RMR MPR 124gr OAL

what length is required for them to pass the plunk test?

I load that bullet for 4 different 9mm pistols. Two of which I load to 1.030 oal.

One of them is the new S&W Shield EZ.

Axis II said:

Not sure I quit at 1.035 because it was starting to Bell the case.

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Keep going. let us know what it is.

Axis II said:

Not sure I quit at 1.035 because it was starting to Bell the case.

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It is a 9mm, right? Surprised it is belling the case, given that it is a tapered cartridge. With Dillon dies you always get a little of that, even on straight wall cases. They pass the plunk test and work fine in my guns, though. I also don't have to worry much about setback.

Axis II said:

Not sure I quit at 1.035 because it was starting to Bell the case.

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Clarification please? Did you mean “bell” or “bulge” the case as in it’s set so deep in the case you’re seeing a bulge? Hopefully it’s not a Maxxtech HS?
Do you need a bullet OAL or cartridge COL? I’m able to load these at 1.120” COL across several 9mms.

If it were me, I’d either ream the bore or get a different bullet. I’ll only do compressed loads if the published load data indicates so. I would not attempt that in 9mm. Good luck!

Your bullets have a very short nose and M&P's have a short throat that will require them to be seated deep in the case. This is 'normal' for these kind of bullets and short throats. I load for a M&P also and have the same issues. For example, a Sierra 125 JHP (another bullet with a short nose) has to be seated to 1.023" to just barely fit and pass the plunk test in one of my M&P barrels. Reduce the powder charge as necessary for the shorter OAL.

Case bulge at the bullet base happens, depending on the brand of the case, how deep the bullet goes and how far down the brass has been sized. It's fine as long as the round chambers.

There is no need to be concerned with compressed powder charges (though there are probably some few exceptions) in many handgun rounds. Here's what the professionals say about compressed powder,

"A full case, or lightly compressed charge is an ideal condition for creating loads with the most uniform velocities and pressures, and oftentimes, producing top accuracy."

http://www.hodgdonreloading.com/reloading-education/reloading-beginners/compressed-loads

There's nothing horrible about compressed charges in a 9mm. Many loads for 9 Major have compressed powder, and with many of these powders they are loaded well over normal 9mm pressures. Here's an example:

https://www.ssusa.org/articles/2018/1/9/how-to-use-9-major-in-a-short-barrel/

I'm thinking there's something else going on here. I have reloaded RMR JHPs to 1.020" OAL with no problems and not compressing Unique. As matter of fact, I use that bullet for my "Just in Case" handloads and it fits all of my 9mm pistols and if there is a bulge, it's not noticeable...

Seem really short. I agree with the compressed load comments. I load the same bullets for many different guns. Glocks, Sigs and a Keltek Sub 2K and they are all loaded at 1.095 for all guns

In my Glock 19 Gen 5, I needed to go to 1.090" max to pass the plunk test with the RMR 124 MPR. I ended up going with 1.060", which is the same as the min prescribed by Hornady for their 124 grain XTP, which I've also loaded successfully. I use the Hornady Rev 10 load data for the RMR 124 MPR, as the RMR bullet is shorter than the XTP.

That does seem short, but that’s not really in and of itself, a problem.... so long as reliability isn’t effected.
My favorite and most bestest 9mmLuger loads are compressed pretty tight.

I use a 4 die set, the last being a taper crimp. I had the same problem when I started loading .40 cal, and they wouldn't plunk. I use a Lee Classic Turret for most pistol cartridges and I took the indexing rod out and loaded a lot of 50 rounds single stage. As I went through the steps, I checked and adjusted/tweaked each die. My problems went away, and when I started loading 9 mm I used the same steps and setup. Never had a problem with any of the 9 mm, and I've loaded a bunch.

Have a blessed day,

Leon

Ghost In The Fog said:

Seem really short.

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Yer right. My faux pas. Cannot say what happened, but in my log I have 1.020. I just went and checked my stock and found 9mm, 124 gr JHP loads to be 1.120", Nosler data. My JIC 124 gr JHP JHP is 1.060"...

This is exactly why I normally don't post any load data and never use any load data I see on line...