RMR 124gr FMJRN & Ruger PC Carbine

[tcoz]

If anybody is loading RMR 124gr FMJRN bullets in their PC carbine can you please tell me what COAL or CBOL you’re using and is this the max length that you found you could use or just what you decided on?
I'll be purchasing a carbine soon and want to see whether I can use the same bullet seating spec that I’m using in my 9mm handguns.

Thank you.

 

[LiveLife]

While RMR 124 gr FMJ RN will pass my KKM and Lone Wolf barrels with longer leade at longer OAL, for my newest Lone Wolf barrel with shorter leade, I need to seat shorter at 1.130". Comparison picture below also shows other bullets' OALs that work for this barrel with shorter leade for reference.

Many are reporting Ruger PC carbine barrel has shorter leade but 1.130" should work. Looking to hear what owners of PC carbine report as max working OAL for RMR 124 gr FMJ RN.

 

[tcoz]

bds, I saw that comment on another thread but I’m trying to see if I can get some info specific to the PCC. I’m currently loading to 1.140” for a P320 and RO Compact. I have about 3000 rounds loaded and I’m holding off on any more until I find out. Thanks for your response.

 

[tcoz]

While RMR 124 gr FMJ RN will pass my KKM and Lone Wolf barrels with longer leade at longer OAL, for my newest Lone Wolf barrel with shorter leade, I need to seat shorter at 1.130". Comparison picture below also shows other bullets' OALs that work for this barrel with shorter leade for reference.

Many are reporting Ruger PC carbine barrel has shorter leade but 1.130" should work. Looking to hear what owners of PC carbine report as max working OAL for RMR 124 gr FMJ RN.

Just to clarify this for me, is the base to ogive (the important measurement) length the same for all of these RMR 124gr bullets pictured?
If that’s the case, the people who say that they have to load to a COAL of 1.08 with the 124gr MPR bullet can load the RN bullet to 1.16”. Is this a correct assumption on my part?
If so, then my current COAL of 1.14” with the RN bullet should chamber ok....is this also a correct assumption? I know this isn’t rocket science, but I want to make sure I’m interpreting this correctly.
Thank you.

 

[kidneyboy]

Just to clarify this for me, is the base to ogive (the important measurement) length the same for all of these RMR 124gr bullets pictured?
If that’s the case, the people who say that they have to load to a COAL of 1.08 with the 124gr MPR bullet can load the RN bullet to 1.16”. Is this a correct assumption on my part?
If so, then my current COAL of 1.14” with the RN bullet should chamber ok....is this also a correct assumption? I know this isn’t rocket science, but I want to make sure I’m interpreting this correctly.
Thank you.

I load the 124 MPR at 1.120 (+/- .002) for my Ruger PC9 with no issues. Hope this helps.

 

[tcoz]

I load the 124 MPR at 1.120 (+/- .002) for my PC9 with no issues. Hope this helps.

Thanks kidneyboy. I think that helps to confirm that I’m ok at 1.14 with the 124 RN.

 

[Dudedog]

I loaded the RMR 124 RNS at 1.12 for my pistols.
In some of them I could go longer in others I can't.
In the tests I have done my pistols seem to prefer shorter OALs,
If they are for the carbine only I would see what OAL would plunk and then
maybe do an OAL test to see what it likes best.
Then you can see if it is worth the trouble to make special loads for the carbine or just use the same OAL as
you do for the pistol. (assuming it plunks)
Of course all guns are different some may like longer better some may like shorter better,
no way to tell until you test.

 

[kidneyboy]

Thanks kidneyboy. I think that helps to confirm that I’m ok at 1.14 with the 124 RN.

Keep in mind you read it on the internet and YMMV.
To clarify, It's a Ruger PC9

 

[tcoz]

Got it. My LGS/range has a PCC in stock. I’m going to take a dummy round and see whether they’ll let me run a plunk test on it. Since i just ordered a P365 from them I would think that they’ll oblige me.

 

[LiveLife]

Just to clarify this for me, is the base to ogive (the important measurement) length the same for all of these RMR 124gr bullets pictured?

