Load development method

[DynamicAccuracy]

Ive seen guys shoot ocw, ladder tests, use chronos etc. What im after is for working up a consistent PRS load. Not a benchrest load but one that i can load the same ammo almost any time of the year, maybe have a couple different powder charges for summer and winter because of the extreme temp differences, but one that would shoot pretty well across the board. What is the best method? I can see it being a chronograph but i want input from others with experience.

 

[christopher.dow]

Paul Reid does ok at PRS. Here’s his method: http://www.texasprc.club/preidloaddev/

I do something like it, but I chrono the shots and record them (with group size) in to a modified version of the 6.5 Guys’ spreadsheet. Then I look for a flat spot on the speed graph corresponding to a smaller group. The grouping is influenced by consistent barrel harmonics and the flat spot gives me a range where powder throw differences matter less.

 

[supercorndogs]

You just named the three methods most are using to work up their loads. Choose one. None of them are best.

 

[RNWRKNP]

You just named the three methods most are using to work up their loads. Choose one. None of them are best.

Which do you prefer amigo?

 

[supercorndogs]

Which do you prefer amigo?

I like OCW because I am about 5 minutes from a 100y range. It also takes me less rounds to reach good groups and SDs, then the old 5 shot groups method.

 

[RNWRKNP]

I like OCW because I am about 5 minutes from a 100y range. It also takes me less rounds to reach good groups and SDs, then the old 5 shot groups method.

Learning from you guys so bear with me. OCW method?

 

[DynamicAccuracy]

Paul Reid does ok at PRS. Here’s his method: http://www.texasprc.club/preidloaddev/

I do something like it, but I chrono the shots and record them (with group size) in to a modified version of the 6.5 Guys’ spreadsheet. Then I look for a flat spot on the speed graph corresponding to a smaller group. The grouping is influenced by consistent barrel harmonics and the flat spot gives me a range where powder throw differences matter less.

What chrono do you use? Magneto speed or labradar?

 

[supercorndogs]

Learning from you guys so bear with me. OCW method?

http://optimalchargeweight.embarqspace.com

 

[RNWRKNP]

http://optimalchargeweight.embarqspace.com

Thank you. I’m a framer by trade and we use story boards. These are mine for fire arms and I’ll incorporate that along with my magneto speed.

 

[spife7980]

These are mine for fire arms and I’ll incorporate that along with my magneto speed.

Dont shoot the ocw with the magneato strapped on, it can alter the results. Some get away with it, I havent been so lucky.

Basically with the OCW you are shooting incrementally increasing charge weights. You want to see where several consecutive charge weights impact in a similar position to one another so that when the temp goes up or down your point of impact doesnt change. Once you identify that area you can alternate the seating depth to tighten the group up.

That said Ive been trying a hybrid ladder/ocw method. Ill load up my test with 3 rounds per weight and coloring the bullets with a sharpie and firing them all at the same aim point at 500 yards (the ladder part). Looking at where things are impacting in relation to one another (the OCW part) at distance instead of just 100 yards. The wind does make it difficult, my first attempt left about half of the low end results off the right side of my target board lol.

 

[lte82]

I take one piece of brass, load it in .2 gr increments over and over, and shoot over a chronograph in the back yard into the dirt and record velocities. This holds the case volume, flash hole, etc constant and creates a situation where you can get VERY small velocity variation. Typically I'll find at least one maybe two places where I get flat velocity response to charge weight over say a .4 gr window. Then I'll test in those areas for group size down range just to confirm if it shoots or not, and more often than not it does. I can usually be done with load development in literally less than an hour from start to finish.

 

[Campguy308]

I take one piece of brass, load it in .2 gr increments over and over, and shoot over a chronograph in the back yard into the dirt and record velocities. This holds the case volume, flash hole, etc constant and creates a situation where you can get VERY small velocity variation. Typically I'll find at least one maybe two places where I get flat velocity response to charge weight over say a .4 gr window. Then I'll test in those areas for group size down range just to confirm if it shoots or not, and more often than not it does. I can usually be done with load development in literally less than an hour from start to finish.

I started doing this recently. Has worked well so far. Seems less time consuming and uses less components. 100 yard groups don't tell the whole story IMHO

 

[supercorndogs]

I take one piece of brass, load it in .2 gr increments over and over, and shoot over a chronograph in the back yard into the dirt and record velocities. This holds the case volume, flash hole, etc constant and creates a situation where you can get VERY small velocity variation. Typically I'll find at least one maybe two places where I get flat velocity response to charge weight over say a .4 gr window. Then I'll test in those areas for group size down range just to confirm if it shoots or not, and more often than not it does. I can usually be done with load development in literally less than an hour from start to finish.

