Different kind of OAL question?

[ASCTLC]

I could sure use some help with this topic and here's why: I see people talk/ask about OAL for their loads but not always specifics about exactly what the dimensions are of their bullet. With bullets from the various mfrs being different and case capacity with the bullet seated affecting pressure so much, why isn't the real question about seating depth?

Example: I have have Remington 124 gr JHP bullets but there is no manufactures source for loading data for Remington bullets that I can find, anywhere. Am I just not seeing the information or does it actually not exist?

Without loading data specific to Remington's bullet, how does one determine an OAL (other than it feeds fine in my gun) for such a bullet? I guess if someone *knows* it matches another mfrs bullet exactly in dimension one could use that other mfrs loading data but I'm not overly optimistic one mfrs bullet matches exact dimensions of another.

All that's available is what someone else on the internet has done with that specific bullet and that's a scary way to proceed without intimate knowledge of who's posting that information. As you can see I really need some help here.

Thanks,
Andy

 

[DickM]

You're correct that OAL is specific to each bullet. Also, the published OALs are intended more to ensure proper feeding than to promote best accuracy.

Obtaining a maximum OAL for a particular bullet in your rifle (magazine feeding issues aside) is relatively straightforward. First, close the action on an empty chamber and insert a cleaning rod from the muzzle until it touches the bolt, then place a mark on the rod where it enters the muzzle. Then, insert a bullet (only) into the chamber until it engages the rifling and tap it very lightly with a dowel or whatever to hold it in place. Re-insert the rod until it touches the bullet and mark it again. The distance between the two marks (or a couple thousandths less, if you like) is the maximum OAL for that particular gun/bullet combination. A common starting place for testing to obtain best accuracy is to seat the bullet just barely touching the lands - recognizing that it may not function through the magazine at that length.

 

[ranger335v]

"With bullets from the various mfrs being different and case capacity with the bullet seated affecting pressure so much, why isn't the real question about seating depth?" .... "but there is no manufactures source for loading data for Remington bullets that I can find, anywhere. Am I just not seeing the information or does it actually not exist?"

It would be helpful if you would tell us if your are shooting a rifle or handgun. But, what you are seeking, a hard measurement that will insure safety and good accuracy in any weapon ever made doesn't exist. And it need not exist, you are vastly over-agonising the issue.

First, pressure variations due to seating or construction differences aren't huge unless the differences are huge and that's rarely true. It also differs between handguns and long guns; makes more difference in the handguns, not a lot in rifles and they differ in reverse!

Next, the small differences, any that exist by bullet design, is taken care of by proper load development; "start low, only more up until/or...," etc.

Dick's method of determining the absolute max OAL is as good as that done with any of the "high tech" tools sold for the purpose. It's rare for a factory rifle shooting common ammo to shoot it's best with the bullet jammed into, or even near, the lands. Find the MAX OAL, then seat at least 20 thou deeper and work down until you find the best shooting seating depth.

 

[Walkalong]

I log the diameter and length of all the bullets I load in my Excel log sheet I made. It can be a handy thing to know.

Auto pistols:

Lets say I have worked up a load with bullet "A". I work out an O.A.L. that feeds well. Then I work up a powder bullet combination that I feel that it is safe, accurate, etc.

Then I get a new bullet ("B") and I work out an O.A.L. that feeds well using a good starting charge. (By this time I have a pretty good idea of what this powder does in this caliber so my "good starting charge" may be in the middle of the data)

So, I have my O.A.L. for bullet "B". I do the math and I see that it sits in the case the same depth as with bullet "A". I can skip some work up because I have a reference. I'll probably skip to just under my load for bullet "A" and go from there.

Lets say I do the math and it does not sit as deep in the case as bullet "A". Then I might jump straight to the charge I am using with bullet "A" to continue load development, depending on other variables.

So, it can be a useful tool, but it can not guess pressures for us, and there are a great many more variables. It can however, help speed up the process of working up a load.

