How do you fellas find the lands without a modified case?

[waltk]

Correction. For what it's worth, it's a 5/16-36 thread.

 

[Lapua40X]

Making your own gauge is pretty easy. A length of brass rod matched up with a length of brass tubing soldered to the base of a drilled out case with a stop fashioned onto the tube and you've got a homemade OAL gauge like the one shown here. I made it in less than an hour.

If you want to get a better picture of where the lands contact the ogive, use a little Prussian Blue on the bullet before seating it in the chamber.

 

[snakepit]

So far we have seen a lot of great methods to find the lands. I try to just keep it simple and so far that seems to work pretty good. I do not have the time to make this and make that tool, I simply spent the approximately $32 and bought the Sinclair Bullet Seating Depth Tool. It is a simple and I think accurate tool to use. Before I purchased this tool I would just take a fired case and make a very slight crimp on the case so the bullet would with a little effort slide back and forth, insert it in my rifle, slowly close the bolt, open the bolt, take the shell out and measure the total length and the length to the lands. When I do both of these above methods I usually come out to within .001 to .003 of each other. I may not win a Kewpie Doll when I shoot but I will have fun and that is good enough for me.

 

[ar10ar15man]

ASK BOYD WHAT .003 change in seating depth can do...

 

[BoydAllen]

If you are .003 off from you best seating depth, with a really accurate rifle, you are seriously out of tune for a benchrest match. I was talking with a pretty sharp benchrest competitor recently and when he is close, and fine tuning seating depth, he makes moves of .0015 (corrected from a typo with one two many zeros after the decimal point). Having said that, you can start from somewhere that is reasonably close to where you wanted to, and as long as you have an accurate ogive length measurement for the loaded round (case head to seated bullet near the base of the ogive, with some sort of tool made for the purpose) you should be good to go for a seating depth investigation for that rifle. This is not for finding touch if that is the extent of your workup, but just to have a place to make your moves from in a series of test groups. The main thing is to have a seater setting that you can get back to for that bullet and barrel. Once you have a starting place, you can make as many moves as you need to to get to a place where the targe tells you that you are where you want to be, as far as accuracy is concerned. The only difference between close but different starting places is the number of test groups that it takes to get to the best setting, making small moves. One advantage of a method that gives good repeatable results is if you are chasing the lands, making adjustments to stay in the same place relative to the beginning of the rifling. In that situation, being able to quickly locate a standardized starting place is a real advantage. For my varmint rifles, that have less potential, and have less expected of them, this consists of using heavy thumb pressure on the Sinclair unit's rod, as I set the stop collars. I don't really care if I am a couple of thousandths into the lands, as long as the results repeat well enough for the situation that I am using them for. These days, I am thinking that to make it easier to stay up with throat wear, after I work up a load, for match accuracy, I should measure the throat location with my Stoney Point tool and case, and note how far from that my most accurate seating depth is. That way, I can check on throat wear, particularly if I can remember to set aside the same bullet for all of the measurements, and make any needed adjustments. One more thing that this can do is tell you that your throat has a carbon ring, if it seem to shorten rather than lengthen as the rifle is shot a number of times.

 

[bozo699]

Chris
I have the Hornady and I bought a tap and a drill and make my own.
I think it is a 5/16-56 tap. It's a special. I had to order it.

Ben

Ben,
It's a 5/16X36 tpi tap that you have.


Mike you need to take a heart pill, Boyd has forgot more about tuning a rifle then most of us really know! His methods are precise and the work!!! period the end!! I know they do for a fact as he taught me his methods and I have used many others and his way flat works! Measurements change as the throat wears so its a Moog point to even take a measurement really, although I do so I can get close but I still use his method to get to my optimum seating depth. If your method works for you great but don't Knock methods that work's for a world champion like Boyer.
Wayne.

 

[Raythemanroe]

CZ550 is what I was thinking if you don't have a sinclair or hornady tool

 

[kelbro]

Isn't this one of those areas where 'close' is good enough?

It's just a starting point, right?

You're going to tune + and - until your groups tighten up, aren't you?

 

[CaptainMal]

Was told Hornady will take a fired case and drill it out for you.

A local gunsmith does it for me all the time. He did have trouble but got the correct tap to cut the threads.

 

[waltk]

No offense Mr. Allen, but are you stating someone moving the seating depth .00015?
That's one and a half ten thousands of a inch!
Or just a typo?

 

[BoydAllen]

No offense taken. It was a typo. Thanks for the catch. I will fix it.

 

[snakepit]

ASK BOYD WHAT .003 change in seating depth can do...

I think you missed my point when I made the remark about .001 to .003 of each other. I was not referring to a range of .001 to .003 on the measurements taken using the Sinclair tool method or the case/bullet method. The .001 to .003 was the difference I have found using the two methods compared to each other. Each method by itself usually comes out to a difference of .000 +/- .001 after several measurements. Example, a recent check I did using the Sinclair tool came out with three measurements consisting of two which were exactly the same and the third .001 off. So be consistent and pick which method of the two or which ever method you want to use and make the bullet seating changes for your testing based on using that method.

