Forums
New posts
Search forums
What's new
Articles
Latest reviews
Author list
Classifieds
Log in
Register
What's new
Search
Search
Search titles and first posts only
Search titles only
By:
New posts
Search forums
Menu
Log in
Register
Install the app
Install
Forums
Rifles, Reloading, Optics, Equipment
Reloading
Using chronograph data to determine the best load????
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="ss7mm" data-source="post: 93144" data-attributes="member: 5"><p><strong>Re: Using chronograph data to determine the best load????GonHuntin</strong></p><p></p><p>Guys:</p><p></p><p>This is all very interesting but I think the original post has been forgotten, even though the results have been very interesting.</p><p></p><p>Remember that if you look at what buffalobob said you will easily see that free recoil would have only the weight of the rifle to resist rearward movement. Adding the shooters body, no matter how firm the hold, adds the weight of the body to that of the gun to resist rearward movement. The result would be that the rearward movement of the gun would be less with the body in the way but the velocity at which the gun moves to the rear is very minute compared to the speed at which the bullet travels forward. </p><p></p><p>Simply put, the bullet accelerates so fast that it is out the end of the barrel before the gun has moved very far at all. This is proven by the fact that muzzle brakes work. The bullet, and the gas that is moving the bullet, get to the muzzle and the gasses and pressure interact with the brake before the mass of the gun has moved much, if any. This allows the brake to work.</p><p></p><p>This is probably why Dan didn't see the changes in POI that he expected to. Yes the free recoil guns moved a long ways back but I would think that the bullet was out of the barrel before much, if any, of the rearward movement of the gun had occurred. </p><p></p><p>What does all of this have to do with GonHuntin's original post? Nothing but it's interesting.</p><p></p><p>GonHuntin, I use a chronograph for every round I fire during load development and testing. This doesn't make it right or wrong, it's just that I want all available data I can get my hands on to make my decisions. I do not develop loads based solely on the chronograph data, my main goal is to develop the most accurate load I can. Drops are easy to figure, but it's really hard to hit anything at extended ranges with a fast, but inaccurate load.</p><p></p><p>Most of the time you are not going into load development blind. By that I mean that you are probably loading a cartridge/bullet/powder/primer combination that someone else already has used. You probably have data for that load. You are simply starting at a safe level and working up to an area that is known to be maximum under certain conditions, looking for the most accurate combo in your gun. </p><p></p><p>I use the ladder method and find it works best for me. I start low and work up. I hope to find one or more "nodes" somewhere in the test that indicates to me that the gun "likes" that combination. Every round I fire is documented and goes into my notes. I also make notes of all pertinent field conditions every time I shoot. This is invaluable later on when you go from cold to hot conditions etc. </p><p></p><p>I also check for pressure indicators with every round fired. This is very important and combined with the other data you collect helps with what you are trying to accomplish. Just remember that with a custom action and quality brass, like Lapua, pressure signs may occur later than what you are used to seeing. Some primers will indicate different than others, some brass handles pressure better than others. Don't just keep increasing the loads and dropping the hammer. Be careful and analyze everything you know and everything you are being presented with. </p><p></p><p>I would expect to see the velocities climb as I increase the loads, but remember it's normal to see a round with an increased charge produce a lower velocity than the previous round fired in a ladder test. This is due to the ES that the different loads would produce. One load might show a velocity at the upper range of it's normal group ES and the other might show a velocity at the lower range of it's normal group ES.</p><p></p><p>I look for any velocity changes out of the normal. I don't expect to see the velocities start to drop and I don't expect to see a drastic jump in velocity that doesn't follow what has been occurring with the load increases so far. Remember you are probably working with a combo that has already produced a known velocity. You are just being careful and working up to an accurate, safe load in your gun.</p><p></p><p>At this point you can't be concerned with ES or SD because you are only firing one round per charge. You are simply trying to find the place where your gun seems to group 2 or 3 loads very closely. Later I take the loads in the nodes I have detected and load up several groups of each, in smaller increments, to try and find one that runs in the center of that node and is the most accurate in my gun. I am still concerned mostly with accuracy and am not looking for the best ES or SD.</p><p></p><p>When you get to this point and start testing, say at 100 yards and find a load that produces the best accuracy, you may find that it isn't the one with the best ES or SD. This quite often is the case as it's not written in stone that the lowest ES and SD will always produce the most accurate loads. </p><p></p><p>You then need to test your most accurate load at extended ranges. If I find a load that seems to be the most accurate at 100 yards and also have another that's not the most accurate but has a much lower ES and SD, I will then go to extended ranges and shoot not only the most accurate load at 100 yards but also the ones with the lower ES and SD. I want to find out what combination gives me the most accurate load at extended ranges, not at very close ranges. Sometimes you will be surprised to see what the most accurate load is, in your gun, at extended ranges. Some load combos will tighten up at extended ranges and some will get worse, some will track as expected at extended ranges. You won't know without shooting them all.</p><p></p><p>Now that you have found the most accurate load for you and your conditions you can now play with seating depth, primers etc. and it goes on and on and on if you want to. Just remember to only change one component at a time and do your testing with just that one item changed. Normally, if I'm happy with the results at this point, I will only change seating depth and try some different settings. I don't really like to seat bullets to engage into the lands unless I have to. I try to find a load that lets me start with the bullet just at the lands and then I will try seating in small increments off of the lands since most of what I load for is a hunting setup. Remember, if you do your testing at the lands and then decide you want to go into the lands, you must remember that this is going to increase pressures and you must make changes accordingly. You may find that certain types of bullets like to be seated into, at, or off the lands to a certain point. How much testing you do depends on how anal and picky you are at the time.</p><p></p><p>Just remember that you should be looking for the most accurate, safe load combo for your gun under your conditions. Velocity is not the determining factor and is actually way down the list for me, but it is another valuable tool and indicator that I'm glad I have every time I put a round through the chronograph.</p></blockquote><p></p>