Revolvers:

Pretty much the same thing, except my O.A.L. is very often determined by a cannelure, so I don't have to work out an O.A.L. that feeds because I already have it, and they don't have to "feed" anyway.

It can be a useful tool, but is not that big a deal.

All that's available is what someone else on the internet has done with that specific bullet and that's a scary way to proceed without intimate knowledge of who's posting that information.

Which is why you always start low and work up, or at least reduce 10% and work up, and why it is always said to be very leery of any data posted on the internet.

As you can see I really need some help here.

Just remember. You just asked on the internet.

Got load books? Every single solitary one says start low and work up, watching for signs of pressure/trouble etc.

 

[ASCTLC]

Sorry for not including all the information guys, I didn't realize the question would be pistol versus rifle specific. The examples I give are the 9mm for my pistol but I'm loading for my .357 mag also and somehow got the impression that bullet seating depth differences of just a small amount can mean the difference of totally safe and well above SAAMI.

Example:
WWB 115 gr FMJ = 1.162 OAL
My reload Rem 124 gr JHP = 1.126 OAL
Both bullet bases are seated the same depth at .190

on edit: I've got plenty of manuals and have read them all cover to cover but they relay statements to use mfrs data. But I the bullets I have are sans data from the mfrs and not included in any of the 4 manuals I have and certainly not in any powder mfrs literature. Thus the quest for somehow to understand what the manuals leave out.

Andy

 

[rcmodel]

Most good manuals include full-scale pictures of each bullet.

Lay one of yours on top of the pictures of the same weight bullets.

If the weight, shape, & bullet type are the same, or very nearly so, use that data and OAL.

rc

 

[RandyP]

More experienced reloaders will correct me if I'm wrong here, but building rounds longer than spec simply makes rounds that may not chamber. building shorter than spec increases pressures dramatically and can lead to kabooms

 

[Walkalong]

building shorter than spec increases pressures dramatically and can lead to kabooms

Not necessarily.

9MM is much more sensitive to small O.A.L. changes than .45 ACP, for instance. A .030 shorter O.A.L. in .45 at medium power levels is no big deal (big case & low operating pressures), where in 9MM it is much more critical. (Small case and much higher operating pressures)

 

[Sackett]

Green reloader here, trying to learn through others' posts...This one is close to answering my first potentially dumb question.

I'm planning my first load of 9mm, mainly for experience and will only be punching paper with it. I bought Ramshot Silhouette powder and some Nosler JHP 115gr. bullets. I noticed these are VERY hard to find right now (as are many 'common' components), but I wanted to stick with a published start load to begin with.

Since I'm not particularly interested in terminal ballistics at this point (paper being so easy to kill), can I use the same starting numbers for a FMJ of the same grain bullet? Published Silhouette data doesn't seem to exist for a 115gr FMJ from 'generic bullet inc'.

Many Thanks!

Sackett

 

[Delmar]

Although its generally less of an issue with pistols than it might be with rifles, make sure the cartridge will fit in the magazine. I make up a couple of dummy rounds-no primer/powder for the autoloaders or a single dummy round for my revolver and make sure everything is good to go.

 

[Walkalong]

can I use the same starting numbers for a FMJ of the same grain bullet?

It will be fine to use Ramshots Silhouette 115 Gr JHP start data for a 115 Gr FMJ to work up a load.

I would seat the 115 Gr RN at 1.130 to 1.135 O.A.L. I would compare it to the seating depth they used for the JHP. Ramshot apparently seated the Nosler JHP at 1.169, which is pretty long for a 115 Gr JHP. Your 115 Gr RN is going to be seated shorter and deeper, so I would start getting cautious .3 Grs before I got to Ramshots max with Silhouette and the Nosler 115 JHP at 1.169 (Which is SAMMI max O.A.L. for 9MM by the way)

 

[Art Eatman]

As far as the reloading handbooks and all that, I must have a dozen from through the years. I always double-check the newer books before beginning on a new-to-me cartridge.

