Tonight I decided to load some Berger 155 VLDs PN 30408. I wanted to set them up so they were just touching the lands in my 308. I took the firing pin out of the bolt and made up a dummy round. I loaded the round and closed the bolt with minor effort which I fully expected. I opened the bolt and extracted the round (being pleased it wasn't stuck in the lands which I figured it would be) and looked for any marks on the bullet and saw none. At this time I measured the base to ogive length and recorder it. Just for kicks I reinserted the round and closed the bolt which required no effort. Upon extraction of the round and re-measurement I was shocked to see the bullet had moved back another 0.005" or so. WTH? So, I put it back in and closed the bolt one more time and it moved another couple of thousandths! I am really at a loss as to why this is happening. There are absolutely no marks on the bullet and after trying this scenario several times with the same result I gotta tell you I am at a loss as to what is going on. I have not experienced this problem with the SMK or A-Max bullets. Can someone shed some light on this? I am starting to hear music from the Twilight Zone here.......................
Finding the lands.........or not
- Thread starter magic mike
- Start date
magic mike said:
You might go back and try it again...that is: Chamber the same round again, and lift/lower the bolt handle about 10 times. This should provide some lan's "etching" about the circumfrence of the leading ojive of the bullet where it is obviously touching the lans. Next, you might measure the width of that etching to find out "how far you are into the lans", as the saying goes. You seem to have a moderately "soft seated bullet" that is being pushed back into the case neck as you force the bolt to close??
Dan
Hears an old and effective way to find the lands
cock the action and run a cleaning rod downto though the face of the bolt. {in cocked position}
1 Put a small pencil or pen mark at the muzzle on the cleaning rod.
Open the bolt and take out the bolt from the receiver
3 place your favorite bullet in the chamber to seat the bullet against the lands.
4 Put a short piece of cleaning rod or dowel into the chamber to hold the bullet against the lands.
5 put your cleaning rod down the muzzle , all the way in to touch the bullet. Hold the dowel or short rod and make sure you are pressing with light pressure against the bullet and cleaning rod.
Put a second mark at the muzzle again You will now have Two marks some distance apart.
Measure between the lines and you should be at very good Overall length.
This is a very old but proven way to set Overall Length
cock the action and run a cleaning rod downto though the face of the bolt. {in cocked position}
1 Put a small pencil or pen mark at the muzzle on the cleaning rod.
Open the bolt and take out the bolt from the receiver
3 place your favorite bullet in the chamber to seat the bullet against the lands.
4 Put a short piece of cleaning rod or dowel into the chamber to hold the bullet against the lands.
5 put your cleaning rod down the muzzle , all the way in to touch the bullet. Hold the dowel or short rod and make sure you are pressing with light pressure against the bullet and cleaning rod.
Put a second mark at the muzzle again You will now have Two marks some distance apart.
Measure between the lines and you should be at very good Overall length.
This is a very old but proven way to set Overall Length
How many rounds thru the barrel? The reason I ask is that I have shot barrels until the lands were eroded to the point that is was difficult to get anything clear and repeatable doing what you are doing. If you continue to shoot more and more rounds eventually the lead is gone completely and even so the gun may shoot surprisingly well.
Jet
Gold $$ Contributor
Mike
Ruff up the exterior of your test bullets with 0000 steel wool, seat in your dummy case with the neck tension you normally use and seat it out another .025-.030 then what you did last time.
Chamber it and close the bolt. When removing it, snap the bolt up quickly then extract it. Use a loop/magnifying glass to see the land marks and then measure your ogive depth.
Hope this helps.
Rich
Ruff up the exterior of your test bullets with 0000 steel wool, seat in your dummy case with the neck tension you normally use and seat it out another .025-.030 then what you did last time.
Chamber it and close the bolt. When removing it, snap the bolt up quickly then extract it. Use a loop/magnifying glass to see the land marks and then measure your ogive depth.
Hope this helps.
Rich
Thanks for the help everyone. Just FYI the barrel has 309 rounds down it. So this morning I started over with the dummy round by pulling the bullet and then reinserting it into the case by hand and then putting it back in the gun and closing the bolt. I did this five times, pulling the bullet each time after recording the measurement. To my great relief the measurements only varied a thousandths or so over all. I have no idea what was going on last night but today it's all good and I am satisfied that I have a valid measurement. Sometimes you just have to chalk stuff up to the "Unknown Force". 
Great! I would recommend that you repeat this process from time to time as you shoot more rounds. You will find that the lead/lands move, erode away, and it helps to keep up with it. Also, if you keep shooting the barrel eventually you will find that as this erosion progresses to the point that the marks on the bullet get less and less distinct. I once shot a 223 barrel over 6000 rounds and then when I replaced it I sectioned it so I could look at the front end of the chamber and it was amazing how much metal was gone and it still shot rather well.
