Finding the lands with the bullet

H4831

H4831

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An old, but basic subject that has seen a lot of type on these threads.
When you're seating the bullets, bullets with different shapes, how can determine how to seat them so they hit, or slightly miss hitting, the lands?
There are several ways to do this, but all I want to do here is point out what is probably the simplest, yet accurate way of accomplishing this. And all you need is a wooden dowel that will slide down the bore and a pencil. Canadian Tire have the dowels.
Close the bolt of your rifle. Slide the dowel down the muzzle until it hits the bolt face. With a sharp pencil, or fine point pen, mark the dowel at where it sticks out of the barrel.
Take the bolt out and get a bullet you intend to load. Drop the bullet in the chamber and hold it tight against the rifling with the butt of a pencil.
Carefully reinsert the dowel until it touches the point of the bullet. Put another mark on the dowel.
The difference between the two marks on the dowel, will be the length of your loaded cartridge, with that bullet, that will just touch the rifling.
You can adjust from there, to suit the seating you want.
If you change bullets, remeasure the distance to the end of the bullet that is pushed into the chamber, with the new bullet.
Works with any calibre, any rifle or any bullet.
 
See this is far simpler than loosely fitting a long bullet into the neck and cranking it into the chamber like I tried before.
 
an empty case a bullet of choice and a sharpie. mark the bullet up try in the rifle look for rifling marks. if you can close the bolt or its hard seat the bullet deeper, re apply the marker and repeat.

when you found the oal that your looking for write it and the bullet on on the case, you have also just made a dummy round so you can quickly reset your seating dies if you load more than one different bullet for a peticular chambering.
 
Also recheck when changing bullet lots not just bullet types or brands. Have found .025 difference in lots after a fevered discussion about how the seating die touches the ogive at the same place. :)

I use a cleaning rod that I have and use it the exact same way as the wooden dowel, hasn't let me down yet. I do seat 1st dummy slightly long (.005-.010) so I can fine tune with seater die to 4 (or 5 depending on rifling) very faint marks then subtract .001 from that as my "to the lands" measurment.

Rather than using a marker, I polish the bullet with 000 fine steel wool......land markings stand right out and no xylene sitting on my newly cut rifling.
 
Are most people seating so that the bullets are just touching the lands or seating a little deeper so that the bullets are just off the lands? Or is this another point of fine tuning to find that sweet spot? So far I've never had to worry about this step since I've been either limited by the mags or by what cycles well.
 
That is the best way I have tried thanks for the refresher H4831, if I can add one thing it would be to recheck the depth every couple hundred rounds or so if there is a possibility of throat erosion.

How far off the lands depends on what you are trying to do, for accuracy some will seat hard into the lands. Some Weatherby rifles will have a ton of freebore which gives the bullet a jump before it engages the rifling to help reduce peak pressures. For me a good place to start is .030 off the lands for hunting rifles.

Dan
 
CyaN1de said:
Also recheck when changing bullet lots not just bullet types or brands. Have found .025 difference in lots after a fevered discussion about how the seating die touches the ogive at the same place. :)

I use a cleaning rod that I have and use it the exact same way as the wooden dowel, hasn't let me down yet. I do seat 1st dummy slightly long (.005-.010) so I can fine tune with seater die to 4 (or 5 depending on rifling) very faint marks then subtract .001 from that as my "to the lands" measurment.

Rather than using a marker, I polish the bullet with 000 fine steel wool......land markings stand right out and no xylene sitting on my newly cut rifling.
Click to expand...

using a bullet comparator is a saffer way too.
 
I just took a "no good case(neck was split), used a hacksaw and made a slit in the neck down to the shoulder. Insert bullet and carefully put shell into gun, close the bolt and open carefully bringing cartridge back out. Take OAL.
As for the question about "making a difference" hmmm depends. I went from 2.350 oal to 2.449 oal (20 thousand off lands) and I found no difference in accuracy. Then again, I never changed the powder load. I found with the powder load I use, 2.350 oal which is 0.099 from lands.....the accuracy was pretty darn good.
P.S: Savage Axis 22-250, IMR4895 34.5gr, CCI primers, Hornady 55gr V-max bullets at 2.350 oal
 
pzkw108 said:
using a bullet comparator is a saffer way too.
Click to expand...

A comparator is only useful AFTER you have your measurement to the lands.

After dummy round is made, it is then measured with a comparator and the measurement and lot# of the bullet used are written on the dummy case.
 