I've been doing it that way, now, for sixty years come July.

 

[counterclockwise]

Variations of COAL in the .223 family demonstrated...

 

[Sackett]

Thanks guys. Correction- I 'thought' I bought some Noslers, but the site I placed the order on just notified me that, contrary to all indications, they actually don't have any either. So your input is now even more important.

Not that I dislike improvising or experimenting; I just never thought I'd have to 'wing-it' on my very first reload...

Counterclockwise, are you pullin' my leg?? That's insane!

 

[BrokenWheel]

"Without loading data specific to Remington's bullet, how does one determine an OAL (other than it feeds fine in my gun) for such a bullet? I guess if someone *knows* it matches another mfrs bullet exactly in dimension one could use that other mfrs loading data but I'm not overly optimistic one mfrs bullet matches exact dimensions of another."

Just buy a Hornady OAL gauge ($32) and be done with it? This way you can determine the exact length of your cartridge and not have to deal with pipe cleaners, or "best guess". Its cheap and easy to use, I have no idea why it isnt more popular..

 

[ranger335v]

"...not have to deal with pipe cleaners,..."

I just have to ask, what does that mean?

I have the Hornady/Stoney Point tool. Don't use it much because it's mostly useful to find MAX oal and few factory rifles shoot best seated out there. Meaning it's sorta fun to play with but I really don't need it for seating. Works great to set up FL sizers correctly tho.

 

[Redneck with a 40]

From everything I've read, most .308 match bullets, the 168's and 175's aren't affected much at all by bullet jump. I've been loading my 168 SMK's at 2.830", a little longer than the 2.810" stated in my manual's, they are more than plenty accurate and will feed through the magazine.

 

[wilkersk]

If you measure the base of the bullet from the Ogive to the heel, you should be able to interpolate a base line COAL for any bullet/cartridge combination based on published SAAMI data found in the reloading books.

There's a couple of good pages on the web about how this is done.

http://www.larrywillis.com/OAL.html

http://blog.sinclairintl.com/2009/03/26/determining-bullet-seating-depth/

 

[Franco]

This is a very interesting thread. I note that Nosler's reloading manual has an OAL for each caliber but it's not bullet specific. That seems strange as they can't possibly have the same OAL regardless of bullet weight/design. Notwithstanding my disagreement with their methodology, I have used their OAL and reloaded accordingly regardless of bullet weight. We'll find out if I'm (or they're) off base or not when I finally get back to the range (I have 23" of snow on my driveway).

 

[gdcpony]

I have agonized over this as well in the past and the best solution I have come up with is to measure off the curve of the bullet to the lands. I have found that this is the most important measurement. If two different bullets have different curves, I seat the bearing surface (which is the only part that touches the rifling) to the same distance and work from there. I have found that almost all rifles like this distance to be the same regardless of bullet weight or shape. It is a note I like to make that rifle "A" likes bullets .006 off the lands, and rifle "B" likes them kissing and work with my future loads from there.

I made a piece of aluminum with my three most loaded diameters in it. I check my length with it and ignore the listed one (within reason). I find the depth of the lands (there are several ways to do this) and then I load to it in .001 increments with a bullet I want to use. Then I work my powder charge from min to best (I very rarely get to a max charge). Should I decide to try a different bullet, I seat it to the same OTL (off the lands), and work my load. I might try a bit one way or another after that, but it has never helped me yet.

That said, while the OTL has never moved for a particular rifle for me, the OAL has. Each bullet has its own. A polymer tipped Ballistic Tip will be longer than a hollow point. Heavier bullets will obviously be longer than lighter. Plus, I had a 243Win I threw many different bullets through from 55gr to 100gr. All the same OTL's, but after 3500 rounds the longer ones wouldn't fit the magazine. The barrel was worn out.