Retumbo and barrel length

Earnhardt

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Aug 25, 2012
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I'm using Retumbo for the first time, and had a few questions.
For loads of 100 grains or more, is there a minimum barrel length that a guy should have to allow the powder to fully burn?
26", 28", 30"?

Guns are a .30/378 and .416.

Thanks
 
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elkaholic

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Dec 4, 2008
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hauser, id.
I'm using Retumbo for the first time, and had a few questions.
For loads of 100 grains or more, is there a minimum barrel length that a guy should have to allow the powder to fully burn?
26", 28", 30"?

Guns are a .30/378 and .416.

Thanks

There have been tests run which show that to FULLY burn ,you need at least 36", depending on powder. I wouldn't worry whether or not it was 26" or 30" except you will lose approx. 40'/sec for every inch.......Rich
 

Robinhood493

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Aug 23, 2011
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In my .300 RUM with a 26" barrel with a brake, anything over 102g of Retumbo doesn't have any more velocity increase. I am assuming that it is reaching the point where there it too much podwer to burn completely in a 26" barrel. I could be wrong though, just my opinion.
 

elkaholic

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Dec 4, 2008
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9,888
Location
hauser, id.
In my .300 RUM with a 26" barrel with a brake, anything over 102g of Retumbo doesn't have any more velocity increase. I am assuming that it is reaching the point where there it too much podwer to burn completely in a 26" barrel. I could be wrong though, just my opinion.

I don't know what bullet weight that is with but you could pushing chamber pressure as well! Once you reach a certain point, velocity will not increase much......rich
 

Robinhood493

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Aug 23, 2011
Messages
99
I don't know what bullet weight that is with but you could pushing chamber pressure as well! Once you reach a certain point, velocity will not increase much......rich

It is with 180g Partitions. I get very very slight ejector marks at temps above 90 degress with 103g.
 

g0rd0

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Mar 9, 2012
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610
Location
New germany, NS
barrel lenght and powder are moot unless you know your expantion ratio. Once you know your expantion ratio (ER) then you can choose the best powder for your rifle.
 

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