Determination of "To the Lands"

G

GameBuster

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Just wonderin how y'all calculate the overall length of a particular load to the lands.

I used to repeatedly and incrementally seat the bullet deeper into a dummy round while trying to chamber it after every increment. The point at which it chambers and the bolt closes normally is the length to the lands. I found this to be accurate in certain rifles but not in others...also takes some time particularly if trying to be accurate....

Now I put an empty resized case into the chamber and measure the distance from a constant point at the back of the receiver to the case head. Then I seat a bullet into that same case purposely leaving it long then measure from the same pt on the receiver as before to the case head. The difference between those measurements subtracted from the length of the long dummy is the to the lands measurment. Seems to work pretty good but I'm wonderin if there's a better way.

How do y'all do 'er?
 
Here's what was recommended to me by some of the other guys on the forum:


• Make sure the rifle is unloaded.
• #### the bolt and close it, so that the firing pin is retracted.
• Insert the cleaning rod from the muzzle end, until it stops against the bolt face. (I use a wooden dowel)
• Holding it tight against the bolt face, make a mark with a sharp felt-tipped pen on the rod.
• Remove the rod and set aside.
• Open the bolt and remove from the rifle.
• Take an unloaded bullet (not a cartridge, bullet only) and drop it into the chamber, so that it stops against the lands of the barrel.
• Use a pencil or other short object (wooden dowel, screwdriver) and press the bullet tight against the lands and hold it there with one hand.
• With the other hand (or get help if needed) insert the cleaning rod from the muzzle end until it stops against the bullet, without pushing the bullet away from the lands.
• Make a mark on the rod with your felt-tipped pen.
• Accurately measure the distance between the 2 marks on the rod.
• This distance is your maximum loaded cartridge length for the bullet used, in your rifle’s chamber.
• Subtract 1 millimeter (~1/16 inch) from this length for the optimum cartridge length.
• If you switch to a different bullet, repeat this process for the new bullet.
• For some older rifles with long leads (ledes?), this determined maximum cartridge length may be too long to fit the magazine box and the max. length will have to be adjusted accordingly.

This works quite well and is the only method I've been using since.
 
I use Stoney Point Chamber All tool, however they don't have modified cases for all calibers like my 7.5x55 Swiss, so what I do is cut the neck down with very fine metal saw (I have one with thin blade). I try to cut 3/4 of the neck length. Then I insert the bullet and push the bullet/case inside the action.
Bolt will close the action and I will remove the bullet/case and take a measurement.
I will repeat this 3x for accuracy.
 
I use the Nosler method this has to be done everytime you change to a different type of bullet as ogives are different)

1 Make sure the rifle is unloaded.

2 Take a once fired case from the chamber of the rifle in question.

3 Make a slight dent in mouth of case so it will grip the bullet.

4 Insert the bullet into the case about 1/8 of an inch.

5 Color the rest of the bullet with a black felt marker.

6 Insert dummy case into rifle chamber and close bolt/action.

7 Gently extract the dummy round.

8 If bullet is still in case then examine where the marker dye is scraped to and simply push bullet back to where scrapes end...then take measurement of OAL. Do this several times to get a GOOD accurate average. This will give you a very accurate measurement of OAL to where the ogive is engaging the lands.

9 If the bullet gets stuck in the lands then use cleaning rod to gently tap out and go back to step number 8.

10 Once you have consistent accurate average you can deduct .015 - .030 off of that measurement to move the bullet safely away from lands.

11 It is sometimes neccesary to deduct a little more off the OAL in order for cartridges to properely function in the magazine.

It is surprising what you find when it comes to chambers of different rifles, FREEBORE and loading manuals max OAL measurements.

Your accuracy will GREATLY benefit when you incorporate this practice into your reloading regime.
 
I use an home made tool. It's an unprimed, full lenght resized case of your caliber. After I cut some groove (3-4) around the neck. insert a bullet in it chamber it and it slides in the case when it's again the lands.

Pretty muck the same method as stoney point gauge but for only 0.25$.

heres a picture
Lenghtgauge.jpg


I found out that remington cases will work better with less groove.

Cheers
Gaetoune
 
Here's the method I use. It was posted on this board sometime in the distant past.

MAXIMUM OAL

You can find the MAXIMUM practical overall length for your rifle like this:

-First, have a resized and trimmed to spec case and a flat-based bullet, preferably a heavy, long one.

-Insert that bullet point first inside the case, just enough that it sits tight. Lubing it with some oil on the "tip" can help.

-Now, chamber that "dummy" then extract it slowly. Hopefully, the bullet will still be inside the case and not stuck into the barrel.

-Measure the overall length of that cartridge. This is the length at which any bullet of that caliber will encounter the rifling in that rifle. Set your caliper .005" below that and put it aside.

-Now, take the bullet you intend to load and put it point first into your rifle's muzzle. Push it and turn it so the crown scribes a ring around the ogive where it meets the rifling.

-Screw your seating die on the press till it touches the ram at the top of its stroke, then back it up two full turns. Hand tighten the locking ring. Back the seating stem way up.

-Put the marked bullet in a resized and trimmed case and seat it just a bit at a time, screwing in the seating stem a bit more each time and comparing with your open caliper until the reference mark on the bullet reaches the caliper jaw when the other one is against the case's head. Stop.

You just determined the useful MAXIMUM practical OAL for that bullet ogive shape with .005" play from the rifling (you can always decide if you'd prefer a larger play).

That Max OAL will be different for another bullet of a different ogive shape.

Mark that dummy with a felt pen and set it aside with all data, in a box, for future reference when you'll need to load the same bullet weight and brand.

I usually put a good Lee Factory crimp on the dummy to insure it doesn't budge. Once crimped, I always try it in the rifle's magazine and action just to make sure I didn't goof somewhere. It happens, sometimes...
Click to expand...
 
I use a neck sized case that was fired in that rifle. I cut down the middle of neck to the junction of the shoulder on both sides. This reduces the neck tension to allow the bullet to slide more freely when it encounters the rifling.

Insert the bullet in the case (leaving it out far enough to be sure it will hit the lands) and chamber it, gently closing the bolt. Carefully open the bolt and remove dummy cartridge. Measure this cartridge length and you have the distance to the lands for this bullet. I do this process several times till I'm satisfied that I'm getting consistant readings.

Keep the modified casing so you can use it for the next type of bullet you plan to load for this rifle.
 
Get the Stoney Point gauge, especially if you want to do this operation for multiple cartridges/rifles/bullets. There are just four steps:

1) Insert bullet into brass
2) Insert assembly into chamber
3) Push bullet forward until it contacts lands
4) Measure

No fuss, no muss!
 
I use the Stoney Point OAL gauge,Now called the "Hornady"OAL gauge.
As far as modified cases go,If you know someone with a lathe,a letter "K" drill bit and a 5/16-36 tap you can make just about any modified case you want.
I have only bought one when I first got started and have made dozens
 
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