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9mm Luger COL

Posted: 30 Aug 2009, 08:17
by EmptyBrass
What are you guys using for your COL on a 115 gr FMJ? I'm loading Win FMJ

What Hornady recommends is shorter then any factory round I can find. (1.10) Its almost pushing the bullet all the way into the case.

I measued an American Eagle loaded round and it measures 1.152. Which is closer to the Max COL of 1.169.

Win USA is 1.163 This is the one I'll probably use.

Re: 9mm Luger COL

Posted: 30 Aug 2009, 09:43
by Grantness
1.10" is probably a little on the short side. What is the most accurate factory round in your gun? Maybe try using that OAL. You can always be methodical about it and test the accuracy of rounds w/ varying OAL's (say .005" increments.). Every gun is different, chambers have different throats, etc. You need to find out what works in yours.

One technique that I've heard MO mention is to cut a slit down the side of a sized case and insert the bullet you want to use. Chamber the dummy round, pull it out, and measure that OAL....then subtract ~.05" (or whatever you like) to give you a good OAL to use for that round in your gun.

Re: 9mm Luger COL

Posted: 30 Aug 2009, 21:01
by fatherfoof
Being lazy, I tend to find a factory round that always works, set the equipment for that exact length, and so far it's been foolproof. Now that I said that, watch my next batch be all screwed up.

Re: 9mm Luger COL

Posted: 31 Aug 2009, 04:04
by The Keymaster
It varies a lot by firearm. As an example, I loaded 200 rounds at 1.145 with 4.8 gr of AA2. They were incredibly accurate in my Walther PSP, and they totally sucked in my Sig P229. I made another 50 at 1.150 with 4.8 gr of AA2 and was totally amazed at the difference in the Sig. Bottom line, .005 does make a difference.