I'm looking for some advice on what's worked for you more experienced reloaders.....

In my older version of Metallic Cartridge Reloading, it explains a method of measuring maximum OAL using an iterative process such as this:

1. Seat the bullet in an empty unprimed case just so it fits in the rifle's magazine.
2. Blacken the bullet in a candle flame.
3. Chamber the round and extract.
4. Use an iterative process of deepening the seat depth, blackening the bullet, chambering, etc.. until the bullet no longer shows any black rubbed off. At that seating depth, you know that you're just off the lands.
5. Depending upon bullet type seat an additional amount - the distance off the lands (.01" to .05" for most bullets, but there are exceptions.)

I tried the candle blackening method enough to know I don't think it works in both my 300 WM and 270 because it's very difficult to determine when the bullet is in the lands or not because the black is removed so easily as it's chambered. It's almost impossible for me interpret the markings on the ogive as to whether it's from the lands or just from rubbing the chamber.

I've used the same method as above, but instead of blackening in a flame, I've coated the bullet with magic marker. Then it's much easier to tell because the marker doesn't rub off as easily.

I've used another method where I took an unprimed empty case and split the neck with 2 cuts (perpendicular) down to the shoulder. Then insert a bullet, chamber the round, and then extract. The idea is that OAL of the extracted round is the maximum and touching the lands.

The magic marker method and split neck method produced a maximum OAL measurement within .01" of each other in my 300 WM so I feel pretty confident in those results.

So my question is: Are the above methods accurate enough to give me the confidence to seat the bullets, say .03" off the lands in my 300 WM shooting 200gr Nosler Partitions over H4831 and also H4350? At .03" off the lands my 300WM OAL is about 0.2" over SAAMI listed maximum. How are those SAAMI numbers determined anyways?

I do recognize that if I leave the OAL too long up it can create high pressures so I'm working up loads carefully.

I hear those Stoney Point gauges work slick but I don't know if they're worth the money if the above approaches work just as well.

What do you think....does the homemade McGyver approach work well enough or do I NEED the Stoney Point gauge?

Thanks in advance.

Think Stoney Point

Okay, here is what I have found to be the best way to determine OAL.

Load three dummy rounds to the maximum OAL that will fit in your magazine.

Place those three rounds in the magazine.

Cycle the action of the firearm for all three rounds.

Measure the three rounds.

Set your dies so they will produce a cartridge with the OAL of the shortest of the three.

Period!

I have nothing at all in my reloading room with "Stoney Point" on it. I have never seen the need for their products (other than their bore guides), and I have managed to successfully load for over 45 years. Producing both very fine paper targets and extremely fine food on the table.

If you are concerned, after spending thousands of dollars on firearms and thousands of dollars on reloading equipment and supplies, about the $24 cost of a Stoney Point OAL gauge, then possibly you have to reconsider priorities.

One of my real good friends uses the Stoney Point system and I use the "cut the neck and seat a bullet in the chamber about 10 times" system. I take an average of the OAL, and back off from that about 5 thousands. As I understand the Stoney Point system, it measures from the shoulder to the bore. "My" system measures from the bolt face to the bore. There is a difference!

My system is essentially the same as Ricciardelli's, except that I have to check to see if mine will fit the magazine after I have decided upon an average length. Came up with a wonderfully accurate load for one of my rifles that would not fit the magazine. Fine for target, but not very helpful for hunting. Ku-dude

You determine your presuure limitations AFTER you have set the OAL for that cartridge in that firearm.

I would have ti "guesstimate" that around 96% of my rifles are loaded so that the bullet is just kissing the lands.

And I did not contradict myself...the keyword in that statement was "you".

What i usualy do is drop a bullet through the chamber into the barrel. Then slide a wood dowel down the barrel untill it touches the bullet and make a pencil mark. Knock out the bullet, close the action and slide the dowel against the bolt face. Make another pencil mark and measure the distance between the two marks. This is the oal to lands. Subtract whatever clearance you want and load.

The sinclair tool uses a case FROM YOUR CHAMBER and then takes a bullet at the land and a bolt face to shoulder engagement measurement. these result in a perfect "at the land" measurement in YOUR rifle. I have done it and rechecked it many times over with the same result.

Take a look at the sinclair tool first.

Trouble with the rod down the barrel method, I've measured
Sierra Match bullets with 16 thou. difference in length.
So one has to use the actual test bullet in a case to
adjust the seater stem.
John L.

Thanks for all the responses. If nothing else, some of you have validated my current approach and some have provided other good insight.

One more question...How is the SAAMI maximum OAL determined?