Dusty Stevens
Shiner
If you dont have enough neck tension the lands will grab it upon extraction and make it vary. You say you seated it by hand that is your problem with consistency
I normally a Hornady tool to find where the bullet contacts the lands. In my experience, the Berger VLDs often produce vague results and I assume that's because of the shape. In general, I find that the better the BC, the less reproducible the results are.
In other words, short fat bullets give nice solid results producing the same measurements time after time, while long skinny ones give readings which are a little different over a series of measurements. I've tried alternative methods like smoking the bullets, measuring via a rod down the barrel, etc. but the results are similar.
In other words, short fat bullets give nice solid results producing the same measurements time after time, while long skinny ones give readings which are a little different over a series of measurements. I've tried alternative methods like smoking the bullets, measuring via a rod down the barrel, etc. but the results are similar.
Actually I got the best consistency when I started the bullet into the case by hand and then let the bolt do the seating work. At first I was seating the bullet long in the case with my Wilson seating die and then closing the bolt on it. It did move the bullet back into the case as expected but if I chambered it a second or third time it would continue to move the bullet further into the case. I have no idea how that can happen! I was using my digital calipers, perhaps the battery was low as I had been loading other rounds previous to doing this. I did use the same calipers this morning but doubled checked the measurements with my dial calipers and all was well. Might have to ditch the digital set. Most times in my life I find simpler is better. Thanks for the input.
47WillysGuy
Gold $$ Contributor
My method of finding the lands works like this:
1-Remove the bolt firing pin assembly.
2-Remove the bolt ejector.
3-Install the bolt into action to check free fall of bolt handle.
-There bolt handle should fall free with no binding with an empty chamber.
4-Seat a bullet long in a primer free case(dummy round DR).
5-Insert DR into chamber, install bolt.
6-Gently push bolt and DR towards lands. Stop when any resistance is met.
7-If bolt doesn't fall, seat bullet deeper and do step 5&6 again.
8-Continue seating bullet deeper until bolt free falls as in step 3 or closes with very little resistance.
9-Verify findings.
When the bolt free falls or close to a free fall and the length of the DR doesn't change and shear marks on the bullet ogive made by the lands are visible, you have found the start of the lands. From this dimension is where I seat into the lands (jam) or seat away from the lands (jump).
Tip: Use your very best case, one that has no neck runout. If the DR has bullet runout, the ogive will not be square to the lands. Everything must be parallel. Do it this every hundred rounds or so. You can watch your lands being burnt out.
I use the same DR for the life of the barrel to check land change. When I change bullet lots, I find the lands all over again.
1-Remove the bolt firing pin assembly.
2-Remove the bolt ejector.
3-Install the bolt into action to check free fall of bolt handle.
-There bolt handle should fall free with no binding with an empty chamber.
4-Seat a bullet long in a primer free case(dummy round DR).
5-Insert DR into chamber, install bolt.
6-Gently push bolt and DR towards lands. Stop when any resistance is met.
7-If bolt doesn't fall, seat bullet deeper and do step 5&6 again.
8-Continue seating bullet deeper until bolt free falls as in step 3 or closes with very little resistance.
9-Verify findings.
When the bolt free falls or close to a free fall and the length of the DR doesn't change and shear marks on the bullet ogive made by the lands are visible, you have found the start of the lands. From this dimension is where I seat into the lands (jam) or seat away from the lands (jump).
Tip: Use your very best case, one that has no neck runout. If the DR has bullet runout, the ogive will not be square to the lands. Everything must be parallel. Do it this every hundred rounds or so. You can watch your lands being burnt out.
I use the same DR for the life of the barrel to check land change. When I change bullet lots, I find the lands all over again.
The easiest and most economical method I ever used to measure the distance to the lands is with the Frankfort Arsenal tool. I believe the tool is priced at under $20 and is available at Midway.
Keep in mind that bullet ogives vary even within the same box / lot so make sure you allow for this variation when establishing seating depth.
Keep in mind that bullet ogives vary even within the same box / lot so make sure you allow for this variation when establishing seating depth.
The instructions and method I've described in my post will do a few thing besides just finding the land on one particular
If you change bullet shapes you will also have a new OAL Many brands of bullets are out there and have different ogives , also you will be checking erosion at the same time.
The method was written about in shooters bible years ago and still works
If you change bullet shapes you will also have a new OAL Many brands of bullets are out there and have different ogives , also you will be checking erosion at the same time.
The method was written about in shooters bible years ago and still works
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