C.O.L., Min/Max OAL

[crracer_712]

I'm trying to make a list of loads for the powders/bullet(type/weight)/calibers that I have. In doing this, I decided to get out all my manuals and record data from each (big mistake!). I have the Lee's 2nd edition(not the updated one), I believe the Hornady's 6th edition, a Lymans and a few of those caliber specific paper manuals(IMO, waste of money...)

Anyway, I'd always just used the Lee manual and started at the start loads and worked up, seldom nearing max load. In the Lee manual it states 'Min. OAL'. For example, 9mm Luger has a Max OAL of 1.169. Let's say for a given bullet and load the Lee manual says a Min OAL of 1.140. The way I've always done it is to find a happy medium in there. I always found that the variance in bullets was too great to set at or near Min OAL as I would invariably have a round or two set under Min OAL.

I was under the impression that I had the entire 1.140 to 1.169 OAL to play with here.

Tonight while looking at the manuals, I saw some state C.O.L., but I cannot find if this C.O.L. is a minimum or maximum, or if that is what is has to be. Can anyone clarify this for me?

Now, back to the Lee manual. I liked it because is seems to idiot proof. I always felt is was leaning towards the safe side. But tonight while looking at load data for various powders in 9mm and 380 auto, comparing the Lee to the Hornady, I would Notice that Hornady's start loads are a lot lower, often, than the Lee start loads. I would also see on occasion the Lee having a higher MAX load than what Hornady published.

Granted, I would look at say, 115 FMJ in the Lee manual, using titegroup, and the Hornady would have Hornady's part number for their 115 FMJ. The start and Max loads would be different, sometimes way different.

Next thing that confused me was using plated bullets. I have a bunch of Rainiers and Berrys. All plated round or flat nose, depending on caliber. In the Lee manual, it actually has a small sampling of plated data for 115 gr 9mm. It didn't show a powder that I have. I see where people say to load the plated like a Lead bullet, or a FMJ keeping it under the midway load. Trouble is, in the Lee manual, I compared the same powder for a LRN and the plated, and the Lee manual shows a higher start load for the LRN than it does for the plated bullet's max load. Load data was also very similar between LRN and FMJ.

I decided to get on the powder websites, but out of the powders I have, the website do not show much is any load data that pertains to my bullets, be it looking it up as FMJ or LRN.

For powders I have titegroup, Power Pistol, and Unique (power pistol is new to me, haven't loaded anything with it yet).

Calibers are 380 acp (I have 100 gr. plated RN, both in Berry's and Rainiers), 9mm (115 gr plated RN, Rainers), 40 S&W (180 gr plated taper shoulder flat top, Rainiers), and 45 ACP (200 gr plated round shoulder flat top, Berrys)

I notice the Rainier's 380 bullet has a cupped base where the Berry's is flat. Berry's measures .450, Rainier's is .457 (length), both measure .355 diameter). Rainier's is more pointy, Berry's is more rounded.

Am I OK in thinking I can seat a bullet anywhere between the Lee listed minimum OAL(Hornady's list C.O.L.) and Max OAL for a given caliber? I understand that going over the minimum OAL reduces pressure affecting FPS for a given load. Also understand not to go over Maxium for chambering. When I say Minimum, I am going by a specific bullet 'type' with a particular powder load.

 

[LiveLife]

Determining Max and Ideal OAL for semi-auto pistol loads:

You do not need to use the OAL listed on published load data as often test barrel fixtures (and not real pistols) are used to measure chamber pressures. 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 and fall in freely into the chamber. (If I can't resize a case on the second attempt by rotating the case 90 degrees, I consider the case wall too far stretched/thinned and will toss/recycle the brass).

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 (if the round won't fully chamber, use rcmodel's suggestion of painting the bullet with dry-erase marker to show where it is rubbing). 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). Note: Some headstamp case walls are thicker and you may need to use even less taper crimp by .001" (so for .355" bullet, .375"-.376" taper crimp and for .356" bullet, .376"-.377" 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 your hand. Incrementally decrease the OAL until dummy round reliably feed/chamber. Depending on the pistol/barrel used, Ideal OAL that will work reliably may be shorter than Max OAL. If you are reloading for multiple pistols, use the Ideal OAL that will work reliably in all pistols.

