June 26, 2009, 10:03 PM | #1 |
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General Bullet Question
Ok so when trying to find load data for specific loads I have a question about bullets. Basically how interchangeable are the different types of bullets. Finding a specific load with the powder we have and the bullet we have has been difficult. Right now I am trying to find a load for .38 spl. I have 158gr semi-jacketed soft points and Bullseye or Red dot powder. Is it possible to use the ballistic coefficient and/or sectional density of the bullet to find a comparable one. I found a load for the Lead Round Nose which I think is probably the same or very similar to what I have. I know the BC of the one I have is .159 and the SD is .176. The BC for the load example I found is .170 and the SD is the same .176. So yes now that supplies are getting a little easier to find we will start buying more specifically, but I need to find a good load to use the supplies we have right now. So what do you guys suggest?
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June 26, 2009, 11:34 PM | #2 |
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I have load manuals that only list bullet weight and type, sometimes diameter, sometimes not, with no mention of brands or ballistic coefficient --- sooo--- I think quite a bit of interchangeability is allowable at least with the powder loads listed in these books.
These loads may not approach pressure levels near those of manuals which list specific bullets; I don't know. I've done quite a bit of switching and swapping of bullets over the years, and had no problems and a lot of success in finding accurate loads---but I seldom load maximum or near it. jd
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June 27, 2009, 12:23 AM | #3 |
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If you are trying to find the right load for a given bullet weight, shape, constituency, BC, SD and every other measurable characteristic of the bullet, you are missing a great deal of the fun of reloading. Not to mention, you will only come close, because your handgun is not figured in the load tables. SD and BC are only factors in the bullet's flight.
The primary consideration for loading, after you determine that you have the correct diameter for your cartridge, is the bullet weight and whether it is a jacketed or lead bullet. Anytime you change any one component, even the same bullet weight, always back off your previous load a tad and work back up. |
June 27, 2009, 06:36 AM | #4 |
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call serria bullets tech line 800-223-8799 they are open 8am to8pm. I had some 8mm bullets that I couldnt find load info for. they were a great help even if your not using serria bullets. they explained how to work up a load for a given bullet that has no printed load data.
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June 27, 2009, 08:13 AM | #5 |
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If the OP doesn't mind me injecting a question into his thread, I'd like to ask; given the same weight and diameter, will jacketed bullets create more pressure than cast bullets with the same powder charge?--- or are there too many other variables to consider such as alloy, powder burn rate, etc.. Thanx, jd.
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June 27, 2009, 09:58 AM | #6 |
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Well right now we are still starting out so we are doing mostly starting loads. With that in mind it sounds like really the most important thing is just the weight of the bullet and not so much the type? Then from their whether its jacketed or not when you start making more powerful loads? Now that I look at the books in that way it does make sense. Thanks for the help.
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June 27, 2009, 05:26 PM | #7 |
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Bullets
All bullets are different.
Different manufacturers use different alloys of lead and gilding metal, in different interior designs. So they all have different characteristics of how they react to being jammed through a barrel so abruptly. Sectional density (SD) is simply the ratio of weight to cross section. So all .357 caliber bullets that weight 158 grains will have the same sectional density. Ballistic coefficient (BC) is a measure of how streamlined they are; sectional density has an effect on BC, but not as much as shape and so forth. SD has an effect on loading only in the sense that heavier bullets require slower powders for highest velocity. However, the inner structure of the bullet does effect pressure, as one design will be harder to move through the barrel than another and that resistance to movement increases pressure. Lead bullets tend to cause higher pressures than an equal weight jacketed bullet. Yes, lead has a lower coefficient of friction and should zip down the barrel easier, but the malleability of lead seals off the barrel more fully. With that in mind, starting loads are normally mild enough to allow some substitution without danger. Yes, bullet 'A' will cause higher pressures than bullet 'B', but with starting loads, not enough to exceed the safety limits of a normal firearm. So jump in. The danger lies in finding a strong load (I hate the term 'maximum load', there is no such magic thing - all firearms have different limits!) with bullet 'A', and then substituting bullet 'B' without lowering the powder charge. This will change the pressure level. It may go up or down, but without prior research and information, there is no way to tell. (The same hazard attaches to any change of components: bullet, primer, case and of course powder.) Such a substitution will probably not blow up the firearm, even if it exceeds the SAAMI limit; but it will potentially damage brass, will accelerate wear on the firearm and will damage the firearm over the long term. And yes, it could blow up.
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June 28, 2009, 09:15 AM | #8 |
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thanks that was very helpful. we won't be making anything other than very light loads for awhile so sounds like we are in good shape.
