9mm COL


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gutterman
February 18, 2013, 06:19 PM
Can anyone tell me what the COL for the 9mm would be using a 124 Hornady XTP and 4.2 grns of Titegroup?

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rcmodel
February 18, 2013, 06:25 PM
No.
There is no simple answer to that.

You need to take the barrel out of your gun and use it as a gage to set OAL so it don't hit the rifling leade in the chamber.

All brands of guns are different.

Hornady manual suggests 1.060" is a starting point.
But you still need to make sure it is OK in your barrels chamber.

rc

ATLDave
February 18, 2013, 06:30 PM
Or he could get a case gauge and be assured that it will fit any SAAMI-spec chamber and barrel, right?

Lj1941
February 18, 2013, 06:36 PM
I concure on using the barrel as a guage.I use the barrel of my M&P and never have any problems.

Walkalong
February 18, 2013, 06:44 PM
Or he could get a case gauge and be assured that it will fit any SAAMI-spec chamber and barrel, right?No, the gauge checks headspace and OD, but not anything else. Someone should come along soon and give us a definitive answer on what OAL the 124 XTP is loaded at by the factory.

mike.h
February 18, 2013, 06:53 PM
in Hornady 8th, 124gr HP-XTP - c.o.l. : 1.060". However titegroup is not listed in the powders.

ATLDave
February 18, 2013, 06:53 PM
LE Wilson makes case gauges that check OAL on pistol rounds. http://www.lewilson.com/images/PISTOL_MAX_GAGE.pdf

Walkalong
February 18, 2013, 09:51 PM
Yes, forgot to type that, but it doesn't mean that that bullet combo at that OAL will chamber. The answer is still no, just because it is under or at SAMMI max OAL doesn't mean it will chamber in all guns.

http://www.thehighroad.org/attachment.php?attachmentid=120302&d=1272453749

rcmodel
February 18, 2013, 10:26 PM
Perhaps this thread will put to rest the "if it fits a case length gage it fits them all" misconception.

http://www.thehighroad.org/showthread.php?t=703697

Naw, probably not. :banghead:

rc

mboe794
February 18, 2013, 10:45 PM
The case gauge does not have any rifling to potentially interfere with the round completely chambering. An actual chamber of a pistol does. A full wad cutter seated to 1.169 (max) would probably fit the gauge, but definatley will not chamber in a 9mm firearm.

beatledog7
February 18, 2013, 10:49 PM
Many "spec" reload OALs that chamber in my 9mm case gauge will not chamber in my CZs. Do the barrel test as rc recommends; if you've never done it, you probably need to clean the gun anyway, and this will be a good chance.

Walkalong
February 19, 2013, 08:30 AM
Do the barrel test as rc recommends;
http://www.thehighroad.org/showthread.php?t=506678

ATLDave
February 20, 2013, 12:48 PM
I'm not about to disagree with the many august and learned members who say that cartridge gauges don't test bullet engagement with a barrel, so the following is truly a question, not a quarrel:

I took one of my LE Wilson gauges and dropped a bullet - not a cartridge, just the lump of copper and lead - into it. It did not come out the other side. Does this not indicate that the narrowing of the gauge forward of the cartridge area is sized down to some SAAMI spec? Does SAAMI not specify dimensions for barrel throats?

Again, these questions are not rhetorical. I don't know the answer and am eager to learn.

rcmodel
February 20, 2013, 01:00 PM
Yes, SAAMI has chamber specs & ammo specs.
But they are voluntary standards a U.S. manufacture can use, or not.

But the CZ the OP ask about, as well as German SIG P6's and other foreign made guns do not adhere to U.S. voluntary standards from SAAMI.

The European standards are set by C.I.P., and they are not the same as SAAMI.

rc

ATLDave
February 20, 2013, 01:01 PM
Ah-ha! Now I get it. Thanks, as ever, for the wisdom, rc'.

cja245
February 20, 2013, 01:20 PM
you can do a couple things, but as others said, case gauges are not for determining COAL, they are for max case dimensions including max COAL. You will almost never be using max COAL except maybe in a revolver.