No. The bullets have different bullet base lengths (bearing surface that engages the rifling).

If that’s the case, the people who say that they have to load to a COAL of 1.08 with the 124gr MPR bullet can load the RN bullet to 1.16”. Is this a correct assumption on my part?

Max OAL is determined not by length of bullet to tip but rather how much bullet base/bearing surface sticks above the case mouth before nose (ogive)/bearing surface contact the start of rifling.

And since most people determine max OAL with the barrel by dropping the round into the chamber, you want to measure some resized brass and use longer average length case as shorter case at same OAL will allow more bullet base/bearing surface to stick above the case mouth.

And max OAL may not fit the magazine or reliably feed/chamber from the magazine so we must function check to determine the working OAL until finished rounds reliably feed/chamber from the magazine.

BTW, the OALs I listed for various RMR 124 gr bullets are "working" OAL that reliably fed/chambered from the magazine in Lone Wolf barrel with very short leade. If your barrel has longer leade, your working OAL will likely be longer but shorter lengths should also work (and may produce more consistent chamber pressures for smaller groups ).

 

[Lee Q. Loader]

I think you'll be OK with that bullet at 1.14. The only RN 124 bullet I've loaded was a Berry's which I have always loaded to 1.125. That round "plunks" fine in my Ruger PCC Carbine. Mine's the new takedown model.

 

[tcoz]

No. The bullets have different bullet base lengths (bearing surface that engages the rifling).


Max OAL is determined not by length of bullet to tip but rather how much bullet base/bearing surface sticks above the case mouth before nose (ogive)/bearing surface contact the start of rifling.

And since most people determine max OAL with the barrel by dropping the round into the chamber, you want to measure some resized brass and use longer average length case as shorter case at same OAL will allow more bullet base/bearing surface to stick above the case mouth.

And max OAL may not fit the magazine or reliably feed/chamber from the magazine so we must function check to determine the working OAL until finished rounds reliably feed/chamber from the magazine.

BTW, the OALs I listed for various RMR 124 gr bullets are "working" OAL that reliably fed/chambered from the magazine in Lone Wolf barrel with very short leade. If your barrel has longer leade, your working OAL will likely be longer but shorter lengths should also work (and may produce more consistent chamber pressures for smaller groups ).

I'm aware that OAL doesn’t determine whether a round chambers and that it’s base to ogive length that does but people here are talking OAL and not CBOL so I was trying to correlate them. I had mistakenly assumed that the OAL given for each bullet pictured was yielding the same CBOL and the difference in ogive to tip length was accounting for the difference in the OALs.

Also, the OAL that I’ve been using fits in all of the mags accepted by the Ruger PCC so I know that part isn’t a problem.

As I mentioned earlier, I’ll test a few dummy rounds in the rifle at my LGS. That’s the only way to know for sure.

Thank you.

 

[Lee Q. Loader]

I'm aware that OAL doesn’t determine whether a round chambers and that it’s base to ogive length that does but people here are talking OAL and not CBOL so I was trying to correlate them. I had mistakenly assumed that the OAL given for each bullet pictured was yielding the same CBOL and the difference in ogive to tip length was accounting for the difference in the OALs.

Also, the OAL that I’ve been using fits in all of the mags accepted by the Ruger PCC so I know that part isn’t a problem.

As I mentioned earlier, I’ll test a few dummy rounds in the rifle at my LGS. That’s the only way to know for sure.

Thank you.

When you get your PCC I'll be very interested to know what bullets at what OAL's you load to get them to plunk. I've only shot the RMR 124 MPR through mine and it must to seated to 1.08. I've plunked the 124 RN Berry's at 1.125 but not shot it. The Berry's 124 is not the RN hollow base, heavy plate, it's just the regular RN.

 

[tcoz]

I ran the plunk test with RMR 124gr RN on a PC Carbine today at my LGS. The longest OAL that I tested (dummy rounds) was 1.145 which plunked and dropped out easily. Since my normally loaded rounds are 1.140” I don’t anticipate any problems whatsoever.