9mm MIN OAL


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Vonfon
September 30, 2011, 09:08 AM
I am new to reloading and have a minimum OAL question.
Hornady 124 JHP
CCI Primers
4.0-4.6 231
Range Brass Most F.C and Remington

Shooting my 226 I feed Manufactured Hornady 124 JHP like a champ with an OAL 1.0935-1.1075

I reloaded about 30 rounds half at 4.3 and the other at 4.6 of 231. With an OAL of 1.115-1.123. I am worried at this point about the pressures that might be higher due to being below the lee MIN OAL of 1.142 but my Speer manual gives the COAL TESTED at 1.12. Also seems like I may have loaded .1 grain over should I pull them or start with the 4.3 and give the 4.6 a shot?
Thoughts from people who know what the heck they are doing?

FNG:fire::cuss::banghead:

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bds
September 30, 2011, 09:42 AM
Welcome to THR and reloading! :D

Published load data do not use pistols to test chamber pressures, rather test barrel fixtures or universal receivers. Although this will show max pressures obtained for said barrel groove diameter/length used, it won't tell you what OAL will feed/chamber in YOUR pistol nor what chamber pressures your barrel type and length will produce as many factory barrels have oversized groove diameter and will leak more high pressure gas around the bullet. For these reasons, each reloader must conduct their own tests to determine which OAL will feed/chamber and what powder charge will reliably cycle the slide in their pistol/barrel without exceeding the published max load data.

This repost from another thread should help with determining the Max and Ideal OAL for your pistol to conduct powder charge work up.

http://www.thehighroad.org/showthread.php?p=7608323#post7608323

I keep seeing people using OAL specified in the published load data or using trial and error for different pistols. This is not the best reloading practice and determining OAL should not be a guessing game. Most published load data are made using test barrel fixtures and not actual pistols. For each new bullet we use for reloading, we need to determine the OAL that will work in our individual pistols/barrels before conducting the powder work up.

While most pistols will feed 9mm RN bullets at varying OAL (say typically around 1.125"-1.135"), depending on the bullet nose profile (ogive), as rc posted, you may need to use shorter/longer OAL for your pistol. With any new bullet, you should always determine the MAX OAL using your barrel and IDEAL OAL by manual feeding from the magazine to ensure reliable feeding/chambering before conducting powder charge work up.

1. MAX OAL determines the longest OAL that will drop freely in your chamber without hitting the rifling. Using your barrel out of the pistol, drop a sized case into the chamber to ensure you are full-length sizing your case (it should fall in freely). Next, make a dummy round (no powder/primer) starting at SAAMI max length and taper crimp .020" wider than the diameter of the bullet (.375" for .355" bullet and .376" for .356" bullet). Drop the dummy round in the chamber and incrementally decrease the OAL until the round fall in freely and spin without hitting the rifling.

2. IDEAL OAL determines the longest OAL that will feed and chamber reliably in your pistol/barrel/magazine. Starting at the MAX OAL, manually feed your dummy round by releasing the slide (do not ride the slide with your hand). Incrementally decrease the OAL until the dummy round feed/chamber reliably.

3. POWDER WORK UP. Once you determined the MAX and IDEAL OAL, then conduct your powder work up from start charge to identify the charge that will reliable cycle the slide and produce consistent accurate shot groups.

jem375
September 30, 2011, 09:48 AM
go to the Hornady website and see what they use for oal....

john16443
September 30, 2011, 10:51 AM
Vonfon - Welcome to THR. I've loaded the Montana Gold 124 JHP bullets that are dimensionally identical to the Hornady HP-XTP's you're using with W231 powder. I've loaded up to 4.7 grains at 1.12" COL and my notes indicate this is a 'snappy' load. No overpressure signs, but recoil was more than I was looking for. I've loaded 4.6 grains of W231 down at 1.08" for these JHP's with no ill effects or excessively felt recoil.

I believe your 4.6 grains at 1.115 to 1.123" is OK. The Hornady range for the 115G XTP's is 4.1 to 4.7 grains. Reducing to 4.6 grains for the 124 version is what I would consider a max load, and as stated above, my 4.7g load showed that it was stronger than necessary. The Hornady COl recommendation for the 124g JHP's is 1.06", so loading longer like you did actually will result in a slightly lower than published pressure.

One thing about the Lee book, they don't do any testing, but just republish data from other sources. You have no idea of knowing the test conditions that were used to arrive at the data that is published in that book.

ranger335v
September 30, 2011, 11:03 AM
I believe seating depth is important but maybe less so than it might appear to noobs. Seating MAX loads deeper in small high intensity handgun cartridges can get dicey but simply reducing the charge a tad will allow seating down quite well. That said, seating down and increasing the book max charge a tad may not be so good, right?

