seating on the lands and how to determine the correct length?

[Pwhite11798]

While I have been reloading for over a year for f-class shooting i recently read a new method of measuring bullet length to lands in a chamber. I have a split neck case i put a bullet into the chamber and close the bolt on then I carefully remove the case and measure the length head to ogive. the new method i tried today said to create a slightly longer bullet mark it with permanent marker then chamber the dumbie round, remove from chamber and measure the rifleing marks. Now here is were my confusion begins. When i did this new method it showed rifling marks, shaped like triangles, were .053" long with a .010" ring around the ogive of the bullet. Now if i measure the rifling marks the two methods do not measure the same length. But if i measure the ring imprint they are. So which method is better and more correct.

 

[Erik Cortina]

I doubt you can measure the "marks" precisely enough.

Load a dummy round about .020" long, apply some die wax on bullet, chamber round and close bolt. Snap bolt open and extract round. Do a couple more for insurance and you are done.

 

[Pwhite11798]

after writing this post i found a previous post of yours i believe doing the same method that i was currently using. And as for the new method i tried today i was questioning the acuracy of it anyway. Thanks Erik for the reply.

 

[SWThomas]

I doubt you can measure the "marks" precisely enough.

Load a dummy round about .020" long, apply some die wax on bullet, chamber round and close bolt. Snap bolt open and extract round. Do a couple more for insurance and you are done.

First question: how are you gonna know the round is .020" long if you don't know where the lands are yet?

Second question: if you jam into the lands like that, wouldn't you run the risk of the bullet sticking and being pulled back out slightly upon extraction?

Not being a smart ***. Those are just the first things that came to mind when I read your reply.

 

[Alex Wheeler]

I like to polish a bullet and look for rifling marks under magnification while seating it deeper until the marks disapear. Its the only way that you can share numbers with others. If you look for the marks to disapear, then your touch will be the same as the next guys touch. All other methods vary with technique.

 

[stool]

like your bullet dia at the lands and the dia of your bbl....

I like to polish a bullet and look for rifling marks under magnification while seating it deeper until the marks disapear. Its the only way that you can share numbers with others. If you look for the marks to disapear, then your touch will be the same as the next guys touch. All other methods vary with technique.

 

[Pwhite11798]

Fast that is an idea i never thought of. But like erik said put sizing wax on the bullet tip and repeating the steps till the rifling marks disapear, in therory would give the same results.

 

[Erik Cortina]

I doubt you can measure the "marks" precisely enough.

Load a dummy round about .020" long, apply some die wax on bullet, chamber round and close bolt. Snap bolt open and extract round. Do a couple more for insurance and you are done.

First question: how are you gonna know the round is .020" long if you don't know where the lands are yet?

Second question: if you jam into the lands like that, wouldn't you run the risk of the bullet sticking and being pulled back out slightly upon extraction?

Not being a smart ***. Those are just the first things that came to mind when I read your reply.

You keep seating bullet longer until it gets shorter after closing the bolt.
Bullet will not get stuck, that's what the die wax is for.

 

[rocketron]

I like to polish a bullet and look for rifling marks under magnification while seating it deeper until the marks disapear. Its the only way that you can share numbers with others. If you look for the marks to disapear, then your touch will be the same as the next guys touch. All other methods vary with technique.

+1

 

[dkhunt14]

I like to polish a bullet and look for rifling marks under magnification while seating it deeper until the marks disapear. Its the only way that you can share numbers with others. If you look for the marks to disapear, then your touch will be the same as the next guys touch. All other methods vary with technique.

+1 The only time I get the ring is when the bullet is at max Jam. It seems to be prevalent on A Broughton 5C. I don't know if its the canted lands but the ring seems to disappear after a bunch of rounds. The Kriegers I had never seemed to let the ring. Matt

 

[L.Sherm]

If you have a little short piece of barrel that is your caliber and reamer have a smith run it into the piece of barrel and push a loaded round into it with your hand and you can feel the ogive start dragging when you start touching the lands.

 

[Alex Wheeler]

like your bullet dia at the lands and the dia of your bbl....

I like to polish a bullet and look for rifling marks under magnification while seating it deeper until the marks disapear. Its the only way that you can share numbers with others. If you look for the marks to disapear, then your touch will be the same as the next guys touch. All other methods vary with technique.

Your wrong again buddy, I think you should just give up, may be take up golf? ;D Your barrel diameter and bullet diameter don't mean squat. If one guy uses his bullets in his barrel and the next guy uses his bullets in his barrel, both of their touch numbers will be different but they will still be at actual touch. Now if one guy says I'm off the rifling .010 the other guy can put his bullet exactly .010 off as well. No other method will work that way.

