31.5 of N140 in 6BR

[michaelb]

As you already know, every rifle is different from the next so process averages across them with care.

-Pay attention to your bolt lift, sometimes pressure will show up "by feel" and not be evident on the case head.

-Inspect your case head for ejector wipe marks.

-Inspect fired primers for flattening and also cratering.

Remember fundamentals in load development, especially when loading small volume cases.
example: You may have no problem working up a load increasing by half grain increments in a 300 Winchester Magnum BUT this could present a disasterous problem in a 6 BR.

Per your photos above, I cannot see any signs of excess pressure HOWEVER, I am unable to "feel" your primers to see if any cratering is present.

Notice I put the word "Feel" in quotations again like in my sentence above. I did this to demonstrate that this is an important part in your assesment of how your load is performing.

 

[JFrank]

I was testing today different powder charges for 105gr Hybrids. Unfortunately my Labradar died in the middle of my session at -4 degrees Celsius and my best groups have unknown speed. My groups of 30gr and 31.5gr of N140 show some promise. In fact 31.5 was a one hole group, I think it's a decent 0.2. Isn't 31.5gr N140 a little too much for straight 6BR?
Are there any pressure signs in your opinion (two different fired cases below)?

https://imgur.com/0pTbhtD

https://imgur.com/5pL4iGw

I have no idea how you’re getting that much powder without pressure but I would like to know the lot number on your N140 ?

Jim

 

[marchx]

I have no idea how you’re getting that much powder without pressure but I would like to know the lot number on your N140 ?

Jim

https://imgur.com/eP0CCir

 

[JayBeeYou]

Any chance there is no pressure signs due to N140 being known as medium level of temp sensitivity and your stating test performed at -4 degrees celsius. I would think if you shot that charge weight in a moderate to warm temp things could get spicy real quick.

 

[marchx]

Any chance there is no pressure signs due to N140 being known as medium level of temp sensitivity and your stating test performed at -4 degrees celsius. I would think if you shot that charge weight in a moderate to warm temp things could get spicy real quick.

This sounds like a plausible theory. I dimantled yesterday the whole 31.5gr batch for the sake of security.