifles by serial number and add your notes each time.

Also, just because Johnny Gunsmith chambered all of your guns with the same reamer does not mean they are all "equal" at the end of the leade and beginning of the lands.

Shoot safe brothers.

 

[snakepit]

I use a method that I learned from a prior thread and sorry but I do not remember who posted it. I take a fired case and coat the inside of the neck with JB Weld. I insert long the bullet I want measured being careful not to pull it out at any time and pull some JB Weld out of the neck. I chamber the round and slowly close the bolt and let it set for about 8 hours. The original poster of this method said he used 24 hours but for me I have found 8 hours to suffice. I get about the same readings as using a split neck case and bullet but never have to worry about or wonder if the lands have pulled on the bullet at all. The first time I used this method I did it on three separate rounds of the same lot number bullet as a test and all three had exactly the same readings. Although there is that wait to get your reading you only have to do it one time and not repeat the process several times as I end up doing with other methods.

 

[tenring]

The first indicator of "touching the lands" (I call it kissing) is to find the marks on a seated bullet to verify kissing. The Stony Point (now Hornady) plastic guage is just a rough beginning for the process. I use it three times and write down those measurements, divide them for average then add .010". Then smooth up the bullet surface with 0000 steel wool, and seat the same bullet in an empty sized case using a firm grip bushing. Insert the dummy cartridge and carefully remove (preferably with FP out). Using a 6x loupe, you should be able to see some square marks where the ogive touched the lands. Do this again with bullet seated .005" lower and repeat until marks disappear. Pull bullet up slightly and raise the seater die .001" at a time, until you can barely see a land mark. Immediately write it down for future reference. Some factory barrels are extremely difficult to see the kissing marks.

 

[jaybray]

Lots of excelent info for someone wanting to find the lands and many different ways to skin a cat thats for sure. One thing regarding pressure when seating a bullet into the lands as SFGUY has found. I have found the complete opposite and had blown primers and very hard bolt lift with only 29.5 varget jumped .020 off. Once i was in the lands,this was all from my original measurement ill add, the pressure signs went away and i was able to work up to 30.8 grains till had hard bolt lift again and now use 30.6 grains as my final load. Every rifles different no doubt.

 

[DennisH]

When I use it to find the lands I very gently pushed the rod forward until the bullet made the slightest contact with the rifling, like JUST touching and called it good and made my measurement. In the Forumboss's reply he states to do what I did and then lightly tap the rod 2 or 3 times which I did not.

Tapping the rod 2 or 3 times: Are you tapping with your finger or ?

I personally tap the rod 3 times with my finger and usually end up with a 5 bullet measurement within .002 . I will normally see land marks on the bullet as well. To be sure, I usually load 2 dummy rounds .010 to .020 longer to verify the lands are marking the bullet.

Just curious, Dennis

 

[jaybray]

Yes i just use my finger. I took 6 measurements and was also within .002 one way or the other. I did not however look for land marks on the bullet. Probably should have.

 

[Erik Cortina]

Yes i just use my finger. I took 6 measurements and was also within .002 one way or the other. I did not however look for land marks on the bullet. Probably should have.

Try this: Push rod in as hard as you can and then lock it. Bullet will get stuck, so drop a smaller caliber bullet down the bore to dislodge it. Let us know how consistent your measurements are using this method.

 

[jaybray]

Ill try this later tonight. So would this be the true measurement to the lands? And will i have to adjust powder charge again?