Hi-Power Jack Posted August 17, 2014 Share Posted August 17, 2014 Sorry for placing this in 9mm Reloading - applies to all semi-auto pistols, but I couldn't figure out how to make it more generic. Setting the "best" OAL for your gun involves ensuring that the loaded rounds fit through your magazine and slide easily in and out of your chamber. Once you've set the "crimp" properly, the only component left is the OAL. So, first set your crimp properly, and then leave it alone - no reason to change it once you've removed the belling and the rounds chamber properly. Set your OAL for the longest recommended - then try The Plunk Test - remove the barrel from your gun, and drop the loaded round into the chamber. The cartridge should fall all the way in, without any pushing, and spin freely in the chamber, and drop freely from the chamber if you turn the barrel upside down. IF IT WON'T SPIN OR DROP FREELY, YOUR OAL IS TOO LONG FOR THAT PARTICULAR BULLET IN YOUR GUN. If your OAL is too long, you have to shorten the OAL, and try it again. Once you've found your longest possible OAL for your gun, then you shorten that my .05" and load up 10-20 rounds and try them - make sure they all will spin freely and drop out of the barrel easily. If you get any that are too long, try shortening the OAL a little bit more. FAQ'S 1. "I ran the drop test, and my rounds are still sticking in the chamber" - shorten the OAL 2. "But the longer rounds feed perfectly in ....... gun". - Great. But not in YOUR gun - shorten the OAL. 3. "But I load 124 grain MG FMJ's at .... OAL, and these BBI 124 gr bullets don't pass the Plunk Test". - Exactly right. Now you have to shorten the OAL of the BBI bullets until they pass the Plunk Test 4. "But I'm at ...." OAL, and don't want to go shorter". - Fine. Use another bullet. But if you have 1,000 of these new bullets, they will probably work if you shorten the OAL until they PASS the Plunk Test. 5. "But, I ran the Plunk Test, and they still don't feed." - Exactly right. They will NOT pass the Plunk Test until you load them short enough to drop freely from YOUR chamber 6. "But, the manual says to load them at ...." OAL. And they don't spin/drop in my chamber". - Exactly!! Drop the OAL, shorten the rounds, until they PASS the Plunk Test. 7. "It is really important to me to run these long cartridges in my gun, but they won't feed" - Buy a new gun, have the chamber reamed or shorten the OAL. 8. "I ran the Plunk Test, and they don't feed. I think the bullets are oversized or I don't have enough "crimp". - Set your crimp 1st, then measure your bullets - doubt any major mfgr of bullets is selling incorrect sized bullets, but it's possible. Shorten your OAL until they feed. 9. "Man, that's a Lot of Work". - Welcome to the wonderful world of reloading. 10. "My buddy has the same gun I have, and his cartridges won't feed in my identical gun". - Sorry, guess they're Not Identical. Shorten your OAL and try the Plunk Test in Your Gun. 11. "But, if I shorten the OAL, won't that affect pressure / velocity"? - It might. You must test each change (OAL, etc) for velocity and watch for pressure signs on the primer. 12. "But, this is a Great load - really accurate at ...." OAL - but it won't feed. When I shorten the OAL, it's not as accurate." - Up to you, if you want a very accurate single shot, go with the longer OAL. If you want a reliable gun, go shorter. If you want both (accuracy & reliability) try another bullet. 13. "But, I'm going to a major match tomorrow morning, and my favorite load won't spin/drop". - Too late, procrastinator. Bring along some already tested rounds that work in your gun, and when you get back from the match, work on the proper OAL for your new bullets. 14. "But, my rounds all pass the gauge test from EGW". - Unless your gauge has a 5" barrel, I'd test your rounds in the chamber of the gun you're going to shoot. If they don't pass the Plunk Test in YOUR chamber, you have to shorten the OAL. Sorry for being so long-winded, but every other day we get one or more of these excuses why members can't feed rounds thru their guns. If you have any to add, pls let me know. Hope this helps - should this be in New Shooter Forum? Jack Link to comment Share on other sites More sharing options...
bowenbuilt Posted August 17, 2014 Share Posted August 17, 2014 This should be a sticky...... Link to comment Share on other sites More sharing options...
ZackJones Posted August 17, 2014 Share Posted August 17, 2014 Agree with bowenbuilt. Excellent information here, thanks, Jack! Link to comment Share on other sites More sharing options...
zhunter Posted August 17, 2014 Share Posted August 17, 2014 Sticky vote +2 Link to comment Share on other sites More sharing options...
kneelingatlas Posted August 17, 2014 Share Posted August 17, 2014 Thanks for posting this Jack! If there's one which bears repeating it's #11: 11. "But, if I shorten the OAL, won't that affect pressure / velocity"? - It might. You must test each change (OAL, etc) for velocity and watch for pressure signs on the primer I'd say the majority of popular loads for USPSA are pushing the envelope, even 9 minor loads when you mix heavy bullets and fast powders, so it's important to remember that the shorter the OAL, the higher the pressure and most times that correlates with higher velocity, but not always. Powders can behave strangely when pushed past their limits, so if you get a lower velocity than you expect, you may be at the limits pressure wise with that powder. Link to comment Share on other sites More sharing options...
houser52 Posted August 17, 2014 Share Posted August 17, 2014 I just recently ran into this exact OAL problem with a new bullet I wanted to try, a 9mm, 124 gr. coated RN without a lube groove. I started with the recommended lead bullet OAL from my manual and it failed the plunk test. After shortening several times it still was too long. I'm now at 1.075. Some will still not pass the test but I was unsure to go any shorter. After reading the post above I feel safer now about shortening them enough and adjusting my powder so all will pass the test. Thanks for the info. Link to comment Share on other sites More sharing options...
grouptherapy Posted August 17, 2014 Share Posted August 17, 2014 (edited) 1.050 is the limit last time I cked. Good sticky. Sent from my iPhone using Tapatalk Edited August 18, 2014 by grouptherapy Link to comment Share on other sites More sharing options...
levellinebrad Posted August 18, 2014 Share Posted August 18, 2014 I have some lead that I load down to .990 with wsf. Link to comment Share on other sites More sharing options...
mississaugagunnut Posted August 18, 2014 Share Posted August 18, 2014 Great post. I have a Cz shadow and I have to load some projectiles much shorter than others in order to pass the plunk test. Link to comment Share on other sites More sharing options...
