Powder Lot Changes/case changes

[Wildalaska]

Ran out of powder after loading 1/2 of the rounds I want for Sunday..(6.5x55, 43.8gr RL22 in Lapua 4x fired cases and Fed 210M)

So now got to buy more...

Now I am using far less than a max load...do I need to reduce since I will probably be getting a different lot of the same powder..or becasue I am at a mid range load should I just use my standard load and check for serious velocity changes...

Same question on cases....I know you need to back off if at or near max..but what about at mid range loads.... i have both Win and Lapau cases for 308 as well as Lake City, gonna use the win frist to do work up..

Anybody know of a case capacity refernce site?

WildnoviceAlaska

 

[cracked butt]

If you buy a new lot of RL-22, I doubt you will have any problems or much change in velocity with your loads. Looks like you are probably ~4 gr short of the max load, so I wouldn't worry about it. If you were at or near the maximum load, then I would back off a grain or two and test a few rounds.

 

[only1asterisk]

I don't think I'd worry about that specific load. I would keep them seperate, as there maybe enough change to shift POI.

I wish there was a case capacity reference. I've talked to Mike at ammoguide.com and he is considering it for a future addition.


David

 

[Poodleshooter]

How would you compare case capacity? I've done it with water, but the spread was pretty wide depending on trim lengths and case brand.
You're supposed to reduce when changing lots (I don't)

 

[JNewell]

Unless your at the top of the benchrest crowd, neither probably matters much. Exception: military brass is typically much lower internal volume, which can affect pressure, so I would reevaluate my powder charge when going from SAAMI-spec commercial brass to USGI (or non-SAAMI foreign).

 

[ClarkEMyers]

Were lots of lists when Homer Powley's slide rule was in vogue

There were lots of such lists when Homer Powley's slide rule was in vogue.

Considering the proclaimed differences between say the 7X61 S&H and the 7X61 S&H Super I'd figure such things are reference only.

Time was Remington cases were often said to be thinner for more capacity and harder for less expansion. Bob Hagel wrote about forming cases from different brass to manipulate internal volume and hardness for his purposes.

For my money, in a medium load in a medium cartridge with inherent accuracy and what I will call for want of a better term forgiveness, might say well behaved, I would certainly open a new lot of powder and keep loading without adjustment and expect satisfactory results - for all practical purposes but not for every purpose. For plinking with ex-military iron sighted rifles at milkjugs and pop bottles filled with water (nuisance to gather up all the pieces but do it) I wouldn't give it a second thought.

Then again, the next load might be going into a bad heat treat, wrong headspace swapped out bolt that was overheated when the knob was bent straight and all the rest of a bad scene. Never know.

 

[Wildalaska]

Lucky for me I found the exact same lot number!

WildblessedbythegungodsAlaska

 

[Mal H]

I'm with the others, you're not at max, so full speed ahead whether the lots are the same or not.

However, I wouldn't be so cavalier when it comes to changing cases, especially when you're dealing with commercial vs military cases. The cases from LC may have less volume than the Win or Lapua. That can lead to much higher pressures than you might suspect from a mere case manufacturer change. Use caution in that case (NPI).

 

[Wildalaska]

I have a lot of once fired Lake City but Im gonna hold them in reserve and just use commercial cases...

WildssgAlaska