OP
Erik, is telling you how to how to find jam, I'm telling you how to find touch.

 

[VaniB]

While I have been reloading for over a year for f-class shooting i recently read a new method of measuring bullet length to lands in a chamber. I have a split neck case i put a bullet into the chamber and close the bolt on then I carefully remove the case and measure the length head to ogive. the new method i tried today said to create a slightly longer bullet mark it with permanent marker then chamber the dumbie round, remove from chamber and measure the rifleing marks. Now here is were my confusion begins. When i did this new method it showed rifling marks, shaped like triangles, were .053" long with a .010" ring around the ogive of the bullet. Now if i measure the rifling marks the two methods do not measure the same length. But if i measure the ring imprint they are. So which method is better and more correct.

There are soooo MANY ways in this hobby to spend a lot more time fussing and fooling with something then you need to be doing; Being anal myself, I did the same split case/ homemade dip-stick process as you are describing. My preferred final method with this tool was to twirl the bullet over a burning candel and let the deep carbon color fully blacken the bullet. I had initially also tested methods that others had suggested, first using 0000 steel wool to polish the bullet, or using magic markers to blacken the bullet. But candel flame carbon is the most sensative way to be able to trace bullet contact in the bore. Using a magnifying glass, you will be able to witness the tiniest trace scratch marks using this method, before getting to the point of clearly defined "triangles" (as you put it) and finally that distinctive circular ring mark. This has helped me to find the exact OAL cartridge length which my rifle prefers (.009 to .011 off the lands), and obtain 1/4MOA" 5 shot groups. OK?

Now that you know how to do it the hard way...... throw out your homemade dip-stick. Buy you a Hornady OAL gage and spend more time firing your rifle at the range instead of conducting meticulous CSI investigations over candelabre. Once you have used the Hornady tool to come up with the measurement of where contact is made in your chamber bore, simply use that number and subsequent shorter OAL lengths to determine what your rifle prefers for best accuracy.

 

[GSPV]

The incremental,seating and polishing method seems to work OK for Tony Boyer.

 

[normmatzen]

I use a comparator on my caliper and a slotted neck case and chamber the "cartridge" and measure length from base to ogive with the comparator, a bunch of times and find average after throwing out obvious fliers.

I don't care that this method may not give the "right" numbers, I just care that it is VERY repeatable. Repeatable loads make me very happy! I load to a specific length, usually 0.010 "into the lands" and I don't care if it is actually 0.005 or 0.020 as long as every round is within 0.0015" I use a lab balance accurate to 0.013 gr that is calibrated with a fairly in-expensive mass. I don't care if my powder charge is .1gr off as long as they are all within 0.013gr. I measure seating force when I seat bullets. I don't care what the absolute accuracy on seating force is, but I want to group rounds to better than +/- 2.5 lbs so a complete "for record" string are close to the same.

 

[Joe R]

Now that you know how to do it the hard way...... throw out your homemade dip-stick. Buy you a Hornady OAL gage and spend more time firing your rifle at the range instead of conducting meticulous CSI investigations over candelabre. Once you have used the Hornady tool to come up with the measurement of where contact is made in your chamber bore, simply use that number and subsequent shorter OAL lengths to determine what your rifle prefers for best accuracy.

+1 Here's the link http://www.midwayusa.com/product/570611/hornady-lock-n-load-overall-length-gage-bolt-action?cm_vc=ProductFinding

 

[Footsore]

Doesn't anyone else use the Sinclair tool. I used all the other ways but the sinclair is the Ducks Guts.

http://www.sinclairintl.com/reloading-equipment/measuring-tools/bullet-seating-depth-tools/sinclair-bullet-seating-depth-tool-prod35491.aspx

 

[stool]

its all about a repeatable number for your ammo on your gear in your gun ..as was pointed out.

the stoney point tools are the simplest and easiest to use ..in my opinion...tho i do make my own cases.

 

[Joe R]

stool said: the stoney point tools are the simplest and easiest to use ..in my opinion...

The Hornady OAL gauge is the Stoney Point OAL gauge. Hornady bought Stoney Point.

 

[gotcha]

Somethings missing from the answers........ His bullets are showing major signs of imprint. Meaning he doesn't have a slip fit on his "split neck" case. A properly prepped split neck case shouldn't show any imprint on the bullet at all. The bullet should be pushed into the case by the lands at the 1st bit of resistance. O.K. maybe a VERY small mark on bullet but nothing like OP is experiencing. I think Mr. White needs tips on how to make a functioning split neck case. Oh yes, his throat may also have eroded significantly judging by the marks he describes.