4. Once you determined the OAL that will work well for your pistol/barrel/magazine, next conduct a full powder work up to determine the powder charges that will reliably cycle the slide/extract spent cases and produce the most accurate shot groups by loading 10 rounds of each increment of .1-.2 gr from start charge and work towards max published powder charge. If I am using shorter OAL than published or different bullet that seats the bullet base deeper in the case, I will reduce the start/max charges by .2-.3 gr. If different published load datas vary in start/max charges, I look closer at the barrel length used (such as 4" vs 5") and other reloading component differences. When confronted with differing load data for the same barrel lengths and bullet type, I will side on the safety and use the lower published load data for my start charge.

Next thing that confused me was using plated bullets. I have a bunch of Rainiers and Berrys.

Considerations for conducting powder work up for plated bullets:

Rainier ballistics recommends you use lead load data when Rainier bullet specific load data is not available. I have used Rainier plated bullets with lead and jacketed load data but will use the accuracy of my shot groups to determine when to stop my powder work up (using higher jacketed load data didn't always produce more accurate shot groups). Rainier bullets are rated to 1200-1250 fps.

Berry's MFG plated bullets are sized slightly larger than jacketed bullets and advertised on their website as .356" for 9mm bullets. The larger sized bullets provide better bullet-to-barrel seal, especially for many oversized factory barrels and produce more consistent chamber pressures. Berry's recommends you use start-to-mid range jacketed load data. For .355" groove diameter Lone Wolf barrels in my Glocks, both lead and start-to-mid range load data have produced accurate loads. Regular plated bullets are rated to 1200 fps and thicker plated hollow based (HB) bullets are rated to 1450 fps.

 

[crracer_712]

I see what you are saying about the OAL. I'm wondering, since I will be loading for multiple pistols of the same caliber, could I then simply check the OAL of factory ammo that I use, that I already know chambers in all of my pistols? Providing I am getting the OAL from a factory load that utilizes the same weight and type of bullet? (maybe not so much type, since all my factory loads are mostly FMJ, and I've mostly got plated)

As for powder load, I had usually started at the start load and worked up in the .2grn range. Although, sometimes when using the Lee manual, there has been an occasion where the start and max load was only .3 grn apart.

 

[LiveLife]

could I then simply check the OAL of factory ammo that I use, that I already know chambers in all of my pistols?

That would work if you use the same exact bullet as factory round. Different manufacturers may have slightly different bullet nose shape (ogive) that will allow the bearing surface of the bullet base (part that rides the rifling) to engage the start of rifling at different OALs.

Conducting Max/Ideal OAL tests using your pistol/barrel/magazine ensure OAL that will engage the rifling faster for more consistent chamber pressures to produce more accurate ammunition as less high pressure gas will leak around the bullet when the powder is ignited.

maybe not so much type, since all my factory loads are mostly FMJ, and I've mostly got plated

FMJ and plated RN bullets will have slightly different bullet nose shape (ogive) but if you want OAL that must work in different pistols, for various 115 gr FMJ and 115/124/125 gr plated RN bullets, OALs of 1.125"-1.135" have reliably fed/chambered for me in multiple pistols.

when using the Lee manual, there has been an occasion where the start and max load was only .3 grn apart.

AFAIK, Lee Precision don't conduct their own chamber pressure testing but use other published load data and consolidate them in their manual.

If I am using bullet type that is different from the published load data, I will usually reference current published load data from powder manufacturers (they are available free online) or older load data (2004 Alliant load data, 1999 Winchester load data that have more FMJ/lead loads). For lead load data, I will frequently reference Lyman #49 reloading handbook if lead load data is not available from powder manufacturers.

