10mm 155 grain load

[aplthird]

I am loading 155 grain lead RNSWC over longshot.

 

my starting charge was 8.5 grains and I stopped at 9.0  grains

 

My chrono for three shots were 1341, 1395 and 1326 avg was 1354 at 9.00 grains

 

when I run GRT it says this is an over pressure above 35k.  I see no evidence of primer

 

flow etc.  I also use GRT for 357SIG and 45 acp no issue with those loads.  Any ideas?

[Banacek]

3 hours ago, aplthird said:

I am loading 155 grain lead RNSWC over longshot.

 

my starting charge was 8.5 grains and I stopped at 9.0  grains

 

My chrono for three shots were 1341, 1395 and 1326 avg was 1354 at 9.00 grains

 

when I run GRT it says this is an over pressure above 35k.  I see no evidence of primer

 

flow etc.  I also use GRT for 357SIG and 45 acp no issue with those loads.  Any ideas?

Hodgdon load data website shows a Longshot  load of 9.5grs at 36,300 PSI  and velocity of 1407.  My only concern would be lead fouling but data shows you should be fine up 1400fps without a gas check.

[Joe4d]

Primer flow is about as accurate as reading goat entrails and tea leaves.  By the time you see physical signs of over pressure you are way over already.
That being said you seem to be within book numbers.
You'd really need to chrono at least 10 rounds at say 8.4 , 8.7 and 9.0.. to see whats what  with your standard deviation. Also velocity should be linear, and tends to plateau when you get towards max. 

[aplthird]

6 hours ago, Joe4d said:

Primer flow is about as accurate as reading goat entrails and tea leaves.  By the time you see physical signs of over pressure you are way over already.
That being said you seem to be within book numbers.
You'd really need to chrono at least 10 rounds at say 8.4 , 8.7 and 9.0.. to see whats what  with your standard deviation. Also velocity should be linear, and tends to plateau when you get towards max. 

Will do thanks for the help

[Steven420]

Was gonna say data collection sample size is too small to be accurate representation of SD.