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Pistol Load Development Process on a Progressive Press?


Michael303
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I'm brand new to reloading and I've got my press (RL 1100) all dialed in for the most part.  I think I'm ready to do some load development and testing but I'm hoping to get some feedback on the actual process before I try and fumble my way through it alone.

 

My first question is how many rounds should I make for each test load?  I was thinking 20 but maybe that's too much.

 

I've got some N320 test data off the Vihtavuori website that I was going to use as a starting point.  How far below their starting load data should I start if at all and how many grains should I space the test loads?  

 

Should I be measuring and dispensing the powder for the test loads right on my press or should I prep some cases then load the powder with a trickler and finish them up on the press?

 

Should I be testing recoil springs during this process or should I narrow it down to one load and then test springs?

 

Any feedback is appreciated.

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Normally you start at least 10% below max load and work up. But If you are loading to a certain power factor (say 130-135) you may not even come close to the book max load.

You can first load dummy rounds without powder or primer to check that your overall length fits the magazines, chamber and dry cycles in the pistol.

You can go up .2 grains at a time, checking for signs of pressure before you move up. Five or ten rounds of each should be plenty.

Once you find a load that makes power factor and seems reliable / accurate in your gun, you can load 100 or more and tune recoil springs.

Not all bullet weights / profiles work the same in every gun so I'd recommend against buying in bulk before you are sure.

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Normally you start at least 10% below max load and work up. But If you are loading to a certain power factor (say 130-135) you may not even come close to the book max load.

You can first load dummy rounds without powder or primer to check that your overall length fits the magazines, chamber and dry cycles in the pistol.

You can go up .2 grains at a time, checking for signs of pressure before you move up. Five or ten rounds of each should be plenty.

Once you find a load that makes power factor and seems reliable / accurate in your gun, you can load 100 or more and tune recoil springs.

Not all bullet weights / profiles work the same in every gun so I'd recommend against buying in bulk before you are sure.


Regarding dropping powder, I'd pick either method of dispensing but I'd weigh each one to be sure it's an accurate test.
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19 minutes ago, DesertTortoise said:

Normally you start at least 10% below max load and work up. But If you are loading to a certain power factor (say 130-135) you may not even come close to the book max load.
 

 

Thanks for the feedback.  Can you clarify that 10% below their max load data is a low enough starting point?  I was going to start at or below their starting load and work up but maybe that's a waste of time.  Here's the data I was using as a starting point.  https://www.vihtavuori.com/reloading-data/handgun-reloading/?cartridge=89

Edited by Michael303
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If they have a starting load in the book that's the best place to start. Looking at the predicted velocity on those charts, they are all under minor power factor so you should be able to work up and find a good load.

 

Using this chart for N320, I would load 5 each and shoot them at 25 yards over a Chronograph. I'd go up by 0.1 grains since the difference between starting and max is so narrow.

 

3.9 (starting load, 1017 fps / 126 power factor)

4.0

4.1

4.2

4.3 (max load, 1096 fps / 135 power factor)

 

7f78d62642c5e1aa085befea1d1b3ec1.jpg

 

You can see the starting load is 10% less than max 4.3-.43=3.87 -- rounded up to 3.9. I'm sure they have a more scientific way of determining starting loads based on burn rate etc but it is usually about 10%.

 

 

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Here's the process I use on my 650 when developing new loads.

 

1) Rough set dies and create several dummy rounds

2) Measure overall length (OAL) then case gauge them

3) Confirm these dummies cycle through the gun manually, headspace properly &  plunk/spin in the barrel

4) Confirm OAL hasn't changed because of hand cycling through the pistol.

5) Determine starting powder drop.  Desert T provided some good suggestions.

6) Rather than weigh each case, I tare a lightweight container and cycle 10 drops into it, weigh the result and divide by 10.  This gives you an good estimate of the charge weight for each round.

7) Repeat step 6 two additional times to confirm consistent drops.

10 ) Load 10 rounds of each charge weight.  For our sport, I typically increase in increments of 0.2 grains. 

11) Shoot 2 strings of 5 rounds each across the chrono, starting with the lightest charge weight.

12) Recover shell casings and inspect spent case and  primer.  This is especially important when working with non-standard/published loads like 9 major.

13) Once you're satisfied, move on to the next higher rung of  your ladder.

 

One could spend a lot of time in the above 'do loop' however the point of diminishing returns comes pretty quick, considering the size of the typical USPSA/IDPA target and the distances they are shot at.

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6 hours ago, DesertTortoise said:

If they have a starting load in the book that's the best place to start. Looking at the predicted velocity on those charts, they are all under minor power factor so you should be able to work up and find a good load.

 

You can see the starting load is 10% less than max 4.3-.43=3.87 -- rounded up to 3.9. I'm sure they have a more scientific way of determining starting loads based on burn rate etc but it is usually about 10%.

 

Thanks for the additional detail.  That's helpful.  I wasn't looking close enough apparently because I didn't notice that the starting load was actually only 10% under.  It just didn't sound like enough when I read it and I guess my inexperience was leading me to believe the window would be bigger.

 

57 minutes ago, muncie21 said:

Here's the process I use on my 650 when developing new loads.

 

One could spend a lot of time in the above 'do loop' however the point of diminishing returns comes pretty quick, considering the size of the typical USPSA/IDPA target and the distances they are shot at.

 

Thanks for the detail.  There are a couple great tips I wouldn't have thought of. 

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