OAL and COL

[saunderscc]

I am new to reloading and having just tried a couple of loads at different charges and different OALs, I am curious how much a difference the OAL makes. If I am over the MIN that is posted for that charge and bullet, what difference does it make to adjust within those limits? And also what is COL? If I go to Hodgdon's site they list the COL, is this the same thing as the MAX OAL?

[DssG19]

If I'm not mistaken COL/OAL is the same. COL is catridge overall length, OAL just drop the C.

[Steve Koski]

Saunders,

If you load to a longer COL than shown in the data, you'll get lower pressures and lower velocities. How much lower depends on a lot of things. Generally you pick a COL that is a good match for the bullet and your gun (feeds reliably, fits in mag) and then work up a load that you like at that COL.

I default to using the longest COL that works (or something close to it). This keeps peak pressures down.

COAL = OAL as DssG19 said.

Koski

[saunderscc]

So if I stray from the OAL info and go longer, what would that loss in pressure effect? Would it give me FTE, Fail to chamber the next round? I am using the Lee Modern reloading info for my rounds, 124 gr copper plated RN, 4.6 grains of WSF, and a MIN OAL of 1.095. But this data is off the 124 gr. lead data, since it doesn't have the Copper platted at the 124gr level. Would I be fine to stay at 1.095 with the 4.6 grains (NEVER EXCEED is 4.7 grains)?

[colorado4wheel]

If the bullet profiles are both RN then you can compare them pretty close to 100%. Problem is no ones bullets are truly the same as the next guys bullets. So a JHP from Winchester may be somewhat different then one from Remington. They are close but never assume with reloading. If you increase the COL then you can get issues with feeding as eventually your cartridge will simply be too long. The bullet can also jam into the rifling causing other problems (setback). Keep things in the middle ground unless you have a good reference otherwise. Obviously as the cartridge gets shorter then pressure goes up and that will increase velocity and to the extreme can cause major pressure issues. Your FTE (failure to extract) should not be a length issue if you have a reasonable length for your cartridge.

[saunderscc]

If the bullet profiles are both RN then you can compare them pretty close to 100%. Problem is no ones bullets are truly the same as the next guys bullets. So a JHP from Winchester may be somewhat different then one from Remington. They are close but never assume with reloading. If you increase the COL then you can get issues with feeding as eventually your cartridge will simply be too long. The bullet can also jam into the rifling causing other problems (setback). Keep things in the middle ground unless you have a good reference otherwise. Obviously as the cartridge gets shorter then pressure goes up and that will increase velocity and to the extreme can cause major pressure issues. Your FTE (failure to extract) should not be a length issue if you have a reasonable length for your cartridge.

Yeah I think I had my loads were too long. Glad to see you over here Colorado4Wheel.

[Steve Koski]

Saunders,

If making a load a tad bit longer lowers the power enough to give you a failure to eject, then your load was "borderline too weak" to begin with.

If you're shooting them in a Glock 9mm, you may need to stay up near max to get 100% functioning. Glock 9's are known to like warm ammo.

I poached the following data from: http://data.hodgdon.com/cartridge_load.asp

It shows 4.7 to 5.3 gr for a 124 FMJ. If it were me, I'd bump up my charge to around 5 grains and see if I got reliable functioning. I've loaded many a plated round using FMJ load data. Just "work up to it" again, and you should be fine. If you're not sure what it means to "work up" a load, check the link in the "new reloaders, read this first" sticky thread in this forum.


Cartridge: 9mm LugerLoad Type: PistolStarting Loads
Maximum Loads
Bullet Weight (Gr.)ManufacturerPowderBullet Diam.C.O.L.Grs.Vel. (ft/s)PressureGrs.Vel. (ft/s)Pressure 124 GR. FMJ Winchester WSF .355" 1.169" 4.7 1015 27,700 PSI 5.3 1115 32,700 PSI 124 GR. LEAD RN Winchester WSF .355" 1.169" 4.0 945 22,200 PSI 4.7 1055 27,300 PSI



Take care,

Koski

[saunderscc]

Thanks Steve, I plan on working up some new loads for the weekend and try again. I really appreciate the help!

[Jammer Six]

If I gave a measurement of length as a "tad", my dad, who is a REAL carpenter, (as opposed to the newbies, who only have thirty or forty years in) would beat me.

[DssG19]

Yeah I think I had my loads were too long. Glad to see you over here Colorado4Wheel.

I don't think you're too long at 1.095, that seems kinda short.

[saunderscc]

I don't think you're too long at 1.095, that seems kinda short.

My loads were at 1.128 at that point. The min is 1.095, but I never had any at that length.

[Jammer Six]

When I started measuring each round, I noticed that they were not coming out the same length. So I called Dillon.

In a Square Deal, he advised me that the die and press is only accurate to about .007.

So now I set a range instead of a number for C.O.L., like 1.250-1.265.

