Question about COL

[Wanted]

I know this has been asked, but I'm having a hard time finding it,in search. I have manuals, an older Hodgdon for example that don't list a COL for loads. Can you help me with understanding this concept?

1. If no info is given, how do you determine COL? W/o being dangerous?

2. Is there a formula for determining COL. Such as when you reduce a load 10% to get a start point?

3. I know to use my barrel to do a drop test (in leu of a case gauge) is there other equations or factors to look at? Thank you everyone for helping me to learn to think for myself.

[High Lord Gomer]

The Hodgdon's web site does list the suggest COL for their loads:

http://data.hodgdon.com/cartridge_load.asp

I hesitate to tell how I arrive at my OAL, as I am fairly new at this, too. In addition to chamber checking, you should also check to make sure that the rounds insert and feed well in/from your magazines.

[twodownzero]

My process is to load them as long as I can, while ensuring that they function properly. This is different for every gun. I like to maximize the case capacity if possible. I have found that longer ammo (so long as it isn't hitting the rifling) feeds more reliably.

Beware of any load data that doesn't include COAL. Pressure = force / area

Edited February 17, 2010 by twodownzero

[dbxdm9]

Lots of sources for recipes fail to provide OAL. Spec for a 9mm is 1.169". I start just under this and test dummy rounds in the barrel to see if they drop in/out easily, and twist around. Then feed some from the mag to ensure they chamber fully. If so, load up some live rounds and test with a chrono. You can then compare your velocity to specs (which often do give velocity.) If you decide to go shorter, do so in very small increments and check the case on each fired round for signs of excess pressure.

[DWFAN]

I also load as long as possible, either the barrel or magazine will tell you when its too long. I can usually find a minimum OAL for a given load. If I am above that, Im usually good to go. Ive also heard that loading long helps accuracy. Ive not tested this myself, but my loads are more than enough accurate.

[superdude]

potentially useful information here:

http://www.38super.net/Pages/Overall%20Length.html

[Wanted]

I.ve been trying to load long also. It seems like maybe even most of the data I've seen keeps them on the short side. 1.100, 1.090 and such.

[Steve_P]

You generally won't have a problem loading longer than the manual states for a given recipe. I know that a few manuals that I have list the COL as a minimum value to use for a particular load. Just make sure that what you do settle on works well in any gun you plan on running them in, and all your mags.

Good luck,

Steve

[Wanted]

Thanks everyone. That's a great read looks for targets.

[fltbed]

In auto loading pistols, the cartridge OAL is critical for functioning. Load the bullet to short and the round could nose dive on the feed ramp and jam the slide.

Load it to long and it may be longer than the magazine will allow or it could hang up on the ejection port or you can wind up with the dreaded three point jam (round in contact with the breach face, feed ramp and the top of the chamber) or worse get the bullet stuck in the rifling.

A side effect is that, as you shorten the OAL you decrease the size of the combustion chamber inside the case which will increase pressures.

I use this method to determine the guns OAL for whatever bullet I‘m loading first:

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 my OAL another .010 or, if it's real long, to the max OAL that will function through the magazine.

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

Once I know the bullets OAL in my gun, I’ll work up my load from there.

Hope this helps.

Jeff

[Wanted]

Nice. I'l try rhis.Thanks