 

[FROGO207]

BDS has laid out the process really well so not much to add here. IMHO a lot of reloaders that are just starting out want a "magic" way to get good ammo fast and there is no way to speed up good trial and effect data. When first reloading I tried to load something that fit all my 45 ACP pistols by guess and had poor results. I settled on figuring out which one required the shortest OAL and using it as my standard length for blasting ammo. When I wanted more accurate ammo I did a workup for each pistol by varying OAL and propellant type/amount/bullet type to get best results. This took literally years to get where I am happy with each loading. This said, there were some combos that I rejected on the first try as they did so poorly. Keep in mind that factory ammo has to be usable in any firearm and never will be the best load for yours so the mediocre results you get are expected from it.

 

[crracer_712]

Well, my main concern was simply that this is the first time using plated bullets. Prior to this I've always used FMJ or JHP (which i still have, just trying to reload some plinking loads cheaper).

BDS, the 1.125-1.135 is in fact the OAL that I do generally set to for my 9mm. I was using some Remington 124 gr FMJ and I found they were all a little different. Having my seating die set the first 10 test rounds to roughly 1.130. After the test rounds were fired I started to load the other 90 rounds. After about 10 rounds I checked the OAL on them to make sure everything was ok and found a couple down to 1.119 (The load data was for 125 gr FMJ in the lee manual and it showed a min. OAL of 1.125). I was concerned about higher pressure with too little OAL. I ended up raising the seating die and finished loading, those that were over 1.135, I re-seated again.

 

[ranger335v]

"Tonight while looking at the manuals, I saw some state C.O.L., but I cannot find if this C.O.L. is a minimum or maximum, or if that is what is has to be."

Book OAL is a vastly misunderstood figure because it's rarely defined as it should be; book OAL/COAL is only what the book makers used to develop their listed data, it's not a law for us to follow or die. Small capacity, high intensity autoloader HANDGUN cartridges (9mm, 10mm, .40) using fast burning powders are sensitive to the initial burn space but even with them it's not very critical unless we're on the ragged edge of a KABOOM. What determines the max and minimum is best found by finding what is needed for the ammo to feed and chamber reliabily, THEN (properly) develop the powder charge at that length.

Unlike handguns, seating deeper in rifles actually reduces the start and burn pressures by giving the bullet an easy running start before hitting the restriction of the rifling.

 

[crracer_712]

Thanks! makes sense.

 

[kingmt]

All of the advice so far has been good but your concern may be a bit much. I normally start my loads with a factory round. I put the factory round in the die then crank the crimp down as hard as I can by hand then do the same with the seater. I don't use book data because most of my powders aren't in there. I work up until my slids function correctly. This is my starting load for my powder. If I was using book data I would work down to this point.

After you learn a little more about pressure then try your hand at adjusting OAL.

 

[1SOW]

I was under the impression that I had the entire 1.140 to 1.169 OAL to play with here.

You DO, if your pistol and mags will accept/feed it.

The oal listed in the manuals is the MINIMUM oal. Anything "shorter" will have "HIGHER case pressures"--not good. Anything "longer" will have "LOWER" case pressures--no problem.

When you seat shorter than published, there is less free space in the case. This will raise pressure with the loads listed.

When you seat longer than published, there is more open space in the case. This will lower case pressures with the load listed.

If your pistol will accept a longer oal and the bullet doesn't contact the leade or rifling (Including any press OAL variations), it's safe to do.

Hope this makes sense.

 

[crracer_712]

Perfect, you answered my exact question.

I was aware of the MAX OAL, you quoted me, and that was just for clarity (the way I worded that).

It was mostly the difference in wording between manuals. I started with the dummies manual (Lee's), and it says 'min OAL'. The others usually just say C.O.A.L., with no mention of minimum. As usual, I was reading too much in to it, thinking maybe it had to be exact. With the Lee manual, I didn't read that in to it, but then again, I actually read the Lee manual.... I skimmed through the others looking for my answer, but never found it.

No plans to load Max OAL, just wanted to make sure I had a little lee way and was understanding the pressure part right.