View Full Version : 9mm distance from riflings
nickaballison
02-09-2013, 09:25
Hey guys i am starting to reload for my 9mm for both cost effectiveness as well as accuracy improvements. When you guys figure out your bullet seat depth, what have you found to be the most accurate distance between bullet and riflings? I am loading xtreme bullets 115RN, with blue dot powder.
You'll probably find you are going to be limited in your OAL because you will have to load them to fit in your magazines.
SA Friday
02-09-2013, 12:45
Mag restrictions rule OAL in pistols. I'm sure there is an exception out there, but I have yet to find one. Load for mag length clearance.
madmike283
02-09-2013, 15:27
I agree with everyone above pretty much. You can start long, and just shorten it a little at a time chamber checking in the barrel you'll be using the load in. I think, in general, you want to be as close to the rifling as possible. I backed off maybe .005" to give me a little wiggle room. Then I checked that length in my mag. It was very close to too long, I probably shortened another .005" to make sure I don't have problems in the mag.
So, long story short; load it as long as you can for the barrel first, then check the magazine fit. Shorten, if needed, until you have proper operation in the magazine.
nickaballison
02-09-2013, 15:41
Wow i never thought that would be the case but you are absolutely right. I put a bullet just snug in a belled case and it would not touch the riflings in my kahr cw9 but slightly engaged riflings on my sig p239. I will start backing it off just until it fits the mag and try another .010" to make sure i dont jam in the mag. Thanks for your hlep.
Great-Kazoo
02-09-2013, 16:46
if you want to go crazy, take winchester white box, S&B, federal, remington 115gr factory. measure OAL and see how much variation there is between mfg AND ammo lots. I load my 115gr fmj using mixed brass and 4.0gr TG set @ 1.114 OAL. Works / cycles across the board in all my 9's
dogbreath650
02-10-2013, 12:53
Don't forget to do a load workup once you find what OAL works best in your pistol. If you have a shorter OAL that what your reloading manual specifies you need to adjust your powder load accordingly as your pressures will be higher with a shorter OAL. Start low and work up...
SA Friday
02-10-2013, 13:34
I agree with everyone above pretty much. You can start long, and just shorten it a little at a time chamber checking in the barrel you'll be using the load in. I think, in general, you want to be as close to the rifling as possible. I backed off maybe .005" to give me a little wiggle room. Then I checked that length in my mag. It was very close to too long, I probably shortened another .005" to make sure I don't have problems in the mag.
So, long story short; load it as long as you can for the barrel first, then check the magazine fit. Shorten, if needed, until you have proper operation in the magazine.
No disrespect, but this is just pistol ammo. Short of owning some obscure type of pistol, pick a length that fits in the mag and cycles in the gun and load after working up a basic round. .005" might make a difference in rifles, but that doesn't do squat in a basic pistol target round. I've seen as much variance as .02" in the OAL just from press flex. I was shooting 30-40k rounds in USPSA a year at one point, and played around with all kinds of different loads and played around with what actually made a difference in accuracy and pressure. OAL makes the most difference in how well the gun will cycle. It will hardly ever effect accuracy like a rifle. It will raise and lower chamber pressure, but in basic target ammo, especially 9mm, it rarely will make any significant difference.
I loaded some hp once at the same length as my rn and it would load in the magazine and fire, but would catch if you tried to unload the weapon. Then you have a round that you must leave in the chamber or fire. I'm not sure your going to see measurable accuracy improvements by loading an auto longer, focus on different powder charges maybe.
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