TOOL TIP: Make Your Own Length-to-Lands Gauge
To achieve best accuracy with a rifle, you must control bullet seating depth very precisely, so all bullets end up in the same place relative to the entrance of the lands, every time. There may be multiple cartridge OALs which prove accurate. However, with each, you first need to determine a “zero” point — a reliable, and repeatable OAL where the bullet is “just touching” the lands.
There are tools, such as the Hornady (formerly Stoney Point) OAL Gauge, that will help you find a seating OAL just touching the lands. However, the tool requires that you use a special modified case for each cartridge you shoot. And, while we find that the Hornady OAL Gauge is repeatable, it does take some practice to get in right.
Make Your Own Length-to-Lands Gauge with a Dremel
Here’s an inexpensive alternative to the Hornady OAL tool — a slotted case. Forum member Andris Silins explains how to create a slotted case to measure length to the lands in your rifle:
“Here’s what I did to find length to lands for seating my bullets. I made four cuts into the neck of fire-formed brass. Then I pressed the bullet in lightly and chambered the entire gauge. As the cartridge chambers, the bullet slides back into the case to give you length to lands. It took less than five minutes to get it cut and working. A little light oil in the barrel just past the chamber helps ensure the bullet does not get stuck in the lands. It works great and is very accurate.
I made the cuts using a Dremel with a cut-off wheel. You can adjust tension two ways. First, you can make the cuts longer or shorter. Longer cuts = less tension. If you used only three cuts instead of four you would get more tension. The trick is to be gentle when you open and close the bolt. If you ram the bolt closed you may wedge the bullet into the lands. When you open the bolt it helps to keep a finger or two near by to guide the case out straight because the ejector wants to push it sideways.”
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Tags: OAL Gauge, Reloading, Seating Depth, Stoney Point
I have been using this exact method for 35 years. Saw it in an old copy of the American Rifleman. You can also use the bulleted case to set your die seating stem.
Great idea…I just used it in my .223 14″ T/C so now I know exactly where my different bullets touch the lands and how to adjust for the jump I desire. Thanks…I’ll use this for all of my calibers !!
I used a Dremel with the cutoff wheel to modify a case this way. I even brushed out the mouth of the case afterward. But I didn’t clean out the case too. Stupid! Enough grit was in there to get in the chamber and scratch the case when I was using it. And some seemed to be embedded in the chamber wall, too. Cosmetic only, but still Stupid!
This isn’t new. I’ve been doing this for 10+ years . . . . Thought everybody knew this one.
Additionally you can measure the wear of the chamber easily allowing you to adjust for the life of the barrel. Key is keeping good records of rounds pushed through.
If you order multiple match barrels at the same time and hopefully from the same lot of steel, using the same reamers you can have a better idea of when to change barrels, how similar both barrels are and during a competitive season. Less surprises, during a match.
Great idea worth repeating as some of the younger shooters probably don`t know of this..The one thing I have found is even in the same lot of bullets I have found varing ogive lengths,,kinda frustrating…..
I just started reloading recently and this was an obvious no brainer way to get the lengths to touch the lands. I use this when changing bullet types to find the right length for each one. Once I have it set I measure the ogive length and make notes then the next time I am loading those bullets I have dial my dies in pretty quick to adjust for seating depths of each. I like them to be just in the lands a touch I find the best.
Not all that experienced, so forgive me if I am asking an obvious question: If this device is made using a fire-formed brass … meaning it was fired in the chamber you are reloading for…how can the bullet remain in the brass case? There is no tension left on the neck to hold the bullet.
DW…just neck size a fire formed case. then there will be just the right tension (adjusting for 3 or 4 cuts with dremel). Or simply smoke the bullets with a candle works too!
I did this and it worked well but my question is the saami oal is 3.290 for a 7mm rem mag after doing this my measurement is 3.36 what do i do next do i seat 1-2 thousandths deeper but this will still be over saami is this safe?
Wow. Awsome idea.
Scot the Sammi specs are very conservative that is why most factory loaded ammo don’t shoot for beans. When I find out where the bullet touches the lands I seat just a hair more. As long as the bullet is not crammed into the rifling it’s completely safe and makes your rifle a lot more efficient.
Smoke the bullets with a candle, then you can see if the bullet has hung in the rifling.
If you put the bullet in the rifling you will get a sharp pressure increase. Do you get pressure marks you can pull the bullet of the rifling and the pressure marks will often disappear.