Laughingdog Posted August 18, 2014 Share Posted August 18, 2014 Just bear in mind that there's no reason to have to randomly try a bunch of different lengths, dropping in one after another for the "plunk test". That's a pointless waste of time. Doing this, you can determine the maximum length load for any particular bullet/barrel combo without having to load a single dummy round. http://www.brianenos.com/forums/index.php?showtopic=196723&hl= I just calculated the maximum length for two bullets last night to load in my CZ-75 in a couple of minutes, and that included field stripping the gun. So the first rounds I loaded dropped in and out flawlessly, right off the bat. Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted August 18, 2014 Author Share Posted August 18, 2014 Laughingdog, sounds like a great alternative:) I'll stay with random, but for those so inclined, your technique looks excellent. :bow: Link to comment Share on other sites More sharing options...
ToddKS Posted August 18, 2014 Share Posted August 18, 2014 I like the idea of using Laughingdog's technique to baseline what should be max and then follow that up with the plunk test on some dummy rounds. That would save you from the random starting point but still give you the physical verification of the plunk. It is a little extra effort but I spend a lot of time reloading anyway. Link to comment Share on other sites More sharing options...
grouptherapy Posted August 18, 2014 Share Posted August 18, 2014 Once it's set for that barrel and the crimp is good let it roll. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Laughingdog Posted August 21, 2014 Share Posted August 21, 2014 I like the idea of using Laughingdog's technique to baseline what should be max and then follow that up with the plunk test on some dummy rounds. That would save you from the random starting point but still give you the physical verification of the plunk. It is a little extra effort but I spend a lot of time reloading anyway. As long as you include a 0.010"-0.020" buffer, you should be fine every time...at least with the rifling. something to keep in mind is that the case wall gets a little thicker as you move towards the base. So if you're doing a load that is under 1.100", you'll find an increase in the number that don't pass case gauge. When you do, it's a bulge in the middle of the case, not the base of it, that's hosing you. Link to comment Share on other sites More sharing options...
1sickPuppy Posted September 6, 2014 Share Posted September 6, 2014 Thanks for the write and comments. I'm going to try out these techniques... Link to comment Share on other sites More sharing options...
mjmagee67 Posted September 7, 2014 Share Posted September 7, 2014 You forgot the; if you don't like the short AOL you can have the chamber opened up to accept the longer AOL. I own several 9mm, I got a Kimber Target II and I would have had to shorten the round way more that I want to, so my gunsmith opened up the chamber. Now the gun runs great and doesn't take a different load. Link to comment Share on other sites More sharing options...
GARD72977 Posted September 12, 2014 Share Posted September 12, 2014 You forgot the; if you don't like the short AOL you can have the chamber opened up to accept the longer AOL. I own several 9mm, I got a Kimber Target II and I would have had to shorten the round way more that I want to, so my gunsmith opened up the chamber. Now the gun runs great and doesn't take a different load. 7. "It is really important to me to run these long cartridges in my gun, but they won't feed" - Buy a new gun, have the chamber reamed or shorten the OAL. Link to comment Share on other sites More sharing options...
basman Posted September 12, 2014 Share Posted September 12, 2014 Great! thanks. Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted January 21, 2015 Author Share Posted January 21, 2015 Can anybody add to this list? Link to comment Share on other sites More sharing options...
Steve RA Posted January 21, 2015 Share Posted January 21, 2015 To possibly save some time and effort, if you are buying a custom barrel direct from the mfr, contact them and ask if they will throat the barrel to a dummy round you send them. If they will, this will save time and aggravation. Just make up a dummy that fits in your magazines with a little room to spare (lengthwise) and send it, then you can load as long as you will be able to, magazine wise. Try to make the dummy with as blunt a round nose bullet as you have/can find so that anything you want to load in the future will fit. Link to comment Share on other sites More sharing options...
Youngeyes Posted January 21, 2015 Share Posted January 21, 2015 This was great Jake. I must have missed it the first time. It's cold as hell here and the dog just peed on the rug... I know. I'll go shorten the OAL on my loads.. Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted January 21, 2015 Author Share Posted January 21, 2015 Just because your dog peed they're, doesn't mean you have to shorten their OAL. There not always in need of shortening. Sounds like its really coooolllllllddddd they're. Hope it warms up for you over their. Link to comment Share on other sites More sharing options...
1sickPuppy Posted January 31, 2015 Share Posted January 31, 2015 Is it better to go with the longest OAL that clears the chamber and mags? Link to comment Share on other sites More sharing options...
Steve RA Posted January 31, 2015 Share Posted January 31, 2015 Maybe !!! Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted January 31, 2015 Author Share Posted January 31, 2015 Is it better to go with the longest OAL that clears the chamber and mags? As Steve said, MAYBE. Best to 1. make sure you leave enough clearance that you don't find a round too long - back off "the longest" a bit, and, 2. experiment - might be more accurate at lower OAL's - but be cautious re: reducing your powder charge a bit to prevent too much pressure - have to be cautious in developing loads. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now