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# of Rounds for Chrono?
#1
So I've had to switch powders and need to redevelop a 45acp load. This means a lengthy chrono session. Just wondering how many rounds to chrono for each load.

Just wondering what everyone thinks is a good number.

I know that more is better, but I have 26 different recipes I need to chrono.
NRA (Life), GOA, FOAC (Life), NAGR, AMGOA

RocketFoot's Minion since 09-07-2012
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#2
26 different loads? Wow!
In my mind 10 seems to be a good number. Easy to do math with. Smile
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#3
P89;156610 Wrote:26 different loads? Wow!
In my mind 10 seems to be a good number. Easy to do math with. Smile

math isn't an issue... I have a ProChrono Digital and the USB interface to hook to my laptop. Can easily review the info and it does all the calculations.

Yes... 26 different loads. I have 4 different bullet types and new powder. Need to check each load with each bullet. Since I'm shooting (hehe) for a competition load that needs to make a certain powerfactor I need to start with the min recommended load and take it to the max. I don't trust what I read on the internet.
NRA (Life), GOA, FOAC (Life), NAGR, AMGOA

RocketFoot's Minion since 09-07-2012
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#4
I guess that depends on whether or not you are looking to gather all of your data in one session.

With 26 loads I could see 3 rounds being enough to narrow you down to 2 charges for each, then return to the range with 10 rounds each for final determination.

If you are looking to do it all in one shot you could probably get away with 5 rounds each.

I recently had very good luck by using QuickLoad in a nonconventional manner that some would probably caution as being unwise or risky. I started by picking loads out of a manual that corresponded with my target velocities for both 165gr and 180gr bullets. The charges were within ranges I have loaded before I just didn't know what velocity to expect out of the particular gun in question. At the chrony, both ended up running about 180pf and needed to be toned down. I opened up QuickLoad and put in the powder charge and bullet info. The resulting calculated velocity was substantially below my actual results, actually a bit more in line with what the book said. I increased the barrel length in the software until the velocity matched my actual results (IE QuickLoad thought I had an 8" barrel when in reality I had a 5") then stepped the powder charge down until it showed the velocity I wanted. Loaded a few rounds up at that charge and they were right on the money.
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#5
I do 10.
NRA Life Member, NRA Certified Instructor:  HFS, Pistol, Rifle, PPIH,PPOH
Suarez Combat Arms Instructor School
Admit nothing.  Deny everything. Demand proof.
If we lie to the government, it's a crime. If the government lies to the people, it's called politics.
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#6
I know the name of this thread isn't "Chronographs: Useful Tool or Annoying Distraction to Guy in the Next Lane" but I've never understood the need for knowing the speed of a pistol round. I've reloaded for years working up hundreds of loads and never once used a chronograph. When I'm trying out a new powder or bullet I just load up 50 rounds ea. in a range of powder and bullet weights and then head off the range to shoot them. I do 25 on one trip and 25 on a subsequent trip to avoid biasing my results with the "sucky day" error. What does the chronograph tell you that the holes in your target don't and why is that important? I'm not busting balls, I'm just curious.
Ammunition, it's the new lead bullion. Buy it cheap and stack it deep.
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#7
Rik Bitter;156644 Wrote:I know the name of this thread isn't "Chronographs: Useful Tool or Annoying Distraction to Guy in the Next Lane" but I've never understood the need for knowing the speed of a pistol round. I've reloaded for years working up hundreds of loads and never once used a chronograph. When I'm trying out a new powder or bullet I just load up 50 rounds ea. in a range of powder and bullet weights and then head off the range to shoot them. I do 25 on one trip and 25 on a subsequent trip to avoid biasing my results with the "sucky day" error. What does the chronograph tell you that the holes in your target don't and why is that important? I'm not busting balls, I'm just curious.

For the various shooting sports you are required to meet a designated minimum "power factor" which is a calculation based on velocity and bullet weight. The name of the game is finding a load that will just barely make power factor out of your gun. Running hot loads leads to fighting the muzzle and slower follow up shots leaving you at a disadvantage to your competitors.
The law? The law is a human institution...
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#8
Rik Bitter;156644 Wrote:I know the name of this thread isn't "Chronographs: Useful Tool or Annoying Distraction to Guy in the Next Lane" but I've never understood the need for knowing the speed of a pistol round. I've reloaded for years working up hundreds of loads and never once used a chronograph. When I'm trying out a new powder or bullet I just load up 50 rounds ea. in a range of powder and bullet weights and then head off the range to shoot them. I do 25 on one trip and 25 on a subsequent trip to avoid biasing my results with the "sucky day" error. What does the chronograph tell you that the holes in your target don't and why is that important? I'm not busting balls, I'm just curious.

I will chrono some pistol loads, but not all. I have one 45 load that was coming out around 1080-1100 fps on average. I know they weren't close to the recomended max load, but the numbers weren't jiving with the manual.
NRA Life Member, NRA Certified Instructor:  HFS, Pistol, Rifle, PPIH,PPOH
Suarez Combat Arms Instructor School
Admit nothing.  Deny everything. Demand proof.
If we lie to the government, it's a crime. If the government lies to the people, it's called politics.
Paying for welfare is slavery.
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#9
csmith;156645 Wrote:
Rik Bitter;156644 Wrote:I know the name of this thread isn't "Chronographs: Useful Tool or Annoying Distraction to Guy in the Next Lane" but I've never understood the need for knowing the speed of a pistol round. I've reloaded for years working up hundreds of loads and never once used a chronograph. When I'm trying out a new powder or bullet I just load up 50 rounds ea. in a range of powder and bullet weights and then head off the range to shoot them. I do 25 on one trip and 25 on a subsequent trip to avoid biasing my results with the "sucky day" error. What does the chronograph tell you that the holes in your target don't and why is that important? I'm not busting balls, I'm just curious.

For the various shooting sports you are required to meet a designated minimum "power factor" which is a calculation based on velocity and bullet weight. The name of the game is finding a load that will just barely make power factor out of your gun. Running hot loads leads to fighting the muzzle and slower follow up shots leaving you at a disadvantage to your competitors.

Correct. That's my purpose for reloading is IDPA and USPSA competitions. I need to make 165,000 power factor. So a 230gr. bullet needs to travel 718 ft/sec. If I'm at a match and my ammo is chronographed less than that, I'm DQ'd. So I aim for 740 ft/sec on all my .45 loads to have a margin of error since weather conditions effect results.

If I was simply reloading for plinking then I probably wouldn't care too much.
NRA (Life), GOA, FOAC (Life), NAGR, AMGOA

RocketFoot's Minion since 09-07-2012
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#10
bigdawgbeav;156611 Wrote:I don't trust what I read on the internet.

Kinda makes this thread pointless, doesn't it? Angel
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