# Determining best OAL?



## gregkdc (May 19, 2008)

I got some tax money and bought the Lee 50th kit along with everything else I needed to start reloading. 
One area I am still a little confused about is determining the best OAL. Some people claim that you are better off with the bullet ogive right on the lands, while others say that you want a little jump to the lands. So I tested a few cartridges with differing OAL’s. I made 3 five round sets of the starting load for my .30-06 and varied the OAL from minimum to maximum as follows 3.330, 3.335 and 3.340. As it turns out the load with OAL of 3.335 did the best, this is no surprise as it is not at the extremes of length. So my next testing will be to make 3 more batches of ammo and very the length using 3.335 as the starting point. 
Anyway how do you guys determine what length works best for your rifle? Is it just a matter of trial and error? Also when you find an OAL that works best what do you do when you try different bullets I assuming this where a seating gauge comes in?

P.S. pulling the trigger on your first reload is a little scary but exciting!


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## Critter (Mar 20, 2010)

It sounds like you are doing it the right way. I have rifles that like the bullet just off of the lands and I have one that likes a big jump from the case to the lands. It is all trial and err. Also if you plan on using the reloaded rounds for hunting make sure that the bullet is deep enough that it doesn't fall out of the case when the rifle is under recoil along with fitting in the magazine.

As far as different bullets of the same weight start where you found it works best with the first rounds then experment some. If the weight changes you need to play around with that load.


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## Bax* (Dec 14, 2008)

This is something that I have always been confused by. I have never been able to figure out how to tell where the bullet sits in relation to the lands.

Any input on that?


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## Critter (Mar 20, 2010)

Bax* said:


> This is something that I have always been confused by. I have never been able to figure out how to tell where the bullet sits in relation to the lands.
> 
> Any input on that?


The way that I did it was to make up a unprimed dummy round. Then chamber it with the bullet way out. If it had problems chambering I would seat it a little bit deeper, if it got stuck in the lands I would take a cleaning rod and knock it out and retry. Then once I had the maximum length of the loaded round I would mark it with a black marker pen with the weight of the bullet. Then whenever I needed to change the bullet seating depth on the die I could just pull that round out and put it in the seating die and adjust it.

There are other ways but that is how I did mine.


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## waspocrew (Nov 26, 2011)

gregkdc said:


> P.S. pulling the trigger on your first reload is a little scary but exciting!


I know! You start thinking... did I measure the charge right? Etc, Etc.

I think you've got off to a great start already! I would just echo what critter mentioned about starting from the point you found to work (as long as it's the same weight bullet).

Bax,
I'm no reloading expert by any means, but this is how I found the best OAL for my 700 .308... I took a resized case and made a few vertical cuts into the neck. I used a dremel to do this part. Check for any burrs on the outside and remove if necessary. I then barely seat a bullet and then chamber it. The lands will seat the bullet the rest of the way. Open the bolt and remove and then measure the OAL. I did this 3 or 5 times and then averaged it out just to be safe. I was using Barnes bullets and they like a .05" jump, so I subtracted .05" from my OAL and that's where I worked from. I then loaded up a few rounds and either increased or decreased the now determined OAL by .005".

This is when I decided that I had the right OAL for the 165 TSX:
[attachment=0:25w72dad]reload shots.jpg[/attachment:25w72dad]

The group would open up if I seated deeper or longer, so I stuck with this. Hope that helped!


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## gregkdc (May 19, 2008)

Critter said:


> The way that I did it was to make up a unprimed dummy round. Then chamber it with the bullet way out. If it had problems chambering I would seat it a little bit deeper, if it got stuck in the lands I would take a cleaning rod and knock it out and retry. Then once I had the maximum length of the loaded round I would mark it with a black marker pen with the weight of the bullet. Then whenever I needed to change the bullet seating depth on the die I could just pull that round out and put it in the seating die and adjust it.


That sounds like a pretty good way of going about it.

Also I am shooting a .30-06 that the reloading manual says has a maximum OAL of 3.340. If a person's rifle can handle it i.e. won't get jammed etc. do you ever go beyond that number or is it one of those holy commandments you never violate? I am just curios as it looks right now I will never need to do that.


