O.A.L. Adjustment

Hog head · March 19, 2015, 06:47 AM

I'm loading for a .308 auto loader and have a question about OAL. How far can one keep working the bullet into the case before it becomes unsafe. whats the rule for how much bullet can be past the bottom of the neck if any. I Know the min in the neck is at least one bullet dia and I know the procedure for load work ups (start low and sneak up) but not not much about OAL.

243winxb · March 19, 2015, 08:13 AM

Quote:

How far can one keep working the bullet into the case before it becomes unsafe.

Should be fine using a starting load. There is a point on the ogive where the bullet diameter gets smaller than .308". As a general rule, this area should not go below the case mouth. You want the full bearing surface of the bullet in contact with the neck. Seat to deep and the bullet will fall into the case, unless the powder stops it.

Hog head · March 19, 2015, 09:52 AM

I thought this would be fine but wanted a second opinion. I did this for my 223 bolt gun and it worked out with excellent results. I just didn't know if I got lucky and didn't get hurt or if it would all good. My best powder/bullet combo is in the middle of the scale if I seat .005 deeper each time I would think I would see any pressure issues before a problem arises. Thanks for the reply

AllenJ · March 19, 2015, 10:26 AM

Here is an excellent link to a post with information about COAL and pressure spikes.

Bart B. · March 19, 2015, 10:44 AM

There is no standard depth for seating any caliber bullet in a case neck. Whatever grips the bullet to hold it in place when another round's fired and lets it feed from the magazine reliably is good enough. One caliber deep past the case mouth's a myth that started decades ago.

The bullet's jump to the rifling is not critical until you shoot your stuff into no worse than 1/4th MOA at 100 yards. And with a given OAL set up with a new barrel or bullet, remember the rifling throat grows longer about .001" for every 10 to 30 shots fired; depends on the amount of powder burned and powder types. Are you going to seat them .001" shallower every dozen or two shots?

With over the counter sporting rifles and military rifles, one typically will not notice any difference in accuracy while the throat erodes away 1/10th inch from its starting point. So, I don't think it's worth the time and ammo to shoot a few groups to see which one's the smallest for a given OAL. Especially when no two groups of the same load are the same size anyway; the smallest one you shoot happens just as often as the largest one.

Seat bullets 1/16th inch shorter than magazine length the shoot them. If accuracy's not good, change the charge weight by a full grain, then try again.

BWM · March 19, 2015, 12:33 PM

ALL reloading books gives AOL for there bullet! Some has a very thin point and some are rounded. 308 150 Gr AOL 2.745 168 Gr AOL 2.800 125 Gr AOL 2.780 110 Gr AOL 2.595 so you can see there is a starting point. There is a way to find the thought by putting a bullet in a fired case jest close the case mouth a very little and start the bullet very little put in your gun close all the way then remove it easy so as not to move the bullet then mike the AOL. That will tell your max AOL you should set the bullet 5 thousand back into the case when reloading This AOL is only good for that bullet because different makers has different shape bullets of the same weight. I hope this help you out. GOOD LUCK

Bart B. · March 19, 2015, 12:51 PM

I think reloading data's OAL is only an example its author chose for the chamber he used. It rarely will give the same fit and clearance in all the other chambers it will be tried in. If it fits as desired to start with, that's good enough.

If you give the same set of components to ten people to develop a load for a given rifle, they'll probably have 10 OAL's they get best accuracy with. And ten different powder charge weights, too.

BWM · March 19, 2015, 12:59 PM

Yes that is true. But it is a starting point. For people that has been reloading for years we know all of this. So we should give them a starting point that will help them out. Have a safe day

Bart B. · March 19, 2015, 01:41 PM

If most people that have been reloading for years we know all that, they sure don't practice it when reloading.

Some people who've never reloaded a round in their lives know that good accuracy in a rifle is maintained over a 3000 to 4000 round barrel life while the throat advances 1/10th inch during that time. That's how much a given round's OAL being the same will have the bullet's jump to the rifling increase.

