.308 Win - 175gr Sierra Match King with IMR 4064 (part 1)

Published on June 5, 2018
Duration: 42:39

This video details a .308 Win AR-10 build featuring a 20-inch JP Super Match barrel and tests 175gr Sierra Match King reloads using IMR 4064. The host compares handloads against Federal Gold Medal Match factory ammunition, both suppressed and unsuppressed. Results show factory ammo performed exceptionally well suppressed, while handloads tightened groups with increasing powder charges, peaking at 42.0 grains.

Quick Summary

The best unsuppressed group size of 0.912 inches was achieved with a charge of 42.0 grains of IMR 4064 behind a 175gr Sierra Match King bullet. Velocity increased linearly, suggesting slightly higher charges might match factory speeds.

Chapters

  1. 00:00Hardware Overview: AR-10 Build
  2. 00:54Components & Factory Baseline: 175gr SMK, IMR 4064
  3. 03:42Powder Comparison & Load Data: IMR 4064 Ladder
  4. 07:14Reloading Process: Priming & Seating
  5. 16:37Range Testing: Unsuppressed Accuracy
  6. 19:57Range Testing: Suppressed Accuracy
  7. 21:54Results & Analysis: Factory vs. Handloads

Frequently Asked Questions

What is the optimal powder charge for 175gr Sierra Match King bullets in .308 Win using IMR 4064 based on this test?

The best unsuppressed group size of 0.912 inches was achieved with a charge of 42.0 grains of IMR 4064 behind a 175gr Sierra Match King bullet. Velocity increased linearly, suggesting slightly higher charges might match factory speeds.

How did the Federal Gold Medal Match factory ammunition perform in this .308 Win test?

The Federal Gold Medal Match factory ammunition, featuring 175gr Sierra Match King bullets, performed exceptionally well, especially when suppressed, achieving a tight group of 0.611 inches.

What components were used for the .308 Win handloads in this video?

The handloads utilized 175gr Sierra Match King bullets, IMR 4064 powder ranging from 40.4 to 42.0 grains, Lapua brass, and CCI 200 large rifle primers, seated to an overall length of 2.800 inches.

Why is tuning the gas block important for an AR-10 in .308 Win?

Tuning the adjustable gas block is crucial for optimal cycling and accuracy, particularly when switching between suppressed and unsuppressed shooting configurations. It ensures the rifle functions reliably with different ammunition types and suppressor setups.

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