Home Forums Reloading Big Game Rifles Determining OAL

In the absence of having a Stoney Point Gauge to determine maximum cartridge OAL using the ogive of the bullet; what about seating a bullet long in the casing which would allow it to touch the rifling when chambered, then gently closing the bolt to push the bullet back into the cartridge casing? Voila, maximum cartridge length to the ogive of the bullet that can be measured from the ejected dummy round? or is this not a good idea/way to make that dimensional determination?

Thanks in advance for the feedback from those that know best about this subject, Dave.

That’ll work if the bullet doesn’t get stuck in the lands. I used to use a fired but unsized case, dented it slightly so if the bullet got stuck, it would have a scratch on it so I could replace it in the case to the end of the scratch and measure…..established OAL thusly.

It works but you need to do it so that the bullet can move in the case but not by hand. I neck size just the end of the neck to give the right amount of grip. You will learn how much is right by doing it several times. Also, you need to do about 10 readings so that you don't get a false reading and use that. When I consistently get the same reading, then I stop.

mark the bullet with a black sharpie marking pen (or soot from an open flame) so you will know if the bullet pulled out of the case when you removed the cartridge from the chamber... then measure the overall length with a bullet comparator insert installed on a dial caliper... it takes a little practice to get the neck tension right, but you'll get the hang of it...

Just use a case with a split neck if you have one, or split a neck with a Dremel. Take several measurements to be sure. Definitely use a comparator otherwise consistency will be practically impossible.

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My method also.

Gauge
Case

For $50, peace of mind. And that is at cabelas which they are usually a little on the high side on things.

Yes, did that for years, still do.
Have bought a Hornady compairitor for CBO, to get an exact reading for the seating die for that bullet, as I do change the seating die setting when working with a different bullet.

In the "old days" I used a dowel rod and a razor blade. Anyone else?

I use a couple of methods. One is the Hornady modified case with all of the measuring parts. The second is to use a split casing made with a Dremel. I always measure OAL and CBTO. I find it helps to have more than one measurement, more than one source and more than one method. It’s interesting when doing this. You will find the best manufacturer of bullets because the cheap Speer and some Hornady have a lot of variations where the Berger and Barnes have the fewest.

That is the method most load manuals suggest. No need for any gadgets. The only thing I'd add to what you just said is soot the bullet first.

This is very important because sometimes the lands will grab the bullet just a little and pull it out of the case just a bit, or even all the way. Here's a good example of when that happens and what to look for:


Just push the bullet back until you see no witness mark and then measure that:

The measurement you get there is to the lands. I then subtract .020" and call that my OAL for that lot of bullets. Make record of that in a book:


Sometimes you don't have to push the bullet back into the case, but sooting the bullet will tell you the real story. I use a once fired (from that rifle), but unsized piece of brass for this.

When doing it this way, do it at least 5 times to get a good average. Using a different bullet from the same box every time. I've been doing it this way for years with great success. I don't know why other guys choose to use gadgets when a simple method doesn't cost a dime. And also, most bullets manufactured today have tight tolerances. The ones with poly tips will give very consistent measurements. The old speer bullets not so much. Most of these guys that measure base to ogive don't shoot competitions where schidt really matters. In any case, measuring from base to tip works just fine, as long as you get a good average.

I used the two sticks method .

You can use a felt tip marker to paint the ogive vs smoking the cartridge. Both methods work well.

Yup, but I used a cleaning rod and masking tape.

Both work for all but the absolute most finicky competitive shooters/

I made up 2 round aluminum disks with thumb screws that fit snugly on the cleaning rod.

Never had a real need for anything more complicated.

If the bullet has an exposed meplat, then you need to use a non-deformed bullet to use; works extremely well for any tipped or FMJ bullet.

MM

That's what I did too, Jordan. Worked fine.

Thanks all for sharing some of your wisdom and helping with my learning curve!

I always keep black sharpies on the bench for this purpose. Touching the lands leaves highly visible marks in the ink.

I adjust the seater to the point where that mark becomes square, as long as it is wide.

An infamous contributor once quoted: "Kiss, find pressure, rock on". Advice which has served me well on most of my rifles. The exception was cured with a trip to Pac-Nor.

Sharpie for me. Very few factory hunting rifles I own will have the bullet touch the lands at magazine length anyway, so all you're doing is an exercise in determining where the "kiss' occurs and then you know how far off the lands you are. Being a deaf, dumb, blind man, knowing this crap doesn't help me that much for my hunting rifles. I find the OCW at max COAL first, then (maybe) screw around with seating depth.

I have used the same system as RiverRider for many years with good results.