New Brass growth?

[waterhome]

In an effort to make my loading better I bought a new batch of Petersen brass and I am starting a new experiment. I am trying a eldx bullet. I think one of the areas where my data started to get inconsistent was after the first firing on my last batch of brass. Through the course of that brass life I think a couple things led to poor performance. I think case growth after the first firing and using coals really hurt my data and though this was my first go around, I would like to do this next test and get better results.

My question is how do you account for case growth after the first firing so your results remain consistent through the life of the brass? I also bought a pair of comparators to stop using coal as a measurement.

 

[wind gypsy]

My question is how do you account for case growth after the first firing so your results remain consistent through the life of the brass? I also bought a pair of comparators to stop using coal as a measurement.

What things are you looking to remain consistent that you've observed being inconsistent?

Results on firings after the first are more likely to be consistent with each other than with the virgin firing.

 

[waterhome]

I was never able to obtain better accuracy than off the shelf loads.

I think there are a lot of places that I went wrong but the more I study and learn I think that a few factors contributed.

-barrels speed up and mine did which I didn’t realize soon enough as I borrowed a chrono early on. I bought one now.
-I think my biggest issue was using coal since that measurement can be off by 5 to 10 thou
- using multiple types of brass after trying multiple off the shelf loads I did buy some Hornady brass but it was mixed in and I don’t think I quite understood how much variance this introduces to the process
- I have also bedded this rifle so I’m considering it a new rifle and starting over.

All and all no regrets I learned a lot and dropped some animals but I want this 2nd attempt to yield better results.


I am going to find jam again and pick a load that will get me close to my desired mv and test groups at 5 different seating depths.

Once I find something that gives me a good dice or triangle shape I’ll do some more exploration in that node.

Since finding my new load will likely take all 50 of my new pieces of brass I don’t want to find some really good data and then feel like I am shooting a different batch on the second firing. So how do you guys account for the growth of the brass in the second firing of new good brass (Petersen)?

 

[wind gypsy]

So how do you guys account for the growth of the brass in the second firing of new good brass (Petersen)?

Why do you think something needs to be accounted for? It's going to likely have a slightly different velocity than it had on a virgin firing. As long as it's not over pressure, so what. Other than that, there's nothing to account for.

Don't get wrapped up into thinking every aspect of a load has some perfect little window that is optimum. Use good brass (peterson is probably a good start) and powder and bullets known to work well near universally in a given cartridge. Don't eff it up with shitty loading practices, and wala, good ammo.

I'd recommend the "painless load development" thread before you chase load dev fairy tales for years like many of us have.

 

[Harvey_NW]

I am going to find jam again and pick a load that will get me close to my desired mv and test groups at 5 different seating depths.

Once I find something that gives me a good dice or triangle shape I’ll do some more exploration in that node.

In an attempt to save you some components, I suggest poking around in the reloading forum and reading the thread wind gypsy suggested, as these topics have been beat to death ad nauseum. Nodes don't exist, seating depth doesn't matter. Shoot large sample sizes for better results.

Since finding my new load will likely take all 50 of my new pieces of brass I don’t want to find some really good data and then feel like I am shooting a different batch on the second firing. So how do you guys account for the growth of the brass in the second firing of new good brass (Petersen)?

Finding a load with a decent quality rifle and quality components usually takes about 15 rounds. Load to a functional length, and shoot a couple test charges in increasing increments up to or near max to make sure there are no signs of pressure. Shoot 10 at the same POA and assess the dispersion. If it isn't acceptable, drop the charge weight at least a full grain or more and shoot 10 more. If that isn't acceptable, swap powder or bullet. After all your brass is fired, FL resize and bump the shoulders back .002-3" using the correct bushing to measure the datum on the shoulder with your comparator. If there is any signs of pressure with fireformed brass, drop the charge weight another grain, and roll on.

 

[TaperPin]

As long as brass doesn’t grow too long for the chamber, there would be no noticeable difference on target between long or short brass. It’s a variable, but as Windgypsy said, it’s not something to spend time on. There’s nothing wrong with trimming cases every time, it’s just not doing anything for the most part.

The way I understand it, the first time brass is fired velocities are usually slightly less because it takes some energy away to expand the brass.

With some guns you may not be able to obtain better accuracy than factory loads. Factory loads can have powders not available to handloaders and its probably not a coincidence that they are usually heavily crimped.

 

[wind gypsy]

I won't argue that nodes don't exist and seating depth doesn't matter. Just that I think it's a waste of time for most people to:
A- Try to find some perfect load - most of the time the results that got you there wont be repeatable or will change as the barrel condition does anyway
B- Mess around with a load that doesn't shoot well enough at any reasonable charge weight and at a wide range of seating depths

 

[gelton]

My method is to take 10 once-fired pieces of brass, measure them, and then trim the entire batch to the shortest of the 10 you measured.

There is a train of thought that says trimming your brass too short contributes to developing a carbon ring.

For that reason, I don't trim again until it is at max and only trim it back .005 not to the minimum in the books.

 

[TaperPin]

In an effort to make my loading better I bought a new batch of Petersen brass and I am starting a new experiment. I am trying a eldx bullet. I think one of the areas where my data started to get inconsistent was after the first firing on my last batch of brass. Through the course of that brass life I think a couple things led to poor performance. I think case growth after the first firing and using coals really hurt my data and though this was my first go around, I would like to do this next test and get better results.

My question is how do you account for case growth after the first firing so your results remain consistent through the life of the brass? I also bought a pair of comparators to stop using coal as a measurement.

Without knowing more about your rifle and cartridge, think of this as a gross oversimplification and blanket statement, not that it does or doesn’t apply to your situation.

Many established accuracy practices are hard to see, or have less of an impact if the groups are usually large. The resolution just isn’t there and it makes finding slight trends, nodes, etc. very hard if not impossible to identify quickly, if at all. If other potential variables are not minimized it also complicates load development. The scope, mounts, bedding, trigger, front and rear rest, bench, shooter, shooting technique, cleaning practices, etc. need to be sound.

In reloading you hope for the best, but keep putting money in the piggy bank for a better barrel.

 

[wapitibob]

My stw brass grows almost .020 at the shoulder datum over 3 firings. I fire all new brass with odd bullets and a powder I no longer use before I use them for real. I don’t bump the shoulder or trim after that first firing, or firing #2.
I size, bump, and trim after firing #3 and subsequent firings. I have seen no difference on the target at 600 between firing #2 and firing #5.