Determining OAL....

[jcountry]

This seems like a neat way to get a good idea of max OAL for a semi-auto pistol (from another forum.)

-Anyone tried it?

When testing a new bullet, the first thing to determine is what over all length (OAL) works in your gun. Every chamber is different, bullet ogives are different, so what works in one gun may not work in another.

With autoloading pistols, OAL is more about the gun functioning. To short of an OAL and you can get nose dive feed jams. To long of an OAL and you get bullets sticking in the rifling, three point jams, etc. There are many ways to determine your chambers OAL with whatever bullet your using. I use this method:

Things you’ll need:
1. Dowel rod that fits down your bore. (cleaning rod will work in a pinch)
2. Exacto knife, razor blade or scribe.
3. Dial calipers

With the action closed, insert the dowel rod through the muzzle till it’s resting against the breach face and scribe a line on the rod at the muzzle.

Now insert the bullet you plan on loading into the chamber and hold it against the rifling with something. (another piece of dowel rod, cleaning rod, etc.)
Reinsert the dowel rod till it’s resting against the nose of the bullet and scribe another line on it at the muzzle.

Measure the distance between the two lines and you now have the maximum OAL for that bullet in your chamber. (I normally back off another .010-.015 and load up a few dummy rounds to check function through the mags and proper ejection of a live round).

I know there are other ways of determining max OAL that are more precise and more expensive, but I’ve always found this method more than adequate for my needs.

Once you know what OAL works in your gun. Then, it’s time to start looking at powder choices and data. Since there are so many variables involved with developing load data, reloading isn’t exactly a plug and play endeavor, so you will almost always find conflicting data between the manuals. Take the average max load between at least three manuals and back off that number by 10% and you have your start load.

We’ll use your 9mm and 125 gr. bullets as an example. We see max loads anywhere between 5.0 gr.-6.0 gr. Using 5.5 as our average max and backing that off by 10% we get 4.9 gr. as our start load. Load ten rounds and test them. Work up or down, using 10 round test groups, in 1% or 0.1 gr. increments till you find the load you want. Once you know what the gun likes, you can load up a bunch and have fun.

 

[1006]

I applaud any effort for safety and precision. The above method sounds reasonable but a bit over complicated.

Here is another way to handle guns with magazines.

First, verify that your brass is sized properly by test fitting an empty piece into the barrel's chamber.

Load it as long as you can for the mag. Then drop it in the barrel's chamber while the barrel is removed from the gun. If it drops all the way in, you are done. If it is too long, go back to the press and shorten it a little at a time until it drops into the chamber.

 

[jcountry]

I applaud any effort for safety and precision. The above method sounds reasonable but a bit over complicated.

Here is another way to handle guns with magazines.

First, verify that your brass is sized properly by test fitting an empty piece into the barrel's chamber.

Load it as long as you can for the mag. Then drop it in the barrel's chamber while the barrel is removed from the gun. If it drops all the way in, you are done. If it is too long, go back to the press and shorten it a little at a time until it drops into the chamber.

I agree.

It does seem like a lot of work to get at the same thing.... But I just thought it was kinda clever.