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Old February 4, 2012, 10:15 PM   #1
MEATSAW
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How to estimate OAL without having to mess up a bunch of rounds

I am setting up a Lee turret press and I got my lee deluxe 4 die set for loading up some .40S&W. Question is how many turns out on the loading die to set proper depth/OAL? I don't want to have to do trial and error and load up a bunch of wrong bullets if I don't have to. If I could start out close to right on that would be great. I am using A#5 powder and using 155 gr Rainer FMJs. Thanks for any assistance!
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Old February 4, 2012, 10:18 PM   #2
Brian Pfleuger
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Start long and work down. You shouldn't really mess up too many.
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Old February 4, 2012, 10:22 PM   #3
wncchester
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There is no reason to mess up any. Never mind the book OAL, keep your first powder charges maybe .5 gr. under book max, start out long and slowly work down until you can crimp in the cannalure.
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Old February 4, 2012, 10:30 PM   #4
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Go with the OAL they used with the data in the manual you are using. Set the seating die so you know it will be long. Keep seating the bullet a little lower and checking it with your calipers until you reach that OAL. Then take the barrel out of your gun and drop the round in. If it goes all the way in then you are good to make more at that OAL. If not you have some more adjusting to do. Keep an eye on the OAL to make sure you don't go too short. Shorter OAl will raise pressure so start at the start load and work up. I also make a dummy round with just a case and bullet so when I need to adjust to a different bullet profile I back out the seater stem, raise the dummy into the seater die and screw the stem down until it touches the dummy round, take all the guess work out.
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Old February 4, 2012, 10:51 PM   #5
amathis
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+1 for what Crusty said

+1 for what Crusty said.

Dummy rounds are your friend!

When I start out with a new load, I set it to my closest dummy round that has the longest OAL. From there you just work down slow. Otherwise you may crimp the case prematurely and end up with a buckled case. . . . . (don't ask)
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Old February 4, 2012, 11:28 PM   #6
BDS-THR
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Quote:
Originally Posted by CrustyFN
Go with the OAL they used with the data in the manual you are using.
You do not need to use the OAL listed on published load data as testing barrel fixtures (not real pistols) are used to measure chamber pressures and using published OALs WILL NOT ensure reliable feeding/chambering of finished rounds in your pistols.

Determining OAL should not be a guessing game and I use the following process for semi-auto loads whenever I use a new bullet:

1. Make sure resized cases drop freely into the barrel chamber. If not, adjust the resizing die to ensure the cases are resized full-length (bottom of resizing die almost "kisses" the shell holder/plate) and fall in freely into the chamber.

2. Determine Max OAL - Make a dummy round (no powder/primer) and perform the barrel drop test with the barrel out of the pistol starting with the SAAMI max OAL until the dummy round falls into the chamber freely with a "plonk" and spin without hitting the start of rifling. To determine the amount of taper crimp to return the flare back to flat, I usually add .020" to the diameter of the bullet (So for 9mm .355" diameter bullet, .375" taper crimp and for .356" bullet, .376" taper crimp).

3. Next determine Ideal OAL - Load the Max OAL dummy round in the magazine and manually release the slide without riding the slide with hand. Incrementally decrease the OAL until dummy round reliably feed/chamber. Depending on the pistol/barrel used, Ideal OAL that will work reliably will vary. If you are reloading for multiple pistols, use the Ideal OAL that will work reliably in all the pistols.
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Old February 5, 2012, 12:16 AM   #7
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I don't have any Lee dies, but I have lots of RCBS. For RCBS the seating plug uses a 1/4-28 thread size. If Lee uses the same, this will apply, otherwise you can do the math.

A 1/4-28 thread has 28 "teeth" per inch. The distance between each tooth on the thread is .036 inches, so one full turn of the rod lowers the seater plug .036 inches. A half turn lowers it .018, and a quarter turn lowers it .009 inches. Round that off to .040 for a full turn, .020 for a half turn, and .010 for a quarter turn. If your starting cartridge is too long, simply subtract the desired length from the starting length to see how much shorter you need it, and adjust the rod the number of turns accordingly.

If your starting OAL is 2.500 inches and you want an OAL of 2.440 inches, the difference is .060 or 1-1/2 turns down. Simple. Then fine-tune a couple of thousandths either way to get it exact.
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Old February 5, 2012, 01:31 AM   #8
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I ignore book oals,They are meaningless to me and don't always fit all guns.
Lee seaters don't use 1/4-28 threads(they are 5/8-20) so the numbers above are not te same,but they are close.The one Lee seater I have moved approx .055 per revolution.

I just take the barrel out of my gun and screw the seater plug down till the oal looks to be plenty long(if you have any factory rounds similar,they can be used as a GENERAL length for now).Drop the round in the barrel,doesn't fit? with calipers roughly measure how far above the hood it is.then drop the seater down almost that amount.Reseat,try in barrel,if it doesn't fit drop setar 1/2turn,repeat process till the round "plunks". I go an additional 1/4 to 1/2 turn beyond that.

Now make sure it fits the mag,then cycle the gun,If it feeds load up several and shoot.If they don't feed well,turn the seater another 1/2 turn and repeat.
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Last edited by dunerjeff; February 5, 2012 at 01:42 AM.
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Old February 5, 2012, 02:41 AM   #9
Sport45
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Quote:
Originally Posted by MEATSAW
Question is how many turns out on the loading die to set proper depth/OAL? I don't want to have to do trial and error and load up a bunch of wrong bullets if I don't have to.
Back the seating stem way out and then back the die body way out.

