Author Topic: newb needs info on OAL for RMR `124 gr HP's & RN's for my CZ75 SP01 Tactical  (Read 809 times)

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Offline 86304

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After looking over this info:
http://www.czfirearms.us/index.php?topic=34225.msg189131#msg189131
and used it to figure out my max OAL for
RMR 124 gr RN 
 https://rmrbullets.com/shop/bullets-for-reloading/9mm-115-grain-rmr-fmj/?v=7516fd43adaa
and RNR 124 gr HP
https://rmrbullets.com/shop/bullets-for-reloading/new-rmr-9mm-124-grain-jacketed-hollow-point-made-in-house-by-rmr/?v=7516fd43adaa

I came up with the following info:
The Round nose averaged (25 rounds) around 1.194 (subtract .015) for an OAL of 1.179

The Hollow points were more all over the place for lengths (16 rounds) !.080 to 1.093 but most were around 1.087 (less .015) for an OAL of 1.072

Do these numbers sound right?

SPO1SHADOW

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I am loading mine at 1.130. They will go out to almost 1.140 in all of my unthroated guns. You don't have to load them short as many HP's require. The best accuracy for me was at 1.130. You need to do the plunk test in your guns to find out how long they will go in your particular gun and then load them at different lengths to find out which is more accurate. I would think you will find this between 1.120 and 1.140.

Any of the jacketed round nose bullets should go out to 1.160 in a stock barrel. Again you need to do the plunk/push test as noted in Wobbly's post to see how far they can go. Most of the load data for JRN is between 1.140 and 1.160 in length.

Edited to reflect the correct name for the push test post.
« Last Edit: July 10, 2017, 07:55:52 PM by SPO1SHADOW »

Offline 86304

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"Again you need to do the plunk/push test as noted in Idescribe's post "

LInk?

Thanks, Bob

SPO1SHADOW

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"Again you need to do the plunk/push test as noted in Idescribe's post "

LInk?

Thanks, Bob

http://www.czfirearms.us/index.php?topic=34225.msg189131#msg189131

Offline IDescribe

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I think he meant Wobbly's stickied post. ;)

As to the RN -- there are two limits to maximum OAL: what the chamber will allow, and what the magazine will allow.  You have determined the approximate maximum that the chamber will allow.  The maximum the magazine will allow is supposed to be 1.169 with just about every 9mm Luger pistol made, with the common exception being 1911 pistols chambered for 9mm.  When your chamber allows longer than 1.169 that the magazine allows, you recognize that the magazine is the limit, and you should probably consider the working maximum 1.160 (for the cushion), and know that you may or may not find loadings to be more accurate even shorter than that. ;)

As to the JHP, we have some conflicting info:

I am loading mine at 1.130. They will go out to almost 1.140 in all of my unthroated guns. You don't have to load them short as many HP's require. The best accuracy for me was at 1.130.

Received my order of the RMR 124 JHP.

Push at 1.055-1.057 and deduct from there.

The Hollow points were more all over the place for lengths (16 rounds) !.080 to 1.093 but most were around 1.087 (less .015) for an OAL of 1.072

I have never loaded one of these bullets.  I will say that between you, Copemech, and SP01Shadow, at least one of you is wrong, and maybe two. 

Copemech posted a photo of the 124gr RMR JHP (on the right) next to some XTP (on the left):



Just looking at those bullets, it seems highly unlikely to me that those RMR are going to load especially long for a JHP, and I would expect them to have typical max OAL for CZ pistols with JHP in the range of 1.07-1.10, and possibly even shorter.  But we have three conflicting push test results here.  I have on a couple of occasions found the push method of max OAL determination to produce poor results, and it is now step 1 for my determination of max OAL instead of the entire method.  My method now:

I do one push with a fired case in the chamber to a ball park number, then load a dummy a little longer than that -- size the case, no primer, no powder, seat the bullet significantly longer than the push result, crimp, then verify that the bullet is too long to allow the cartridge to fully chamber in the barrel.  From there, I shorten the bullet, test it, shorten it, test it, shorten a few thousandths, test it, a few thousandths shorter, test it again -- you get the picture.  When I test in the chamber, I insert all the way, and I try to spin it between my thumb and forefinger.  When it's too long, it won't spin.  As it you shorten the OAL, you'll get to a point where the bullet will spin, but you can feel the bullet dragging.  Then you will hit an OAL where there is no drag at all.  That is the absolute max, from which you should then deduct .010-.015.  I'm not saying this process is a must-do all the time.  But in this case, where people are coming up with three significantly different max OALs with the same bullet in the same chamber design, it's probably a good idea for you to get very precise with it and know for sure your numbers are good.


