More OAL Questions

[photobiker]

Been following the thread on the 124HBFN OAL.  Now I'm using Berry's 124 HBRN.  I originally loaded to 1.14 because it seemed like a safe popular OAL that other people were using.  Followed the drop test and my 75B accepts 1.23 in. OAL. Drops in, spins and falls out.  Now logic, in my head, says that the closer the bullet is to the rifling the more accurate, the bullet is right there ready to go no gaps no opportunity for anything not perfect.  Now this leaves only 0.14 in. of bullet in the case.  Is that enough?  Is there a positive/negative to loading at this length or should I let the end shooting results make that decision?

Started checking on things  1.23 inches won't clear the mag.  New question.  I longer better with the same reasons as above?

[Wobbly]

The longest OAL you can count on fitting in the mag is the SAAMI max of 1.169" (29.70mm).

You might pick up the very last iota of accuracy by pushing your bullet out to near the rifling when you shoot bench rest and you've already done a million other things. But having the bullet near the rifling is mostly internet folklore. Especially for a pistol.

Please don't take my word for it, it's easy to do your own testing. Just load up 5 rounds at 1.160, 5 at 1.150, 5 at... well you get the picture. Then go shoot those from a rest and measure it for yourself. You'll see that something nice and short works out much better.

 

[1SOW]

Yea defiantly a thicker notebook.

I had to use the computer and bought a second hard drive (multi-Gig) specifically for a crash back-up.  I had to have SOMEWHERE to store Wobbly's great reloading pictures.  
I also have computer made "ammo box load labels" and stick one for each final load on the boxes and one on the wall next to my reloading press for quick reference back-up..

  or should I let the end shooting results make that decision?

BINGO!
re whats the gain or loss on loading shorter?  Shorter leads to less case volume and potentially higher pressures.  It also increases the "grip on the bullet" by the case neck tension which 'should' increase pressures too (micro-seconds more before release).  Will hitting a feed ramp nudge a short-seated bullet out of being concentric?   see below.

This leads to more questions.

And I suspect, it always will.  Some things just don't always follow logic or the published rules in a linear fashion.

When you get a PERFECT load, please let me know!  I need another one.
 

[Wobbly]

Didn't know about the SAAMI thing, obviously.  Internet folklore, don't know anything about that.  My only reloading reading has been here or Lyman or Hornaday. 

May I call your attention to the your reloading manual. Both Lyman and Hornady show the SAAMI cartridge dimension drawing. All the numbers given on that drawing are the MAXIMUM physical size permissible for that cartridge to fit into all guns. "A picture is worth a thousand words." That's why the drawing is there.

It just seemed to made since that the closer to the beginning the less chance of something going we'll say off course. 

That would be true in a slow-acting bolt action bench rest gun. But in a auto handgun, the cartridge is being slammed around and beat to death going up the mag, and then from the feed lips, up the ramp and into the chamber. It's not that your imagination is unclear, it's that the thinking (in this case) has been selective. So you got the right answer, but for the wrong gun.   

I have about 80 reloads at 1.14 and 1.13 at various grains.  Next set of reloads I'll do as you say and see what the results are.  I think I'm going to need a thicker notebook.  Another thought is to maybe do as you say tomorrow for Sunday and take those with me as well.  Got a plan.  Yea defiantly a thicker notebook.
This leads to more questions.

This is really good. Excellent thinking, sir. 

Go ahead, be creative. Play with your new sport. 

[noylj]

Been following the thread on the 124HBFN OAL.  Now I'm using Berry's 124 HBRN.  I originally loaded to 1.14 because it seemed like a safe popular OAL that other people were using.  Followed the drop test and my 75B accepts 1.23 in. OAL. Drops in, spins and falls out.  Now logic, in my head, says that the closer the bullet is to the rifling the more accurate, the bullet is right there ready to go no gaps no opportunity for anything not perfect.  Now this leaves only 0.14 in. of bullet in the case.  Is that enough?  Is there a positive/negative to loading at this length or should I let the end shooting results make that decision?

1) can the rounds fit in the magazine? If not, you need to reduce the COL so the round fit.
2) SAAMI is for industry. Reloaders are free to vary.
3) Common COL is seldom optimal for YOUR gun.
4) Load a couple of dummy inert rounds (no powder or primer) and test functioning with various COLs. Also, when you chamber a round, check the before and after COL to see if there is any case set-back. I consider 0.002" of set-back maximum.
If your long COL fits the magazine, feeds and chambers, and there is little to no bullet set-back, you are good to go.
One problem with 9x19 is that there are cases out there with extremely thin case walls. So thin, that the sizing die can't decrease the case ID enough for the expander to bring the case ID back up to 0.353-0.354" and the bullet will set-back with just a touch. Be sure to do a "push" test of the round against the bench with thumb pressure to be sure the bullets are firm in the case. I find cases like this about 1-2 out of 300 rounds loaded. I toss these cases.

