Forums
New posts
Search forums
What's new
Articles
Latest reviews
Author list
Classifieds
Log in
Register
What's new
Search
Search
Search titles and first posts only
Search titles only
By:
New posts
Search forums
Menu
Log in
Register
Install the app
Install
Forums
Rifles, Reloading, Optics, Equipment
Reloading
Salt Bath Annealing setup and quantitative assessment.
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="entoptics" data-source="post: 1642365" data-attributes="member: 104268"><p>To quantitatively assess the efficacy of annealing with the salt system, I took 40 pieces of well used brass, annealed half for 6 seconds at 500° C ± 5° C (932° F ± 9.3° F), and left the other half alone. All brass were treated the same except annealing, and all were loaded on the same equipment in the same session.</p><p></p><p><em><strong>Brass Specifications</strong></em></p><p>MAI brass (Norma manufactured)</p><p>≥4 firings</p><p>Originally neck turned</p><p>Weight sorted to ± 0.2 gr</p><p>Length sorted to ± 0.002 OAL</p><p>FL Sized to bump shoulder 0.002" ± 0.001"</p><p>Bushing sized to ~0.002" neck tension</p><p></p><p><strong><em>Load Specifications</em></strong></p><p><em>208 ELD-M</em></p><p><em>76.2 gr H1000 hand weighed to exactly the same charge on PACT scale</em></p><p><em>Federal 210M primers</em></p><p><em>≤ 0.003" runout (most <0.002")</em></p><p><em>3.590" OAL (~0.02" off lands)</em></p><p><em></em></p><p><strong><em>Shooting Specifications</em></strong></p><p>Savage LRH 300 WM with 24" Shilen Heavy Sporter bbl (otherwise OEM)</p><p>5-25 Sig Sauer Whiskey 5 at 25X</p><p>200 yard target</p><p>65° F, 55% RH</p><p>Obnoxious, but mostly bearable, mirage</p><p>2-5 mph full value wind, left to right. I tried to shoot in the breaks (makeshift flags at 100 and 200).</p><p>Prone, bipod, rear bag rest, chest/chin in a makeshift "nest" of pillows and blankets. With this setup, I can routinely hold the crosshair well inside a 0.25 MOA circle and break the trigger.</p><p></p><p><strong><em>Testing Results</em></strong></p><p>Red = Not annealed (n = 19)</p><p>Blue = Annealed (n = 19)</p><p>4 shot groups were fired, alternating from annealed to un-annealed for a total of 40 rounds.</p><p>Velocity was measured using a LabRadar. Individual tracking files were inspected and culled to reduce errors associated with LabRadar's wonky algorithm for calculating velocity, which is subject to spurious readings from one or two bad tracking data points.</p><p>Groups were measured using SubMOA shooting app for the iPhone.</p><p></p><p><em>Velocity</em></p><p>[ATTACH=full]135408[/ATTACH] </p><p></p><p><em>Group Size</em></p><p>[ATTACH=full]135409[/ATTACH] </p><p></p><p><strong><span style="font-size: 14px"><em>Summary of results</em></span></strong></p><p><strong></strong></p><p><em><u>Annealed brass (n = 19)</u></em></p><p>Average velocity = 2783 fps</p><p>Extreme spread = 40 fps</p><p>Standard Deviation = 9 fps</p><p>Average group size = 0.55 MOA (0.36 MOA minus worst flier)</p><p>Smallest group = 0.43 MOA</p><p>Largest group = 0.74 MOA</p><p></p><p><em><u>Un-annealed brass</u></em></p><p>Average velocity = 2797 fps</p><p>Extreme Spread = 60 fps</p><p>Standard Deviation = 16 fps</p><p>Average group size = 0.74 MOA (0.39 MOA minus worst flier)</p><p>Smallest group size = 0.51 MOA</p><p>Largest group size = 1.07 MOA</p><p></p><p><strong><em>Comments on results</em></strong></p><p>I scrubbed the crap out of my rifle before I did the tests, which might explain the gradual velocity loss through time. The first two groups were also terrible, so I omitted them from the results, based on the same logic. The ES/SD for both sets is biased a little high because of the velocity drift. In all cases, the individual 4 shot strings had lower ES/SD than the average.</p><p></p><p><strong><em>Summary</em></strong></p><p>Though of limited scope, I feel that this test indicates that salt bath annealing has a positive affect on precision. This was literally my first attempt at annealing, using the "wisdom of the crowds" (i.e. google) recommended setup and parameters, and I saw nearly a quarter MOA better groups and ES/SD was reduced by ~30%.</p></blockquote><p></p>
