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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
7mm Allen Mag test rifle finished.....
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<blockquote data-quote="Fiftydriver" data-source="post: 76353" data-attributes="member: 10"><p>Holy CRAP!!!!</p><p></p><p>I guy is away from the shop for a day and a half to a family reunion and when he gets back theres +40 new posts to read!!! /ubbthreads/images/graemlins/shocked.gif</p><p></p><p>Well, I read all the posts and while I wanted to reply to each one individually, I also want to get some sleep tonigh!!</p><p></p><p>So I will group my comments together.</p><p></p><p>First off, all this discussion has alot to do with big cases, heavy bullets, and high performance. I do not see a hijack going on here. Powder selection is probably second only to bullet selection in my mind for the Allen Mags to get top performance.</p><p></p><p>That said, I agree that 50 BMG is totally suitable for the 7mm Allen Mag with the 175 and 200 gr bullets, I have just not gotten to the point of actual testing yet. It will come though.</p><p></p><p>As far as Burn temps with ball and stick powders, I have no scientific data to type to back up my comments, what I do have though is test a barrel using Retumbo chambered in 257 STW and then taking that exact same barrel and testing it with AA8700 in my Allen mag and actually being able to feel the difference in barrel temp with my hand. Five shots with the STW and I could not hold the barrel, 8 shots with the AA8700 and while the barrel was very warm, I could hold it comfortable.</p><p></p><p>You guys know far more then I do about scientific testing, I am just a simple rifle maker that sees things pretty black and white and to me the ball powders keep barrel temps lower.</p><p></p><p>This may be to some result of less bore friction caused by the powder itself???</p><p></p><p>Comparing AA8700, H-870, H-50BMG and WC872. The current lot of 8700 I have has a burn rate nearly identical to Retumbo. I deduce this from the fact that in the 270 Allen Mag, they produce nearly identical velocities with the 130 gr Ballistic Tip when using the same powder charge.</p><p></p><p>The earlier lot of 8700 was nearly identical to the old H-870 which I have found to be at least the same or slower burning then H-50BMG. I say this because in the 50 BMG I get less velocity with the same powder charge under the same bullet using H-870 compared to H-50BMG which again tells me that the ball powder is slower.</p><p></p><p>Please keep in mind that in cool temps that H-870 may be slightly slower then H-50BMG and in warmer temps it may be slightly quicker burning. </p><p></p><p>I will tell you that I have never seen a lot of AA8700 or H-870 burn as slow as the lot of WC872 I am using now.</p><p></p><p>Again, I am a simple guy, from what the data tells me this is how I would rate these powders in burn rate:</p><p></p><p>AA8700</p><p></p><p>H-870/H-50BMG very close on average</p><p></p><p>WC-872</p><p></p><p>Now the difference between 870/50BMG and 872 is not dramatic but it is there.</p><p></p><p>Also, thanks for the pics of the 200 gr ULD in comparision to the 160 gr Accubond. My figures that stated the 200 gr ULD was 0.060" longer then the 160 gr Accubond was in reference to the full diameter body of the bullet which was clearly illistrated by ss7mm, thank you!!</p><p></p><p>I will read through the posts again tomorrow as I am sure I missed some things I wanted to touch on. </p><p></p><p>Basically, I am happy with the results so far with the 7mm Allen Mag but to be honest until we get the 1-7 30" barrels to test, we are just playing around with this round. Data will continue to come in as soon as I get it tested on the range. I will be testing some 175 gr SMKs next to see what we can do in a 26.5" barrel. Basically the reason for this testing is to get me a start on the 175 gr ULD RBBT bullets as I know they will be a superior bullet option. Not that the Sierra is a good bullet because it is, its not a Wildcat though!!</p><p></p><p>I will reply more tomorrow, good night and great conversation, no need to apologize to me.</p><p></p><p>Kirby Allen(50)</p></blockquote><p></p>
[QUOTE="Fiftydriver, post: 76353, member: 10"] Holy CRAP!!!! I guy is away from the shop for a day and a half to a family reunion and when he gets back theres +40 new posts to read!!! [img]/ubbthreads/images/graemlins/shocked.gif[/img] Well, I read all the posts and while I wanted to reply to each one individually, I also want to get some sleep tonigh!! So I will group my comments together. First off, all this discussion has alot to do with big cases, heavy bullets, and high performance. I do not see a hijack going on here. Powder selection is probably second only to bullet selection in my mind for the Allen Mags to get top performance. That said, I agree that 50 BMG is totally suitable for the 7mm Allen Mag with the 175 and 200 gr bullets, I have just not gotten to the point of actual testing yet. It will come though. As far as Burn temps with ball and stick powders, I have no scientific data to type to back up my comments, what I do have though is test a barrel using Retumbo chambered in 257 STW and then taking that exact same barrel and testing it with AA8700 in my Allen mag and actually being able to feel the difference in barrel temp with my hand. Five shots with the STW and I could not hold the barrel, 8 shots with the AA8700 and while the barrel was very warm, I could hold it comfortable. You guys know far more then I do about scientific testing, I am just a simple rifle maker that sees things pretty black and white and to me the ball powders keep barrel temps lower. This may be to some result of less bore friction caused by the powder itself??? Comparing AA8700, H-870, H-50BMG and WC872. The current lot of 8700 I have has a burn rate nearly identical to Retumbo. I deduce this from the fact that in the 270 Allen Mag, they produce nearly identical velocities with the 130 gr Ballistic Tip when using the same powder charge. The earlier lot of 8700 was nearly identical to the old H-870 which I have found to be at least the same or slower burning then H-50BMG. I say this because in the 50 BMG I get less velocity with the same powder charge under the same bullet using H-870 compared to H-50BMG which again tells me that the ball powder is slower. Please keep in mind that in cool temps that H-870 may be slightly slower then H-50BMG and in warmer temps it may be slightly quicker burning. I will tell you that I have never seen a lot of AA8700 or H-870 burn as slow as the lot of WC872 I am using now. Again, I am a simple guy, from what the data tells me this is how I would rate these powders in burn rate: AA8700 H-870/H-50BMG very close on average WC-872 Now the difference between 870/50BMG and 872 is not dramatic but it is there. Also, thanks for the pics of the 200 gr ULD in comparision to the 160 gr Accubond. My figures that stated the 200 gr ULD was 0.060" longer then the 160 gr Accubond was in reference to the full diameter body of the bullet which was clearly illistrated by ss7mm, thank you!! I will read through the posts again tomorrow as I am sure I missed some things I wanted to touch on. Basically, I am happy with the results so far with the 7mm Allen Mag but to be honest until we get the 1-7 30" barrels to test, we are just playing around with this round. Data will continue to come in as soon as I get it tested on the range. I will be testing some 175 gr SMKs next to see what we can do in a 26.5" barrel. Basically the reason for this testing is to get me a start on the 175 gr ULD RBBT bullets as I know they will be a superior bullet option. Not that the Sierra is a good bullet because it is, its not a Wildcat though!! I will reply more tomorrow, good night and great conversation, no need to apologize to me. Kirby Allen(50) [/QUOTE]
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7mm Allen Mag test rifle finished.....
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