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June 28, 2009, 09:50 AM | #9 |
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Don't think that very light loads are always bound to be safe and satisfactory. Use pressure tested handbook loads with the customary 10% reduction for a starting load. And yes, the difference between jacketed and lead does matter.
Anecdote warning: A very light load with a jacketed bullet can lead to a stuck bullet or even a stuck jacket. I saw the latter happen. A guy here did not want those nasty old lead bullets in his nice new gun, so he loaded some 158 grain jacketed softpoints as though they were swaged lead wadcutters. A few shots into the session, he heard a strange report but thought nothing of it because he could see a new hole in the target. He kept shooting and then found a bulge in his barrel when he cleaned it. What had happened was that the low pressure load had let the bullet jacket stick in the bore while the lead core shot out clear to the target under inertia. The next bullet hit the lodged jacket and bulged the barrel. We found all the pieces in the berm behind the target frame the next day; core, jacket, and the following bullet with the nose formed to the shape of the indentation in the bottom of the stuck jacket. The stuck jacket was packed full of target paper and backer cardboard, the following bullet had driven it all the way to the target. |
June 28, 2009, 11:29 AM | #10 |
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verti89 - lite loads
Be careful with the "very lite loads" since they have their own special hazards to consider.
Need to really watch out for a squib. Add extra step of bore check after each individual "very lite load" fired. Single load by hand only. I would strongly recommend using the starting loads in the Manuals to define what you mean by "very lite load". And also consider that the way these perform in "your" weapon may not produce the same results as the test results in the Manuals. I have seen what happens when "very lite loads" are taken at face value and I don't want it happening to me or those around me. Use single shot instead of mag feed - and check barrel each time when working in the "very lite load" area. |
June 28, 2009, 03:40 PM | #11 | |
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Quote:
I was incorrect in my statement that SD is only a factor in bullet flight. But for working up a load, SD is really only important if you are working up a hunting load. SD is a significant factor in penetration. |
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June 28, 2009, 03:43 PM | #12 |
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When I said very light loads I was in fact referring to starting loads referenced in several manuals. I also know that jacketed vs just lead makes a difference. My original discussion said as much. Really what I am getting at is if I find a load for a JHP but what I have is a JFP, or in reality, I found a load for a JFP and I actually have SJSP, can that starting load be used with the slightly different bullet type? From what I have read on here it does sound like if both loads are jacketed and of the same weight, the starting load for one should produce perfectly safe, if not necessarily the most accurate, loads in the other.
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June 28, 2009, 03:50 PM | #13 |
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Yes.
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June 28, 2009, 09:27 PM | #14 |
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Load for the bullet weight. Who made it or its shape doesn't matter. You don't really need to worry about the BC either.
Don't use jacketed bullet data for cast bullets. It'll drive 'em too fast and you'll get leading.
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June 28, 2009, 11:40 PM | #15 | ||
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Quote:
Quote:
So try your best to match bullet profile when transposing load data, or adjust the COL to keep seating depth consistent. |
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June 29, 2009, 10:04 AM | #16 |
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Ok then so how do I determine the length of a bullet I don't actually have??
The bullets I have are semi-jacketed FP where just the tip of the lead is exposed. The closest I can find are LRN or FMJ. |
June 29, 2009, 10:50 AM | #17 |
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Great thread, I will be watching and reading. I am a new reloader and I have a few load books(speer and horandy) also I go to all manufactorers web site, I never find a load with exact bullet, brass, primer and powder. I guess thats what Bud meant by missing the fun, I read and read and start with a 10 round batch and go from there. So with all the variables which are the most important? Bullet weight and grams of powder? And then there is COL and is bullet design key to COL? My first 45acp load was so light it wouldn't push the slide back far enough to chamber the next round, glad I didn't load 100 of those. Lots of fun, learning to reload, can't wait to get to rifle cartridges.
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June 29, 2009, 11:45 AM | #18 | |
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Quote:
If you use the same bullet profile, it should be close enough. Two FMJ round nose bullets in the same weight should be damn close in length. You just don't want to transpose COL's for drastically different profiles, like FMJ and JHP. I'm just hypersensitive to this factor because I load a lot of .380, and there's so little room in that case that a few hundredths of an inch variation in depth can be significant. If you like, PM me with a bullet brand/type, and I'll look up its specs in QuickLOAD. |
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June 29, 2009, 01:48 PM | #19 |
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We don't worry about finding the same case and primer but we do try to find the same bullet and obviously the same powder. Finding the right bullet has proven somewhat difficult.
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June 29, 2009, 01:51 PM | #20 |
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Deleted because I liked someone else's answer better.
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