SPO1SHADOW

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It depends on which 124 grain HP you get. The made in house will load out to 1.140 in my P-07 and P-09 the one they offer that they didn't make will not. The "in house" bullets do not have the short fat ogive you have pictured. Do i need to make a video of measuring the OAL and then doing the plunk test to prove this or what? I believe we are speaking of 2 different bullets here.

In house 124 HP's


Loaded to 1.130
« Last Edit: July 10, 2017, 04:23:24 PM by SPO1SHADOW »

Offline IDescribe

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Do i need to make a video of measuring the OAL and then doing the plunk test to prove this or what?

Not for me.  ;)   I'm just advising someone who came asking for OAL confirmation to take extra care his numbers are good because we have three different people reporting three different max OALs for what may or (now) may not be the same bullet.  ;)   


I believe we are speaking of 2 different bullets here.

I'm pretty sure now that that is the case.  Here's a pic from DAN_69GTX:



That goes along with yours.  What Dan is calling the old 124gr JHP is the one RMR notes Made in-house by RMR and that appears to be the one in your pic.  The other 124gr JHP is the one that RMR notes *NEW*, but they're still labeled RMR.  Does that mean RMR is not making them in-house?  And if that's the case, and they're NEWer than the in-house, why would RMR pay someone else to make a bullet to compete directly with their in-house bullet?


ANYWHO, to the OP, my advice stands, go the extra distance and get a very precise max OAL with this bullet so that you know your numbers are good.  ;)

« Last Edit: July 10, 2017, 07:47:51 PM by IDescribe »

Offline 1SOW

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What all are saying is that Eastern European chambers are designed around the round nose bullet.
Each CZ or other pistol may vary a little between chamber sizes.  "My" CZ 75 Shadow loads longer than ID's 75.
Try to get some sample bullets either from the manufacturer or someone here to test your chamber using the PUSH and PLUNK tests shown in the stickies by Wobbly.

I can load PD 124 gr JHP at 1.098 easily (A very good bullet!).  ID and some others have to load much shorter due to their chamber size.

.



SPO1SHADOW

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Until recently RMR was a bullet distributor and didn't make any bullets at all. i have been purchasing from them for a long time. They got started offering Xtreme copper plated bullets and sold those under their name for years along with pulled and second bullets. Their "in house" JHP is very similar in shape to a FMJ with a long thin ogive and it will load longer than most other JHP's. i stated i am loading mine @ 1.130 in several unaltered Stock CZ barrels and i stand by that statement. There would be no reason you would have to load this bullet super short as it is basically an FMJ with a hollowed point. Because they offer 2 different bullets i can understand how this could be confusing but my statement to the OP was based on what he put in as a link referring to the in house bullets. When i am wrong, as you said, i will readily admit it and even go back and change my post as such. i am not wrong this time.
« Last Edit: July 11, 2017, 12:03:08 PM by SPO1SHADOW »

Offline copemech

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Until recently RMR was a bullet distributor and didn't make any bullets at all. i have been purchasing from them for a long time. They got started offering Xtreme copper plated bullets and sold those under their name for years along with pulled and second bullets. Their "in house" JHP is very similar in shape to a FMJ with a long thin ogive and it will load longer than most other JHP's. i stated i am loading mine in several unaltered Stock CZ barrels and i stand by that statement. There would be no reason you would have to load this bullet super short as it is basically an FMJ with a hollowed point. Because they offer 2 different bullets i can understand how this could be confusing but my statement to the OP was based on what he put in as a link referring to the in house bullets. When i am wrong, as you said i will readily admit it and even go back and change my post as such. i am not wrong this time.

This explains a lot and obviously there are two different RMR bullets. At one tine a while back there seemed to be one described as the old style and then the new style was developed. At the time I ordered mine a couple months back it seems I got the new style and haD TO LOAD SHORT AT 1.040! A few days back I looked at their website and there were TWO  124 JHP's listed.

