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Old June 9, 2019, 07:48 AM   #1
ReloadKy
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book suggested OAL or your own OAL determination

How many of you all use the published / suggested OAL in reloading manuals or use your own determination of what your rifle likes? Just trying to see what some of you seasoned veterans of the reloading press like to do.

The reason I am asking is I came across something when reloading for my 7mm mag. I have excellent results reloading rounds at 3.280. I wanted to try some Sierra Game Kings 140 gr. The suggested OAL from sierra is 3.240. I have been trying the 3.240 and have gotten decent results just not what I am looking for in terms of accuracy.
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Old June 9, 2019, 08:11 AM   #2
F. Guffey
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book suggested OAL or your own OAL determination
There is COL as in case overall length, there is MAX COL and then there is off the lands.

Straight-a-way; I am the fan of the running start, I want my bullets to have that jump start. Don't get me wrong I believe it is cute to stuff your bullets onto the lands, because of factory, I do not like the ideal of having the bullet setting still at the lands when everything behind it gets busy. I like that feeling of knowing my bullets are going to hit the lands a-running.

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Old June 9, 2019, 09:20 AM   #3
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Experience suggests tailoring your seating depth to your rifle's particular chamber can help in the accuracy department. The quick and easy answer is to seat to published data, the longer road is to develop your handloads to your chamber... this may or may not give you any benefit, sometimes a rifle just doesn't perform well with a particular bullet.

I don't necessarily agree with F.Guffey's statement... if you think about it, once the bullet is in motion it doesn't necessarily mean it stays in motion... hitting the rifling is like a car hitting a speed bump.
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Old June 9, 2019, 09:26 AM   #4
Don Fischer
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I like to seat my bullet's to just off the lands. I use a cleaning rod to get the starting length from and go from there. The COL in the manual will let the round chamber in all rifle's. But the bolt face to ogive is not the same in all rifle's. So I measure mine for the starting length. I like to have the bolt close on the seated bullet without being able to feel the bullet rub on the lands and without being able to see skuff mark's on the bullet at the ogive from the lands. You can actually get skuff mark's without being able to feel it with the bolt. The OLL will change a bit from one round to another but the length to the ogive won't change and that is the one you need to consider. Ogive to bullet tip can vary from one bullet to the next. Bolt face to ogive will not change.
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Old June 9, 2019, 09:33 AM   #5
F. Guffey
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if you think about it, once the bullet is in motion it doesn't necessarily mean it stays in motion...
I want my bullet past the refiling before it know it is there.

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Old June 9, 2019, 09:45 AM   #6
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As Don Fischer states, bolt face to lands will not change, it is fixed and constant.

In my auto load pistol I use a fired unsized case and a bullet to find the Max length for that barrel and that bullet. I then reduce length .005" to move the bullet off the rifling. From there I will adjust for accuracy. I do also compare this length to the published length and make powder adjustments as I feel needed.
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Old June 9, 2019, 09:59 AM   #7
F. Guffey
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As Don Fischer states, bolt face to lands will not change, it is fixed and constant.
And then there is throat erosion.

I am the fan of knowing the distance from the rifling to the bolt face.

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Old June 9, 2019, 11:52 AM   #8
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Quote:
Originally Posted by F. Guffey
There is COL as in case overall length, there is MAX COL and then there is off the lands.
I have never understood "COL" to refer to "case overall length." In fact, the concept of case "overall" length is, IMHO, an oxymoron. Overall means only one thing -- the length of an entire assembly, measured as an assembly. Case length is case length -- it isn't in any way an overall measurement.

I have always seen and thought of both C.O.L. and C.O.A.L. as referring to Cartridge OverAll Length.
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Old June 9, 2019, 03:19 PM   #9
David R
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I load for accuracy. If it shoots good at What the book says, I go for it. If it shoots best with the bullet touching the lands, then that is where it is.

In my 45 ACP, the cartridge headspaces on the lead bullet. Just load so the base of the case is flush with the hood.

I have an M1A that shoots best with bullets longer than the magazine will hold. SO I can have best accuracy and load one at a time or sacrafice some for semi automatic action. Its a compramise.

Usally its about .015 short of the lands, but it all depends on the rifle. In the case with the M1A, the throat is worn to a 3 on the guage. With my 243 its .015 short of touching. My 308 likes book spec. Go figure.....

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Old June 9, 2019, 03:53 PM   #10
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Quote:
Originally Posted by Aquila Blanca
I have always seen and thought of both C.O.L. and C.O.A.L. as referring to Cartridge OverAll Length.
Actually, they are:

Cartridge Overall Length (C.O.L.), post-1950s, and Cartridge Over-All Length (C.O.A.L) before then. The difference between the compound word overall and the hyphenated form over-all is that before the 1950s the compound form meant all things considered, while the hyphenated form referred to the physical length of something. Between my 1948 Webster's 2nd Edition and 1962 Webster's 3rd edition, the hyphenated form was dropped and both meanings were brought under the compound spelling.
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Old June 9, 2019, 04:39 PM   #11
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To actually answer the OP

I find where the bullet touches the land in any given gun I shoot. I have a home machined version (not for sale) of the Hornady tool, its all metal and more accurate.

I also load a blank and make it longer by .050 and then decrease it until I just get a bit of sticky on the extraction.

Then I back it off .020 for the initial load.

Then I load a spread of usually 1/2 grain going low to high and 10-15 each and see what I get for best groups (5x)

When I get one that is looking better than others then I play with adjusting COAL if I have any left or load up more at home all too long. I take my small press with me to the range and adjust COAL to see what works better.

I measure on the bullet Ogive not the tip.