I enjoy reading Boyd's comments and have learned a considerable amount from the information he has shared with us.

 

[fguffey]

Hey fellas,

I am wondering the best practice to go about finding my seating depth/jam/jump length in a 6AI. I have a modified case for 6mm but they do not make one for a 6mm AI. What method would you recommend to find the length to the lands with a particular bullet?

Thanks,
Chris

Modified cases can be purchases from Hornady, or the reloader/shooter can make modified cases by simply drilling the flash hole/primer pocket to a diameter that will accommodate a cleaning rod. After drilling the flash hole/primer pocket seat a bullet, the seating depth is of little concern as long as it is not too long, then remove the bolt and chamber the modified case with the bullet in the chamber, After chambering the modified case use a cleaning rod to push the bullet out until it stops at the lands, after the bullet contacts the lands the modified case become a transfer.

I use the transfer to transfer to the dimensions of the chamber to the seating die, all that is required of the reloader is a good understanding of the seating stem above the seater die is to be zero off the lands with a height gage or dial caliber. after zeroing the protruding stem, the height gage can be used to seat the bullet ‘off the lands’, remembering if the case was not fired in the chamber the difference in length between the chamber and case from the shoulder back to the head of the case and back to the bolt face should be added.

I have never been concerned with modified cases they did not make/sell, they do not sell modified cases for long chamber, they do not sell short modified cases, they only sell modified cases, I want my cases to match my chambers.

When I set up to drill cases for modified cases I drill the flash hole/primer pocket on at least 20 cases, and bullet hold, I am the fan of bullet hold, I want all the bullet hold I can get, others use a cut neck case to lesson bullet hold. On occasion when the bolt is closed on the shredded neck cases, the bullet stays in the lands, again, I want all the bullet hold I can get.

F. Guffey

 

[kartracer]

Chris
I have the Hornady and I bought a tap and a drill and make my own.
I think it is a 5/16-56 tap. It's a special. I had to order it.

Ben

Ben,
It's a 5/6X36 tpi tap that you have.


Mike you need to take a heart pill, Boyd has forgot more about tuning a rifle then most of us really know! His methods are precise and the work!!! period the end!! I know they do for a fact as he taught me his methods and I have used many others and his way flat works! Measurements change as the throat wears so its a Moog point to even take a measurement really, although I do so I can get close but I still use his method to get to my optimum seating depth. If your method works for you great but don't Knock methods that work's for a world champion like Boyer.
Wayne.

omg you guys need to stop already,way to much info

 

[300meter]

EASY, SIMPLE, nothing to buy, no drilling or tapping.

1. Make a dummy round by seating a bullet in one of your cases that you know will be too long and will touch the lands.
2. Remove the bolt from rifle and insert the dummy gently until it stops in the chamber. The bullet will be contacting the lands.
3. From the muzzle, carefully insert a cleaning rod into the barrel. With one finger, push lightly against the base of the dummy round, while with your other hand, using only your index finger and thumb, gently move the cleaning rod down the bore until it contacts the bullet.
4. Once the cleaning rod has made contact with the bullet, push a little more and you will feel the bullet disengage from the lands. You will be able to feel this contact between your two hands. Move them both in the same direction and learn to feel the bullet engagement against the lands.
5. Leave the cleaning rod in the barrel. Remove the dummy round from the chamber. Return to your reloading press and seat the bullet slightly deeper into the case, thus reducing the overall length. I reduce the length by .005 increments.
6. Return to the rifle and repeat steps 4 & 5 until the bullet no longer contacts the lands. Using .005 increments, you know the bullet is .001 to .005 off the lands.

Hope this helps. Practice a little and you'll will be amazed at the feel you develop for the contact of the bullet. If you don't believe what your feeling, mark the bullet with a felt tip marker. If there's contact you'll see it on the bullet.

 

[seanpmc69]

The method I learned 25+ years ago from my now 90 yr old Grandpa (who still shoots every day), is to "smoke" the bullet. Set the depth where the lands mark the smoke, but don't mark the bullet itself.

We have the modern equipment nowdays, but back then we did it with a carbide fueled iron sight blackener. A Zippo lighter running slightly "rich" will produce enough carbon/smoke to do it as well.

 

[Joe Maisto]

and how do you account for the fact that bullets in a given box can vary from .005 to .010 or more ??

i suppose for hunting accuracy...min of deer..its ok, but not when one is trying to make small holes in paper...

hi aj

The question the man asked should be answered by people who in fact shoot competition BR, and NO one else.
Another long time HOF shooter showed me his way. He ( and now I) blacken a bullet seated long in an unprimed case, bolt it home slowly, examine the marks on the bullet, and adjust from there. Boyd is in the ball park with his knowledege, as many of us are that actually shoot BR....mikeinco...

 

[Joe Maisto]

The method I learned 25+ years ago from my now 90 yr old Grandpa (who still shoots every day), is to "smoke" the bullet. Set the depth where the lands mark the smoke, but don't mark the bullet itself.

We have the modern equipment nowdays, but back then we did it with a carbide fueled iron sight blackener. A Zippo lighter running slightly "rich" will produce enough carbon/smoke to do it as well.