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## waspocrew (Nov 26, 2011)

gregkdc said:


> Also I am shooting a .30-06 that the reloading manual says has a maximum OAL of 3.340. If a person's rifle can handle it i.e. won't get jammed etc. do you ever go beyond that number or is it one of those holy commandments you never violate? I am just curios as it looks right now I will never need to do that.


If I remember hearing right, the published OALs are set to be safe for nearly every rifle. This results in a lot of free bore. When I loaded my .308, the bullets were seated way past that length. I think you're ok as long as you watch for pressure. Also, the published OAL will help keep the correct neck tension on the bullet.

When messing with the OAL, make sure that you can still fit the round in the magazine. I have a Tikka I am going to load for and the box mag is going to definitely limit figuring out the best OAL. I guess I'll just seat as far as I can go, and then mess with the powder charge. I guess it's one less variable to worry about!


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## DallanC (Jan 13, 2009)

It all depends on your specific rifle. How big is the magazine? How is the feed angle of the chamber? Those all vary and can give some leeway in your overall COL for the cartridge.

The distance between the bullet olgive and the riflings is called "Freebore". Just as a side note, Weatherby purposely gives alot of freebore in their magnum rounds to get a good jump in speed before the bullet engages the rifling. It works well for them.

Every rifle is different, some can be picky, others dont care. You need to find you what YOUR rifle likes. I wouldnt sweat micro MOA accuracy in a hunting rifle either... 1-2 MOA is plenty for 90% of people big game hunting.


-DallanC


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## Bo0YaA (Sep 29, 2008)

waspocrew said:


> gregkdc said:
> 
> 
> > P.S. pulling the trigger on your first reload is a little scary but exciting!
> ...


That's exactly the same way I do it and it works great. However, before I start messing around with OAL I usually go through standard loads with a standard OAL. I have yet to find a load that I needed to adjust my OAL from published specs in order to get sub moa accuracy. Up to this point its been more about powder, bullet combination. I'm sure if I took some of my loads that shoot 1/2"-3/4" groups and messed with the OAL I could get them shooting though the same hole. However, I'm a hunter not a match shooter and I figure 3/4 or hell even 1" moa groups at 100 yards is good enough for the distances I ever plan on shooting.


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## Bo0YaA (Sep 29, 2008)

Oh and here is a load I was able to find in my .300. It shoots better then I am able to. I panicked on the 5th shot and pulled it :mrgreen: .

73 grains of IMR-4350
165gr Speer Hot Cor
CCI-250 primer
Trim-2.610
COAL-3.340


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## waspocrew (Nov 26, 2011)

[quote="Bo0YaA"
However, I'm a hunter not a match shooter and I figure 3/4 or hell even 1" moa groups at 100 yards is good enough for the distances I ever plan on shooting.[/quote]

I completely agree, I'm not too concerned about groups either.... messing with OAL is just something to do to keep making reloading interesting!


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## Wes (Jan 3, 2008)

Here is a list of tools that take all the guess work out of determining your rifle's max OAL when the bullets are touching the lands 
http://www.sinclairintl.com/.aspx/pid=3 ... -standard-
http://www.sinclairintl.com/.aspx/pid=3 ... fied-Cases
http://www.sinclairintl.com/.aspx/pid=3 ... rator-Body
http://www.sinclairintl.com/.aspx/pid=3 ... ert-30-cal
You will also need a good caliper. 
Each rifle will have it's own preference where it likes the bullet to be seated. My custom 7mm mag likes them touching the lands. Groups will open up as I move away from the lands. My 22-250 will put 5 bullets in one hole touching the lands and will also open up as I move back but will group in the same hole again at .120 off the lands. Berger has some great tips for determining the best OAL for your rifle.
http://www.snipershide.com/forum/ubbthr ... ype=thread
Hope this helps
Wes


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## Cooky (Apr 25, 2011)

A past thread on the topic.
viewtopic.php?f=15&t=36582
The final answer is in the shooting.


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## longbow (Mar 31, 2009)

I bought a OAL gauge many years ago and used it many many times. They're cheap and easy to use. You should buy one.
I usually start .010 off the lands and develop my powder charge there. Then I mess with the OAL, checking magazine function and chambering with each change I make. I also keep a close eye for high pressure signs. Sometimes I end up jamming .010+ into the lands and sometimes I end up seating bullet way back. I'm quite surprised at how many times I end up back around .010 off the lands.


