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Posted: 3/24/2010 8:52:06 PM EDT
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I'm back with another load question - this time 9mm. I am keenly aware of how important it is to work up loads and base it on good data. I found the info I needed to work up my .223 loads and I get to go shoot them tomorrow. In the mean time, I thought I'd start on a 9mm load for my Glock 17- but am wondering if I have enough information to proceed. My sense is that I need to cross reference what I've found with at least one more source & that I shouldn't proceed until I do. I'm looking to gut check that here.
I've got IMR SR-4756 powder & Hornady 124 GR HP/XTP bullets. The Hodgdon site doesn't have a load for this specific bullet, but does have a load for a 125 GR FMJ for my powder. 125 GR. SIE FMJ IMR SR 4756 .355" 1.090" 4.5 973 25,700 PSI 4.9 1037 28,700 PSI My Speer manual doesn't have any comparable loads for this powder; Lyman doesn't have any loads for this bullet either - but they do have loads for lighter (115 GR) bullets for SR-4756 (min= 4.5, max= 6.2 (compressed)). This is telling me that the load Hodgdon cites for my heaver bullet may be in the ballpark, but it's not apples to apples... Based on the one load that I have for a similar bullet (but not exactly the same) for my powder, it seems logical to start at 4.5 GR and stop by 4.7, checking for pressure signs. But - my gut is telling me that what I really should have is an actual load for the specific bullet and powder, especially since I can't cross reference "close" bullets in this powder across several sources. Am I being too anal or should I just carefully work it up with what I have? I'm not keen on blowing myself or my gun up, so I appreciate being able to come here to pick your brains as I learn! Rick |
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First there are no hard and fast rules for what you are asking. If a bullet is similar in bearing surface, profile and slightly heavier then the data for this heavier bullet can be used for a lighter bullet. Usually, but not always, you can somewhat exceed the max load of the heavier bullet for the lighter bullet. However the max for that lighter bullet is in question. also if a bullet is different in profile then other factors are influenced, in this case, seating depth may be effected. If it seats deeper the charge may show pressure signs sooner.
This is where watching for pressure signs and a chronograph come in. A chrono can tell you where your velocity is at and give you an idea where your load ranks. |
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river_rat -
That makes sense and it helps... I guess my first concern in looking at my situation is making sure I have a valid starting point - one that I can have some confidence that I'm in the game without doing harm or shooting a squib. If I have that, I feel a bit better about being able to work the load up a bit. But, I lack a chronograph... so what I'm doing as I work up would be judged by pressure signs / accuracy. So, my intent is to not even attempt to (intentionally) get near max without more reloading experience. 4.5 GR "feels" safe when I think about the data I do have, but quite honestly I don't know what I don't know. I wish I'd bought a Hornady reloading manual (even better, I wish their data was online, but alas - I can't find it). |
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Quoted:
I am keenly aware of how important it is to work up loads and base it on good data. My sense is that I need to cross reference what I've found with at least one more source & that I shouldn't proceed until I do. I'm looking to gut check that here. But - my gut is telling me that what I really should have is an actual load for the specific bullet and powder, I think your gut is telling you something. I would go with that and find some additional data. I'm very cautious when it comes to a new caliber, bullets and/or powders. I just feel better about it when it comes time to pull the trigger. I too have found that the data available differs between manuals, pamphlets, sites and the Internet. Some manuals are more conservative than others. Some reloaders have a lot more experience. I still have to feel comfortable with the final product in my firearms and in my hands. That being said, let's just say that a conservative manual had a lower starting charge and a higher max, you may just miss what your looking for. Go with your gut. |
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Quoted:
river_rat - That makes sense and it helps... I guess my first concern in looking at my situation is making sure I have a valid starting point - one that I can have some confidence that I'm in the game without doing harm or shooting a squib. If I have that, I feel a bit better about being able to work the load up a bit. But, I lack a chronograph... so what I'm doing as I work up would be judged by pressure signs / accuracy. So, my intent is to not even attempt to (intentionally) get near max without more reloading experience. 4.5 GR "feels" safe when I think about the data I do have, but quite honestly I don't know what I don't know. I wish I'd bought a Hornady reloading manual (even better, I wish their data was online, but alas - I can't find it). Ok, let me put it this way. First I would try to find data that would be from a similar type bullet be it the same weight or slightly heavier. If I could not I would probably go with the start load you found and gradually work up in .1 gr. increments until I noticed sharper recoil, sharper muzzle blast, extraction problems, signs of pressure on the case different than other "normal" loads shot from that pistol. Anything out of the ordinary or suspicious would be reason to stop there. If I thought the seating depth was a limiting factor I would start a couple tenths less. I would also seat the bullet out as far as possible and still get good function. If you have used this bullet before you should know where this is. If not go with the published length for that bullet, longer if possible. This will give you as much air in the case as possible to help reduce pressure. Just be sure to not go so long that the bullet engages the rifling. Unlikely but needs to be checked. Only make up a few to start with so you don't have to pull a bunch of bullets. Go about this responsibly and listen to your pucker factor. I can't and won't guarantee anything. Reloading can be dangerous and demands caution but it isn't black magic either. |
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Quoted:
Hornady 7th Edition, page 799. 124 gr XTP. C.O.L. 1.060 SR-4756 4.1 - 900fps. 4.6 - 950fps. 5.0 - 1000. 5.5 max - 1050fps. If you load brand x. I suggest you buy brand x's manual. The one book that will just get you by is Lee's 2nd Edition. Much appreciated! Yes - at least one more manual is on the shopping list! |
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