Made my first attempt at reloading tonight. Put 125gr. rn over 3.9gr. of bullseye (9mm) cci primers. My question is what should my over all lenght be. I can't find this exact bullet in Lymans 49th edition and I'm not sure how critical it is. I would just as soon start off right. Thanks in advance, Skip
First reloads?
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OAL is pretty important in a cartridge like the 9mm.
The OAL length is important to function, but the internal case volume, which can get reduced by a bullet seated too deep is the real problem you have to watch out for. Even slight reductions in case volumes raise pressures A LOT, and the 9mm is a high pressure cartridge to begin with.
The OAL length is important to function, but the internal case volume, which can get reduced by a bullet seated too deep is the real problem you have to watch out for. Even slight reductions in case volumes raise pressures A LOT, and the 9mm is a high pressure cartridge to begin with.
I think you should find load data in a book which uses that bullet, or switch to the bullets that are in the Lyman #49 manual.
If you were loading a low pressure round like a .38 Special (16,000 CUP), it wouldn't be that important. But the 9mm operates in the 33,000 CUP range and bullets seated even slightly too deep can cause it to go overpressure.
If you were loading a low pressure round like a .38 Special (16,000 CUP), it wouldn't be that important. But the 9mm operates in the 33,000 CUP range and bullets seated even slightly too deep can cause it to go overpressure.
anomad
Member
Keep them on the longer side. Look at some similar bullets and heavier ones and go for a longer OAL that will still fit in your magazine. Measure a few factory loads that you might have laying around for comparison. You picked a challenge for your first attempt since the exact bullet isn't in your reference material and you're working with those tiny components.
For example, data.hodgdon.com lists 1.169 as the longest COL of any of their 9mm loads. Bullet shape will obviously play a big part in this, since a hollow point will have a flat tip vs. a round nose that is long and "pointy".
But I agree with cp1969, too short could seriously reduce the volume of the reaction chamber and increase pressure.
For example, data.hodgdon.com lists 1.169 as the longest COL of any of their 9mm loads. Bullet shape will obviously play a big part in this, since a hollow point will have a flat tip vs. a round nose that is long and "pointy".
But I agree with cp1969, too short could seriously reduce the volume of the reaction chamber and increase pressure.
Dragon88
Member
1.160 if that feeds in your pistol(s) well and chambers correctly.
ArchAngelCD
Moderator, SWCA Member, Absent Comrade
When you can't fide the "exact" bullet in the load manual you are using it's fine to use a bullet of the same bullet composition, weight and PROFILE of your bullet. You said you loaded a 125gr RN bullet so any 124/125gr Round Nose bullet data will be fine. (be sure not to mix data for jacketed and lead bullets)
Skip Sackett
US Veteran
The issue really isn't the OAL as much as it is seating depth. I have posted about this before but I am afraid that few really understand the issue. While using data for ANY RN bullet is good advice IF you stay on the longest side possible, shortening the OAL can be really dangerous in some firearms.
Take a look at two 230gr RN plated bullets:
The one on the left is a Berry's and on the right a Ranier. Now, I have loaded these bullets for years in the 45ACP and have used the same load for either one. That being said, the difference is that this is a low pressure round and the firearm is on the 1911 platform with not internal feed ramp.
If this was for a Glock 40S&W the story would be much different. With the extra pressure of the round, the .030" deeper seating with the same OAL, I would reduce the charge a bit, probably .2gr and see what the chronograph said. It would tell me if the pressure was "similar" if the velocity was close using the same powder.
So, the point of this post is to make you compare on what really matters, seating depth. What is the profile of the data's bullet? Is it a "pointy" RN or more round? More round means a shorter bullet, hence, less in the case at the same OAL. That is a good situation. Is your bullet more pointy, meaning a longer bullet, at the same OAL that would mean that the seating depth would be much more and could raise pressure considerably.
Either way, always follow this rule, start low and work up, looking for signs of pressure.
Just for curiosity, Skip, what are you shooting these out of?
Take a look at two 230gr RN plated bullets:
The one on the left is a Berry's and on the right a Ranier. Now, I have loaded these bullets for years in the 45ACP and have used the same load for either one. That being said, the difference is that this is a low pressure round and the firearm is on the 1911 platform with not internal feed ramp.
If this was for a Glock 40S&W the story would be much different. With the extra pressure of the round, the .030" deeper seating with the same OAL, I would reduce the charge a bit, probably .2gr and see what the chronograph said. It would tell me if the pressure was "similar" if the velocity was close using the same powder.