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## DallanC (Jan 13, 2009)

If you really want to use calipers to measure a bullet, do NOT go off the tip to the base, that can vary alot. Measure off the olgive of the bullet using a Comparator, I use this one:

http://www.midwayusa.com/product/365474 ... 3-calibers

-DallanC


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## gregkdc (May 19, 2008)

After firing many rounds of ammo I have discovered that my gun likes to have the bullet either touching the lands or slightly seated into the lands but it didn't really make much of a difference between the two. 

I have also noticed that weather or not I am on or off the lands and even with starting loads I am getting flat primers. :roll: How accurate are flat primers for determining pressure? The gun is a .30-06, I am using winchester large rifle primers and brass with 165 grain sierra spire point boat tail bullets. I have tried IMR 4046 in different amounts from minimum(48 grains) to maximum(52 grains) all shot fine and although there were no other signs of high pressure all had flat primers. I have also tried H380 on and off the lands with minimum loads of 51 grains and an intermediate load of 54 grains, both of these loads also had flat primers. I wasn't too concerned until I shot the last load, not only did the primers flatten but the cases started to get stuck so I quit shooting that load. I can't think of waht could be causing the problem.


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## waspocrew (Nov 26, 2011)

I'm still pretty new to reloading, so I'm interested to hear from others with more experience. I have heard that when you seat bullets into the lands or closer into the lands, pressure can increase quite a bit. Think of your truck tire parked right next to the curb. It takes a lot more energy to push your tire up and over the curb than if you had a little bit of a run before the curb.


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## Cooky (Apr 25, 2011)

Please. Never, ever, ignore pressure signs. Flat primers are a bad thing, a sticky bolt is half a step from disaster. Waspocrew is right on the money. Seating on or in the lands is something the target and benchrest guys do for extreme accuracy, but they know how to deal with the increased pressures. When you are that close to the edge anything (dirty bore) can push you to the point where things start to break.


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## gregkdc (May 19, 2008)

Cooky said:


> Please. Never, ever, ignore pressure signs. Flat primers are a bad thing, a sticky bolt is half a step from disaster. Waspocrew is right on the money. Seating on or in the lands is something the target and benchrest guys do for extreme accuracy, but they know how to deal with the increased pressures. When you are that close to the edge anything (dirty bore) can push you to the point where things start to break.


That's what I thought, the weird thing is that I am getting flat primers even when seating the bullets to the normal OAL (way off of the lands), and with starting loads. Could it be the primers? I wasn't too worried about it until I started getting stuck cases (2 of them) and I stopped shooting that batch. For what it is worth I had some factory winchester power points that performed even worse, flat primers, smudge around the primers and even more stuck cases, could it be a problem with my gun? I never really paid much attention to this before I started reloading so I don't remember how past ammo has performed in my gun. It is probably too early to tell but both times I have seen primer problems was with winchester primers.


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## gregkdc (May 19, 2008)

One other thing, I didn't make myself too clear about the stuck cases. The gun I am shooting is a single shot that has a spring loaded ejector. If the case is stuck with more force than the ejector develops then it doesn't come out. This ejector isn't that strong as it only took a very mild tap with a cleaning rod to get the cases out. If this had been a bolt gun I think the bolt would have no problems, and may feel just a little sticky rather than stuck.


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## Cooky (Apr 25, 2011)

How do things look and act compared to factory ammo? Clean the heck out of it, then shoot some cheap Winchester factory loads and see.


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## gregkdc (May 19, 2008)

Cooky said:


> How do things look and act compared to factory ammo? Clean the heck out of it, then shoot some cheap Winchester factory loads and see.


Compared to the winchester power points better, and just a little worse than low end federal or remington. I bought some different primers CCI instead of winchester to see if that is part of the problem. Apparently winchesters are the hottest ones out there, it just seems weird that I would get pressure signs with minimal loads using all of the same components that were recommended. I also bought a hornady case length gauge just to see if that is the problem what the heck it was only $9.00. I will start over with the minimal load and let you guys know how it goes.


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