I am mostly using Hornady bullets these days, I find an occasionally really wild variation where one will be .030 longer than the rest. So with a grain of salt, good to check two different bullets.
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Old June 9, 2019, 04:40 PM   #12
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I want my bullet past the refiling before it know it is there.
That is known as a smoother bore musket. Windage tends to be kind of wild.
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Old June 10, 2019, 06:55 AM   #13
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I'm typically loading 5.56, so I'm usually stuck with 2.26" OAL whether I like it or not. Other than that, I load 9mm a little on the long side (again, I use heavier bullets). M1 Garand gets the OAL that's in the book.
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Old June 10, 2019, 11:00 AM   #14
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I typically shoot cast. I typically shoot heavy for caliber projectiles.

If I'm not dealing with a magazine-fed rifle, I load as long as I can, lightly engraving the lands.

I've found that loading to that length generally saves time in load development.

If I'm dealing with feeding from a magazine, I'll load to the longest length that will fit and feed.
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Old June 10, 2019, 11:26 AM   #15
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Determining the OAL for a particular rifle is the last step I do in a series of "experiments" for getting the most accuracy. Sometimes I don't get that far. I start with the bullet manufacturer's recommended OAL for a particular bullet and when working on a load vary powder charges, then might change powder, then maybe primer or brass, but last attempt would finding "optimum" bullet seating. This works for me and as an example for my Ruger 308 I used Nosler bullets seated to Nosler specs., and varied powder charges (IMR 4895) and got several 7/8"groups @ 100. This doesn't happen with very gun, but I rarely see a great improvement from "custom" OAL...
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Old June 10, 2019, 01:51 PM   #16
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Quote:
Originally Posted by David R
In my 45 ACP, the cartridge headspaces on the lead bullet.
It shouldn't.
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Old June 10, 2019, 02:15 PM   #17
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I use published COAL as a guide to what the company used to develop their data - or even just a reference to which crimp groove they used (on the more oddball multi-groove/cannelure bullets) for that particular cartridge.

I can use that data to decide whether or not I think a powder charge adjustment is necessary when I use a different COAL. ...Which I nearly always do. I load very few cartridges to published COAL.
My favorite 9mm likes it short.
My 6.5-284 Norma likes 'em long.
My 6x45mm has almost zero published data and I usually have to seat very short.
My commercial 7x57mm can take bullets seated VERY long (so I do it).
And on down the line...

I load to whatever COAL I want, or the gun prefers. I really only use published COAL as a reference for powder charge adjustment, due to my differing COALs and the accompanying change in usable case capacity.
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Old June 10, 2019, 06:00 PM   #18
hounddawg
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this is how I do it

https://thefiringline.com/forums/sho...d.php?t=599693

a couple of weeks later used the same method with a 6CM in this thread

https://thefiringline.com/forums/sho...1&highlight=55

those are the last two loads I developed, coincidence or not I found at least 2 good loads that way
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Old June 10, 2019, 07:18 PM   #19
ReloadKy
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It is interesting to me to see how each reloader sees fit how to figure it out. Always more than one way to skin a cat!!!
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Old June 10, 2019, 07:34 PM   #20
David R
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Quote:
Originally Posted by Aguila Blanca View Post
It shouldn't.




You do it your way, I will do it mine.

25 yard targets. Cartridge headspacing on the bullet.


It worksfor me.

300 yards. 60 grain Linotype gas check bullet, Remington 700 VL 22-250
SR4759 powder 2800 fps. 5 1/4" 14 shot group. Bullet into lands.

David

Last edited by David R; June 10, 2019 at 07:49 PM.
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Old June 11, 2019, 03:54 AM   #21
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I use Hornady OAL gauge to check the length of my chamber for each of my rifles and usually start with 25 thousands off the lands, usually works well except for the Barnes ttsx which they suggest 50 thousands off the lands. I do have a Model 7 Rem in 7-08 that shoots cup and cores better at 50 off the lands.."That is what works for me"..
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Old June 11, 2019, 06:12 AM   #22
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For rifle rounds am using col suited (reliable/accurate/safe) for firearm(s) being loaded for. Have several rifles that will accept certain bullets considerably over standard max col.

While off subject, will also load 45 acp lead bullets into the rifling if suitable. Have gotten excellent accuracy doing this, and can really improve the accuracy of an otherwise mediocre pistol.
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Old June 11, 2019, 11:56 AM   #23
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Personally I won't fire any handloads in my 45 ACPs (3) where the the bullet is jammed into, or sits/headspaces on the rifling. The plunk test just shows a cartridge will chamber and how deep. What stops the cartridge from traveling deeper, like a bullet in/on the rifling, is not shown...
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Old June 11, 2019, 02:14 PM   #24
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The published/suggested OAL in reloading manuals is SAAMI spec. SAAMI Max OAL for the 7mm Mag is 3.290".
The whole off-the-lands thing is not necessary as it's a load tweaking technique only and is a 100% trial and error thing done after you have worked up the load.
"...You do it your way, I will do it mine..." You're not head spacing on the bullet even if you want to or think you are. The ACP head spaces on the case mouth.
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Old June 11, 2019, 03:41 PM   #25
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Originally Posted by T. O'Heir
The published/suggested OAL in reloading manuals is SAAMI spec.
Nope. Look at Sierra's or Hornady's databooks and next to each bullet is its own separate COL which is the one the manual authors used in their testing of the load.

Quote:
Originally Posted by T. O'Heir
You're not head spacing on the bullet even if you want to or think you are. The ACP head spaces on the case mouth.
Not headspacing on the mouth when it can't. If the bullet contacts the throat to stop the cartridge moving forward in the chamber before the case mouth reaches the end of case body portion of the chamber, it can't determine head clearance and therefore is not determining head space.
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