ultrablue

The OAL for a 9mm is 1.169. Why do I see some OAL's as low as 1.11 and 1.12? Right now all of my loads are 1.155 to 1.156. My 9mm xdm4.5 cycles fine and knocks down steel. The only unknown for me right now is the power factor and I am planning on a chrono session this Friday with these loads. You get the minimun OAL from the bullet recipe in the reloading manuals. As a new reloader, I do not go below it. You can adjust it longer to figure out the best OAL for accuracy. Longer OAL will have a small effect on velocity, but not much. I shoot an XDM 9mm. Currently, I am loading N320 4.2 grains with a 124 grain MG bullet. I have tested it at 1.145 to 1.160 and had minimal changes in velocity. Power factors varied from 132 to 128. The recipe calls for the load to be 1.142. N320 fills the case up nicely so I wouldn't go below 1.142. If you do go shorter, the end result could be a compressed load, which is bad. The powder manufacturer that does the testing publishes it with their load data. Thanks Red Ryder. Going to the range today for testing. Will let you know the results with the Bullseye powder.

The OAL for a 9mm is 1.169. Why do I see some OAL's as low as 1.11 and 1.12? Right now all of my loads are 1.155 to 1.156. My 9mm xdm4.5 cycles fine and knocks down steel. The only unknown for me right now is the power factor and I am planning on a chrono session this Friday with these loads.

In various discussions overall length comes up as a statistic. I have a Dillon case gauge and thougth this was for diameter and length as a go no go gauge. If you change the overall length of a round from my length of 1.156 to something shorter am I to assume this will produce a higher pressure (less empty space in the case) meaning a higher velocity? I guess I didn't realize this could also be a variable?

Thanks folks. Sounds like between 20 and 30 for a good evaluation of PF.

How many rounds should be fired for a chrono session?

I have noticed a difference in the case weight that is why I started weighing the bullets. At your stated .2 variance for my condition starting at 123.8 to 124.2 I have 67 bullets that fit that criteria. That means only 39% work. Is that acceptable from the bullet manufacturers? I have just started shooting USPSA. (4 qualified matches under belt) Since you are shooting USPSA, I wouldn't worry about it. If you can shoot 3" groups at 25 yards then you are good to go. I weighed a box of Sierra 115 grainers and they were all 114.9 to 115.0. The new Zero 115 weighs 114.9 to 115.1. This is a must for shooting 1" groups at 50 yards. I would suggest that you continue to use the bullet that you are currently using until you can out shoot the load and gun. When you are first starting out you would be best served to work on draws, reloads and shooting on the move. The rule of thumb is that the more expensive the bullet the more consistant they will be. Load for quantity with a little less emphasis on quality and shoot. Shoot a bunch. Thanks for the help. Here is a vid of me last week.

Cabela's had Winchester for 28/k just on 8/26/11 in store if you have one near you.

As a newbie I just wanted to check some things out to make sure I was doing the right thing. I bought my Dillon to produce large quantities in a short period of time. After this initial learning curve I just want to make ammunition that is reliable. The XTreme bullets I am using are plated.

I have noticed a difference in the case weight that is why I started weighing the bullets. At your stated .2 variance for my condition starting at 123.8 to 124.2 I have 67 bullets that fit that criteria. That means only 39% work. Is that acceptable from the bullet manufacturers? I have just started shooting USPSA. (4 qualified matches under belt)

I started the reloading process as a newbie. I have been diligent with the weights and measures and sizes. All has worked well so far. I weighed several completed rounds and noticed what I would call large swings in weights. From 0 to 1.5 grains in overall weight. I have checked the powder measure frequently and that has been consistent at 4.0 grains of Bullseye. I started to weigh a group of the 124 gr XTreme bullets and here is what I found; 172 weighed The range is from 122.9 gr to 124.7 gr. 28 weighed in at 123.9 gr 20 weighed in at 123.6 gr 16 weighed in at 123.3 gr 13 weighed in at 124.3 gr 13 weighed in at 123.4 gr 12 weighed in at 123.8 gr 12 weighed in at 124.1 gr The rest of the pieces fall in the stated range above. Is this a typical range of weights to see in 1000 pieces and how does it effect velocity and power factor? Should I weed out the lower weights and where should the cutoff be?

Folks, I have a chrono now and will start the process of measuring the loads. I will update as soon as possible. Thank you for all of the good help.

Great theoretical questions. How do you plan for the instances you question? Going to get a chrono and start tetsing to know where I am at.

Thanks for the offer. I am in Southeast Wisconsin. That might be considered God's Country.

Thanks for the answers folks. I knew the minimum per USPSA was 125 for minor power. I don't have a chrono so that is part of the dilema. IF just going to the range and everything cycles I guess was really the question. From a technical standpoint and for match rules I understand the need for the chrono data. As a newbie I was excited that everything worked. I haven't found the exact load I used in any manuals. It was from reading and asking questions to start with that initial recipe. Next question; If I use 124 grain bullets for matches should I stay with that for general paper or go to 115 grain?

Got my new Dillon press up and running. Great machine. Even the kids say it looks like a little factory. Loaded 124gr bullets with 4.0 grains of Bullseye. XDM 4.5 ran great with this load and the felt recoil was lighter than factory 124gr ammo. My question, Do I need to chrono this? How important is the chrono measurement? I am shooting USPSA as production, minor and yet to be classified.

Cleaned the striker and chanel. Lots of grease and gunk. Should have listened to other folks about cleaning that out the first time. Went to range last night and no double fires or malfunctions.

1000 rounds thru the gun and never happened before. Safety is key in USPSA. Happy trigger fingers are not welcome. trigger pull on this gun is still pretty stiff.

At the range yesterday and my SR9c experienced three double fires. Last week ran grest with American Eagle 124 gr ammo. Same ammo yesterday. Anyone else experience this or have a solution? Called Ruger and they didn't have any ideas.