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Posted: 8/17/2009 12:56:43 PM EDT
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Does anyone having any information on this for a .308 Win |
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IMO, normal 175 grain data should be the starting point, BUT, the 175 grain API bullets are longer than a normal 175 and will take up more room inside the case if loaded to the correct OAL. I'd look at standard 175 data and reduce the charges a bit to start.
ETA: I just looked at the ones I've got and apparently I misremembered the weight. Mine are 155 grains, and are 1.45" long. For reference, I checked a 175 grain SMK and they're .200" shorter at 1.25" long. That means they are going to be much longer than a standard 150 or 155 grain bullet. About the best thing I can think to do would be to seat a boat tail bullet like the 155 SMK to the proper length in a resized/decapped case, check the water capacity, and do the same for the API. Whatever the reduction of internal volume(water capacity) is percentage wise, reduce the charge by a like amount. I'm not an expert, but I would think that would get you in the ball park of what it should be. |
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there are compressed loads listed as well. What type of brass will you be using. military or commercial?? .mil reduce the charge by 10%, commercial you can go either way that you feel comfortable with as long as you have several lists of load data for a similar bullet. Regular AP is long as well, depending on what powder will also be useful info, some are more bulky than others.
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The data I found was for AP not API.
But try finding that powder for M993. LOL. M61 AP uses IMR 4475 powder (not generally available to us). http://www.gun-shots.net/ballistics-chart.shtml ME......I'd experiment. See the above suggestion(s). I'd be looking in that direction. Start low and work your way up. Aloha, Mark |
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Quoted: there are compressed loads listed as well. What type of brass will you be using. military or commercial?? .mil reduce the charge by 10%, commercial you can go either way that you feel comfortable with as long as you have several lists of load data for a similar bullet. Regular AP is long as well, depending on what powder will also be useful info, some are more bulky than others. Prob. be looking to put it in some Lapua brass...m14 API is running me $2 a bullet so it's going in the best brass I have! |
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Quoted: there are compressed loads listed as well. What type of brass will you be using. military or commercial?? .mil reduce the charge by 10%, commercial you can go either way that you feel comfortable with as long as you have several lists of load data for a similar bullet. Regular AP is long as well, depending on what powder will also be useful info, some are more bulky than others. Prob. be looking to put it in some Lapua brass...m14 API is running me $2 a bullet so it's going in the best brass I have! |
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Well looking at some of my data here, the rounds I was using, I used 163 grain data and LC 08 cases the LR not nato. using IMR- 4320 with a start load of 37 grains. I did not see any signs of overpressure. Unfortunately I didn't have a chrono so I couldn't tell you the average FPS.
Sierra bullets rifle second edition lists a BT round with IMR-4320 starting at 40.9 grains If you can get your hands on a few other reloading manuals that should help and reduce your start load for safety. |
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Quoted:
Well looking at some of my data here, the rounds I was using, I used 163 grain data and LC 08 cases the LR not nato. using IMR- 4320 with a start load of 37 grains. I did not see any signs of overpressure. Unfortunately I didn't have a chrono so I couldn't tell you the average FPS. Sierra bullets rifle second edition lists a BT round with IMR-4320 starting at 40.9 grains If you can get your hands on a few other reloading manuals that should help and reduce your start load for safety. Good post. 
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This guy did a nice little write up on AP vs API 30 cal. http://www.surplusrifleforum.com/viewtopic.php?f=76&p=546334 |
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Quoted:
This guy did a nice little write up on AP vs API 30 cal. http://www.surplusrifleforum.com/viewtopic.php?f=76&p=546334 The bullet he has pictured does not look quite like what I have. 175gr SMK on top, 155 API on bottom. 
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