bullets not found in my reloading manual
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DukeConnor
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Get a chrono and start laddering.
stillquietvoice
Contributing Member
@Rocky1954 welcome to the forum, chri ograph data is likely your best indicator with out shipping out your reloads to have them pressure tested. I too haven't seen many differences as long as the bullets were similarly constructed, ie cup and core. My first reloading manuals listed several bullets that could use the same data, even nosler online data has several bullets tested with the same powder weights.
As long as you're talking about the same, or even similar bullet weights and similar bullet construction you can use the same starting load data. But as you work up you may find that you reach a max load at a lower powder charge with some bullets than with others.
Even with bullets of the same weight there are major differences in shape. And how much of the bullet is actually in contact with the barrel. A long 180 gr 30 caliber boat tail target bullet has a much smaller surface in contact with the barrel than a round nose flat based 180 gr hunting bullet. The hunting bullet will have more resistance moving through the barrel, and develop more pressure. Meaning max powder charges may be slightly different.
For example, if I found data for a 165 gr bullet, but not 168 gr I'd use the 165 gr data to start working up my load. But chances are good the 168 gr bullet will need a bit less powder. But then again maybe not.
Also similar bullets can probably use the same load data, at least to start. If I had data for 150 gr 30 caliber Hornady SST's, but not 150 gr Nosler Ballistic Tips I'd not have any problem using the same data. But a 150 RN bullet will probably use different load data than a boat tail pointed bullet. Once again starting loads would probably be OK and if you never plan to load anything but mid-level loads you'd probably be fine. But if you want to start working toward max loads you could see some differences.
The biggest difference is with the newer solid copper bullets. Copper is lighter than lead and in the same bullet weight copper bullets are a lot longer. That changes things. The load data for copper bullets is going to be quite different than conventional lead bullets.
Even with bullets of the same weight there are major differences in shape. And how much of the bullet is actually in contact with the barrel. A long 180 gr 30 caliber boat tail target bullet has a much smaller surface in contact with the barrel than a round nose flat based 180 gr hunting bullet. The hunting bullet will have more resistance moving through the barrel, and develop more pressure. Meaning max powder charges may be slightly different.
For example, if I found data for a 165 gr bullet, but not 168 gr I'd use the 165 gr data to start working up my load. But chances are good the 168 gr bullet will need a bit less powder. But then again maybe not.
Also similar bullets can probably use the same load data, at least to start. If I had data for 150 gr 30 caliber Hornady SST's, but not 150 gr Nosler Ballistic Tips I'd not have any problem using the same data. But a 150 RN bullet will probably use different load data than a boat tail pointed bullet. Once again starting loads would probably be OK and if you never plan to load anything but mid-level loads you'd probably be fine. But if you want to start working toward max loads you could see some differences.
The biggest difference is with the newer solid copper bullets. Copper is lighter than lead and in the same bullet weight copper bullets are a lot longer. That changes things. The load data for copper bullets is going to be quite different than conventional lead bullets.
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Rocky1954
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jmr This is very helpful. It seems that the amount of contact is at least if not more important than the shape of the base of the bullet. If we have just a flat base and a boat tail, if the bullets are shaped similarly, i.e. like a SST then from what you are saying there should not be much of a difference at least in the starting loads. Am I correct?
thank you to stillquietvoice
thank you to stillquietvoice
AJC1
Member
Botail bullets are longer than flat bases. That improves bc but requires a higher twist rate for the same weight to stabilize. Pressure is a combined effect of weight and bearing surface.
Hollowbase will weigh less than an equally sized bullet and are designed to run slower with less of a charge....
Hollowbase will weigh less than an equally sized bullet and are designed to run slower with less of a charge....
Bcwitt
Member
Ive never experienced a start load that was very problematic, other then being to light to cycle a semi. Not very scientific, I admit, but i find if i adhere to acredited data, i wont be in trouble.
lordpaxman
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@Rocky1954, welcome to THR!
Lots of variables that affect pressure in this system.
There are software programs like Quickload and GRT (free) that can be configured with different bullets in the same virtual test fixture and give you pressure curves. It’s software, so, obviously not measured by some means however it’s easier and cheaper for us that don’t have access to measuring equipment.
Lots of variables that affect pressure in this system.
rfwobbly
Member
1. First buy a chronograph. That will give you more information about your loads than a library full of manuals ever will.
2. You can typically use the Starting Load from any manual as long as the bullet weight and bullet construction are the same. The only issue here is when you have plated bullets because thickly plated bullets behave more like jacketed, while thinly plated bullets act like lead bullets. This knowledge will come with experience.
3. Then load 5 to 8 rounds at each higher powder weight using the exact same OAL. These are called "incremental loads" and allow the shooter to slowly (and safely) work up "the ladder" one increment at a time to the next higher load. At the lowest loads, you may discover the loads are too anemic to operate the gun's mechanism, so you can skip those.
