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Posted: 7/10/2012 5:50:21 PM EDT
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So I found my hunting load(HP) or at least one I can make a good run of with my current supply.
I also have some round nose(same weight as the HP) that I want to load for target. I want to keep in the same power range as the hunting round. So my question is, if I measure the different in projectile length and change seating depth so it is equal and keep the same powder charge(charge space and weight staying the same) is this a viable target/plinking scenario? I know it won't equal the accuracy of working up a separate charge for the most part. But I want to keep the feel of the hunting round and have some fun, without killing my good stash. |
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10mm pistol, 6" barrel, 180gn XTP's with 8.7gn of power pistol @ ~1260 FPS (just a tad faster than Hornady Custom rounds with same projo), COAL 1.26.
The round nose are sierra target jacketed 180gn. The difference in projectile length is.03; with the round nose being the shorter, obviously. I've worked the above load all the way to ~10 grains of PP and had one round actually top 1400fps out of a string. And actually no nasty signs of over pressure, which is why I wouldn't think there would be a problem with pressure on the prospective target round. Just looking to see if anyone has tried this route. I know most like to work up each projectile to find the sweet spot, but for paper punching I don't need the sweet spot. I would like to keep it around the same feel as the hunting round though, just for muscle memory and such. |
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Quoted:
The round nose are sierra target jacketed 180gn. . You sure about this bullet? I didn't know Sierra made a 180gr 10MM RN. http://www.sierrabullets.com/index.cfm?section=bullets&page=handgun&caliberID=21 |
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The theory is that with different shaped bullets of the same weight you might find considerable different velocity/presure.
The different bearing length (basicly the amount of surface area of the bullet that is in contact with the bore) has a effect on when the bullet starts to move. With greater bearing length the bullet stays in place for a bit longer and the powder burns more efficiently due to the smaller space and creates higher preasure. Sounds like you have a warmish load to begin with,back down the load a bit (5 to 10%?) with the new bullet and check velocity as you bring the powder up to your intended load. If you were useing a more mild load I would suggest just to do it but when you have a near max load things happen at a faster rate, a simple change of bullet shape or brand ,even with the same weight could drive you way over the line. How much time is it going to take to load 3 shells with a 10% reduced charge,3 more with a 6% reduction and 3 with a 3% and 3 at your full load? The percentages I am refering to are down fron your full intended load . I will do the math, rounded to the nearest tenth the 10% reduction is 7.8gr, the 6% is 8.2gr and the 3% is 8.4 gr. These are based on your original charge of 8.7gr. I myself would not change the bullet length setting on your die. As long as the new bullet (RN) shoots reliably at that length just load both bullets with the die set the same (one less thing to have to mess with) I am thinking you are going to end up shooting both these loads with the same die setting and the same powder charge (with a result of only slightly different velocities) but it never hurts to be cautious when reloading |
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Quoted:
Quoted:
The round nose are sierra target jacketed 180gn. . You sure about this bullet? I didn't know Sierra made a 180gr 10MM RN. http://www.sierrabullets.com/index.cfm?section=bullets&page=handgun&caliberID=21 You are correct. Looked again and they are Speer. |
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Quoted:
The theory is that with different shaped bullets of the same weight you might find considerable different velocity/presure. The different bearing length (basicly the amount of surface area of the bullet that is in contact with the bore) has a effect on when the bullet starts to move. With greater bearing length the bullet stays in place for a bit longer and the powder burns more efficiently due to the smaller space and creates higher preasure. Sounds like you have a warmish load to begin with,back down the load a bit (5 to 10%?) with the new bullet and check velocity as you bring the powder up to your intended load. If you were useing a more mild load I would suggest just to do it but when you have a near max load things happen at a faster rate, a simple change of bullet shape or brand ,even with the same weight could drive you way over the line. How much time is it going to take to load 3 shells with a 10% reduced charge,3 more with a 6% reduction and 3 with a 3% and 3 at your full load? The percentages I am refering to are down fron your full intended load . I will do the math, rounded to the nearest tenth the 10% reduction is 7.8gr, the 6% is 8.2gr and the 3% is 8.4 gr. These are based on your original charge of 8.7gr. I myself would not change the bullet length setting on your die. As long as the new bullet (RN) shoots reliably at that length just load both bullets with the die set the same (one less thing to have to mess with) I am thinking you are going to end up shooting both these loads with the same die setting and the same powder charge (with a result of only slightly different velocities) but it never hurts to be cautious when reloading Great post! I hadn't even though about the change in bearing length. That does make sense how that will effect things. Maybe I can get some carbon paper and figure out the bearing difference as well, just for reference. I also think I will keep the same COAL and see how they shoot. Maybe even make a string of 8gn charge to test the water and see if going to 8.7gn will even matter. Or what it may need to get to similar velocity. |
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Quoted:
You are off the Sierra velocity charts for that bullet weight in a 10mm pistol and are up in the 44 magnum range. That does not seem right. Meh... Load the 10mm like it should be not a slightly hotter .40cal and you should get into Magnum ranges maybe closer to 41mag than 44. But like I said I did get those 180 XTP up to 1385-1400 range. The spent casings seemed to indicate relatively safe(but probably pushing it a little), But the accuracy went to hell so I backed it down to where groups where best. And I also tested other factory ammo and the Hornady Custom using the same 180XTP was around 20-30 FPS less than my reloads and grouping very similar. In my eyes that projectile definitely has a sweet spot in terms of velocity; for my setup at least. |
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