(For what it's worth, seating deeper - within rational limits - for rifle loads decreases pressures.)

bds
September 30, 2011, 11:15 AM
Seating MAX loads deeper in small high intensity handgun cartridges can get dicey but simply reducing the charge a tad will allow seating down quite well. That said, seating down and increasing the book max charge a tad may not be so good, right?
That what I used to think until I saw the significant variations in different published load data.

Differences in published load data most likely come from different case, primer, OAL, test barrel length, test barrel groove diameter, bullet type and nose profile (ogive) used (Lyman #49 used .401" groove diameter barrel for their testing with .400"/.401" diameter bullets instead of the typical .400" groove diameter test barrel).

Sum of these variations can result in different chamber pressures they used to average max pressures and publish their load data.

For this reason, unless I can duplicate the load data components exactly, I give myself some buffer head room and use mid-high range load data with powder manufacturer's published load data as reference.

So if you are using max load data, I would be concerned about any factors that would increase chamber pressure.

Be safe.

Rule3
September 30, 2011, 11:17 AM
If you are loading a Hornady 124 XTP bullet it is better to go by the Hornady manual than the Speer manual. The XTP is not the same bullet as a Gold Dot

Hornaday's new manual #8 lists 1.060 for the XTP (HP) part #35571, but they also use cases that have a trim to length of .749 so you need to allow for this slight difference.

rcmodel
September 30, 2011, 12:38 PM
Case length has no effect on cartridge OAL.

If the case is longer or shorter, the bullet just seats inside it more, or less.
But the cartridge OAL from case rim to bullet tip remains the same.

rc

ranger335v
September 30, 2011, 06:04 PM
"That what I used to think until I saw the significant variations in different published load data."

Well, that's true too but the guy's new so I like to keep it simple. IF the manual's data IS max - for him - getting short and hot is NOT the right way to go! And your note explains why I hate to see people tell noobs to "get as many manuals as you can and cross reference them." Nonsense, any manual has usable data and increasing the options doesn't help the poor guy, it just confuses him - and in this instance for Vonfon. People who know what they're doing can handle the differences easily but noobs can't!

I've been reloading since '65. For the first five years I only had ONE manual, on the sage advice of a very wise man in my old gun club, and I never felt I needed anything else until I got a new cartridge that was not listed in my old manual. By that time I could easily handle the various book differences, mostly by understanding that none of the books were hard scientific data tables but just what the book makers did with their guns and I knew mine was different from any of theirs and their results couldn't be directly duplicated in mine.

Rule3
September 30, 2011, 06:21 PM
Case length has no effect on cartridge OAL.

If the case is longer or shorter, the bullet just seats inside it more, or less.
But the cartridge OAL from case rim to bullet tip remains the same.

rc
Yes, I know not what I was thinking.:o Maybe trying to match it to a cannelure if it had one.??

rfwobbly
September 30, 2011, 07:54 PM
Vonfon -
Welcome to THR.

If you want to load Hornady bullets, then you need to refer to Hornady reloading data for the best results. Hornady recommends a minimum OAL of 1.060" for the XTP (#35571). Using Win231 would have a load range of 3.9gr to 5.2gr, so you are certainly in the right neighborhood.

But when they say 3.9gr as a starting load, they mean load 6-10 at that level, then starting working up slowly from there. Picking out loads in the middle of the range and then loading several dozen is great way to find out you need to unload several dozen. And unloading is not nearly as much fun. :eek:

I would highly recommend you load 10 at 4.0gr and that will let you stair step up 4.0, 4.3, 4.6gr. Personally I'd use a 0.2gr step and get more resolution, but this is not my show.

Hope this helps! ;)

gamestalker
October 1, 2011, 01:26 AM
Welcome to The High Road Vonfon, and of course the world of reloading as well!

So you would be loading Hornady part #35571, right? Hornady has a published OAL of 1.060" for that one, so you should be just fine with the OAL your using. I think most of us agree that seating bullets is specific to each particular firearm. I do feel it is important to not seat deeper than published but if it for some reason unavoidable do so with a proper full work up to avoid problems.

I'm running those Hornady 124's right at 1.090" in Remington brass, but I've also run this load from Win. and Fed brass with no significant difference. That OAL feeds 100% reliably in our Taurus PT-111, Beretta 92FS, and a G-17.

CCI-500
HS6 - 6.7 grs.
124 gr. XTP
OAL - 1.090"

Velocity from all 3 firearms is consistently in the 1225 fps neighborhood with very mnimal +/- variance. This particular load is .1 gr. under Hogdon's max. for a 125 gr. FMJ, so that offer's a little bit more room to work than is published.

Just a note on OAL, 9mm specifically. Though most AL straight walled cartridges are some what pressure sensitive to OAL, the 9mm is hyper sensitive in this respect. Speer did some testing back in the day (#10 edition) and found that a jacketed bullet load that was producing a normal predicted 28,000 cup, more than doubled to 63,000 when the bullet was seated .030" deeper than the recomended or SAAMI published OAL. Considering the OAL your using is above the Hornady published OAL, your going to be just fine.

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