[QUOTE="entoptics, post: 1642365, member: 104268"] To quantitatively assess the efficacy of annealing with the salt system, I took 40 pieces of well used brass, annealed half for 6 seconds at 500° C ± 5° C (932° F ± 9.3° F), and left the other half alone. All brass were treated the same except annealing, and all were loaded on the same equipment in the same session. [I][B]Brass Specifications[/B][/I] MAI brass (Norma manufactured) ≥4 firings Originally neck turned Weight sorted to ± 0.2 gr Length sorted to ± 0.002 OAL FL Sized to bump shoulder 0.002" ± 0.001" Bushing sized to ~0.002" neck tension [B][I]Load Specifications[/I][/B] [I]208 ELD-M 76.2 gr H1000 hand weighed to exactly the same charge on PACT scale Federal 210M primers ≤ 0.003" runout (most <0.002") 3.590" OAL (~0.02" off lands) [/I] [B][I]Shooting Specifications[/I][/B] Savage LRH 300 WM with 24" Shilen Heavy Sporter bbl (otherwise OEM) 5-25 Sig Sauer Whiskey 5 at 25X 200 yard target 65° F, 55% RH Obnoxious, but mostly bearable, mirage 2-5 mph full value wind, left to right. I tried to shoot in the breaks (makeshift flags at 100 and 200). Prone, bipod, rear bag rest, chest/chin in a makeshift "nest" of pillows and blankets. With this setup, I can routinely hold the crosshair well inside a 0.25 MOA circle and break the trigger. [B][I]Testing Results[/I][/B] Red = Not annealed (n = 19) Blue = Annealed (n = 19) 4 shot groups were fired, alternating from annealed to un-annealed for a total of 40 rounds. Velocity was measured using a LabRadar. Individual tracking files were inspected and culled to reduce errors associated with LabRadar's wonky algorithm for calculating velocity, which is subject to spurious readings from one or two bad tracking data points. Groups were measured using SubMOA shooting app for the iPhone. [I]Velocity[/I] [ATTACH=full]135408[/ATTACH] [B][I][/I][/B] [I]Group Size[/I] [ATTACH=full]135409[/ATTACH] [I][/I] [B][SIZE=14px][I]Summary of results[/I][/SIZE] [/B] [I][U]Annealed brass (n = 19)[/U][/I] Average velocity = 2783 fps Extreme spread = 40 fps Standard Deviation = 9 fps Average group size = 0.55 MOA (0.36 MOA minus worst flier) Smallest group = 0.43 MOA Largest group = 0.74 MOA [I][U]Un-annealed brass[/U][/I] Average velocity = 2797 fps Extreme Spread = 60 fps Standard Deviation = 16 fps Average group size = 0.74 MOA (0.39 MOA minus worst flier) Smallest group size = 0.51 MOA Largest group size = 1.07 MOA [B][I]Comments on results[/I][/B] I scrubbed the crap out of my rifle before I did the tests, which might explain the gradual velocity loss through time. The first two groups were also terrible, so I omitted them from the results, based on the same logic. The ES/SD for both sets is biased a little high because of the velocity drift. In all cases, the individual 4 shot strings had lower ES/SD than the average. [B][I]Summary[/I][/B] Though of limited scope, I feel that this test indicates that salt bath annealing has a positive affect on precision. This was literally my first attempt at annealing, using the "wisdom of the crowds" (i.e. google) recommended setup and parameters, and I saw nearly a quarter MOA better groups and ES/SD was reduced by ~30%. [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Rifles, Reloading, Optics, Equipment
Reloading
Salt Bath Annealing setup and quantitative assessment.
Top