Rossi Rifleman

I guess the first thing that I should admit is I've sloppy in my reloading of .45 XTP 300g Magnum bullets. Fortunately, no harm came from my mistake. My mistake was loading the XTP magnum the same way I was loading the standard XTP. The XTP magnun is a lONGER bullet (.813) than the standard XTP (.782) and I was loading it to the same 1.600 OAL. Meaning, I was seating the bullet deeper and using up more interior case space. I was crimping above the cannelure to achieve the OAL of 1.60

Here my proposed method for continuing so I can load the XTP Magnums in the cannelure. Since the standard XTP seat deeper when crimped to the top cannelure by .44", I can trim my cases down .44" .o44 to 1.241 which would leave the OAL of 1.609. And since I was already seating the longer XTP Magnum to 1.600 the internal volume of the case should remain virtually the same (well plus .009).

Is my thinking flawed???????

Is a picture that might explain it better.

Flawed? .... maybe a little .... I think the math looks a bit skewed as the difference looks more like 0.044.

Kinda like NASA and mixing feet and meters programming a Mars lander .... kaboom!



jd

mr.surveyor, you're absolutely correct. I put the decimal in the wrong place. haha I will correct it in red so other readers want be scratching their heads wonder what the heck we're talking about. haha

won't your 45 feed a longer oal?
I'd have to measure to be 100% sure, but I'm pretty positive I'm running my 255gr rnfp at more like 1.630
it is too long for my pops 73 win, but all of my 92's move it along like butter.

I used a couple of my reloading spreadsheets to verify the case length change. Your numbers with the case length change are correct but I was curious about how the reduction effects everything within the column of the case.
The change in case length from 1.285" to 1.241". Shortening the case reduces its capacity by 1.8 grains of H₂0.

Whenever I have a need to trim cases on a continuing basis such as you are getting ready to do, I order a custom Case Length Gauge from Lee Precision.

RD, as always I (we) appreciate that you always go beyond the call of duty to provide us with the best information. Thank you.

I measured my new Starline cases. They ranged 1.269 to 1.277. Many fall in the 1.271 range. So if I trim all to 1.271 and seat the 300 XPT Magnum at the top of the cannelure they will be right at 1.62 OAL.

runfiverun, the one a dummy loaded I made at 1.62 does cycle through my Rossi and fit in the cylinder of my Blackhawk. I'm going to make 10 dummy rounds with these measurement to make sure they will ALL cycle. I don't want to be on a bear hunt and realize my 92 is really a single shot. If all goes well with the dummy rounds, I'll start over with my testing.

Lesson learned: (I can just see Ranch Dog and others on here smiling at my revelations) Time spent up front measuring and planning is time saved in the long run. To quote a line from the great trilogy, Lord of the Rings, "Short cuts often make for long delays" haha

RD, this is the case trimmer I own. It's a lot of physical error, but I can adjust the the length of trim.
MidwayUSA: Lyman Universal Carbide Case Trimmer

I have the same trimmer but once I commit to a particular non-standard length, I go with the Lee for the long haul.

I went with the powered version of that lyman, right after I length trimmed 6- 7.65 argie cases I made from 0-6 cases.
I had 94 more to go and wanted to get them done sometime that week.
but for touching up a small lot of 44 or 45 cases I still dig out the little hand crank trimmer.

I trimmed 10 dummy cases to 1.260. I loaded the 300 XTP-MAG at the top of the cannelure, which gave an OAL of 1.62. They cycled fine in my Rossi and chambered in my Blackhawk. I'll be starting over with my reloading recipes and work up slowly. Also, I will be using CC! 350 primers instead of Winchester primers. I'll post the results.

Make smoke,