Right on my friend !
And...that is the way A long time HOF-er showed me. Stick matches work too. I have one of those "devices" whereby you need to drill a hole and tap it, supposedly for measuring. Ask anyone who has used one and they'll tell you that you never get the same reading twice. That's why mine is full of dust on a shelf.

Another thing..... unless you are using a fine bolt gun, that has been professionaly accurrized, or a custom firearm like we use in the BR group shooting which start at about $2600 (less scope , and MORE if an ejecter and special ejection PORT is cut into the action) OR....600-1000 yd shooting, there is not that much need to go through the motions of having your bullet perhaps .003 off the lands, except for self satisfaction. But it won't count for score.

 

[bozo699]

The method I learned 25+ years ago from my now 90 yr old Grandpa (who still shoots every day), is to "smoke" the bullet. Set the depth where the lands mark the smoke, but don't mark the bullet itself.

We have the modern equipment nowdays, but back then we did it with a carbide fueled iron sight blackener. A Zippo lighter running slightly "rich" will produce enough carbon/smoke to do it as well.

Right on my friend !
And...that is the way A long time HOF-er showed me. Stick matches work too. I have one of those "devices" whereby you need to drill a hole and tap it, supposedly for measuring. Ask anyone who has used one and they'll tell you that you never get the same reading twice. That's why mine is full of dust on a shelf.

Another thing..... unless you are using a fine bolt gun, that has been professionaly accurrized, or a custom firearm like we use in the BR group shooting which start at about $2600 (less scope , and MORE if an ejecter and special ejection PORT is cut into the action) OR....600-1000 yd shooting, there is not that much need to go through the motions of having your bullet perhaps .003 off the lands, except for self satisfaction. But it won't count for score.

Joe,
I was reading your post and agreeing with the most of it till I got to the last of it,...WOW!!!!! that is totally wrong! at 1000 yards is when that .003 is the most critical! having your seating depth finally tuned at 1000 yards is the difference between being average and winning my friend!
Wayne.

 

[Joe Maisto]

The method I learned 25+ years ago from my now 90 yr old Grandpa (who still shoots every day), is to "smoke" the bullet. Set the depth where the lands mark the smoke, but don't mark the bullet itself.

We have the modern equipment nowdays, but back then we did it with a carbide fueled iron sight blackener. A Zippo lighter running slightly "rich" will produce enough carbon/smoke to do it as well.

Right on my friend !
And...that is the way A long time HOF-er showed me. Stick matches work too. I have one of those "devices" whereby you need to drill a hole and tap it, supposedly for measuring. Ask anyone who has used one and they'll tell you that you never get the same reading twice. That's why mine is full of dust on a shelf.

Another thing..... unless you are using a fine bolt gun, that has been professionaly accurrized, or a custom firearm like we use in the BR group shooting which start at about $2600 (less scope , and MORE if an ejecter and special ejection PORT is cut into the action) OR....600-1000 yd shooting, there is not that much need to go through the motions of having your bullet perhaps .003 off the lands, except for self satisfaction. But it won't count for score.

Joe,
I was reading your post and agreeing with the most of it till I got to the last of it,...WOW!!!!! that is totally wrong! at 1000 yards is when that .003 is the most critical! having your seating depth finally tuned at 1000 yards is the difference between being average and winning my friend!
Wayne.

The method I learned 25+ years ago from my now 90 yr old Grandpa (who still shoots every day), is to "smoke" the bullet. Set the depth where the lands mark the smoke, but don't mark the bullet itself.

We have the modern equipment nowdays, but back then we did it with a carbide fueled iron sight blackener. A Zippo lighter running slightly "rich" will produce enough carbon/smoke to do it as well.

Right on my friend !
And...that is the way A long time HOF-er showed me. Stick matches work too. I have one of those "devices" whereby you need to drill a hole and tap it, supposedly for measuring. Ask anyone who has used one and they'll tell you that you never get the same reading twice. That's why mine is full of dust on a shelf.

Another thing..... unless you are using a fine bolt gun, that has been professionaly accurrized, or a custom firearm like we use in the BR group shooting which start at about $2600 (less scope , and MORE if an ejecter and special ejection PORT is cut into the action) OR....600-1000 yd shooting, there is not that much need to go through the motions of having your bullet perhaps .003 off the lands, except for self satisfaction. But it won't count for score.

Joe,
I was reading your post and agreeing with the most of it till I got to the last of it,...WOW!!!!! that is totally wrong! at 1000 yards is when that .003 is the most critical! having your seating depth finally tuned at 1000 yards is the difference between being average and winning my friend!
Wayne.

Wayne,

Sorry you MIS-READ my post. It was meant to say -that is where it will show up ! When I read it again, that is what I get out of it. Perhaps I shopuld have worded it differantly.
Aside from that, we seem to agree on things. Now all we have to do is watch the temp, humidity, and wind. Fortunately, I've been using an excellant lot # of 8208, whereby temp didn't matter too much. Almost out now and may have to resort to using some RE-11 I've had since the 60's, or some of my 2230.