I use a range of fifteen thousandths, Dillons' seven thousandths either way. :coolgleamA:

[918v]

You must understand that bullets are mass made on multiple carbide dies. No two dies are exactly alike and produce slightly dofferent bullets. Because the seater stem contacts the side of the bullet nose, and not the very tip, slight dimensional differences between bullets will result in different OAL's. Add to that varrying case tension and you compound the problem. The harder it is to seat a bullet, the longer the resulting OAL. Then you have progressive dimensional issues that add to the problem.

Seriously anal benchresters buy bullets made on a single machine. These bullets come out of one die and are the most consistent.

If you want a perfectly consistent OAL, however, you can add another step to your reloading operation: Take a case mouth expander die and adjust the expander stem so that the bullet tip of a loaded round touches the bottom of the stem. Adjust the expander stem to push the bullet down in the case on the upstroke. Because this seats the bullet referencing off the bullet tip, and not the bullet ogjive, the resulting OAL will always be dead on.

[DssG19]

When I started measuring each round, I noticed that they were not coming out the same length. So I called Dillon.

In a Square Deal, he advised me that the die and press is only accurate to about .007.

So now I set a range instead of a number for C.O.L., like 1.250-1.265.

I use a range of fifteen thousandths, Dillons' seven thousandths either way. :coolgleamA:


My LnL AP with hornady dies can vary by about .004, I was wondering the same thing.

[layusn1]

Sooo...say you worked up a load you are pretty happy with, consistent .5in or less 5 shot groups, in your bolt rifle that used the manual's OAL but didn't ever do anything to determine the best OAL for your firearm...would you leave well enough alone or start playing with the OAL to see if you could make well enough into spectacular?

[Jammer Six]

If you want a perfectly consistent OAL, however, you can add another step to your reloading operation: Take a case mouth expander die and adjust the expander stem so that the bullet tip of a loaded round touches the bottom of the stem. Adjust the expander stem to push the bullet down in the case on the upstroke. Because this seats the bullet referencing off the bullet tip, and not the bullet ogjive, the resulting OAL will always be dead on.
I'd have to read that a few times.

I was messing with the die that seats the bullet, before I called Dillon, and it's not the seating or the bell that makes the difference-- it's the crimp.

The Square Deal, with the crimp die I have in it, pushes the bullet down into the case as it crimps, and it does so by an amount that varies.

I did manage to set the die that pushes the bullet down into the case so that it did so the same each time, but then the round gets crimped, and then it varies.

[918v]

In order to be consistent, you have to seperate seating and crimping into two steps. In order to be perfectly consistent, you have to seperate seating/crimping into three steps. First, you seat the bullet with the seater die, about .010" too long. Then you fininsh seating with the case mouth expander die. Then you crimp with the crimp die. That way all the bullets bottom out against the bottom of the seater stem and you get perfectly consistent OAL.

[Jammer Six]

How does the seater stem affect the crimp process?

They're separate dies, separate steps.

[Steve Koski]

918v - Hella good idea for perfect COL achievement. Leave it to you to dream that up! I like.

[WILL TERRY]

HANDLOADING my own cartridges for 48 years. NEVER ever have I had to use such shenanigans to produce EXTREMELY close LOA--yes !!! L O A ...-- on any batch of handloaded rifle or pistol cartridges I've ever produced.
As we speak I am between 850,000 and 900,000 cartridges handloaded.
Furthermore the length of cartridges was designated as it's LOA--length over all-- forever until a bunch of yahoos on the internet who were too lazy to read the history of their sport started making up all the designations and abbreviations etc as they went along. Pretty soon no one had any idea what the hell the other guy was talking about. YE GADS !!! Is it any wonder they also do not know how to set a seating die not a crimp die nor a simultaneous seat/crimp die.

[DssG19]

HANDLOADING my own cartridges for 48 years. NEVER ever have I had to use such shenanigans to produce EXTREMELY close LOA--yes !!! L O A ...-- on any batch of handloaded rifle or pistol cartridges I've ever produced.
As we speak I am between 850,000 and 900,000 cartridges handloaded.
Furthermore the length of cartridges was designated as it's LOA--length over all-- forever until a bunch of yahoos on the internet who were too lazy to read the history of their sport started making up all the designations and abbreviations etc as they went along. Pretty soon no one had any idea what the hell the other guy was talking about. YE GADS !!! Is it any wonder they also do not know how to set a seating die not a crimp die nor a simultaneous seat/crimp die.


LOA thats oldschool gangster stuff. I'll bet you have some awesome reloading stories.:yesnod:

[WILL TERRY]

LOA thats oldschool gangster stuff. I'll bet you have some awesome reloading stories.:yesnod:

YES I DO !!!! I use to get paid to write about it and had a hell of a lot of fun doing so. The handloading of ones very own cartridges is like inch thick frosting on a cake named shooting. I still cannot imagine ANYONE who calls himself a " shooter " not handloading his own cartridges. The sad truth of the matter today is very few of the newbies are handloaders perse', and I am not too sure even the word " reloader " applies to all those who went directly into loading on Dillon style--or any other type of progressive--tooling. Many, maybe most, do not even understand how the dies do their work, and WHY !!! They may end up making viable ammunition but they're nothing past being machine operators.
WHY DO YOU THINK ALL THE GUNS ARE BEING BLOWN UP THESE DAYS ???
When I was a young buck--right after the Civil War--you never heard of guns being blown up by their owners. The first one i ever saw blown was a S&W K38 on display at Camp Perry in the late 1950's and it was the talk of the town. We all gaped at it in slack jawed amazement !!!! Now, it is as common as...well....progressive loading machines. IMAGINE THAT !!!

