The Firing Line Forums - View Single Post - Noobie Question: How Exact Do You Need to Match Load Data?

FoundFather · April 15, 2025, 01:20 AM

OK, I know the right answer is: completely exact. But with shortages of many components, some producers discontinuing production, and high haz mat and shipping charges making small purchases uneconomic, it's tough. So I am hoping you guys can help out the new guy here!

I am just starting out in reloading. I bought a press, dies and some supplies a couple years ago and would like to try to use what I've got. My current goal is to load some .40 S&W, mild not wild, for practice reloading. Later I would like to load 10mm where cost savings are greater and facotry loads often unsatisfactory.

The powders I have on hand I origianlly bought with a different goal in mind, to relaod for .32 S&W ("short") which is super hard to find factory loaded. I was persuaded that wasn't a good calber for a beginner, so I am putting that off for a while. Powders I have are Unique, Red Dot and Bullseye. All fast burners, maybe not ideal for .40 and certainly not for 10mm. I have the most Bullseye so would like to get some use out of it loading for .40.

Alliant publishes limited data for Bullseye in .40. One recipe I am eying is for Speer 180 gr CPFN, Federal cases, CCI 500 SPP primers, and 5.7 grains of Bullseye. Alliant recommends -10% for starting load.

I assume other brands of cases are subsitutable. I have been saving .40 brass but it is mixed headstamps. Fortunately, I have CCI 500 SPP.

Problem is the bullets. I have large quantities of two bullets. Both are by Montana Gold, which is no longer operating but had a reputation for good quality. They are both jacketed. I have the most of 180 grain FMJ FN: http://montanagoldbullet.com/10mm-40-180gr-fmj-1-000ct/

These are pretty close, but not identical, to the Speer 180 gr CPFN in the published recipe. The Speer bullets are plated, not jacketed. I understand my jacketed bullets may casue higher pressures. Are they safe to use with this recipe?

I also have some 165 grain bullets from Montana Gold that are similar to the 180's, but CMJ "Complete Metal Jacket" with copper jacket on the base as well, sort of like a gas seal. (They no longer show these on the web site.) The data Alliant publishes for 165 grain bullets are for 165 gr Speer GDHP. Can I use my bullets with a receipe that calls for hollow points? I would like to use the 165's for this and save the 180's for 10mm.

Any guidance most appreciated.

April 15, 2025, 01:20 AM	#1
FoundFather Member Join Date: October 15, 2022 Posts: 35	Noobie Question: How Exact Do You Need to Match Load Data? OK, I know the right answer is: completely exact. But with shortages of many components, some producers discontinuing production, and high haz mat and shipping charges making small purchases uneconomic, it's tough. So I am hoping you guys can help out the new guy here! I am just starting out in reloading. I bought a press, dies and some supplies a couple years ago and would like to try to use what I've got. My current goal is to load some .40 S&W, mild not wild, for practice reloading. Later I would like to load 10mm where cost savings are greater and facotry loads often unsatisfactory. The powders I have on hand I origianlly bought with a different goal in mind, to relaod for .32 S&W ("short") which is super hard to find factory loaded. I was persuaded that wasn't a good calber for a beginner, so I am putting that off for a while. Powders I have are Unique, Red Dot and Bullseye. All fast burners, maybe not ideal for .40 and certainly not for 10mm. I have the most Bullseye so would like to get some use out of it loading for .40. Alliant publishes limited data for Bullseye in .40. One recipe I am eying is for Speer 180 gr CPFN, Federal cases, CCI 500 SPP primers, and 5.7 grains of Bullseye. Alliant recommends -10% for starting load. I assume other brands of cases are subsitutable. I have been saving .40 brass but it is mixed headstamps. Fortunately, I have CCI 500 SPP. Problem is the bullets. I have large quantities of two bullets. Both are by Montana Gold, which is no longer operating but had a reputation for good quality. They are both jacketed. I have the most of 180 grain FMJ FN: http://montanagoldbullet.com/10mm-40-180gr-fmj-1-000ct/ These are pretty close, but not identical, to the Speer 180 gr CPFN in the published recipe. The Speer bullets are plated, not jacketed. I understand my jacketed bullets may casue higher pressures. Are they safe to use with this recipe? I also have some 165 grain bullets from Montana Gold that are similar to the 180's, but CMJ "Complete Metal Jacket" with copper jacket on the base as well, sort of like a gas seal. (They no longer show these on the web site.) The data Alliant publishes for 165 grain bullets are for 165 gr Speer GDHP. Can I use my bullets with a receipe that calls for hollow points? I would like to use the 165's for this and save the 180's for 10mm. Any guidance most appreciated.