March 19, 2015, 06:47 AM	#1
Hog head Member Join Date: March 26, 2009 Location: east TN. Posts: 66	O.A.L. Adjustment I'm loading for a .308 auto loader and have a question about OAL. How far can one keep working the bullet into the case before it becomes unsafe. whats the rule for how much bullet can be past the bottom of the neck if any. I Know the min in the neck is at least one bullet dia and I know the procedure for load work ups (start low and sneak up) but not not much about OAL. __________________ The government is like a baby's alimentary canal,with a happy appetite at one end and no responsibility at the other............Ronald Reagan

March 19, 2015, 09:52 AM	#3
Hog head Member Join Date: March 26, 2009 Location: east TN. Posts: 66	I thought this would be fine but wanted a second opinion. I did this for my 223 bolt gun and it worked out with excellent results. I just didn't know if I got lucky and didn't get hurt or if it would all good. My best powder/bullet combo is in the middle of the scale if I seat .005 deeper each time I would think I would see any pressure issues before a problem arises. Thanks for the reply __________________ The government is like a baby's alimentary canal,with a happy appetite at one end and no responsibility at the other............Ronald Reagan

March 19, 2015, 12:33 PM	#6
BWM Senior Member Join Date: November 6, 2013 Location: SW IN Posts: 438	ALL reloading books gives AOL for there bullet! Some has a very thin point and some are rounded. 308 150 Gr AOL 2.745 168 Gr AOL 2.800 125 Gr AOL 2.780 110 Gr AOL 2.595 so you can see there is a starting point. There is a way to find the thought by putting a bullet in a fired case jest close the case mouth a very little and start the bullet very little put in your gun close all the way then remove it easy so as not to move the bullet then mike the AOL. That will tell your max AOL you should set the bullet 5 thousand back into the case when reloading This AOL is only good for that bullet because different makers has different shape bullets of the same weight. I hope this help you out. GOOD LUCK __________________ Man that likes guns. Navy. USS Ponchatoula AO 148 USS Vesuvius AE 15 Last edited by BWM; March 19, 2015 at 12:51 PM.

March 19, 2015, 12:59 PM	#8
BWM Senior Member Join Date: November 6, 2013 Location: SW IN Posts: 438	Yes that is true. But it is a starting point. For people that has been reloading for years we know all of this. So we should give them a starting point that will help them out. Have a safe day __________________ Man that likes guns. Navy. USS Ponchatoula AO 148 USS Vesuvius AE 15

March 19, 2015, 10:26 AM	#4
AllenJ Senior Member Join Date: December 11, 2009 Location: Northern California Posts: 1,766	Here is an excellent link to a post with information about COAL and pressure spikes.

March 19, 2015, 10:44 AM	#5
Bart B. Senior Member Join Date: February 15, 2009 Posts: 8,927	There is no standard depth for seating any caliber bullet in a case neck. Whatever grips the bullet to hold it in place when another round's fired and lets it feed from the magazine reliably is good enough. One caliber deep past the case mouth's a myth that started decades ago. The bullet's jump to the rifling is not critical until you shoot your stuff into no worse than 1/4th MOA at 100 yards. And with a given OAL set up with a new barrel or bullet, remember the rifling throat grows longer about .001" for every 10 to 30 shots fired; depends on the amount of powder burned and powder types. Are you going to seat them .001" shallower every dozen or two shots? With over the counter sporting rifles and military rifles, one typically will not notice any difference in accuracy while the throat erodes away 1/10th inch from its starting point. So, I don't think it's worth the time and ammo to shoot a few groups to see which one's the smallest for a given OAL. Especially when no two groups of the same load are the same size anyway; the smallest one you shoot happens just as often as the largest one. Seat bullets 1/16th inch shorter than magazine length the shoot them. If accuracy's not good, change the charge weight by a full grain, then try again.

March 19, 2015, 12:51 PM	#7
Bart B. Senior Member Join Date: February 15, 2009 Posts: 8,927	I think reloading data's OAL is only an example its author chose for the chamber he used. It rarely will give the same fit and clearance in all the other chambers it will be tried in. If it fits as desired to start with, that's good enough. If you give the same set of components to ten people to develop a load for a given rifle, they'll probably have 10 OAL's they get best accuracy with. And ten different powder charge weights, too.

March 19, 2015, 01:41 PM	#9
Bart B. Senior Member Join Date: February 15, 2009 Posts: 8,927	If most people that have been reloading for years we know all that, they sure don't practice it when reloading. Some people who've never reloaded a round in their lives know that good accuracy in a rifle is maintained over a 3000 to 4000 round barrel life while the throat advances 1/10th inch during that time. That's how much a given round's OAL being the same will have the bullet's jump to the rifling increase.