[DssG19]

You've loaded 850,000+ on a single stage? I take it you're not a big fan of the progressive? you were handloading long before I was an itch in my daddy's pants. I gotta lot to learn form you ol'buddy.

[WILL TERRY]

You've loaded 850,000+ on a single stage? I take it you're not a big fan of the progressive? you were handloading long before I was an itch in my daddy's pants. I gotta lot to learn form you ol'buddy.

OH NO, I do not mean to leave the wrong impression here. I do use progressive presses and have for 20 years. BUT, I did not learn the ropes on a progressive press when I started loading my own in 1960. From a single stage RCBS press [ and a LYMAN 310 too for some ] I went to a CH 333 in '71, still using the single stage press for rifle ammunition , mind you, and bought my first progressive in 1989. So, I guess that makes it 19 years now, not 20 that I've used a progressive press. I still load all my rifle ammunition on an RCBS A2 press.

[Jammer Six]

Back in MY day, we didn't have NOTHING to play with!

We didn't have no progressive presses, we didn't have no electricity, we didn't have no cars! If I hadn't been born a boy, I wouldn't have had ANYTHING to play with!

Nothing!

Back in MY day, we played with ROCKS!

We HIT them against each other, and we made a GAME out turning big rocks into little rocks! We didn't have NOTHING! And when the rocks got too small to play "Break The Rock" with, we THREW them at each other! Things didn't get no better until one of us invented GRAVEL! And I'm not talking about no GRAVEL PIT, I'm talking about HAND MADE GRAVEL! From back in the DAY, when EVERYTHING was made by hand! ESPECIALLY the gravel!

You modern kids don't know how GOOD you have it, what with all your TV, and your STEREOS, and your EIGHT TRACK TAPES!

If you'd been born back in MY day, we'd have put a BIG ROCK ON YOUR FOOT, and you'd have been TRAPPED there until you figured out how to play "Break The Rock", like the REST of us!

And that's the way it was, and we LIKED it!

[918v]

How does the seater stem affect the crimp process?

They're separate dies, separate steps.

It does not affect the crimp process, but does affect OAL consistency. I'll explain again:

The interior profile of a typical seater stem is conical. It seats bullets by applying pressure on the sides of the bullet nose. Small differences in bullet nose diameter at the contact point result in large differences in OAL. An expander die, however, seats bullets by applying pressure to the very tip of the bullet. Variaces in bullet nose diameter have absolutely no effect on OAL.

You seperate seating and crimping into three steps. First, seat the bullet in the case with your regular seating die. Seat the bullet so the OAL is a bit too long. Second, reseat the bullet with a case mouth expander die adjusted in such a way that the expander stem pushes against the bullet tip. Third, crimp as usual.

I have been using expander dies to seat flat-point/ JHP bullets for ever. They work extremely well for seating HBWC bullets in the 38 Special.

[Jammer Six]

Okay, I see that.

That makes for super accurate SEATING.

It's not the seating I'm having trouble with-- when I take rounds out and measure them after seating, they're all within one thousandth. Seating, on my press, is quite accurate.

It's the crimping that changes that. My crimp die pushes the bullet down into the brass as it crimps, apparently, and it does so by different amounts.

Before crimping, they're all very close. After crimping, they're all shorter than they were before crimping, and they do vary up to seven thousandths each direction.

[Steve Koski]

What kind of crimp die?

If you want them super duper consistent, you may have to use the same headstamp/series brass, and trim the cases.

[Jammer Six]

It's the standard issue crimp die from Dillon-- it's a Square Deal B, which only takes Dillon dies.

It's the die it came with. Dillon says it's only accurate to plus or minus seven thousandths. I have found that to be true, so I use a range of fifteen thousandths, like 1.260-1.275.

When I do that, they virtually all pass.

[918v]

If your crimping is pulling your bullets further down into the case, then you are overdoing it.

If you want to continue with that heavy crimp, then trim your brass to the same length. That way the crimping process will pull all the bullets to the same degree, and your OAL will remain consistent.

[Jammer Six]

{light coming on}

Of course!

The brass is different lengths, (because it's .45 brass, and I have never trimmed it) so the crimp die hits it in a different place for each round!

We need a smily for use when the light comes on.

[918v]

45 ACP cases vary as much as .010" in length, so they all get crimped differently. Some guy outh there designed a crimp contraption that uses a lever and a weight to crimp all rounds by the same amount no matter what the case length. I crimp my 45 ACP ever so slightly, just enough to remove the bell from the case mouth.

[Phunahm]

I usually use the same RN bullet on my 45 so I have a factory loaded round and set the bullets to that length......