Finding the lands question

[EricF517]

Well I decided to play around and am wondering if I have done this right or not. I know it would have been easier to buy the gauges to do this but don't have the money. So here is what I did.

So what I did was barely set a bullet (175smk) into a piece of brass.

I chambered the round into the rifle. It came out

This is what I am assuming are the land marks

 

[dmgreene]

Re: Finding the lands question

If you get the neck tension right it will work. Make sure that the bullet doesn't pull back out when extract the round. The bullet can get stuck in the lands and pull it out several thousandths. If you can repeatable measurements you should be good to go.

 

[Brain]

Re: Finding the lands question

OAL is not the best indicator as tip to ogive length will vary.

If it's all you have to work with right now then it'll have to do, but expect a variation among loaded rounds and account for it seating depth adjustments.

 

[EricF517]

Re: Finding the lands question

I was going to repeat that test a few to see if the numbers came out the same. Then I was going to drop down about 0.01 from the lowest number I got.

With the ogive # I am going to use the Hornady comparator to match them up when and if I run a different bullet.

 

[22skip]

Re: Finding the lands question

Years ago before I bought my Stoney Point OAL gauge and bullet comparator set (now Hornady) I would do as you did with the bullet and Sharpie but I would take some pliers and put a shallow, sharp dent in the lip of the neck (un-sized case)to give just slight tension on the bullet that will allow it to move easily and leave the bullet out long. Chamber the round and the dent in the neck will scrape the black off the bullet as contact with the lands pushes the bullet into the case - you can then reset the bullet back to where the scratch stops to be sure that's where it was when fully chambered and contacting the lands, they will stick quite often when you open the action and extract. As others mentioned, measuring from the ogive is much more consistent and you can load closer to the lands much more safely. The bullet comparators are what you need for this and there are several types available or you can easily make your own.

 

[jbell]

Re: Finding the lands question

The best way to find the jam is to buy a quality bullet comparitor and some 0000 steel wool. Load a round and seat the bullet long. Remove the firring pin assembly from your bolt and chamber the round. You remove the firring pin assembly to get better feel of the round chambering. Extract the round and look at the ogive and you will see the land marks (if its long the marks will look like long rectangles or long scratches). Record this measurement (you are not relying on the bullet to be seated back by the lands). Seat the bullet .005 in deaper and polish the marks off w/ the steel wool (do this radialy so the marks will show up better). Rechamber and inspect. You do this untill the bolt closes easier and the marks from the lands disaperar. If you followed this you now know have a .005 in window of the jam # now go back to the last measurement that you had contact and load 1 more round at this # polish and chamber. Then follow this procedure above but this time do it in .001 in increments. When the land marks disapear yoy now know the exact jam #. If you do this you will only load 2 rounds and I fully load them and shoot them later so not to waste components. Following this doesnot rely on using the same pressure on the bullet and case as does the stoney point and sinclair tools, this method is much more consistant I know b/c I own both tools and tried all 3 several times.

 

[Jburt]

Re: Finding the lands question

Hey Eric I have the gauges for this if you would like to make your life easier. I also work in Howell so we could arrange something if you didn't wanna go through all that trouble. Just pm me if you want to set something up.

Justin

 

[Suasponte]

Re: Finding the lands question

Take a case that is on its last legs and split the case neck with a dremel tool and diamond cutting wheel. Polish the case neck and remove all burrs from cutting the neck. You can then squezze the case neck with your fingers to get neck tension. Seat your bullet several times measuring each time and this will give you your distance to the lands with that bullets style.

Terry