Lee Loader

Doing a little bit of agonizing getting ready to load 9 mm for the first time and it all hinges I'm trying to find the correct oal. . After quite a bit of research I've came up with the way to measure the maximum oal that would be repeatable for any pistol cartridge and bullet used. It would be specific to whatever Barrel I was trying to fit but could be made more generic.

That said I'm curious how all of you make that determination. We all know the reloading manual gives you that information for specific bullets but we also know not all round nose bullets are the same .
Depending on manufacturer or you're casting mold they are going to vary from one manufacturer to another. Also not all manufactured bullets are listed in the manuals. An example would be the bullet I'm
getting ready to load from Bayou bullets. You may find a similar profile but it may not be exactly the same.

I'm going to do another post later with pics about how I am going to measure for any bullet that I'm using oal if it's not in the manuals. For now I'm just curious what you all are doing

Most will tell you they use the barrel to find a MAX oal (as long as it fits it the magazine) for an auto loader. Adjust from there. Revolvers, as long as the cylinder will handle. However "most" revolver bullets have a cannelure that will determine length.

On autos I start with the longest that fits the magazine and shorten it a little at a time until it fits the chamber of the barrel.

Generally I start with what the manual says for the load and bullet. If it fits and cycles, I'm good. That all goes out the door when you get to loads for long range shooting like IHMSA, but that's another topic all together.

Stay well, be safe, make smoke,

Book OAL as a starting point and the Plunk Test as a final answer. I do not shoot my handloads out of a cartridge gauge so I don't use one to check my ammo. The barrels on my pistols and rifles and the crimp grooves/cannelures on my revolver bullets have the final say...

After taking some measurements of which I created a post to show what I did I discovered the book AOL would have been incorrect for this bullet that I am using as it doesn't match anything exactly in the book.. I also discovered the original starting point but I had assumed from reading and looking at the load data in the books would have been incorrect also. Also when I measure Factory rounds they're much longer then what would work with this particular bullet. . If you get a chance look at my notes in the new post and tell me what you think

mikld wrote:Book OAL as a starting point and the Plunk Test as a final answer. I do not shoot my handloads out of a cartridge gauge so I don't use one to check my ammo. The barrels on my pistols and rifles and the crimp grooves/cannelures on my revolver bullets have the final say...

After screwing around with gauges this is also my spproach except I use the Hornady length gauge and bullet comparator for rifles. When I decided to shoot 230 grain FMJ that had no cannelure in my 45 Colt revolver I just measured the length of the cylinder. Making that my OAL meant the bullet was sested the width of the case rim short of the cylinder face. For cylinders that have rim recesses you simply subtract teice the rim thickness to arrive at the same place.

How did you determine the "book" was wrong for your particular bullet? No not every RN bullet is the same but you will get a general idea and a starting point, confirmed by the plunk test. IIRC, before manuals started using OAL they used seating depth. For example, my Complete Guide to Reloading lists a seating depth of .250" for a 124 gr MC bullet.

Don't overthink the process. Use starting loads and close book OAL, checked with the plunk test, and work up if necessary, watching for irregularities in performance...

mikld wrote:How did you determine the "book" was wrong for your particular bullet? No not every RN bullet is the same but you will get a general idea and a starting point, confirmed by the plunk test. IIRC, before manuals started using OAL they used seating depth. For example, my Complete Guide to Reloading lists a seating depth of .250" for a 124 gr MC bullet.

Don't overthink the process. Use starting loads and close book OAL, checked with the plunk test, and work up if necessary, watching for irregularities in performance...

if you look at the thread DIY tool for measuring overall cartridge length I measured with the specific bullet to where the bullet with engage the lands and grooves location and it was much shorter man the published data for a different round nose bullet. . Then I found data from two different sources it's suggested the bullet be seated 10 to 15 1000 short of the lands and grooves.

Since books don't agree with each other there is always more than one "right".