In order to participate in the GunBroker Member forums, you must be logged in with your GunBroker.com account. Click the sign-in button at the top right of the forums page to get connected.
Options
9mm OAL
AzAfshin
Member Posts: 2,986 ✭✭
Thanks to Karl and all you gents, I learned how to do the proper OAL for my 45 ACP rounds by using the barrel and having the bullet seat 0.005-.010 below the heel of the barrel.
But this doesn't work for the 9mm since there is no heel like the 45 barrel. How do you determine the proper OAL for your 9mm barrels?
But this doesn't work for the 9mm since there is no heel like the 45 barrel. How do you determine the proper OAL for your 9mm barrels?
Comments
So far I've been using the drop in method where I drop the completed round in the barrel. If it doesn't plunk in easily, then I seat the bullet a little deeper. Once I get that plunk, then I do another quarter turn on the seater die and use that OAL. But was wondering if there is a better way.
If it fits the gage and the bullet does not stick out the end, it will normally fit your gun unless you have some special chamber arrangement.
As for seating to deep, see the specs on line for that type bullet.
Best of luck
If you want to tweek the reloads for accuracy, then it is by trial-and-error. Functioning reliability comes first, accuracy second.
Use a factory round to set the seating depth with a similar shaped bullet.
Bruce, while I appreciate the feedback, that still provides a wide range of OAL from optimal to actually dangerous such as a bullet that is seated too far in.
So far I've been using the drop in method where I drop the completed round in the barrel. If it doesn't plunk in easily, then I seat the bullet a little deeper. Once I get that plunk, then I do another quarter turn on the seater die and use that OAL. But was wondering if there is a better way.
A bullet seated WAY too deep will indeed drive pressures to "Oh My Lord" levels. However seating it to fit the magazine without nose drag and feed flawlessly trumps anything you can do to increase accuracy in a pistol. I have found that chasing a OAL for a pistol to be a waste of time; handguns are simply not accurate enough to know the difference.
Set COL as long as possible to have case head still at that location or very slightly higher.
I make two inert dummy rounds, set the COL at max and work the COL down until the two dummy rounds fit the magazine and feed and chamber and that becomes my COL for that bullet.
Your COL (OAL) is determined by your barrel (chamber and throat dimensions) and your gun (feed ramp) and your magazine (COL that fits magazine and when the magazine lips release the round for feeding) and the PARTICULAR bullet you are using. What worked in a pressure barrel or the lab's gun or in my gun has very little to do with what will work best in your gun.
Take the barrel out of the gun. Create two inert dummy rounds (no powder or primer) at max COL and remove enough case mouth flare for rounds to chamber (you can achieve this by using a sized case-expand-and-flare it, and remove the flare just until the case "plunks" in the barrel).
Drop the inert rounds in and decrease the COL until they chamber completely. This will be your "max" effective COL. I prefer to have the case head flush with the barrel hood. After this, place the inert rounds in the magazine and be sure they fit the magazine and feed and chamber.
You can also do this for any chambering problems you have. Remove the barrel and drop rounds in until you find one that won't chamber. Take that round and "paint" the bullet and case black with Magic Marker or other marker. Drop round in barrel (or gage) and rotate it back-and-forth.
Remove and inspect the round:
1) scratches on bullet--COL is too long
2) scratches on edge of the case mouth--insufficient crimp
3) scratches just below the case mouth--too much crimp, you're crushing the case
4) scratches on case at base of bullet--bullet seated crooked due to insufficient case expansion (not case mouth flare) or improper seating stem fit
5) scratches on case just above extractor groove--case bulge not removed during sizing. May need a bulge buster.
load some and test to suit your gun.