[Wobbly]

Been following the thread on the 124HBFN OAL.  Now I'm using Berry's 124 HBRN.  I originally loaded to 1.14 because it seemed like a safe popular OAL that other people were using.  Followed the drop test and my 75B accepts 1.23 in. OAL. Drops in, spins and falls out.  Now logic, in my head, says that the closer the bullet is to the rifling the more accurate, the bullet is right there ready to go no gaps no opportunity for anything not perfect.  Now this leaves only 0.14 in. of bullet in the case.  Is that enough?  Is there a positive/negative to loading at this length or should I let the end shooting results make that decision?

But there's an error on your logic, as explained previously.

1) can the rounds fit in the magazine? If not, you need to reduce the COL so the round fit.

And, like it or not, you'll be right back down to 1.169"

2) SAAMI is for industry. Reloaders are free to vary.

That may be the most dangerous tidbit of information I've ever seen. 
So are you saying that because we reload we don't have to follow SAAMI chamber pressure limits, or are you saying that because we reload we don't have to follow SAAMI physical dimensions? Just asking for clarification here before someone uses 38 Special dies to re-size 9mm cases and then fills the case to the rim with rifle powder.

I contend that as reloaders we MUST adhere to both SAAMI physical sizing and chamber pressure data. If we don't follow their sizing, then the cartridges we prepare may not fit and/or seal to the chamber wall. And we MUST follow appropriate load data because the limits on all load data is the pressure limits of the steel from which the chamber and barrel are formed.

The imperative then is to learn how to correctly read the SAAMI data presented in the manuals.


All the best. 

[noylj]

Dear Wobbly:
SAAMI sets up test conditions for the industry. These conditions include the maximum COL allowed for testing (which is really what, to a reloader, would be the minimum COL). Thus, the industry tests with what we would consider very short COLs. As reloaders, we are free to load longer--note: that is what the OP was talking about and what I referred to--and, in fact, are EXPECTED to load longer. This is where one of the manuals got the "Maximum COL" they refer to in their manual--it isn't the maximum COL for reloading but rather the maximum COL allowed for industry-approved testing.
We can also size the case down more or less than the SAAMI drawings.

[Wobbly]

Dear Wobbly:
SAAMI sets up test conditions for the industry. These conditions include the maximum COL allowed for testing (which is really what, to a reloader, would be the minimum COL). Thus, the industry tests with what we would consider very short COLs.

That may or may not be true. But that is NOT what you said.

You made the 'blanket' statement:  2) SAAMI is for industry. Reloaders are free to vary. With no clarification or reference to COL. In effect your statement reads: Reloaders are free to vary ANY dimension. And many of our new reloaders will take that and 'run with it".

As reloaders, we are free to load longer--note: that is what the OP was talking about and what I referred to--and, in fact, are EXPECTED to load longer.

That statement is true. I have said this many times myself.

This is where one of the manuals got the "Maximum COL" they refer to in their manual--it isn't the maximum COL for reloading but rather the maximum COL allowed for industry-approved testing.

Which manual ? Be specific. All manuals I have show the same dimensional drawing from SAAMI. For the 9x19, the maximum COL for RN is 1.169 inches, as per these drawings.

We can also size the case down more or less than the SAAMI drawings.

Again, this is an UNTRUE statement.

? A reloader or his die set may take the cartridge case slightly smaller than the dimensions in the drawing. That part is true and permissible. However only within limits. You obviously can't use 32 Auto dies to reload 9x19. But if your 9x19 dies make your cartridge case diameters .007" smaller, then that's probably a good thing.

? A reloader or his die set can make cartridges that exceed the dimensions in the SAMMI drawing , but they may NOT fit into the mag or chamber. Yes, there are certain military and police weapons that have looser chamber dimensions so that in battlefield conditions, dirty/muddy ammo can be shot. But that is NOT true of the vast majority of guns made for public use, and especially NOT true of CZ guns.  Bottom line, if you exceed the maximum dimensions on the SAAMI drawing (with some dimensions by as little as .001"), then your cartridges may not chamber in a CZ.

Adhering to SAAMI cartridge dimensions is the entire point of the "cartridge gauge" so many reloaders buy. If it were not true, then there wouldn't be several companies making the things.

All the best.