So, the point of this post is to make you compare on what really matters, seating depth. What is the profile of the data's bullet? Is it a "pointy" RN or more round? More round means a shorter bullet, hence, less in the case at the same OAL. That is a good situation. Is your bullet more pointy, meaning a longer bullet, at the same OAL that would mean that the seating depth would be much more and could raise pressure considerably.
Either way, always follow this rule, start low and work up, looking for signs of pressure.
Just for curiosity, Skip, what are you shooting these out of?
Isn't seat depth measured by overall length. I got some local info today so I'm confident enough to try these out tonight and see how they go. Only did up 10 rounds but I think I will go a little long on the next batch. I have a s&w 669 and a beretta 92Fs. I carry a G29 or G19 but will not be running cast through them needless to say. I will at some point be looking for a good bullet recommendation for the glocks and my K9 . Thanks for the info. Tomorrow I'll start on the 38 spl.'s
Skip
Skip
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Skip Sackett
US Veteran
Skip,
No, seating depth is measured from bullet, not cartridge length. The longer bullet in the picture, seated to the same OAL has a greater seating depth. It means nothing in the 45ACP because the round is so low pressure.
This difference in say, a 40S&W in a Glock 22 or 23 or 27, may be devastating.
Let me see if I can draw a picture and post it.
Think about the reason that Elmer Keith made his bullets like he did. They weigh the same, or near it, to the traditional weights for each caliber, but much, much more of his bullets are outside the case rather than inside. Why do you think that was?
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I understand the the increased pressure problem, thats why I ask the question in the first place. Didn't want to break anything on to first outting. If you google "125gr. lrn load data" it seems like alot of people have the same question and there doesn't seem to be a striaght answer. Just trying to make informed decision. I think I'll stick with wisdom of this tread and start around 1.160 and see how things function The .38spl. with 148gr. DEWC and 3.5 of Bullseye might be easier on the learning curve to start. Thanks to All
Skip
Skip
Skip Sackett
US Veteran
Skip Sackett
US Veteran
Now, here is how to apply this knowledge. Look at the loading manual you are looking at for data. How is that bullet shaped that weighs 125gr? How is yours shaped? Steeper nose? More round? Same weight but much shorter?
Let's say you find data that says x.xgr of QST powder for that 125gr bullet with an OAL of 2.300". You look at your bullet and see that yours is going to end up much, much more into the case than the one they list in their data. What do you do? 2.300" is what works in your guns. Every one.
Start low and work up first but here is what I do: For every .030" more bullet that is inside the case, I reduce my fast burning powders by .2gr. .060" more inside the case and I reduce the minimum load by .4gr and work up from there. I have a chronograph and at some point I should hit the desired velocity. I can almost guarantee that it will be at a reduced charge than the posted data.
The opposite is true as well. If my bullet is much more round than the one in the data, and seating depth is less, I may go over published data maximums if I haven't reached the velocity I want.
Now, listen to this, MAY and do are two different things. I didn't start out doing things this way. Strictly by the book. You should too. Get some rounds under your belt but pay attention to what causes what to happen. Make notes. Maybe mental notes are good enough for you, not for me!
I want to state this again: I may go over published data if the OAL or the seating depth is much, much longer than the data lists in my manuals. I don't want someone to get the wrong idea here.
Hope this explanation helps.
Let's say you find data that says x.xgr of QST powder for that 125gr bullet with an OAL of 2.300". You look at your bullet and see that yours is going to end up much, much more into the case than the one they list in their data. What do you do? 2.300" is what works in your guns. Every one.
Start low and work up first but here is what I do: For every .030" more bullet that is inside the case, I reduce my fast burning powders by .2gr. .060" more inside the case and I reduce the minimum load by .4gr and work up from there. I have a chronograph and at some point I should hit the desired velocity. I can almost guarantee that it will be at a reduced charge than the posted data.
The opposite is true as well. If my bullet is much more round than the one in the data, and seating depth is less, I may go over published data maximums if I haven't reached the velocity I want.
Now, listen to this, MAY and do are two different things. I didn't start out doing things this way. Strictly by the book. You should too. Get some rounds under your belt but pay attention to what causes what to happen. Make notes. Maybe mental notes are good enough for you, not for me!
I want to state this again: I may go over published data if the OAL or the seating depth is much, much longer than the data lists in my manuals. I don't want someone to get the wrong idea here.
Hope this explanation helps.
Skip Sackett
US Veteran
Best I could do on short notice in Excel. If I would have fired up the other laptop, I could have really geeked out and used AutoCad!
