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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
More range testing with 338 Allen Magnum XHS rifle....
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<blockquote data-quote="Fiftydriver" data-source="post: 155633" data-attributes="member: 10"><p>Dave,</p><p></p><p>From the Carbon Wrapped barrels I have built on, it seems they tend to run pretty quick as far as velocity potential compared to other barrels.</p><p></p><p>To be honest, I will admit that Lilja barrels are probably about the slowest barrels out there I have built on but some of the most accurate as well. That is why I am fine to give up some top end velocity potential for accuracy.</p><p></p><p>I suspect that is why you are seeing the velocity you are getting in that very short barrel. If that were a Lilja barrel you would probably be running a full 75 to 100 fps less then what your seeing but I am sure accuracy would be great.</p><p></p><p>I have been thinking about getting a wrapped barrel for another lightweight project. I have 7 on order right now for customer rifles if they ever show up and then I will be able to provide definate velocity comparision numbers between the two but in all my testing of different barrels, the wrapped barrels are running around 75 to 100 fps more then what the same lenght Lilja will get with same pressures.</p><p></p><p>I would suspect that a carbon wrapped barrel of 33" on this rifle would be producing 3400 fps easily without any ejector marks of any kind.</p><p></p><p>I do not see any ejector marks until I hit 146.0 gr of H-50BMG. And those are very faint. At 148.0 gr they are more defined. Not as heavy as I have seen with some handloads used by other shooters on a regular basis but more then I like to see in one of my rifles or that I would recommend to a customer.</p><p></p><p>For now, 3350 to 3370 fps is plenty for me at comfortable, long case life pressures.</p><p></p><p>As far as your powder testing. I have found similiar results. US-869, at least the lots I have is much more similiar to Retumbo in burn rate then H-50BMG. In fact its far to fast in burn rate for my needs with my 338 Allen Magnum except perhaps with 250 gr bullet weights.</p><p></p><p>That is just my lots of powder however but I have been hearing similiar reports from my customers using this powder in my other more conventional Allen Magnums. For heavy weight bullets, in my opinion, a bit slow in burn rate and not apporiate in my Allen Magnums for the most part. It works but there are better choices out there.</p><p></p><p>As far as WC872 is concerned. It is a great burn rate for any bullet in the 338 Allen Magnum over 300 grains. It has a relatively narrow pressure window where it works well. On the bottom end you can see some hangfires. On the upper end it works very well but can be temp change sensitive. I do like this powder however and all of my lots of WC872 has been measureable slower in burn rate then H-50BMG. Generally taking 3-4 gains more powder to match muzzle velocity as H-50BMG in most cases.</p><p></p><p>With the 266 gr tipped Wildcat Bullets, I think you will be much better served still using H-50BMG. When I tested these bullets I used 145.0 gr and that was a very mild load in my heavy rifle which shows pressure signs dramatically sooner then my lightweight Heavy Sporter Xtreme rifle seems to.</p><p></p><p>I personally feel that H-50BMG will offer about the perfect burn rate for this bullet when you take into consideration that the baring surface is similiar to the 300 gr SMK but the overall length is longer then the SMK and the weight is 44 grains less.</p><p></p><p>As such, you need a slightly quicker burn rate powder then would be optimum for the 300 gr SMK but not significantly faster like you would get with US869.</p><p></p><p>In my testing with this bullet, I suspect that in my HSX 338 AM I will top out at around 150-151 grains under this bullet which when using H-50BMG will give me right around 98-99% load density, what more could you ask for???</p><p></p><p>WIth US869, again I would predict there will be around 5 grains less powder used when you reach top pressures, at least from what I am seeing with my lot of powder.</p><p></p><p>Combine this with the much denser powder column produced by the ball powder, you will have much lower load densities which is not the best thing with a ball powder.</p><p></p><p>In spite of what has been advertised about US869, it is no better in changing temps then any other ball powder I have tested, at least not in my small to medium bore Allen Magnums and Allen Xpress rounds.</p><p></p><p>The advertisements are all for the results Hodgdon got testing with the 50 BMG so to be fair to them, this powder may have a totally different personallity in the big 1/2" bore but it is still sensitive to temp changes in smaller bore, large capacity round.</p><p></p><p>I think you will see from your tests that H-50BMG will be THE best powder for the new lighterweight 266 gr bullet from Wildcat. You will get the most velocity with the tightest velocity spreads and should be the most stable under temp changes. </p><p></p><p>When I get my big order of 266 gr pills, H-50BMG will be the only powder I test unless it does not offer me what I have already seen with this powder and this bullet.</p><p></p><p>In my lightweight 338 AM HSX I suspect that I will be pushing 3500 fps very hard with this bullet!!!</p><p></p><p>More to come soon.</p><p></p><p>Kirby Allen(50)</p></blockquote><p></p>