Your best bet is to use the barrel (removed from the gun) as a gauge. you want to seat till the case is fully chambered and the bullet is just touching the rifling. Then back off just a bit. This will usually give you the best accuracy.

Also you can compare it to a factory FMJ round. When comparing side to side, seat the XTP so it is fully inside the ogive of the FMJ. This generally will give you the most reliability.

Somewhere in between the measurements from these two methods is generally where I end up for best reliability and accuracy.

bds
February 20, 2013, 01:34 PM
+1 Although using the case gauge to check the outer dimensions of your finished rounds is a good idea to ensure they will work in ALL barrels, I prefer to custom tailor my rounds for my barrels so they produce optimal accuracy. Using the longest OAL that will reliably feed/chamber in your pistol/barrel/magazine will minimize high pressure gas leakage to produce more consistent chamber pressures which will result in enhanced accuracy. ;)

Your Max/working OALs will be based on your barrel's leade/freebore lengths and the start of rifling (Use the barrel drop test to determine the Max OAL and function check to identify the working OAL).

http://www.thehighroad.org/attachment.php?attachmentid=180081&stc=1&d=1361381643

Otto
February 20, 2013, 02:19 PM
The barrel plunk test tells you nothing about rim diameter, thickness or damage.
It can also fail to detect Glocked brass that aligns with the unsupported part of the chamber.
I use the barrel for determining OAL but the Wilson gage is used for all other aspects of the loaded round ie. bullet diameter, body diameter and length.
If my round won't fit the Wilson gage, it gets rejected.

gamestalker
February 20, 2013, 03:55 PM
Every gun has it's own OAL needs. But Hornady does publish the OAL they tested it at, but there is no promise that the OAL they used will function properly in your firearm. My recommendation is to learn and then practice using your barrel for determining OAL.

The OAL Hornady tested it at was 1.060" from a S&W M-39, 4" barrel 1-10 twist. Who knows how that will function in your chamber though?

Hornady doesn't show Tite Group in there data. Sierra does for there 125 gr. Jacketed bullets 3.7 - 4.4 grs.. Speer also does for there 124 gr. jacketed 4.0 - 4.4 grs..

GS

bds
February 20, 2013, 04:47 PM
Can anyone tell me what the COL for the 9mm would be using a 124 Hornady XTP and 4.2 grns of Titegroup
After you determine the OAL that will work with your pistol/barrel/magazine, I would follow the lower load data for JHP bullets and work up from 3.8 gr instead of starting out at 4.2 gr.

Hodgdon load data (http://data.hodgdon.com/cartridge_load.asp)
125 gr Sierra FMJ Titegroup OAL 1.090" Start 4.1 gr (1069 fps) 27,300 CUP - Max 4.4 gr (1136 fps) 30,600 CUP

Lyman #49
125 gr Sierra JHP Titegroup OAL 1.075" Start 3.8 gr (962 fps) 26,100 CUP - Max 4.2 gr (1045 fps) 31,200 CUP

ATLDave
February 20, 2013, 05:19 PM
As long as we're on the subject, I don't suppose anyone has a good formula or method for figuring out what a reduction of OAL by X does to pressure/max loads? IOW, if a published load shows 1.2600 OAL and I want/need to make it 1.2500, is there a predictable way to anticipate what pressure change would result and/or what reduction in charge is needed to hold pressure constant?

(My current understanding is that the answer is "no, not really," but since rc' and others are dropping knowledge, I'm asking.)

rcmodel
February 20, 2013, 05:37 PM
There is no formula that I ever heard of.

The manufactures can't even all agree on the numerical order of all the powders in a burn rate chart.
The book publishers can't even agree on what a MAX load is for any given caliber & bullet.
Or the OAL it should be.

I guess Quick-Load software would give you a guesstimate.

But thats all I know of.

rc

ATLDave
February 20, 2013, 05:48 PM
Thanks. That's all consistent with what I thought I knew, but figured I'd ask.