4. Know your manual's bullet velocity at Max Load. As you shoot your incremental loads at higher and higher powder weights, be watching the chronograph for loads that approach the maximum velocity, because this is warning you of a Max Load (maximum safe chamber pressure) situation. For instance, if the velocity at Max Load was listed as 1275 fps and you just shot an incremental load that measured 1262, then you are finished. That is the Max Load for that specific bullet/powder weight/OAL combination in that specific gun. This is because the next increment might possibly take you to 1295.
- If you are smart, you will shoot each of these incremental loads at a fresh target. You will generally find that the most accurate loads come in the middle of the load zone.
- If your increments were (for instance) 0.3gr (loads of 4.1gr, 4.4gr & 4.7gr) and you best accuracy was at 4.4gr, then you can always go back and test with smaller increments at 4.3gr, 4.4gr and 4.5gr in a second test.
- Again, it needs to be emphasized that the OAL is the same for all rounds. You want a test where only ONE variable (the powder weight) is changing, otherwise the test is useless.
- If you use the same target distance for ALL load testing over several years, then by keeping your targets you can begin to compare bullets and powder accuracies.
- Some manuals do not list velocities at Max Load. If you have one of those, then you need a better manual.
- Do not count on "reading primers" to tell you the Max Load. You will see for yourself that is a totally inaccurate method.
Hope this helps.
2. You can typically use the Starting Load from any manual as long as the bullet weight and bullet construction are the same. The only issue here is when you have plated bullets because thickly plated bullets behave more like jacketed, while thinly plated bullets act like lead bullets. This knowledge will come with experience.
3. Then load 5 to 8 rounds at each higher powder weight using the exact same OAL. These are called "incremental loads" and allow the shooter to slowly (and safely) work up "the ladder" one increment at a time to the next higher load. At the lowest loads, you may discover the loads are too anemic to operate the gun's mechanism, so you can skip those.
4. Know your manual's bullet velocity at Max Load. As you shoot your incremental loads at higher and higher powder weights, be watching the chronograph for loads that approach the maximum velocity, because this is warning you of a Max Load (maximum safe chamber pressure) situation. For instance, if the velocity at Max Load was listed as 1275 fps and you just shot an incremental load that measured 1262, then you are finished. That is the Max Load for that specific bullet/powder weight/OAL combination in that specific gun. This is because the next increment might possibly take you to 1295.
- If you are smart, you will shoot each of these incremental loads at a fresh target. You will generally find that the most accurate loads come in the middle of the load zone.
- If your increments were (for instance) 0.3gr (loads of 4.1gr, 4.4gr & 4.7gr) and you best accuracy was at 4.4gr, then you can always go back and test with smaller increments at 4.3gr, 4.4gr and 4.5gr in a second test.
- Again, it needs to be emphasized that the OAL is the same for all rounds. You want a test where only ONE variable (the powder weight) is changing, otherwise the test is useless.
- If you use the same target distance for ALL load testing over several years, then by keeping your targets you can begin to compare bullets and powder accuracies.
- Some manuals do not list velocities at Max Load. If you have one of those, then you need a better manual.
- Do not count on "reading primers" to tell you the Max Load. You will see for yourself that is a totally inaccurate method.
Hope this helps.
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jmorris
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It turns into a long drawn out discussion, generally.
If you ask a specific question you can probably get to your answer a few days/pages faster.
Cliff notes version is that reduction in internal case volume (bullet takes up more space), an increase in mass and an increase in the friction between the bore and bullet, all have tendencies to raise pressure.
There are exceptions though, like seating a bullet out to the point it contacts the rifling, that increases internal case volume but doesn’t allow the bullet to get a running start before hitting the rifling, so pressure goes up vs a little “free bore”.
High Plains
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Equal caliber and weight Nosler Accubonds and Partitions used to be shown as having different muzzle velocities despite the same amount of the same powder. A rep at the Nosler ballistic lab told me the difference was due to the lesser amount of obturation the Partition achieves due to the basic A-frame design of the Partition not engaging the rifling the same way as the Accubond. Basically the Accubond makes a tighter seal in the barrel. OK, I get it.
If you load Barnes bullets, use data specifically for those bullets. In my limited use of Barnes TSXs I found they were accurate. I also worked up a lot of loads before finding the best——with H-4350 and the longest COL I could and still feed from a full magazine.
This is a great place for good advice, so never be afraid to ask.
If you load Barnes bullets, use data specifically for those bullets. In my limited use of Barnes TSXs I found they were accurate. I also worked up a lot of loads before finding the best——with H-4350 and the longest COL I could and still feed from a full magazine.
This is a great place for good advice, so never be afraid to ask.
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