OAL

[tkvalead]

What determines the OAL of the Cartridge? Is there a formula to determine the OAL?

[Wreck-n-Crew]

Could use a little more info but powder type, bullet type should Give you an OAL on the load data charts, These can be found on the Powder website.

Also you can sometimes get the load data from the bullet manufacturer.

Also load data can be found in hand loading books which I recommend for anyone starting out without someone to teach them.

Is there a specific load data you are looking for?

Caliber, bullet weight and powder type would be helpful.

[tkvalead]

As of right now I have 9mm Berry plated bullets 124 gr. Have IMR 700X powder and CCI small pistol caps. I have a CZ75 P01 pistol. I do have a couple of books, a Lee 4th edition and the newest edition of Speer. I guess I'm just not understanding what I'm reading.

[jepp2]

What determines the OAL of the Cartridge

In published load data, the OAL is simply a record of the length of the test rounds. Why it is important is because the OAL determines bullet seating depth. And bullet seating depth can have a large impact on pressure. If you use a different bullet (same grain and basic type such as round nose) it can have a different length. So even if you load it to the same OAL, your bullet seating depth and pressure may be different.

On the 9mm, you will find OAL's as short as 1.010" to as long as 1.169" (the SAAMI max). But depending on your pistol, you need to determine what the maximum OAL length is for the bullet you are loading. And if the bullet seating depth is different, than you may need to adjust the powder loading to obtain the same pressure.

[Huskerguy]

As of right now I have 9mm Berry plated bullets 124 gr. Have IMR 700X powder and CCI small pistol caps. I have a CZ75 P01 pistol. I do have a couple of books, a Lee 4th edition and the newest edition of Speer. I guess I'm just not understanding what I'm reading.

Yes, OAL can be a bit confusing and not the most exacting science. In your example you gave us that it is a 124 grain Berry plated bullet. However, it does make a difference how the bullet is shaped. For instance I shoot Berry's 124 grain HBFP (flat point) bullet at 1.065 in my CZ. I shoot the Berry's 124 grain HBRN (round nose) at 1.150. Same weight bullet but different profiles.

I confirmed my OAL by doing was is commonly called the "plunk test." I also checked for signs of pressure because as stated above, the more you push the bullet down the case the more potential there is for increased pressure.

[Wreck-n-Crew]

IF it were me my starting load would be 2.9 and my AOL 1.090".


But if you get no further post with some tested data I would Call Winchester powders @ 913-362-9455 7:00am to 5:30pm Central Monday-Thursday.

That way you are sure.

[F. Guffey]

OAL, over all length, then there is case length, then there is the case head to the ojive length. There is COL, case overall length, the overall includes the bullet right out to the tip of the bullet, cases with too great an overall length could have problems fitting the magazine and or having trouble with the bullet hitting the lands before the bolt closes.

F, Guffey

[CherokeeT]

"What determines the OAL of the Cartridge? Is there a formula to determine the OAL?"

To answer your specific question, what will feed from your magazine and fully chamber in your firearm. The "plunk" test gives you the initial OAL for what will chamber. This way you know the bullet is not impacting the leade of the rifling when chambered. I usually start a little long and keep seating deeper until the cardridge will fully seat when droped into the chamber. If it will fit and feed from your mag(s), then you got it.

Since you should always start low, you can work up your powder charge using published data until you get the performance you want. The OAL for your gun probably will vary from the published data, hence start low and work up.

[Crusty Deary Ol'Coot]

Well, considering you do not indicate in your first post - yes you do in the second - what the cartridge is, I'll say this about that.

First issue is SAFETY followed by reliability of function. First and foremost.

Then as per rifles which I will address, there is the "magic" clearance of "X" number of thousands back from bullet contact with the lands that is spoken of. Now, that is a good place to start in many cases, but simply will not work in others due to a number of reasons.

Is it a hard fast rule that the bullet MUST be "X" distance from the lands and no more or less? Simple not so, as proven by many rifles that shoot very well and have variations of throat or leade length.

It is even said by some that changing bullet seating depth will have the same effect as to changing barrel harmonics as does the Browning/Winchester "Boss"

A person, in a rifle, can develop loads in which the bullet is, in fact, touching the lands, and do so with no safety or over pressure issues. OR they may produce loads in which the bullet is seated at what would usually be considered an excess distance from the lands and again do so safely and possibly with good accuracy .

This is part of "working up" loads for one rifle is all about, the goal being a product which gives the best performance possible from that one firearm.

So, Following the manufactures recommendations as to O.A.L. cartridge length is a very good place to start, but from there, it comes down to what makes the difference between "reloaders" and "handloaders" the latter group being those who product loaded ammo with more care, consideration AND testing then just simply have something that goes bang.

For most of us, we will never shoot a handgun well enough to ever see any positive or negative by varying the O.A.L. from that recommended by the bullet manufacture ------------ It therefore comes back to safety and reliability of function.

Crusty Deary Ol'Coot

[Jim243]

Sorry unless Berry's has changed their policy, you are NOT going to find any load data for their bullets. Most people say to use load data for those bullets half way between Lead bullets (Max) and Jacketed bullets (Max).

