What is acceptable FPS differance when reloading??

[Mag 300]

I have been using an old chrono and now just bought a more accurate one. what is the acceptable differance between reloads ????
I load to within the grain and .02 grains on a scale perp flash hole, iue a Giruad to trim all the same length. use same primers, redding bushing dies for .002 neck tension and coat the bullets with HBN

some loads I saw 5 shot group at 11 fps differance " very happy" then had some at 60 fps??? CRAP

Where is the accuracy window ?????

Thaks Bill

 

[Lindy]

Re: What is acceptable FPS differance when reloading??

Extreme spread, more correctly known as the range, of a small group of shots is not a reliable metric for determining a good load, though it may be used to identify a bad one. For more information on that subject, see:

http://www.shootersjournal.com./Features/Haps/EnglemanChronographStatistics.pdf

 

[Suasponte]

Re: What is acceptable FPS differance when reloading??

Bill,

I like to keep my loads in the 30fps range. I chrono in 10 shot groups and want to see my ES less than 30fps and my SD less than 10.

Terry

 

[Lindy]

Re: What is acceptable FPS differance when reloading??

You might wish to read that link. Your true ES is probably closer to 6 times the S.D.

 

[Suasponte]

Re: What is acceptable FPS differance when reloading??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lindy</div><div class="ubbcode-body">You might wish to read that link. Your true ES is probably closer to 6 times the S.D.
</div></div>

I tried the link and cannot get to the page, it locked up my computer.

Terry

 

[Mag 300]

Re: What is acceptable FPS differance when reloading??

Terry read it its a great explanation , I tried to get to much in in one day new chrono 2 new rifles with 100 rounds each for a OWC comparison.
But did get the lead narrowed down a lot so all in all a great day
Bill

 

[Lindy]

Re: What is acceptable FPS differance when reloading??

Assuming that you have Adobe Acrobat reader on your computer, just download it to a file, and then open the file.

If you don't have Acrobat reader, you should. It's free, and there's a lot of good information available in that format.

http://get.adobe.com/reader/

 

[ChrisGarrett]

Re: What is acceptable FPS differance when reloading??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bill Stoffels</div><div class="ubbcode-body">I have been using an old chrono and now just bought a more accurate one. what is the acceptable differance between reloads ????
I load to within the grain and .02 grains on a scale perp flash hole, iue a Giruad to trim all the same length. use same primers, redding bushing dies for .002 neck tension and coat the bullets with HBN

some loads I saw 5 shot group at 11 fps differance " very happy" then had some at 60 fps??? CRAP

Where is the accuracy window ?????

Thaks Bill </div></div>

Here's my own personal take on the Standard Deviation game:

Most factory ammo (not a large sample size): SD of 20-30 fps.

Reloaded Ammo:

15-20 fps: Decent, better than factory.

10-14 fps: Things are working pretty well

Single digits, I'm slobbering all over myself.

On 12/10/09, I clocked 15 groups of 5 shots for 75 rounds total at 100 yds off a bench with bipod and sandbag shooting my Savage LE2b 308 rifle.

50 were 25 and 25 of Varget @ 45.5 under 25 older Palmas and 155 Scenars. All were weighed off my ChargeMaster 1500 as a single batch.

The other 25 were 42.5grs of RL-15 under 168 SMKs.

All but one of the groups had SDs between 13-21, the sole group being of single digits was 7.9. It was one of the 168gr loadings. There was no rhyme or reason to the 50 155s being spread out, but for the barrel being hot at times.

Here is the target:

At 600 yds plus, it might show up as vertical stringing, but before that, I don't think it matters other than getting one to figure out why they differ the way they do and why they all ARE NOT single digits.

Chris

 

[Downzero]

Re: What is acceptable FPS differance when reloading??

I just look for single digit SDs.

 

[Hummer]

Re: What is acceptable FPS differance when reloading??

Don't know about now but the ammo loaded for the Marine Corps Team at Quantico for the M14s had to have SD of 10 or less about 20 years ago. I understand now they just buy their 5.56 ammo and don't do that much in the loading room any more. Any one know what the latest practice is?

 

[MitchAlsup]

Re: What is acceptable FPS differance when reloading??

In my opinion, anything ES under 30 is OK
In my opinion if you can get down to 15 SD you are on top of your reloading game. If you can get SD into single digit territory over a 10 shot string, you can write books about your reloading techniques.

 

[JerkeeJoe]

Re: What is acceptable FPS differance when reloading??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MitchAlsup</div><div class="ubbcode-body">In my opinion, anything ES under 30 is OK
In my opinion if you can get down to 15 SD you are on top of your reloading game. If you can get SD into single digit territory over a 10 shot string, you can write books about your reloading techniques. </div></div>

Hmmm, I haven't been reloading forever, but among the small group of guys I shoot with, about 75% of the strings chronoed have SD in single digits using an Oehler 35 with 3 screens and 2 measurements for each shot. For me, SD higher than 13-15 is unusual. The guys I shoot with post here also and will probably come along and confirm this.

Joe

 

[308sako]

Re: What is acceptable FPS differance when reloading??

Deleted in protest!