Unknown Munitions 300 Norma Load Development

UM Development

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Feb 18, 2021
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After starting this position a couple weeks ago I finally got to the range today for my first customer load development. The rifle was built by Lane Precision and chambered in 300 Norma. It was one of Lane's customers rifle that had been shot several times--not sure of the round count. Here were my load development steps and results.

1. Mounted the scope, a Nightforce 5-25 ATACR

2. Borescope the barrel with my Hawkeye borescope. There was a lot of carbon in the grooves and even some on the lands There was also some substance adhering to the chamber walls. It took two applications of JB Bore Paste to get the carbon off the lands. There was a little in the grooves when I was done but that is okay. I then cleaned out the chamber. Carbon that doesn't come out easily is called "hard carbon". It needs to be kept off the lands for optimum performance, and JB Bore Paste and Iosso are the only cleaners I know of that will remove hard carbon.

3. Measured the throat using the Hornady OAL tools and a Mitituyo digital caliper. It was throated very long. The 230 Berger needed to be .060" off the lands in order to have an adequate amount of bullet shank in the case neck. Many don't like the idea of a bullet that far off the lands, but an advantage is if you can find a load that works at that seating depth, it won't be as sensitive to throat erosion as bullets that are seated close to the lands.

4. I had the Unknown Munitions crew load up my test loads. That way the people and processes we use in loading our ammo is used to load the test rounds. The test loads used Peterson brass, Fed 215 primers, N570, and Berger 230s. They were seated .060" off the lands and the loads were 87-90 grains in 1/2 grain increments. All these loads were safe in this rifle, they may not be in yours so start low and work up.

5. Bore sight the scope and get on paper

6. Shoot the test rounds. Three-shot groups at 100 yds. Chronograph is a Lab Radar. I shot from a Sinclair Competition front rest with all purpose top and Protektor rear bag.

The results:

N570 87 gr 2981 FPS ES 23 .703"
N570 87.5 2975 FPS ES 3 .502"
N570 88 2986 FPS ES 26 .261"
N570 88.5 3009 FPS ES 10 .321"
N570 89 3017 FPS ES 11 .876"
N570 89.5 3041 FPS ES 15 .357"
N570 90 No Velocity .554"

My bad on the no velocity, 100% user error. Based on the customers desires we chose the 89.5 grain load for the ammo. The red semi-circles are an inch inside diameter.

Jason Williams 300 Norma Lane Precision.jpeg

Here is another interesting picture. It is the bore sight target. The shots are numbered. The bore was clean and cold on the first shot. After the second shot I adjusted the crosshairs. I adjusted again after the third shot. Shots 4 and 5 had the same adjustment. Based on this target, I'd say this barrel needs thee fouler shots before it's at its peak accuracy.

Staring From a Clean Barrel.jpeg
 
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U

UM Development

Newbie
Rokslide Sponsor
Joined
Feb 18, 2021
Messages
6
What is the cost for you to do that?

Generally, $600 for a standard case, $700 for a magnum case, $800 for a Lapua size gun case. If the barrel has hard carbon then it's another $50 for me to clean it. Scope mounting is $50. The price for 50 rounds of loaded ammo is on the website.
 

Wrench

Senior Member
Joined
Aug 23, 2018
Messages
2,233
Location
WA
If struggle with carbon, the foul out 3 will almost always pop it off because of the thin layer of copper under it. They're out of production, but available and the solution is simple to make.
 
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