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Rifles, Reloading, Optics, Equipment
Reloading
OBT + QuickLoad experiences?
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<blockquote data-quote="benchracer" data-source="post: 1249756" data-attributes="member: 22069"><p>I have done a lot of load work using OBT, along with QL and a good chronograph, during the past couple of years. I have found it to work very well.</p><p></p><p>The OBT/QL method does not replace load development, but it can make the process more efficient. I have also found it to be very helpful in developing stable long range loads.</p><p></p><p>OBT theory states that the window for a given node is typically +/- .020 ms. I have observed this to roughly translate to a velocity window that is about 60 fps wide, though the size of the window may sometimes be larger or smaller.</p><p></p><p>I don't personally adjust the burn rate factor. I believe the OBT method works best when seating depth testing is done first. I perform the Berger seating depth test with a starting load, using the velocity data from that test to reconcile actual results with QL predicted results. My experience has been that predicted velocities for nodes and max tend to be accurate, though the powder charge required to get there tends to differ between predicted and actual.</p><p></p><p>One of the biggest mistakes I see people make, when using QL, is the tendency to treat predicted powder charges as gospel. Doing that is a VERY BAD IDEA! Powder charges are heavily dependent on burn rate, which is probably the least static variable in the entire equation.</p><p></p><p>In the summer and fall of 2015, I experimented heavily with the OBT method of load development, trying to determine its limitations and how best to integrate it into my personal load development process. It was interesting to watch the ES and SD numbers narrow as the predicted node was approached and widen on the other side of the node. I successfully developed several long range loads by shooting them over a chrono, at short range into a backstop, tuning them solely with velocity data, before shooting them for groups at ranges varying from 100 to 500 yards.</p><p></p><p>I haven't personally attempted the OBT method with a powder not supported by QL. In such cases, I use the Newberry OCW method, which has consistently yielded good results for me. I used the OCW method before I owned a chronograph, though it could easily be paired with a chronograph for more refined results. </p><p></p><p>The OBT method gets me there with fewer rounds fired and is more versatile/flexible, though there is strong correlation between the two methods. Essentially, the OBT method gives you a velocity target and allows you to narrow the range of powder charges for testing. Being able to predict the velocity range(s) where the node(s) will fall is useful in selecting components and allows for greater adaptability with respect to available facilities during load development.</p></blockquote><p></p>
[QUOTE="benchracer, post: 1249756, member: 22069"] I have done a lot of load work using OBT, along with QL and a good chronograph, during the past couple of years. I have found it to work very well. The OBT/QL method does not replace load development, but it can make the process more efficient. I have also found it to be very helpful in developing stable long range loads. OBT theory states that the window for a given node is typically +/- .020 ms. I have observed this to roughly translate to a velocity window that is about 60 fps wide, though the size of the window may sometimes be larger or smaller. I don't personally adjust the burn rate factor. I believe the OBT method works best when seating depth testing is done first. I perform the Berger seating depth test with a starting load, using the velocity data from that test to reconcile actual results with QL predicted results. My experience has been that predicted velocities for nodes and max tend to be accurate, though the powder charge required to get there tends to differ between predicted and actual. One of the biggest mistakes I see people make, when using QL, is the tendency to treat predicted powder charges as gospel. Doing that is a VERY BAD IDEA! Powder charges are heavily dependent on burn rate, which is probably the least static variable in the entire equation. In the summer and fall of 2015, I experimented heavily with the OBT method of load development, trying to determine its limitations and how best to integrate it into my personal load development process. It was interesting to watch the ES and SD numbers narrow as the predicted node was approached and widen on the other side of the node. I successfully developed several long range loads by shooting them over a chrono, at short range into a backstop, tuning them solely with velocity data, before shooting them for groups at ranges varying from 100 to 500 yards. I haven't personally attempted the OBT method with a powder not supported by QL. In such cases, I use the Newberry OCW method, which has consistently yielded good results for me. I used the OCW method before I owned a chronograph, though it could easily be paired with a chronograph for more refined results. The OBT method gets me there with fewer rounds fired and is more versatile/flexible, though there is strong correlation between the two methods. Essentially, the OBT method gives you a velocity target and allows you to narrow the range of powder charges for testing. Being able to predict the velocity range(s) where the node(s) will fall is useful in selecting components and allows for greater adaptability with respect to available facilities during load development. [/QUOTE]
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