How are you maintaining neck tension over those loadings? On the surface it looks like you are risking more variation doing it this way. It seems like it would take more than an hour to size and anneal it 10 times. It seems like it would take 10 minutes to do the same with 10 pieces of brass. If your brass shows so much variation you can't get a load in it. The load you find in a single piece, is not going to work in all your brass and that brass should be filed in the trash can. Or sorted by volume.

 

[lte82]

How are you maintaining neck tension over those loadings? On the surface it looks like you are risking more variation doing it this way.

The first time I ever tried firings a piece of brass multiple times was just to see how long it would last before I had case head or neck split issues or needed to trim. What I noticed was that velocity was very consistent across every firing so I had an idea that it might be useful to try for finding flat spots in the velocity / charge weight curve. So to answer the question, the neck tension variation across a lot of firings, especially if you do it back to back to back, hasn't really made much difference on the end result.

 

[christopher.dow]

What chrono do you use? Magneto speed or labradar?

I use LabRadar because I can measure speed and shoot groups at the same time without affecting POI. It’s fiddly, but that capability make it worth it for me. The mobile app makes the post-setup operation much easier than it was before.

 

[Milo 2.5]

I've always said, chrono numbers shrink right along with group size. That said, I still don't think I'd trust chrono numbers as my only method, I've seen some pretty tight numbers not hold vertical at distance. I try to find a range of chargers, .4gr enough that will hold vertical at 500 yards, go from there. IME, even 5/8"vertical at 500, will turn into 2-3 inches at a grand. You need non windy days for this, and can be a real pain at times.

For the last yr I've shot a lot of RL 16, and can say, even a .1gr increment is going to yield more speed, so I'm not accustomed to flat spots. I'm going to try get a load for a Dasher with 16 and a 110 Sierra and will head out shortly.

 

[RNWRKNP]

Dont shoot the ocw with the magneato strapped on, it can alter the results. Some get away with it, I havent been so lucky.

Basically with the OCW you are shooting incrementally increasing charge weights. You want to see where several consecutive charge weights impact in a similar position to one another so that when the temp goes up or down your point of impact doesnt change. Once you identify that area you can alternate the seating depth to tighten the group up.

That said Ive been trying a hybrid ladder/ocw method. Ill load up my test with 3 rounds per weight and coloring the bullets with a sharpie and firing them all at the same aim point at 500 yards (the ladder part). Looking at where things are impacting in relation to one another (the OCW part) at distance instead of just 100 yards. The wind does make it difficult, my first attempt left about half of the low end results off the right side of my target board lol.

I really appreciate the info dude. Generally I have done the increments you mention with 5 rounds of .2 increments in powder charge and then play with depth. I can’t remember if it was you or someone else but the magneto after the fact was already on my radar. I still don’t understand finding that sweet spot you refer to for the two temperature extremes utilizing the magneto and powder charge......but I’m getting there. I’ve already pulled the methods down and will grind through them and circle back around with questions. Thanks again?

 

[RNWRKNP]

http://optimalchargeweight.embarqspace.com

Just read through quickly and that’s some extremely cool info that I intend to incorporate. Thanks again amigo.

 

[spife7980]

As the powder gets hotter it creates more pressure, if it’s cold it creates less. That means the bullet will be coming out faster or slower.

Another way to find out how it shoots with the bullet coming out faster or slower is the add or subtract a tenth or two of powder. If it stays shooting consistent at that tenth or two above and below then it should stay consistent in the hot or cold temps and that’s what’s called a node. It’s a sweet spot in the barrel harmonics where all of the bullets are exiting ideally. Obviously right now we are in the hot time of the year so you would want to find the higher end of that node because temps won’t be any hotter than this and should only get colder (unless you’re southern hemisphere)

Sometimes you can luck into a sweet group when all the wrong things happen just right but you can never repeat it, that’s because you were just lucky and not really in a good harmonic mode. The next time out the conditions and variables have shifted just enough that you don’t get lucky. Finding a load that shoots well a smidge higher and lower gives you a wider buffer for those slight changes.

The ocw identifies those zones by looking for where the centers of your groups impact in relation to one another at 100 yards in both the vertical and horizontal planes.
Ladders do it by seeing where they impact at the same elevation to one another at distance since wind can push things horizontally a bit at distance.

 

[Deleted member 113831]

My method is different than most. I don't have the time I used to have, so I have short cut the process.

I use the longest overall length I can tolerate, and find the max charge for my combo ( I fire 2 rounds each in .2 grain increments over the magnetospeed watching cases and velocities) . Then I subtract 2% from the max powder charge. This puts me in the velocity window I want to be in, and gives me enough room for any variations due to heat so I won't be locking bolts when it is 100*F.

