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Posted: 4/4/2013 3:52:27 PM EDT
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im losing about .005" on my COAL when chambering. Is this enough to warrant concern? Called Hornady (dies Im using) and they seemed to imply everything was in spec (but issued me a RA anyway to send in my die + some of my brass to make sure). When I really press the round against the floor it will move in. Should I send the die in or is this normal? (This is with going from resizer straight to seater. No expander even used and it does this.) Details: Press: LnL Dies: Hornady 3pc (9mm) Brass: Blazer, Speer, FC - doesnt seem to matter Bullet: XTP HP 124gr COAL: 1.090 Thanks.
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| i use a Lee FCD in the last station to crimp separately. As I understand, Neck tension is built off of the sizer die, and taper crimp is only to remove the bell from expansion. I thought over expansion was the problem, but as I said, I can go from resize straight to seat, and still have the same tension issues. |
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Quoted:
Let's put that statement in perspective.
setback in a 9mm can raise pressure a lot. its not acceptable. Get a taper crimp die and crimp it until it won't move. Yes, significant set back is not acceptable, as that can increase pressures with some 9mm loads using some powders. But we're generally talking about visible amounts of set back where the bullet moves back in the case 1/8", 1/4" etc - not .005" that you have to measure with calipers. I just took a quick measure of the depth of a 9mm case and got .582, then I subtracted the depth to which the 124 grain bullet is seated (OAL of the bullet minus what is still sticking out of the case) and got .240. That leaves an internal space the diameter of the inside of the case that is .342 in depth. Whether you figure it by volume, or just look at the reduction in depth, with .005 setback you get the same result - a decrease in case capacity of only 1.5%. A 1.5% decrease in volume will be lost in the noise of case to case differences. More to the point, a perfectly acceptable 0.1 gr variation in powder charge will have way more impact on pressure than .005" of setback. So...I'd argue that set back of only .005" on chambering is acceptable. |
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Anytime you shove a round up a feed ramp in an auto pistol you could get either a slight amount of setback and/or maybe a slight amount of bullet deformation.
Setback due to riding up a feed ramp multiple times is a genuine issue with ammo that is loaded and then unloaded daily in carry firearms and had probably been responsible for a few Glock KABooms. .005 doesn't sound out of the ordinary, especially if you aren't sure of the exact C. O. A. L. of that particular round to begin with. My guess is that if you load on a progressive you'll have slight COAL variations to begin with because of tool head slop. I wouldn't worry about .005" setback but I would shoot that round relatively soon before it makes too many more trips up the feed ramp. Edited to add. Neck tension is suppose to be what we use to hold the bullet but I also make sure I have my LFCD crimp setting set to as much as I feel comfortable with, especially in 40, if the crimp is barely digging in to the jacket and that doesn't impact accuracy I'm all for it. |
| I solved the problem with a Lee U-die. Now the neck tension is perfect. I sent the Hornady sizing die back with some brass but havent heard anything about it yet. I also borrowed a friends RCBS sizing die and had the same issues as with the Hornady dies, so I think I narrowed down the problem to thin brass. Either way, the U-die got me up and running. I am curious to see what Hornady does though. Thanks for the replies everyone. |
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I had a thread a week ago about exactly this same issue, except .45acp , & .40s&w, (my first ever loads) , I deduced the same thought that practice ammo is typically not
loaded and ejected repeatedly as is SD ammo. I undoubtedly had some concerns so I queried the hive which stirred the usual debate. As I was reading the responses member 1911 smith posted an article in which the writer was deliberately setting back the bullets , in a G22 of all guns  , to the point of actually tapping the bullet INTO the case with a
HAMMER with no ill effects. You should be able to find it in the search , only if your search fu is far better than mine. Shoot with confidence . |
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I had a thread a week ago about exactly this same issue, except .45acp , & .40s&w, (my first ever loads) , I deduced the same thought that practice ammo is typically not loaded and ejected repeatedly as is SD ammo. I undoubtedly had some concerns so I queried the hive which stirred the usual debate. As I was reading the responses member 1911 smith posted an article in which the writer was deliberately setting back the bullets , in a G22 of all guns , to the point of actually tapping the bullet INTO the case with a
HAMMER with no ill effects. You should be able to find it in the search , only if your search fu is far better than mine. Shoot with confidence . Here is the link: https://plus.google.com/+luckygunner/posts/CiVxdHvWjYS HOWEVER, That specific example should not be used as evidence of anything. In order for that information to be useful from a scientific and practical point of view specific information is required. They need to measure the pressure. What is the pressure of the standard rounds and the pressure at each of the overall lengths tested? This matters because they need to know the start and end points, and what limits they're pushing, if any. For example, let's say that the standard OAL load has a pressure of 25,000 psi, and the most deeply seated rounds have a pressure of 35,000 psi. That's an awful big change, but what does that mean? Well, the maximum SAAMI pressure limit is 35,000 psi, so they've learned that you don't have a failure at SAAMI maximum pressure. But you wouldn't expect to. Maybe their maximum pressure was 45,000 psi. Is that a potential risk? Maybe not since the 40 S&W proof load pressure is 47,000 psi. So they've shown that they didn't have a failure at the proof load pressure limit. But that was probably already tested at the factory before the gun was shipped. Again, they might not have learned anything. Without the pressure information they're simply guessing about the potential meaning and consequences of the test. Also, their results might apply only to the ammo they tested and not to ALL the other brands of ammo on the market. Thus someone might get the impression from their test that setback isn't a problem, no matter how severe, and subsequently suffer an injury or gun/case failure based on their results. In short, their methods leave a lot to be desired from a scientific and practical perspective. While the results are of interest, without knowing the pressure of the tested rounds one cannot come to a genuinely practical conclusion. |
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We both did this at 1911forum, including the Ramshot chart. Ramshot data was gleaned from cartridges having neck tension. Seating depth with adequate neck tension is apples, setback as a result of lost neck tension is oranges.
