OBT and quickload

[jrb572]

I am just getting around to trying this with my quickload. I have a few questions for those who have done this before.

1. It says to use a fired case for the measurement. I use FL sized cases. Should I be using the FL case water measurement instead?

2. It also says change your velocity to match what you are actually getting. How is that done? I am within 60 fps of quickload.

I pretty much understand how to change everything else that is needed. I appreciate any help. For those that might not be familiar to what I am talking about. Here is a link:

http://the-long-family.com/optimal barrel time.htm

 

[savagedasher]

I am just getting around to trying this with my quickload. I have a few questions for those who have done this before.

1. It says to use a fired case for the measurement. I use FL sized cases. Should I be using the FL case water measurement instead?

2. It also says change your velocity to match what you are actually getting. How is that done? I am within 60 fps of quickload.

I pretty much understand how to change everything else that is needed. I appreciate any help. For those that might not be familiar to what I am talking about. Here is a link:

http://the-long-family.com/optimal barrel time.htm

I use a fired case un size trimmed the same go finding case capacity.
Barrel time is nothing I deal with .
Z1 and PM and the lingth to get 95 percent of bullet speed with the powder used . Larry

 

[Jeff A]

If you are going to use OBT, then yes, use fired cases either with the primer in or removed and inverted. I do the test with 10 cases and average them. You have to be careful about how you fill the cases as well. Here are the instructions from NECO:

1 Remove & save primers
2 Clean cases
3 Cases should be of equal length
4 Insert spent primers upside down
5 Weigh and record the weight of the empty cases
6 Fill the cases with room temperature water until the surface of the water level is concave in the neck of the case.
7 Weigh and record the weight of the cases.
8 Add water to the cases until the water level is convex.
9 Weigh and record the weight of the cases.
10. Subtract one from the other and do an average.

 

[rardoin]

An easier way to get the water capacity in weight is to add about 5% of alcohol to my water (I use isopropyl) to reduce surface tension. I fill the case with a syringe with a long needle until it is at the case mouth. If overfilled or underfilled you will get a distinct 'fish eye' reflection but when it is perfectly filled flush with the mouth the surface will be flat and the reflection will disappear. Very easy and quick.

 

[jrb572]

Thanks. Any idea on how to adjust the burn rate so I can make what FPS I am getting to match quickload?

 

[rardoin]

Thanks. Any idea on how to adjust the burn rate so I can make what FPS I am getting to match quickload?

You can change the burn coeficient (Ba) by selecting it in the powder menu box and manually input the value you desire. I don't have the program with me ATM but if you pull down the help menu it will describe the process.

 

[Zero333]

To the left of the powder there is a box with a hand holding a pencil, hit that and you'll be able to adjust the rest of the parameters. Then Adjust the burn rate Factor BA up or down.

I read that adjusting the Weighting Factor also works, which of course it does indeed change the pressure and velocity outputs, but I don't know for a fact if this way is acceptable.

 

[brantfredrickson]

I'm new(8 months) to Quickload. And I'm intrigued by the thought of using Quickload to obtain more precise groups. At first I used barrel time to search for a load that prints the smallest groups. Barrel time is like having a treasure map that says dig here. You still have to dig a number of holes(load testing) in a small area, but its better than digging a zillion holes in a 160 acre field.

Secondly I started to look at the Z1 and Pmax lines. I ran simulations with different powders to find the closest match. When I started to shoot the most promising powder and my groups got smaller at the node. I thought about this, and I don't have an understanding of how this works. In addition this worked once in a row, and we use to say in the lab, once in a row don't make it so. I would be willing to listen to anybody's thinking on this.
Last I've noticed if I've got the Z1 and Pmax lines close to each other, and I change the weight of the bullet, I can get the the lines to lay on top of each other. I haven't had a chance to verify the importance of this by printing targets, but its in the future.