BTW, one of the most puzzling experiences of my relatively-young reloading career was finding that two manuals had start/max loads for the same powder and very similar bullets that had NO OVERLAP. In other words, one manual's max load was under another's start load! That's when I decided that finding one set of published data would not generally be sufficient to me - I want multiple sources.

greybeard57
February 20, 2013, 06:29 PM
BTW, one of the most puzzling experiences of my relatively-young reloading career was finding that two manuals had start/max loads for the same powder and very similar bullets that had NO OVERLAP. In other words, one manual's max load was under another's start load! That's when I decided that finding one set of published data would not generally be sufficient to me - I want multiple sources.

I'm so new with reloading I think I'm moving backwards sometimes. :)

With that said, I was wondering if those loads may have been measured differently? The CUP test is slowly being supplanted by the PSI test procedures from what I understand and the same manual may have both procedures listed for the same configurations. Just a thought.

bds
February 20, 2013, 06:43 PM
The CUP and PSI do not correlate with each other. I simply use them as different scales to gauge chamber pressures.


one of the most puzzling experiences of my relatively-young reloading career was finding that two manuals had start/max loads for the same powder and very similar bullets that had NO OVERLAP. In other words, one manual's max load was under another's start load!

The differences in published load data are from difference in barrel lengths, groove diameter of the test barrels, primers used, etc. which will affect the velocities/chamber pressures measured.

A key example of this is Lyman #49 and the 40S&W load data which used larger .401" groove diameter test barrel instead of more typical .400". If you compare Lyman #49 40S&W load data with Hodgdon load data, it will be higher.
Hodgdon load data - Hornady case (.845" Trim Length) - 4" Barrel length (1:16" twist) - Winchester SP primer
180 gr Hornady XTP W231 OAL 1.125" Start 4.1 gr (797 fps) 23,800 PSI - Max 5.0 gr (947 fps) 32,900 PSI

Lyman #49 load data - Winchester case (.845" Trim length) - 4" Barrel length (1:16" twist) - Winchester SP primer
180 gr Sierra JHP W231 OAL 1.115" Start 5.0 gr (927 fps) 20,400 CUP - Max 5.6 gr (1015 fps) 22,800 CUP
Due to these reasons, when I am doing my initial load development, I will compare all available load data (and the test specs) and use the lowest start/max charges for my powder work up.

I don't suppose anyone has a good formula or method for figuring out what a reduction of OAL by X does to pressure/max loads? IOW, if a published load shows 1.2600 OAL and I want/need to make it 1.2500, is there a predictable way to anticipate what pressure change would result and/or what reduction in charge is needed to hold pressure constant?
This is what I do. If the working OAL that I am using for my load development is significantly shorter than the published OAL for the same nose type of the bullet, I will calculate the actual bullet seating depth (OAL - length of bullet = bullet seat depth). If the bullet seat depth is greater than say .010"+, I will incrementally decrease my start/max charges for my load development.

Here's an example for 9mm Missouri 125 gr RN bullet (SmallBall) which is shorter with longer bearing surface which gets seated deeper in the case neck than other RN bullets with shorter bearing surface (see picture below and compare MBC RN to Dardas and ZCast RN bullets):

http://www.thehighroad.org/attachment.php?attachmentid=173742&d=1350888604

For calculation purposes, I will use 1.125" as OAL for the CN bullet (.620" in length) and 1.080" OAL for the RN bullet (.565" in length).
1.125" - .620" = .505" bullet seat depth for the CN
1.080" - .565" = .515" bullet seat depth for the RN

So based on my calculations, the bullet base will get seated .010" deeper with the MBC RN bullet when I use 1.080" OAL.

Here's current Hodgdon load data (http://data.hodgdon.com/cartridge_load.asp)
125 gr LCN W231/HP-38 OAL 1.125" Start 3.9 gr (1009 fps) 25,700 CUP - Max 4.4 gr (1086 fps) 31,200 CUP
So for my work up, I used 3.6 gr as my start charge and 4.1 gr as my max charge (I did work up to 4.4 gr but I got leading at 4.2-4.4 gr).