H4831, I am using this all the time, well almost.
I have some brass rods and some sleeves that i have made from aluminum that I can set screw to the rod with thumb screws. My rods have some heat shrink tube to protect the bore.
It works very well and would recommend it to those that want a true measurement.

257Roberts
 
Excellent post H4831!


The only thing I'd add, is to watch for those guns that have a longer throat than the magazine will allow.
That is to say you load up your cartridges and find out they don't fit the mag.

Also in the case of tube magazine firearms, you could end up with a jammed rifle if the load is too long for the design of the cartridge lifter.
 
Excellent post H4831!
Click to expand...
Yep - best way IMO also. Years back I came up with this wrinkle on the same.

I usually use a 1/4" dowel (only won't do my .222 - I use a 1/8"). I bought an O ring that fits tightly on it. I close the bolt watching the dowel is down on the bolt face - not up on an extractor, ejector or firing pin (bolt cocked) - and slide O ring to muzzle. Then I only have to mark the dowel where the bullet tip indexes (see photo with pen mark at the muzzle). I sometimes mark that on masking tape wrapped on the dowel - easy then to remove previous pen marks.

A bit low tech but works good 4me.

IMG_0442.jpg
 
Crayon or candles , did it to figure the whole chamber configuration , then add and subtract to get closer and closer to lands . Resharp the candle if needed , totally safe- Biggs
 
I would argue that dowel or any method that measure COL from the tip of the bullet is not accurate as lots of bullet tips vary even from the same box.
Bullets with plastic tips or hollow points will vary the least.

I think that simplest method is to make dummy round by using resized case and starting bullet in seating die than inserting in chamber and closing bolt. Done.

Use this dummy to set seating die and bullet ogive will touch rifling.
I don't use marker as I can see rifling marks on unpolished bullets.

IMO measuring from ogive is more accurate.
 
My system is a bit different but works. I just finished it for a similar thread and thought I'd copy it here.

The tools necessary to determine the seating depth of any particular bullet are included with your rifle and seating die. To begin, make up a dummy round using a resized unprimed case and a flat based bullet. Place the bullet firmly nose down in the casing, then chamber it in your rifle. The flat base will contact the rifling and the ejected cartridge will provide a mirror image of the length from the bolt face to the rifling. Keep this cartridge for future reference.

Next we need to determine how deep to seat your bullet of choice. Take a bullet from the box and place it nose down in the muzzle of your rifle, then with firm steady pressure, turn the bullet in your fingers so that the rifling scribes a line on the bullet. This line indicates where the bearing surface of the shank meets the ogive. Now make up a second dummy cartridge in an unprimed resized case. This one with your bullet of choice seated base down is seated until the scribed line on the bullet matches the length of the flat base of your first dummy round. When these lengths match, your second dummy round has the bullet's bearing surface just touching the rifling ahead of your chamber. This dummy round too should be kept for reference. It can be used to quickly set your seating die when you again wish to shoot that particular bullet.

The final step is to fine tune the seating depth of your bullet, assuming you want a jam into the rifling or a jump to it. The threads of your seating stem provide a precise measurement into or away from the lands. For example, if you use RCBS dies, the seating stem uses 28 turns per inch thread, so a quarter turn gives you .009" of travel, a half turn .018", three quarters .024", and a full turn is .036".
 
Andrzej said:
I would argue that dowel or any method that measure COL from the tip of the bullet is not accurate as lots of bullet tips vary even from the same box.
Bullets with plastic tips or hollow points will vary the least.

I think that simplest method is to make dummy round by using resized case and starting bullet in seating die than inserting in chamber and closing bolt. Done.

Use this dummy to set seating die and bullet ogive will touch rifling.
I don't use marker as I can see rifling marks on unpolished bullets.

IMO measuring from ogive is more accurate.
Click to expand...

This is what I was lead to believe is the most accurate method for seating bullets. Measuring from the ogive eliminates the inconsistent bullet tip variable. YMMV.
 
Thanks for posting H4831,
it seems that everybody has their own variation as how they find bullet seating depth. The method I use as stated above works for me and If I use the dimensions that I acquire and seat the bullet in a prepared case by as much as .002" longer with the bullet that I used to take the measurement, I cannot chamber the round without moving the bullet. Once I find the true length to the lands I then take the OAL from the Ogive and set my depths from there. If I then measure the length from the bullet nose I have found that it only varies by as much as .005".
It's a lot of fooling around to find this out but that is what I have found and as I said it works for me.

There is some things that you have to watch out for,
Make sure the gun is calked or the firing pin is removed, and make sure that the dowel is resting on the bolt face on not on the extractor. Both will give you a false reading.
257 Roberts
 
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