Brownells - Jack Rowe, Master Gunsmith Series, Bore Size and Proofing, Part 6 of 6

Published on May 30, 2012
Duration: 8:42

This video, part of the Brownells Jack Rowe Master Gunsmith Series, delves into the intricacies of shotgun chokes and barrel modifications. Master Gunsmith Jack Rowe explains the various types and lengths of chokes, contrasting UK and US standards for skeet and full chokes. He strongly advises against improper choke modification techniques, emphasizing the use of proper reamers from the breech end to avoid damaging the barrel and invalidating proof marks. Rowe also discusses the risks associated with altering forcing cones and bore sizes, highlighting how such modifications can weaken barrels and reduce their value.

Quick Summary

Master Gunsmith Jack Rowe advises against improper choke modification. He stresses that chokes should be reamed from the breech end using specialized tools to avoid damaging the barrel and invalidating proof marks. Altering forcing cones or bore sizes also weakens barrels and reduces their value.

Chapters

  1. 00:08Introduction & Headspace Gauge
  2. 01:11Understanding Shotgun Chokes
  3. 01:33Standard Choke Dimensions
  4. 02:02Recessed Chokes Explained
  5. 02:17UK vs. US Choke Standards (Skeet)
  6. 03:19UK Full Choke vs. US Full Choke
  7. 04:37Improper Choke Modification Warning
  8. 05:04Correct Choke Reaming Technique
  9. 06:06Ideal Choke Geometry
  10. 06:29Forcing Cones & Barrel Weakening
  11. 07:31Consequences of Bore Size Alteration
  12. 07:55Invalidating Proof Marks

Frequently Asked Questions

What are the key differences between UK and US shotgun choke standards?

The UK traditionally used fractional inch measurements for choke constrictions (e.g., 0.040" for full choke). In the US, standards like Skeet 1, Skeet 2, Improved Cylinder, Modified, and Full have specific constriction values, with Skeet 2 being around 0.011" and Improved Cylinder around 0.009".

What is the correct method for modifying shotgun chokes?

Master Gunsmith Jack Rowe emphasizes that chokes should be modified using specialized choke reamers, working exclusively from the breech end of the barrel. This ensures precision and prevents damage to the barrel's integrity.

Why should gunsmiths avoid altering forcing cones or bore sizes?

Altering forcing cones or bore sizes by removing metal weakens the barrel, reduces the firearm's value by invalidating proof marks, and is unlikely to significantly reduce recoil as some users might hope.

What are the risks of improper choke modification?

Improper choke modification, especially using reamers from the muzzle, can result in uneven constrictions, damage the barrel, create a poorly functioning choke, and invalidate the firearm's proof marks, compromising its safety and value.

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