As a comparison, 1999-2005 Winchester load data for lead 124 gr RN bullet (which doesn't list OALs) showed start/max of 3.3 gr - 4.0 gr. In the end, 3.8-4.0 gr of W231/HP-38 worked out for me.

http://www.thehighroad.org/attachment.php?attachmentid=176515&stc=1&d=1356273892

I may have been overly cautious with my powder charge reduction but thankfully I had the older Winchester load data to reference. For the lower pressure 45ACP loads, .010" reduction in OAL may not translate to much but for higher pressure 9mm/40S&W loads, I would reduce .2-.3 gr to start my work up and later may work up to published max to see how things go.

YMMV

ArchAngelCD
February 21, 2013, 01:13 AM
in Hornady 8th, 124gr HP-XTP - c.o.l. : 1.060". However titegroup is not listed in the powders.
The brand new Hornady 9th Edition manual lists the same data as the 8th Edition posted above.

BUT, all the other advice in this thread is good too...

engineermike
February 21, 2013, 01:31 AM
I've loaded 9mm anywhere from 1.060 to 1.135, I think the SAAMI max COL is 1.169 for 9mm. (Just going off memory here) As shone above different bullets have different shapes and different over all dimensions. (Some bullets are longer than others even though they are 9mm) You can use the published load data and start out at the lower end and work your way up. But as you shorten you COL, using the same powder charge, the pressures go up. (That's assuming you are using the same bullet each time) Look over at the Hodgdon's web site and they have load data for Titegroup.

greybeard57
February 21, 2013, 06:31 PM
I read a page the other day that explains the difference very well about OAL per different shape of bullet and how those different shapes work inside the magazine and how it affects bullet jump from crimp to rifling. For semi-auto it gives as an example a SWC v RN bullet. Obviously if the SWC was loaded at the same OAL as the RN there would be no way it would A) enter the magazine and B) chamber correctly even if it somehow where forced into the magazine. And it showed that even two different brands of RN may have different ogives causing different headspace problems. The easy solution is to take a known factory or handloaded bullet that works well in the gun and eyeball the two side by side. The standard that every other bullet design needs to stay inside of is the one that works. Clear as mud? If not visit the page for more info. It makes it a lot clearer.

http://38super.net/Pages/Overall%20Length.html

FWIW- my first conservitive reloads where at 1.148-1.155 oal. loaded with Winchester 115 RNHB with 4.3gr win231 and federal primers. They worked, but more powder was needed because I had a lot of sooting. The second batch was increased to 4.5gr. at the same depths. I made a few at each depth within that range up above. The shortest length suggested was 1.100 for my load. This was from Ron (Don?) at Hodgdon's whom I called to find out what recipe I could use since there wasn't one published for this combination. One question I asked was how the OAL influenced this combination with this powder. He said that since w231 is such a fluffy powder it's not a problem. The bullet depth will not affect the pressures to a violent degree unless the OAL is seriously short or the bullet has no jump space. This jump space is relative the to the speed of burn which influences the pressure spike essentially at the moment of detonation (wrong word but ya know what I mean). This jump allows the bullet to gain momentum before it engages the rifling which slows it down (or, more correctly, prevents it from accelerating) which causes an immediate secondary rise in pressures. The two spikes are so close together they are actually measured as one pressure spike. The biggest variable in pressure is how tight the bullet is inside the rifling. Slight variations in bullet diameter are inevitable in mass production. Keeping the powder charge at reasonable levels will take the stacked tolerances and keep them within acceptable parameters.

Those guys at the powder companies are pretty sharp.

ranger335v
February 21, 2013, 07:34 PM
"Does SAAMI not specify dimensions for barrel throats? "

Only the minimum.

engineermike
February 22, 2013, 06:36 PM
Well graybeard;
I'd say you have a pretty good understanding of the variables with C.O.L. and bullet shape/s. I believe I will save your source and read it a little closer but I did find it interesting and useful.

Thanks;
Mike

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