Quite honestly I was not overly impressed with the Short Fat lads accuracy, but may still try the other one that can load long if it works like SP01 says!
Imay have to call to see what I am buying? But worth a try. And if that don't work I'm just gonna have to save for another PD order!

Offline recoilguy

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I can load PD 124 gr JHP at 1.098 easily (A very good bullet!).  ID and some others have to load much shorter due to their chamber size.

.
My load almost to the exact .001 I load PD JHP 124 to 1.095 (very good bullet) shoot the SP-01 tac and it does pretty well.

RCG
........Its that you shoot!

Offline baldrage

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Just to add to the confusion, RMR also offers (or at least they used to offer, haven't seen for sale in a few months) an in-house PLATED HP that plunked very short in my SP1 Shadow -- 1.055.

Offline 86304

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Thanks to all for the replies.


I do one push with a fired case in the chamber to a ball park number, then load a dummy a little longer than that -- size the case, no primer, no powder, seat the bullet significantly longer than the push result, crimp, then verify that the bullet is too long to allow the cartridge to fully chamber in the barrel.  From there, I shorten the bullet, test it, shorten it, test it, shorten a few thousandths, test it, a few thousandths shorter, test it again -- you get the picture.  When I test in the chamber, I insert all the way, and I try to spin it between my thumb and forefinger.  When it's too long, it won't spin.  As it you shorten the OAL, you'll get to a point where the bullet will spin, but you can feel the bullet dragging.  Then you will hit an OAL where there is no drag at all.  That is the absolute max, from which you should then deduct .010-.015.  I'm not saying this process is a must-do all the time.  But in this case, where people are coming up with three significantly different max OALs with the same bullet in the same chamber design, it's probably a good idea for you to get very precise with it and know for sure your numbers are good.

I will try this method this weekend.

It was such a different number for the hollow points (from the round nose) and such a wide discrepancy that I figured a bit of sage advice would be in order.
Double checking my numbers with the push method yielded similar numbers to the first run using the exact same bullets in the same cases.

Being new to reloading, and needing to try to get everything just right, it seems that getting the finished OAL right is paramount especially with such a small case like the 9mm luger.

Thanks again to everyone for their input (and to anyone else who cares to add their 2 cents)

Bob

« Last Edit: July 11, 2017, 10:40:04 PM by 86304 »

Offline Wobbly

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Being new to reloading, and needing to try to get everything just right, it seems that getting the finished OAL right is paramount especially with such a small case like the 9mm Luger.

Thanks again to everyone for their input (and to anyone else who cares to add their 2 cents)

Bob -
The whole object of the exercise is to help you pick an cartridge OAL that allows the pistol to safely go into battery every time. There is no "right or wrong" OAL.

The Minimum OAL for 9x19mm is around 1.000", and the test I outlined should give you the Maximum OAL. Anywhere between those 2 numbers will work just fine. Often times, if I derive a number such as 1.107", I'll simply knock another 0.007" off and make it 1.100" because it's simpler to read and track.

There is science to reloading. But once you find your mechanical limits, then choosing an OAL is art.

 ;)
In God we trust; On 'starting load' we rely.

Immature reloaders ask: What's wrong with this gun?
Mature reloaders ask: What did I do wrong ?

SPO1SHADOW

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I am hoping to correct some mis-information before anyone orders from RMR. The bullets I have in this thread pictured are NOT the "in house" 9mm bullets sold by RMR. I re-ordered 5k of the in house bullets last week and received them in today. Not the same bullets that are pictured. What they sent me the first time I ordered the in house bullets were their other 124 grain hollow points by mistake and NOT the in house brand. I hope I can correct this mistake before anyone orders the wrong bullets. The bullets that load longer are more expensive than their house brand. I am returning their in house bullets and paying the extra cost for the others. The longer loading bullets are $116.00 per thousand the In House bullets are cheaper but have the short fat ogive and are $99.00 per thousand. Sorry for wrong information. I will have to say RMR's customer service is better than I expected. They are taking them back on their dime and sending the correct bullets out on Monday with free shipping. Hard to argue with that.