Put a factory round similar to the one you plan to create in the shell holder and then run it all the way up.

While holding the press handle down, screw the die body in until the crimp ring seats against the top of the case. Snug down the lock ring.

Screw the seating stem down until the seating plug is firmly pressing on the bullet.

Your seating die is now set up pretty close to where you want it. Make fine adjustments as necessary. When you have the setting you like make a dummy round to use for this the next time you want to load these.
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Old February 5, 2012, 03:32 AM   #10
Kyo
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meatsaw, don't do anything until you get a micrometer
http://www.ebay.com/itm/6-Stainless-...item1c2365a0a5
they are as cheap as 10 bucks shipped to you. please invest in the 10 bucks and don't break your gun/hand/whatever else from doing it wrong.
I am sure you read the instructions on how to adjust the die, what you need to NOT DO is ESTIMATE correct OAL.
Here are some steps because I have the EXACT same press. I just load 45's.
1. get a reloading manual. I picked up lee's for 20 bucks. its a freaking steal cause others cost 50-200 for no reason...
2. order you a caliper.
3. read the book, mainly the section on what type of bullet you are using, whether it be lead, FMJ. also mind the weight of said type of bullet. different weights and types have different needs in powder.
4. take 1 casing with a SPENT primer, and do not put powder in it. Then take 1 bullet and put the bullet into the casing using the press. Adjust your OAL die all the way out. The bullet should be slightly in the case.
5. Measure the OAL of bullet/casing with your caliper.
6. here's the tricky part- every gun is different. I learned that for my .45 the OAL was supposed to be between 2 numbers. a max and a min. if you read the reloading manual it WILL give you both. You have to figure out what runs in your gun best. For example, for my .45 I keep a OAL of 1.230-1.245 inches.
7. Go with the max OAL, and then TEST that round in your weapon. Make sure the slide closes all the way(this was my test for my gun) and if its too short the extractor won't grab it correctly.
8. go lower on the die if you need to, using the same bullet until it fits in your weapon the way you want it to. thats the beauty of reloading.
9. please don't load without a manual and a caliper. otherwise you will blow your hand off, and im not exaggerating here in any way.

edit- although sport45's way makes sense, you should realize factory rounds will have different bullets and different makes. I tested this myself with different kinds such as golden sabers vs hornady XTP's. different OAL. Depending on what type and weight(because the heavier it is, the more there is on the bottom side to push into the bullet) it will all change.
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Old February 5, 2012, 10:35 AM   #11
CrustyFN
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Quote:
You do not need to use the OAL listed on published load data
No but I have always found it to be a good starting point.

Quote:
I ignore book oals,They are meaningless to me and don't always fit all guns.
Thats why I told him to do the barrel test. I guees you would have seen that if you read my whole post.
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Old February 5, 2012, 09:01 PM   #12
wncchester
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Book OAL is what the book makers used to develop their listed data, usually based on SAAMI's mimimum throat OR the cannalure for the bullet used. It's no more a 'rule' for the rest of us to savishly follow than their powder charges are. Point of fact, when I started this stuff most data sources didn't even list an OAL! Just seat pistol bullets in the cannalure and lightly crimp, it's rare they won't chamber and shoot well.

So far as needing a caliper to prevent killing ourselves, I suppose those of us old guys who reloaded for 20 years before dial calipers became inexpensive enough for us to justify having one must have died in our youth.

Last edited by wncchester; February 5, 2012 at 09:07 PM.
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Old February 6, 2012, 09:34 AM   #13
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When in doubt use a round of factory ammunition as a guide, I did this for years before I owned calipers. To be honest the amount to taper crimp you put on with your seating die will be far more important to reliability than OAL as long as you are in the ballpark.

I think Accurate's manual deals with OAL best when they say,

SPECIAL NOTE ON CARTRIDGE OVERALL LENGTH “COL”
It is important to note that the SAAMI “COL” values are for the firearms and ammunition manufacturers industry and must be seen as a guideline only.
The individual reloader is free to adjust this dimension to suit their particular firearm-component-weapon combination.
This parameter is determined by various dimensions such as
1) magazine length (space),
2) freebore-lead dimensions of the barrel,
3) ogive or profile of the projectile and
4) position of cannelure or crimp groove
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Old February 6, 2012, 10:00 AM   #14
CrustyFN
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Quote:
There is no reason to mess up any. Never mind the book OAL, keep your first powder charges maybe .5 gr. under book max, start out long and slowly work down until you can crimp in the cannalure.
Rainier bullets in 40 S&W don't have a cannalure.
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Old February 6, 2012, 07:30 PM   #15
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The "dummy" pattern idea is great once you have developed a load and COAL. I'll admit that I'm economically minded, so I haven't made the dummy round; instead I just use a round like the one I going to reproduce. Grab a reload out of the box and use it as a pattern.

For developing a new round COAL, I do as others have stated. Start long and creep up on the target COAL.

For shore enough new round (with new bullet) development, I will try to determine the maximum COAL length as established by the magazine, pistol feed parameters or chamber. Load at maximum length with allowance for proper feeding or bullet setback off lands.
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