223 Rem - 75gr Hornady BTHP with AR-Comp

Published on October 4, 2021
Duration: 33:09

This video details the process of creating a custom seating stem for 75gr Hornady BTHP bullets to address concentricity issues with compressed loads. Testing reveals that shorter seating depths (around 2.254" OAL) improve bullet alignment and accuracy, with the best group measuring 0.59" at 100 yards. The host emphasizes the importance of matching seating stems to specific bullet profiles for optimal handloading results.

Quick Summary

To improve seating consistency for 75gr Hornady BTHP bullets, create a custom seating stem using epoxy like JB KwikWeld molded to the bullet's profile. Optimal seating depth for accuracy was found to be 2.254" OAL, yielding a 0.59" group.

Chapters

  1. 00:00Intro: Seating Stem Issues with 75gr BTHP
  2. 01:04Custom Seating Stem Creation with JB KwikWeld
  3. 03:52Concentricity & Runout Testing: Custom vs. Standard Stem
  4. 09:13Test Methodology: New Brass & Load Data
  5. 15:40Runout Analysis: Impact of Shorter Seating Depth
  6. 17:23Range Testing Setup: AR-15 & Chronograph
  7. 20:05Group Results & Analysis: Optimal OAL Found
  8. 26:48Conclusion: Optimal Seating Depth & Bullet Comparisons

Frequently Asked Questions

How can I improve bullet seating consistency for 75gr Hornady BTHP loads?

To improve seating consistency, especially with compressed loads, create a custom seating stem. This involves using epoxy like JB KwikWeld to mold the stem's interior to the exact profile of the bullet's tip, ensuring proper contact and reducing damage or runout.

What is the optimal seating depth for .223 Remington 75gr Hornady BTHP bullets?

For the tested load using AR-Comp powder and new Lake City brass, the optimal seating depth was found to be 2.254" Overall Length (OAL). This specific depth yielded the best accuracy, resulting in a 0.59" 5-shot group at 100 yards.

How does bullet runout affect accuracy in handloaded ammunition?

High bullet runout, even a few thousandths of an inch, can significantly impact accuracy by causing flyers. The video demonstrated that rounds with runout up to 5 thousandths produced flyers, while better-aligned rounds contributed to tighter groups.

What powder and primer are recommended for 75gr Hornady BTHP .223 Remington reloads?

The video uses 22.9 grains of Alliant AR-Comp powder and CCI 41 primers with new Lake City brass for their 75gr Hornady BTHP .223 Remington reloads. This combination achieved velocities around 2730 FPS from an 18-inch barrel.

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