 

[J-rod]

Brant,
The Z1 & Pmax intrigues me as well. I read on here somewhere that lining these up made for very accurate and resilient loads.
It only happened to me on accident once. A year or so later when I got QL, I was running previous loads and discovered this phenomena.
I was using H4350 in a 308 with 230gn hybrids...at least I think that was the load. Nonetheless, at 300yds during a ladder/pressure test, ~2gn variance left once really small group. If I can find the picture I will post it.
Since then I have been meaning to test combos that have these two lines on top of eachother.

 

[jrb572]

I will take a look at all of this. I appreciate the help everyone one.

 

[brantfredrickson]

I would have thought that IMR 4350 would be too slow for a 308 win. But Quickload show it as appropriate with a 230 grain bullet. Watch out for the barrel length, cross section area, case capacity. They are what I shoot. I let the program default on seating depth. But still it shows the Z1 on top or close to the Pmax.

 

[savagedasher]

http://i689.photobucket.com/albums/vv253/brantfredrickson/2016-08-08_IMR4350 Berger 230 Hybrid 308Win_1.jpg

<a href="http://s689.photobucket.com/user/brantfredrickson/media/2016-08-08_IMR4350 Berger 230 Hybrid 308Win_1.jpg.html" target="_blank"><img src="http://i689.photobucket.com/albums/vv253/brantfredrickson/2016-08-08_IMR4350 Berger 230 Hybrid 308Win_1.jpg" border="0" alt=" photo 2016-08-08_IMR4350 Berger 230 Hybrid 308Win_1.jpg"/></a>

I would have thought that IMR 4350 would be too slow for a 308 win. But Quickload show it as appropriate with a 230 grain bullet. Watch out for the barrel length, cross section area, case capacity. They are what I shoot. I let the program default on seating depth. But still it shows the Z1 on top or close to the Pmax.

Try h 4350 in a dasher with 105 hybrid . And fill it to 107 percent full . Larry

 

[J-rod]

The load worked great but was a pain to load. It was Win brass, 47gn H4350 and I believe the ogive to base was 2.285" so the OAL was around 3.010". I was jamming it too to help add pressure.If memory serves, velocity was around 2530fps.
Either way, outside of the additional recoil, it was a very forgiving load.
I'm interested in finding out more on this Pmax/Z1 thing.

 

[savagedasher]

The load worked great but was a pain to load. It was Win brass, 47gn H4350 and I believe the ogive to base was 2.285" so the OAL was around 3.010". I was jamming it too to help add pressure.If memory serves, velocity was around 2530fps.
Either way, outside of the additional recoil, it was a very forgiving load.
I'm interested in finding out more on this Pmax/Z1 thing.

The load worked great but was a pain to load. It was Win brass, 47gn H4350 and I believe the ogive to base was 2.285" so the OAL was around 3.010". I was jamming it too to help add pressure.If memory serves, velocity was around 2530fps.
Either way, outside of the additional recoil, it was a very forgiving load.
I'm interested in finding out more on this Pmax/Z1 thing.

Use a long drop tube and a slow pour Larry

 

[J-rod]

Larry, absolutely...I used a 28" drop tube for these loads, and there were still rather compressed.

 

[savagedasher]

Larry, absolutely...I used a 28" drop tube for these loads, and there were still rather compressed.

But the work that's all that matters . Have you tried h 4350 ? Larry

 

[J-rod]

Yes they do work but it slows my reloading down by quite a bit and it takes multiple seating attempts to get the compressed load to the right OAL.
H4350 was the powder I was using.

 

[savagedasher]

Yes they do work but it slows my reloading down by quite a bit and it takes multiple seating attempts to get the compressed load to the right OAL.
H4350 was the powder I was using.

Narrow up the size of the drop tube and dump the powder down the tube . Larry

 

[brantfredrickson]

What make IMR4350 the right powder for a 308 win with a 230 grain Hybrid bullet, or for a Dasher with 105 grain Hybrid bullet? Is it the Z1 limit? Is that the point were all the deterrent coating is burnt up?