[QUOTE="Fiftydriver, post: 155633, member: 10"] Dave, From the Carbon Wrapped barrels I have built on, it seems they tend to run pretty quick as far as velocity potential compared to other barrels. To be honest, I will admit that Lilja barrels are probably about the slowest barrels out there I have built on but some of the most accurate as well. That is why I am fine to give up some top end velocity potential for accuracy. I suspect that is why you are seeing the velocity you are getting in that very short barrel. If that were a Lilja barrel you would probably be running a full 75 to 100 fps less then what your seeing but I am sure accuracy would be great. I have been thinking about getting a wrapped barrel for another lightweight project. I have 7 on order right now for customer rifles if they ever show up and then I will be able to provide definate velocity comparision numbers between the two but in all my testing of different barrels, the wrapped barrels are running around 75 to 100 fps more then what the same lenght Lilja will get with same pressures. I would suspect that a carbon wrapped barrel of 33" on this rifle would be producing 3400 fps easily without any ejector marks of any kind. I do not see any ejector marks until I hit 146.0 gr of H-50BMG. And those are very faint. At 148.0 gr they are more defined. Not as heavy as I have seen with some handloads used by other shooters on a regular basis but more then I like to see in one of my rifles or that I would recommend to a customer. For now, 3350 to 3370 fps is plenty for me at comfortable, long case life pressures. As far as your powder testing. I have found similiar results. US-869, at least the lots I have is much more similiar to Retumbo in burn rate then H-50BMG. In fact its far to fast in burn rate for my needs with my 338 Allen Magnum except perhaps with 250 gr bullet weights. That is just my lots of powder however but I have been hearing similiar reports from my customers using this powder in my other more conventional Allen Magnums. For heavy weight bullets, in my opinion, a bit slow in burn rate and not apporiate in my Allen Magnums for the most part. It works but there are better choices out there. As far as WC872 is concerned. It is a great burn rate for any bullet in the 338 Allen Magnum over 300 grains. It has a relatively narrow pressure window where it works well. On the bottom end you can see some hangfires. On the upper end it works very well but can be temp change sensitive. I do like this powder however and all of my lots of WC872 has been measureable slower in burn rate then H-50BMG. Generally taking 3-4 gains more powder to match muzzle velocity as H-50BMG in most cases. With the 266 gr tipped Wildcat Bullets, I think you will be much better served still using H-50BMG. When I tested these bullets I used 145.0 gr and that was a very mild load in my heavy rifle which shows pressure signs dramatically sooner then my lightweight Heavy Sporter Xtreme rifle seems to. I personally feel that H-50BMG will offer about the perfect burn rate for this bullet when you take into consideration that the baring surface is similiar to the 300 gr SMK but the overall length is longer then the SMK and the weight is 44 grains less. As such, you need a slightly quicker burn rate powder then would be optimum for the 300 gr SMK but not significantly faster like you would get with US869. In my testing with this bullet, I suspect that in my HSX 338 AM I will top out at around 150-151 grains under this bullet which when using H-50BMG will give me right around 98-99% load density, what more could you ask for??? WIth US869, again I would predict there will be around 5 grains less powder used when you reach top pressures, at least from what I am seeing with my lot of powder. Combine this with the much denser powder column produced by the ball powder, you will have much lower load densities which is not the best thing with a ball powder. In spite of what has been advertised about US869, it is no better in changing temps then any other ball powder I have tested, at least not in my small to medium bore Allen Magnums and Allen Xpress rounds. The advertisements are all for the results Hodgdon got testing with the 50 BMG so to be fair to them, this powder may have a totally different personallity in the big 1/2" bore but it is still sensitive to temp changes in smaller bore, large capacity round. I think you will see from your tests that H-50BMG will be THE best powder for the new lighterweight 266 gr bullet from Wildcat. You will get the most velocity with the tightest velocity spreads and should be the most stable under temp changes. When I get my big order of 266 gr pills, H-50BMG will be the only powder I test unless it does not offer me what I have already seen with this powder and this bullet. In my lightweight 338 AM HSX I suspect that I will be pushing 3500 fps very hard with this bullet!!! More to come soon. Kirby Allen(50) [/QUOTE]
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