Neck Runout on Fireformed brass

[sithlord6512]

Was bored tonight so I measured the neck runout on my once fired, unsized/fireformed brass. Average from 10 pieces of brass was .0023".

I remember reading somewhere that fireformed brass can give you information about your rifle. What information does it give you? What is an unacceptable amount of runout for fireformed brass?

 

[rick smith]

Your chamber is not concentric, factory or custom barrel? But in a hunting rifle 0.002" will go unnoticed. Now you can measure runout at each step of your loading process. That will tell you how well your dies/press handle the case.Rick.

 

[bullet]

Yes, in a hunting rifle it will go unnoticed, good point rick. My question is also, factory or custom rifle and how does it shoot?

 

[sithlord6512]

The rifle is a factory Remington 700 chambered in a .300 WSM.

Groups are averaging in .84" (for 10, 3 short groups) with the various OCW loads using H4350 that I have tested . The average for the load that I will be probably sticking with (62.5g of H4350) is 1.09" - not the most accurate, but it is the load that I am confident is safe (ave. velocity is 2928 fps for 3, 3 shot groups, which is below the max velocity projected by QL).

 

[bullet]

The rifle is a factory Remington 700 chambered in a .300 WSM.

Groups are averaging in .84" (for 10, 3 short groups) with the various OCW loads using H4350 that I have tested . The average for the load that I will be probably sticking with (62.5g of H4350) is 1.09" - not the most accurate, but it is the load that I am confident is safe (ave. velocity is 2928 fps for 3, 3 shot groups, which is below the max velocity projected by QL).

That will certainly get the job done and that accuracy is more than acceptable for hunting. H4350 and IMR4350 sure have worked in a lot cartridges and rifles for me through the years.

 

[sithlord6512]

Bullet,

I thought IMR4350 was going to be "THE" powder for me.
Here are results of my OCW test done in May for IMR4350 (temp of -10 C or 14 F - a warm May temperature for the Arctic) - 3 shot groups, but done "round robin" style.

62.9g = 0.48"
63.5g = 0.94"
64.2g = 1.31"
64.8g = 0.59"
65.5g=0.99" (too hot - aveage velocity was 3028 fps, Max load in Barnes #4 is 3003 for 180g TTSX)

I decided to retest around 64.5g (2, three shot groups for each of 64.0, 64.5g, and 65.0g - tested in Sept (temp of 12 C or 53.6 F)
64.0g = 1.09"
64.0g = 1.26"

64.5g = 1.81"
64.5g = 1.16"

65.0g = 1.35" (ave. vel. = 3028 gps - did not notice before, but the exact same average as 65.5g load above - I attibute this to the temp. sensitivity of IMR4350)
65.0g = N/A

The only difference in technique/procedures was the Temperature - However, I wouldn't expect temperature to decrease accuracy, just velocity/POI).

 

[bullet]

Hey, that is cool data, that is neat indeed. Thanks for sharing. I agree, that temp does not always impact accuracy but will all the time affect velocity. If enough of a velocity change takes place it could impact accuracy some. Way cool, thanks again for taking the time to post that info.