BB in Texas
Member
- Joined
- Oct 26, 2020
- Messages
- 33
Would appreciate a reality check on my workup for these 9 mm test loads:
Data:
Hodgdon 9mm 115g LRN IMR Target COL 1.100 Start 4.0 Max 4.5
Lee 9 mm 115g XTP IMR Target COL 1.125 Start 4.4 Max 4.9
My working COL is 1.125 and want to work up loads using two different bullets (both of which I've used with other powders and same COL):
9 mm 115g Xtreme CP RN (COL of bullet is .551)
9 mm 115g RMR FMJ RN (COL of bullet is .561)
According to Hornady, the COL of the 115g XTP is .538.
Since the COL used in the Lee data (1.125) is identical to my working COL, the bullets I use will be seated deeper into the case than would be so with the shorter XTP bullet. With less available space within the case for my test loads (other factors being equal) my test loads should produce more pressure than the XTP bullet with the same charge weight.
I’ve read multiple posts from very experienced members suggesting using lead data for the copper plated bullets while others have suggested reducing the lead data by 10% as the starting load. By either measure that would put the start at 4.0 for the Xtreme CP RN. Seems reasonable to me based on my understanding and experience.
Analyzing the RMR FMJ RN relationship is confusing to me and I’m not sure how (or even whether) to proceed.
What I do know is that I’ve used W231 with identical charges and COL for each bullet (CPRN and FMJ RN) and I simply can’t observe any difference. Based on this experience I’m inclined to use a start charge of 4.0 with both bullets, but what’s the likelihood of a squib in this scenario? Maybe a start charge at 4.2?
As always, thanks in advance for the help!
Data:
Hodgdon 9mm 115g LRN IMR Target COL 1.100 Start 4.0 Max 4.5
Lee 9 mm 115g XTP IMR Target COL 1.125 Start 4.4 Max 4.9
My working COL is 1.125 and want to work up loads using two different bullets (both of which I've used with other powders and same COL):
9 mm 115g Xtreme CP RN (COL of bullet is .551)
9 mm 115g RMR FMJ RN (COL of bullet is .561)
According to Hornady, the COL of the 115g XTP is .538.
Since the COL used in the Lee data (1.125) is identical to my working COL, the bullets I use will be seated deeper into the case than would be so with the shorter XTP bullet. With less available space within the case for my test loads (other factors being equal) my test loads should produce more pressure than the XTP bullet with the same charge weight.
I’ve read multiple posts from very experienced members suggesting using lead data for the copper plated bullets while others have suggested reducing the lead data by 10% as the starting load. By either measure that would put the start at 4.0 for the Xtreme CP RN. Seems reasonable to me based on my understanding and experience.
Analyzing the RMR FMJ RN relationship is confusing to me and I’m not sure how (or even whether) to proceed.
What I do know is that I’ve used W231 with identical charges and COL for each bullet (CPRN and FMJ RN) and I simply can’t observe any difference. Based on this experience I’m inclined to use a start charge of 4.0 with both bullets, but what’s the likelihood of a squib in this scenario? Maybe a start charge at 4.2?
As always, thanks in advance for the help!