6GT Build Part 3: Barrel Break-In

I’ve always wanted a 6GT. Now that it’s complete, it’s time to send rounds down range! In this story, I’ll cover optics, break-in, and some first loads!


Ultimate Reloader LLC / Making with Metal Disclaimer: (by reading this article and/or watching video content you accept these terms). The content on this website (including videos, articles, ammunition reloading data, technical articles, gunsmithing and other information) is for demonstration purposes only. Do not attempt any of the processes or procedures shown or described on this website. All gunsmithing procedures should be carried out by a qualified and licensed gunsmith at their own risk. Do not attempt to repair or modify any firearms based on information on this website. Ultimate Reloader, LLC and Making With Metal can not be held liable for property or personal damage due to viewers/readers of this website performing activities, procedures, techniques, or practices described in whole or part on this website. By accepting these terms, you agree that you alone are solely responsible for your own safety and property as it pertains to activities, procedures, techniques, or practices described in whole or part on this website.

6GT Build Recap

You’ve followed along in the process through videos covering the MDT ACC chassis and build components and barrel and finish work. I was really happy with how everything turned out.

As a recap of the build components:

Here’s a review of the build components:

This whole process required a number of tools, here’s a quick breakdown:

Tools used for this build:

You may notice that I don’t have a no-go gauge listed. A piece of tape on the end of the go gauge added two-thousandths — there’s my no-go gauge. 

ZeroTech sent me their new 4.5-27×50 FFP Trace Advanced Tactical Optic to test. I’ve never used one of their scopes before and decided to give it a try.

What really stood out to me, though it may seem minor, were the alloy flip covers included on the optic – a bit more durable and elegant than the traditional plastic covers. 

Though I haven’t put this optic to a battery of tests just yet, it performed well during break-in.

Hawkins Precision Ultra-Light Tactical Rings

I selected 30mm Hawkins Precision high scope rings for this rifle. Machined from billet aluminum with a black anodized finish, these rings have an integrated cap level to save space. Surprisingly lightweight, they are ideal for hunting applications.

First Shots

I’ve built enough rifles that I’m not concerned about a gun blowing up, but there are always some jitters in the first shot out of a brand new gun you’ve worked hard on. It’s an incredibly exciting moment. This time I relaxed my barrel break-in procedure after talking with Bruce Thom, owner of BAT Machine.

I used to clean after firing each shot. This time I followed a different procedure: 3 shots, clean (3x), 5 shots, clean (3x) and 10 shots, clean (3x). 

The Krieger barrel didn’t require much break-in in terms of fouling. The patches came through remarkably clean. I tested two different bullets, Hornady 110 grain 6mm A-Tip Match and Berger 6mm 109 Long Range Hybrid Target.

As I always do, I collected some velocity data. I didn’t have much of my own data for this gun, just information from MDT and Hodgdon’s reloading data center. 

Some of these results will change about the 200 shot mark, but the information is helpful as I continue in the load development process.

I did some accuracy testing with both bullets and concluded the Berger 109’s seemed to shoot just a little bit better.

What’s Next

Next on the list is full load development and I’m also looking at possibly comparing 6mm Dasher and  6GT on the recoil rig!

I’m also looking into a few different die configurations. For loading break-in ammunition, I used “The” seating die from Short Action Customs and brand new brass.

We have a few other items to investigate on the list, including positional shooting. 

Let us know what you’d like to see and share your favorite 6GT loads! 

Look for Varget, Berger 6mm 109 grain and Hornady 110 grain A-Tip bullets at Midsouth Shooters Supply.

Don’t miss out on Ultimate Reloader updates, make sure you’re subscribed!

Gavin Gear

Leave a Reply

Your email address will not be published. Required fields are marked *