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What SD and ES should I consider good?


nxfedlt1
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seems a bit high,  I am usually down in the 6-7 SD range. I dont use 320 though so maybe its normal. ES of 40 seems high as well. COuld bight u in the rear at a chrono station. Whats your average velocity  at that charge weight ? Try bumping to 4.8, and look over your procedures and equipment, make sure you are getting consistent OAL and crimp...  Also whats the bullet diameter ? How consistent  is that diameter ?

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Looking for really close ES and SD when using mixed brass is a waste of time. The internal case volume from one brass manufacture to the next isn't the same. The same goes for using nickle vs brass cases. You need to eliminate as many variables as possible. The next time you do some chrono testing cherry pick the rounds which all have the same head stamp brass and are all brass or nickle.

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5 hours ago, nxfedlt1 said:

Loading 4.7 n320 with previously fired mixed brass, at 1.185 I'm getting average ES of ~40 and SD of 10-11 on 180gr PC coated purple bullets.

 

How does this compare to what you're seeing?

SD 10-11 is actually pretty good for mixed brass

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Loading 4.7 n320 with previously fired mixed brass, at 1.185 I'm getting average ES of ~40 and SD of 10-11 on 180gr PC coated purple bullets.
 
How does this compare to what you're seeing?

Mixed brass loaded on the progressive I get 10-15 typically. Depends on powder, primer selection too. Some are more some are less. At pistol distances doesn’t change accuracy and keeps ES and power factor in acceptable range.

I don’t think most people are shooting at distances where vertical dispersion is going to be an issue. Which is why it’s so important in the long range rifle game.


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I disagree with a lot of the above.  You want single digit SDs.  I reload mixed HS brass, with two (now) exceptions.  My 40sw minor loads has an SD of 6.75.  My 40 major load has an SD of 6.9.  My Open major 9mm load has an SD of 5.90.  My 9mm minor steel load is a little better, but I don't have access to that data now.

 

Exceptions:  I use RP HS brass for my bullseye 45 load.  SD 4.97.  I have just started using same HS 9mm brass for my Open major load.  I have not yet had a chance to chrono yet.

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On 8/18/2020 at 5:22 PM, SGT_Schultz said:

I care about this stuff when I'm loading for precision rifles.

 

For a pistol that will never get shot past 30 - 35 yards, and on huge targets at that, I don't care

 

This exactly.

 

Don't waste your time worrying about it.

Edited by 4n2t0
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Most anything will do for matches that do not have a chronograph stage. If you want to shoot about 130-132PF for minor or 170-171 PF for major (USPSA), you best get your standard deviations down  You never said how many rounds your data is based on. I would never trust under 20 rounds before a major match.

 

Let's just say that chronograph data is a normal distribution (you can't deal with any other assumption). An average PF of 170 with a 12 standard deviation is saying that your rounds fall between 158 and 182 62% and 146-194 92% of the time of the time. When you only test 3 rounds at chrono you're betting your match in a risky situation. If you want to minimize the standard deviation you have to sort brass by headstamp, adjust the press when needed when you switch headstamps to produce controlled OAL's and minimum standard deviations. 

 

Do yourself a favor.. Load to 132 or 171 depending on what you shoot. Run 20 rounds at your chrono and get a result of 12  standard deviation. Then review your individual results to see how many rounds actually fell below the minimum.  It will be 20%-30%. If you give two of those to chrono you're dead. Its a lot simpler to sort brass, run consistent rounds, and test with enough samples than to spend money and time shooting for no score or for minor with almost  major ammo. 

Edited by Brooke
correct spelling
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On 8/19/2020 at 11:21 AM, slayer61 said:

Loading 10mm 200 grain with Power Pistol in brand new Starline brass I saw an extreme spread of only 8. I was ecstatic!

Try BE-86 my friend... Newer powder not alot of data out but it is slightly faster than Power Pistol. Great performance in same area as power pistol without the boom and dragon fire. Great with the Hitek type coated bullets.

On 8/20/2020 at 4:48 PM, zzt said:

I disagree with a lot of the above.  You want single digit SDs.  I reload mixed HS brass, with two (now) exceptions.  My 40sw minor loads has an SD of 6.75.  My 40 major load has an SD of 6.9.  My Open major 9mm load has an SD of 5.90.  My 9mm minor steel load is a little better, but I don't have access to that data now.

 

Exceptions:  I use RP HS brass for my bullseye 45 load.  SD 4.97.  I have just started using same HS 9mm brass for my Open major load.  I have not yet had a chance to chrono yet.

 

On 8/20/2020 at 7:43 PM, SGT_Schultz said:

No we don't.  Complete waste of time for practical pistol shooting. 

 

 

I am with ZZT, and some folks taking this way to far. I dont get anal sorting brass but dont load 9mm major.
And really I dont feel like I am spending any extra time on it. Right powder for the job and evidently my loading practices are fairly good, because single digit SD loads are the usual for me. If I get some that arnt I assume that powder/bullet/oal isnt so good and stop using it unless I am just trying to use up components for practice ammo.
Really for me it isnt any more time and effort to make good ammo than bad.
Also for the stataticians ? I mean looks like a fun game and all if you are into it, but way too much thought in to this. Load 5-7 over average,  single digit SD and your slowest round over minimum you wont have a problem.

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  • 3 weeks later...

Count me in the barely double digit SD range most times.  Mixed brass on a progressive, honestly don't worry too much about maintaining a single digit SD. 

I agree that <10 would be nice, but I gave up worrying about it unless its uncharacteristically out of line.   I don't shoot Bullseye.   

Build a PF margin in, make decent ammo and practice more.  Pretty sure my shooting is the weak link, not my SD.  ;)

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