Then, I start seating the bullet deeper in .005" increments until I find a spot where the groups tighten up. I haven't had to go further than .045" so far, before finding a load that will shoot and be safe and consistent. If I didn't find a load this way, it is probable that the load is an unsuitable combo anyway.

This method may not produce the absolute smallest groups in some cases, but the loads will workable and consistent, and load developement is fast.

 

[RNWRKNP]

Well fortunately it doesn’t get very hot where I’m at and we dont have wide spreads in temp..........no that’s not right? Would you use the same 2% based on AZ extremes? In the winter (primarily when I shoot) we can easily see 40* spreads over the course of a day. As an example, 40*-80*. Largely why I use Varget in my primary coyote gun (556). Knew that it was a good powder for heat extremes without the understanding of OCW. I have used the Sierra and Nosler ‘most accurate loads’ that have worked well in most cases but now trying to refine what I’m doing. For me, 1/2- is fine as my use is for coyotes at distance. That’s not to say that a 1/4 load would hurt my feelings but unlikely without custom rifle components as I understand it.

 

[Deleted member 113831]

Well fortunately it doesn’t get very hot where I’m at and we dont have wide spreads in temp..........no that’s not right? Would you use the same 2% based on AZ extremes? In the winter (primarily when I shoot) we can easily see 40* spreads over the course of a day. As an example, 40*-80*. Largely why I use Varget in my primary coyote gun (556). Knew that it was a good powder for heat extremes without the understanding of OCW. I have used the Sierra and Nosler ‘most accurate loads’ that have worked well in most cases but now trying to refine what I’m doing. For me, 1/2- is fine as my use is for coyotes at distance. That’s not to say that a 1/4 load would hurt my feelings but unlikely without custom rifle components as I understand it.

I usually work up loads in temps from 50*F to 70*. If I was working up a load in 100* heat, I might just use 1%.

Most people fine tune a load by adjusting powder charge, which in turn, adjusts barrel timing slightly. It has recently occurred to me that velocity is much less important to good groups than everybody thinks. By changing seating depth you are more directly changing barrel timing. It is my opinion that fine tuning seating depth is the quickest most efficient way to find a sweet spot that works within the velocity window I want.

Others will definitely disagree, but that's OK. I don't chase 1/4 minute or even 1/2 minute groups. I can't hold that small in a field environment anyway. If I find a load that will do MOA or better, day in and day out, I'll take that.

 

[supercorndogs]

I never worry about velocity until load development is done, or almost done anyway. I usually chronograph my OCW load on my last trip to the 100y range.

 

[Bradu]

I never worry about velocity until load development is done, or almost done anyway. I usually chronograph my OCW load on my last trip to the 100y range.

I've always done an ocw type load development at 100 to minimize weather effects. Have had great luck doing that and once I determine where I want to be, I load up about 25 and shoot a few groups to confirm that it shoots good then see what my velocity, es and sd's are. I recently tried my 223 with a magnetospeed attached so hopefully it works out lol. We shall see but I bought a mount for future load development so I can keep it off the barrel.

 

[supercorndogs]

I've always done an ocw type load development at 100 to minimize weather effects. Have had great luck doing that and once I determine where I want to be, I load up about 25 and shoot a few groups to confirm that it shoots good then see what my velocity, es and sd's are. I recently tried my 223 with a magnetospeed attached so hopefully it works out lol. We shall see but I bought a mount for future load development so I can keep it off the barrel.

I saw in a thread the other day. That passing over the bayonet effects bullet. I am not sure how much, or if it is just a hypothesis that the turbulence created over the bayonet effects the bullet. My OCW tests run about the same. Usually about 50 rounds. 25 OCW other 25 length, velocity, and group testing. I will shoot groups with my magneto speed but I am always scared to use it on the first 25. I had an experience once that made me think it effected it, but I think I might have run my OCW on virgin brass, which I have found for sure is a no no. I have a couple bullets to work loads for. i might have to mess around and see.

 

[Bradu]

I saw in a thread the other day. That passing over the bayonet effects bullet. I am not sure how much, or if it is just a hypothesis that the turbulence created over the bayonet effects the bullet. My OCW tests run about the same. Usually about 50 rounds. 25 OCW other 25 length, velocity, and group testing. I will shoot groups with my magneto speed but I am always scared to use it on the first 25. I had an experience once that made me think it effected it, but I think I might have run my OCW on virgin brass, which I have found for sure is a no no. I have a couple bullets to work loads for. i might have to mess around and see.

I've shot groups with known loads with it attached and it seems to shoot similar groups as it does without it other than about 2" high. I know which thread you are talking about and understand the concept but I know some people have the gun shoot low with it attached so that kind of throws a wrench in theory. I have only seen it with a couple guns but it's odd that happens.