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RMR round nose vs RMR truncated cone (match winner)


ysrracer

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Has anybody seen any difference in use, function, reliability, accuracy between round nose bullets vs. truncated cone bullets?

 

I'm loading 124 9mm for both semi auto pistol and PCC.

 

I think Blue Bullets changed from round nose to truncated cone a while ago.

 

Thoughts?

 

.

Edited by ysrracer
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IIRC the shape was developed by the Airforce to come up with a non expanding military round that was more lethal than round nose for Berretta M-9... Not sure what the results were, or why for some reason the bullet shape took off in popularity. Was extremely common for 40 to the point I dont think there were too many RN ever made in that caliber.
Supposedly the two shapes hit the feed ramp of an M9 at the same time.

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Some PCC barrels with a narrow chamfer around the end of the chamber will have trouble feeding bullets with a wider meplat or a larger hollow point.  I have such a gun.  JHPs like the Hornady HAP or the Zero clone feed fine.  Wider openings sometimes catch and the bullet sets back.

 

I solved the problem by using JHPs for pistol Open and plated RN for PCC.  I only use the PCC for SCSA and a once-a-year falling steel match.

 

As far as RN vs. TC goes, if it feeds I prefer TC bullets.  They impart energy better to pins and make plates fall just a tiny bit better.  The larger the meplat, the better they do that.

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I tend to get more consistent seating / OAL with the flat points, and I like the nice round hole they leave in targets. RMR though I will say their heavy match winner 9mm (147gr) is one profile that doesn't fit my short throated guns well (CZ). I haven't tried the 124s, but they recommend 124s in short throated chambers.

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Truncated bullets often require a slightly shorter OAL because the full bullet diameter is closer to the chamber than with a RN. The same OAL used with RN can cause the truncated bullets to hit the chamber with full diameter too far forward. Beyond that, they work great. I use coated lead from various makers in TC in PCC and handguns and have to issues at all.

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Mostly yeah. It depends on the shape of the TC. Blues has been fine, Precision - after they redid their profile, is fine. RMRs (147s) not so much. For round nose, the pointier ones are fine, but some of the more blunt/abrupt round nose are still a challenge. I think the Blues 150 RNs were one of the tougher ones to fit short chamber. I had my barrels reamed  on my shorter chambers so I could just load one OAL for everything, except for a new Shadow2 so I'm having to go through and figure out max OALs & shapes again. Somehow over the years I ended up with a bunch of stuff i don't usually shoot that I've been trying to load up and get rid of.

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When I compare the OAL between the RMR 135 FN and the 135 RN I seat the RN @ 1.110 and the FN is 1.085” OAL. But a Precision 125 FN is 1.13 and the RN is 1.075. My gun likes the RMR FN better than the RN too. For some reason they are just easier to get to group well. 

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On 1/8/2023 at 3:55 PM, dtuns said:

I put 200 plus rounds through my GMR-15 this weekend with zero issues 100 of them were in a match. I load mine 1.075OAL

 

I loaded up some 124 match winner (TC) . My OAL is 1.090 before they would plunk.

 

That's close enough, right?

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22 hours ago, ysrracer said:

 

I loaded up some 124 match winner (TC) . My OAL is 1.090 before they would plunk.

 

That's close enough, right?

That's where mine was so I went .015 more so if seating varies I'm still under. My die holds 1.075 +-.005

 

Edited by dtuns
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7 hours ago, dtuns said:

That's where mine was so I went .015 more so if seating varies I'm still under. My die holds 1.075 +-.005

 

That’s interesting, 1.095 is where I seat the 124 MW which is -.015 off the lands in my gun. 

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5 hours ago, ysrracer said:

I only shot 10 rounds in my PCC. They fed fine, but obviously WAY more testing is needed. I will say they make nice clean holes in the targets.

 

 

They do make some clean holes.

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6 hours ago, 85win said:

Have any of you guys tried the 135 grain version? What are your thoughts on that bullet?

I have tried the 135 FN match winners and the regular RN. Hands down the FN. For some reason I can’t get the RN to shoot in my pistol worth a darn but the FNMW are fine. On the RN, the ogive is a little fatter than a Berry’s and I have to seat them deeper by .045 but the Berry’s shoot great. On the 135 FN been loading 3-3.1g E3 for 130pf @ 1.085 or 4g IMR7625 for the same. Very soft shooting on both. 

Edited by Farmer
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