powder volumes

[dancrockett]

When you choose a powder, do you take case fill into acct.? I would like to know if there is an advantage/disadvantage to filling up the case vs. having some space behind the bullet. for example is it worth 5.5grs. just to get 20fps? I am most interested in how it affects barrel life.


180 GR. BER VLD Hodgdon H4831 .284" 64.5grs. 2830fps 60,200 PSI

180 GR. BER VLD Hodgdon Hybrid 100V .284" 59.0grs. 2810fps 59,700
PSI

 

[g0rd0]

case volume dosnt mean a thing. It is used by knowing your case capacity and ballistic barrel length to find your expantion ratio thus giveing a starting point.
As long as you follow published data find your sweet spot and stick with it.

 

[Edd]

When you choose a powder, do you take case fill into acct.?

I do, I always choose a powder that gets as close to 100% fill as possible.

 

[Mikecr]

I'm with Edd.
I go for a balance that is FIRST case fill, then velocity, & work from there for accuracy.
Extra powder is a valid barrel life factor, especially if getting nothing in return. But sometimes better filling powders are cooler/slower(as seen in QuickLoad), which somewhat counters loss in barrel life.
Not so in this case of comparison..
HY100V is listed in QL as a very cool powder. If these numbers are correct(your load ends up matching posted) there is significant gain in barrel life potential. Too much to pass up without trying it first.
See capture of my calcs attached

Otherwise:
Case fill matters (when not running extreme pressure loads), as low density loads can add to ES.
And this is one of only a few things you can influence ES with.

 

[Mikecr]

To add a flip-side scenario to discussion:
The 6XC is a very popular competition cartridge typically running IMR7828, or H4350.
A fellow named Joe Hendricks tested to get the same -with better barrel life.
His resulting solution is the 6CM(Competition Match, not Creedmore). This increased capacity over a std 6XC just enough to use H1000 (a cooler powder) with the same bullets.
Today it represents a success as it does meet his goal.

 

[Trickymissfit]

To add a flip-side scenario to discussion:
The 6XC is a very popular competition cartridge typically running IMR7828, or H4350.
A fellow named Joe Hendricks tested to get the same -with better barrel life.
His resulting solution is the 6CM(Competition Match, not Creedmore). This increased capacity over a std 6XC just enough to use H1000 (a cooler powder) with the same bullets.
Today it represents a success as it does meet his goal.

in my 6/250AI, I found H1000, Retumbo, and 4831SC to be the best for group size with the 107 Sierra and 105 Amax. I have tried two or three other powders, but always seem to come back to these three. The case is not all that much different than the two you mentioned. I'll probably try AA Magpol this year whenever it decides to warm up a tad.
gary

 

[TOM H]

When you choose a powder, do you take case fill into acct.?



I sure do and I like to get a case and bullets just to check. I've been think about a 7mag for future project and the new Hodgdon manual has the data you post for the 7mag. One of my 30-338mag I just neck up 7mag brass so I have plenty of new brass.

I'm sure you looked up Berger site and found the 180gr VLD Hybird was target bullet along with 180gr VLD target and they made 180gr VLD hunting bullet and it's shame Hodgdon didn't list which bullet they used or which H-4831 they used. In no way am I try to criticize your question. I got some 7mm 180gr VLD for another project I'm working on 284. 64.5gr/H-4831 if you seat 180gr VLD in a new 7mag case your bullet be on top of powder maybe little of the BT covered. If you notice Retumbo and H-1000 are more of a compressed load or if you custom throat you could change some of that.

Well good luck

 

[dancrockett]

Thanks for the input guys,
@Mikecr
Thanks for the info, much better than the burn rate charts. looking at your charts, are they saying you will get almost twice the number of accurate shots from your barrel with the Hybrid 100v over the H4831? I was going to buy the H4831 but now I may reconsider

 

[dancrockett]

@ Tom
Thanks Tom, I am very new to this but I have everything except powder and primers, and while trying to choose a powder for my first batch of rounds I noticed the spread in powder weights. In reading through various forums I also noticed that re-barreling seems to be a common practice, with some only getting 400 rounds through before needing to buy a new one, something I would like to avoid for as long as possible. I never realized that shooting had become such a science, but I sure realize I have a lot to learn now.