Not sure that helps, since I don't trust their bullets at all, but that is just me.

For OAL depending on the shape of the bullet you are using, I would go with the OAL for the same shape bullet in a jacketed configuration.

As always start lower than max and work your way up looking for pressure signs.

Jim

[Crusty Deary Ol'Coot]

What Jim said!

CDOC

[BDS-THR]

OAL (Overall Length) and COL (Cartridge Overall Length) both describe the length of the loaded round. OAL is used in Alliant and Lyman #49 load data and COL is used by Accurate/Hodgdon/IMR/Winchester/Ramshot/Vihtavuori load data.

Originally Posted by Jim243

Sorry unless Berry's has changed their policy, you are NOT going to find any load data for their bullets

Accurate load data and Ramshot load data have listed loads for Berry's plated bullets under "BRY" for some time. Vihtavuori load data lists Rainier plated bullets. Hodgdon load data has been listing Berry's plated bullets under "BERB" for 9mm 130 gr RN and recently added 40S&W 155/165/180 gr FP bullets.

Originally Posted by tkvalead

What determines the OAL of the Cartridge?

Not the OAL/COL listed in the published load data but the barrel you use in your pistol. Often, powder/bullet manufacturers measure maximum average chamber pressures using test barrel fixtures and not actual pistols so using the listed OAL/COL won't ensure the finished rounds will reliably feed and chamber from the magazine.

Is there a formula to determine the OAL?

Yes. To determine the working OAL for your pistol/barrel, you first determine the maximum OAL and then the working OAL. Here are the steps.

- Take the barrel out of the pistol and starting with the SAAMI max length of 1.169" decrease the OAL until the dummy test round (no powder, no primer) drops in the chamber freely with a "plonk" and spin without hitting the start of rifling. This is the max OAL.

- Next, reassemble the pistol and lock the slide back. Put the max OAL dummy round in the magazine and release the slide without riding it. If the max OAL won't reliably feed/chamber, you may need to incrementally shorten the OAL until it does (say by .005"). This is the working OAL that works for "your" pistol/barrel and may vary from pistol to pistol. If you load for multiple pistols, use the shortest working OAL.

- Now you can conduct your full powder workup using the working OAL from the start charge.

Hope this helped.

[Unclenick]

You'll find all the following used to mean the total length of the cartridge from stem to stern in this forum and other places.

1. Cartridge Overall Length—post 1960's dictionary English usage of 'Overall'.
2. COL—abbreviation for 1., above.
3. Cartridge Over-all Length—pre-1960's dictionary English hyphen used.
4. COAL—abbreviation for 3, above.
5. OL—Overall Length, short form of 2.
6. OAL—Over-all Length, short form of 4.
7. CL—Cartridge Length, abbreviation for any of the above, omitting "overall" or "over-all".
8. AOL—America Online, an Internet service name commonly transposed from OAL.

I'll use 2., abbreviation for the first version, here:

COL = Case Length + Bullet Length - Seating Depth

Where:
Case Length = a fixed value: either the SAAMI case length or, more commonly, a trim-to length given in load data.
Bullet Length = an average measured length for your lot or the manufacturer's nominal average length (some will tell you, some won't).
Seating Depth = how far below the case mouth the base of the bullet is when the case has the length as defined above.


Constraints:

You can load to any COL that works well in your gun for the way you load and shoot. This assumes you know how to work up a load correctly for non-standard or non-specified COLs. Some extremes in seating depth will take loads out of the SAAMI standard length range. In rifles this can involve seating bullets out further than will fit in a magazine when maximum precision (minimum group size) is required. But if you are not loading singly, other factors have to be considered.

Use the SAAMI drawings for minimums and maximums if you want the cartridges to be able to fit in all SAAMI compliant magazines and to feed from them. SAAMI drawings may be seen at the following sites. Just scroll to the name and click on it to see the drawing (note that Firefox's change to their own PDF reader blocks this action on my copy, so you may need to use IE or some other browser):

Centerfire Rifle
Centerfire Handgun
Rimfire
Shotgun


Effects:

Pressure will tend to increase with seating depth, though this is complicated in many pistol cartridges by the primer unseating the bullet before the powder is fully lit, so that if you take the bullet from a depth at which it is not being unseated to a deeper one where it is, pressure can actually drop. In rifles pressure drops as you seat out further, but only until the bullet gets close enough to the lands to start reducing the amount of gas that bypasses the bullet during bullet jump, which causes it to rise again. So the results of changing seating depth can be unpredictable in some instances. For that reason, always back powder charge off 10% when you make a change and work the load up again at the new depth, just to be safe.

Group size will often change with seating depth. Many rifles have one or two seating depths that are "sweet spots". Many handgun, particularly when using softer bullets than jacketed bullets, see precision increase and metal fouling decrease if bullets are seated out to headspace on the bullet contact with the rifling throat rather than the case mouth or the extractor hook.

Feeding reliability is often affected by length not only as the SAAMI standard shows them, but also some self-loading weapons in particular will function most reliably with the bullet in an even narrower COL range than SAAMI suggests.