An apples to oranges comparison. The purpose for using linked article is to let people know they don't need to freak out over a small amount of setback. 1911forum thread was pretty much brought to a close with two sources, Hodgdons and Sierra. No one suggests that seating depth doesn't affect pressure, however the question posed to both Sierra and Hodgdons was exactly this, "will set back blow my gun up ?" Question answered was this, " no amount of setback will blowup a handgun, provided pistol is mechanically sound." We did this long before a moderator posted article in ammunition forum. You can interject all the scientific/non-scientific hyperbole you'd like, it still doesn't change what both Sierra and Hodgdons ballisticians tell us. dc. eta, Didn't we have conversation on 9mm major ? Setback link made hot |
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I solved the problem with a Lee U-die. Now the neck tension is perfect. I sent the Hornady sizing die back with some brass but havent heard anything about it yet. I also borrowed a friends RCBS sizing die and had the same issues as with the Hornady dies, so I think I narrowed down the problem to thin brass. Either way, the U-die got me up and running. I am curious to see what Hornady does though. Thanks for the replies everyone. Wise man. The "U" die is a must IMHO. I got mine from EGW gunworks out of PA. |
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Perhaps this chart from Ramshot will help answer your question about how much setback influences pressure in the 9mm. <a href="http://s1352.photobucket.com/user/38superdude/media/RamshotOALampPressure_zpse3a59f20.jpg.html" target="_blank">http://i1352.photobucket.com/albums/q656/38superdude/RamshotOALampPressure_zpse3a59f20.jpg</a> Nice chart - thanks. It illustrates WHY I try to use the LONGEST COAL possible without touching the lands. A longer COAL reduces pressure, which makes brass last longer, and is easier on the gun (gun last longer) and usually feeds better, and accuracy is better too. This is true GENERALLY and there are exceptions. But, load long when you can. |
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Perhaps this chart from Ramshot will help answer your question about how much setback influences pressure in the 9mm. <a href="http://s1352.photobucket.com/user/38superdude/media/RamshotOALampPressure_zpse3a59f20.jpg.html" target="_blank">http://i1352.photobucket.com/albums/q656/38superdude/RamshotOALampPressure_zpse3a59f20.jpg</a> Nice chart - thanks. It illustrates WHY I try to use the LONGEST COAL possible without touching the lands. A longer COAL reduces pressure, which makes brass last longer, and is easier on the gun (gun last longer) and usually feeds better, and accuracy is better too. This is true GENERALLY and there are exceptions. But, load long when you can. This! I always try and load as long as possible with 9mm. |
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Quoted:
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Perhaps this chart from Ramshot will help answer your question about how much setback influences pressure in the 9mm. <a href="http://s1352.photobucket.com/user/38superdude/media/RamshotOALampPressure_zpse3a59f20.jpg.html" target="_blank">http://i1352.photobucket.com/albums/q656/38superdude/RamshotOALampPressure_zpse3a59f20.jpg</a> Nice chart - thanks. It illustrates WHY I try to use the LONGEST COAL possible without touching the lands. A longer COAL reduces pressure, which makes brass last longer, and is easier on the gun (gun last longer) and usually feeds better, and accuracy is better too. This is true GENERALLY and there are exceptions. But, load long when you can. This! I always try and load as long as possible with 9mm. ^This^ echo I took an average of 3 mfg fmj OAL was as well as the load data specs. If the OP or anyone else wanted to go crazy[er] pull 3 rounds from any mfg and see what their variance is. Let alone the different OAL per mfg , rounds in each box 
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