[QUOTE="ss7mm, post: 93144, member: 5"] [b]Re: Using chronograph data to determine the best load????GonHuntin[/b] Guys: This is all very interesting but I think the original post has been forgotten, even though the results have been very interesting. Remember that if you look at what buffalobob said you will easily see that free recoil would have only the weight of the rifle to resist rearward movement. Adding the shooters body, no matter how firm the hold, adds the weight of the body to that of the gun to resist rearward movement. The result would be that the rearward movement of the gun would be less with the body in the way but the velocity at which the gun moves to the rear is very minute compared to the speed at which the bullet travels forward. Simply put, the bullet accelerates so fast that it is out the end of the barrel before the gun has moved very far at all. This is proven by the fact that muzzle brakes work. The bullet, and the gas that is moving the bullet, get to the muzzle and the gasses and pressure interact with the brake before the mass of the gun has moved much, if any. This allows the brake to work. This is probably why Dan didn’t see the changes in POI that he expected to. Yes the free recoil guns moved a long ways back but I would think that the bullet was out of the barrel before much, if any, of the rearward movement of the gun had occurred. What does all of this have to do with GonHuntin’s original post? Nothing but it’s interesting. GonHuntin, I use a chronograph for every round I fire during load development and testing. This doesn’t make it right or wrong, it’s just that I want all available data I can get my hands on to make my decisions. I do not develop loads based solely on the chronograph data, my main goal is to develop the most accurate load I can. Drops are easy to figure, but it’s really hard to hit anything at extended ranges with a fast, but inaccurate load. Most of the time you are not going into load development blind. By that I mean that you are probably loading a cartridge/bullet/powder/primer combination that someone else already has used. You probably have data for that load. You are simply starting at a safe level and working up to an area that is known to be maximum under certain conditions, looking for the most accurate combo in your gun. I use the ladder method and find it works best for me. I start low and work up. I hope to find one or more “nodes” somewhere in the test that indicates to me that the gun “likes” that combination. Every round I fire is documented and goes into my notes. I also make notes of all pertinent field conditions every time I shoot. This is invaluable later on when you go from cold to hot conditions etc. I also check for pressure indicators with every round fired. This is very important and combined with the other data you collect helps with what you are trying to accomplish. Just remember that with a custom action and quality brass, like Lapua, pressure signs may occur later than what you are used to seeing. Some primers will indicate different than others, some brass handles pressure better than others. Don’t just keep increasing the loads and dropping the hammer. Be careful and analyze everything you know and everything you are being presented with. I would expect to see the velocities climb as I increase the loads, but remember it’s normal to see a round with an increased charge produce a lower velocity than the previous round fired in a ladder test. This is due to the ES that the different loads would produce. One load might show a velocity at the upper range of it’s normal group ES and the other might show a velocity at the lower range of it’s normal group ES. I look for any velocity changes out of the normal. I don’t expect to see the velocities start to drop and I don’t expect to see a drastic jump in velocity that doesn’t follow what has been occurring with the load increases so far. Remember you are probably working with a combo that has already produced a known velocity. You are just being careful and working up to an accurate, safe load in your gun. At this point you can’t be concerned with ES or SD because you are only firing one round per charge. You are simply trying to find the place where your gun seems to group 2 or 3 loads very closely. Later I take the loads in the nodes I have detected and load up several groups of each, in smaller increments, to try and find one that runs in the center of that node and is the most accurate in my gun. I am still concerned mostly with accuracy and am not looking for the best ES or SD. When you get to this point and start testing, say at 100 yards and find a load that produces the best accuracy, you may find that it isn’t the one with the best ES or SD. This quite often is the case as it’s not written in stone that the lowest ES and SD will always produce the most accurate loads. You then need to test your most accurate load at extended ranges. If I find a load that seems to be the most accurate at 100 yards and also have another that’s not the most accurate but has a much lower ES and SD, I will then go to extended ranges and shoot not only the most accurate load at 100 yards but also the ones with the lower ES and SD. I want to find out what combination gives me the most accurate load at extended ranges, not at very close ranges. Sometimes you will be surprised to see what the most accurate load is, in your gun, at extended ranges. Some load combos will tighten up at extended ranges and some will get worse, some will track as expected at extended ranges. You won’t know without shooting them all. Now that you have found the most accurate load for you and your conditions you can now play with seating depth, primers etc. and it goes on and on and on if you want to. Just remember to only change one component at a time and do your testing with just that one item changed. Normally, if I’m happy with the results at this point, I will only change seating depth and try some different settings. I don’t really like to seat bullets to engage into the lands unless I have to. I try to find a load that lets me start with the bullet just at the lands and then I will try seating in small increments off of the lands since most of what I load for is a hunting setup. Remember, if you do your testing at the lands and then decide you want to go into the lands, you must remember that this is going to increase pressures and you must make changes accordingly. You may find that certain types of bullets like to be seated into, at, or off the lands to a certain point. How much testing you do depends on how anal and picky you are at the time. Just remember that you should be looking for the most accurate, safe load combo for your gun under your conditions. Velocity is not the determining factor and is actually way down the list for me, but it is another valuable tool and indicator that I’m glad I have every time I put a round through the chronograph. [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Rifles, Reloading, Optics, Equipment
Reloading
Using chronograph data to determine the best load????
Top