quote:

maximum allowable OAL for your gun.

There is a way to get this number, skeez. Take a case that is resized. Put a bullet in it seated out further than you would normally. Take the barrel out of your firearm. Take your dummy bullet and see if it will go into the chamber. If it does look at the case head and see if it is flush with the back of the barrel. If it isn't take the dummy round out and seat the bullet just a little deeper and try again. When the bullet is dropped into the barrel you should hear the case mouth hit the end of the chamber before the lead hits the rifling. If the lead hits first it will sound more like a thud than a clink, like the case hit steel. When you get the case to seat properly I suggest you go about .010" shorter. Then see if this length will fit in you magazine. If it does you are good to go.

Having a shallow "seating depth" (You will also see a longer OAL 'cause the front of the bullet is connected to the rear. ) will reduce pressure, all other things being equal.

Seating depth is an issue with this round. I have loaded many of these with LRN bullets. I also find that slower burning powders almost eliminate leading. I am loading a 124gr LRN at over 1000 fps and get no leading and I have no sign of high pressure at all. Skip is right when he says this is a recipe and you need to follow it exactly and seat the bullet to the right depth.

Mark

There is only one more factor that you might want to include in this discussion, since there has been a wealth of good info.

Once you establish the allowable max length for your ammo in your gun, make up some dummy rounds to test how secure your loads will be. Load them in the magazine and, racking the slide rapidly, chamber them. Repat this with the same dummy cartridges several times, making sure to inspect them after each time through the chamber. Check the overall length. It shouldn't change.

What you are trying to do with this test is to make certain that the bullets don't dynamically reseat themselves farther into the case when they are being chambered. I like to run them through the gun three times. If they hold their length after three cycles, then you can feel pretty comfortable that your loading technique and gear are producing enough force to keep the bullets where they need to be.

UPDATE

Loaded a few rounds of the 125 grain LRN @ 4.0 grains Bullseye and an OAL of 1.15". Tested 10 rounds each in Ruger P95, CZ75B, and Springfield 1911. All pistols functioned perfectly, and there were no signs of excess pressure.

The Ruger especially likes this load - grouped 7 rounds in 3 inches at 25 yards. (This gun normally shoots 10 inch patterns with 115 FMJ ammo.)

So, it looks like I've found a good load for what I want it to do.

Thanks to all who contributed to this thread, and to my 9MM "lead-loading" education.

skeez,
Don't run off, friend. One thing you left out. How was the leading in the barrel? I'm sure you aren't a novice but there may be others reading that are so I will be sure to mention this here. Be sure to get all of the lead out before running jacketed bullets back down that bore. You can "iron" the lead into pores in the steel that can affect accuracy later on and will be almost impossible to get clean later on.

Good to hear about your results! Keep tweaking any you may get that block (read Ruger) to shoot better yet!

There was not any lead build-up that I could see. I ran a patch soaked in Kroil through the barrels while they were still warm, so if there is any lead build-up, it should come right out.

The bullets are "hard cast", and I had applied a wash of Lee Alox before loading them. Also, the velocity should have been below 1,000 FPS, so barrel leading should be minimal, if any.

I'll find out for sure tomorrow when I clean the guns.