RMR 124 gr nukes......looking for consensus

[longdayjake]

If the reality is there is that much variation in chamber size in these pistols, then as far as I can see, the above is the consensus. There really cannot be a recommended seating depth. So the advice has to default back to proces outlined in the link NMexJim gave post #2. You have to determine max OAL for your particular barrel and go from there.

If Sierra and Hornady made the call to seat bullets deep enough to chamber in most pistols, including those with very short chambers, then that explains why Sierra has a seating depth of 1.030 for their 125 gr JHP. But even if we or me did the same, that gives us a starting place when it comes to load data for the powders.

The semi-related question then becomes why some gun makers have such shallow chambers? In the link, it was mentioned how accurate those pistols are. Perhaps they get something from a short jump? OTOH, have seen where dedicated target pistols have deep chambers, which would suggest long jumps to the lands.

From a very high altitude, I'm seeing similarities between chambers in 9mm and 308 win.

So, it all started with a marketing ploy. Some idiot somewhere decided that they could save money on throat reamers if they just didn't buy them. Then. to avoid any customer backlash they decided to market those barrels as MATCH barrels. Near as I can tell it started with the Springfield Armory XD with shorter throats but I guess it worked so well that other manufacturers doubled down on the stupid and went to almost nothing at all. A shorter throat means nothing for accuracy in pistols. I've got a few 2011s that I load 9mm stupid long for and I had to buy a throat reamer to get the throat long enough to handle my ammo. That barrel is a KKM and it will shoot a one hole group at 100 yards with ammo loaded even to minimum spec. Barrel quality is what makes a pistol barrel accurate. Not throat depth. The short throat thing is mostly a foreign barrel maker thing. Glock (gen 5 only), CZ, Canik, and a few others. I haven't tested them all but those ones I know for sure have almost no throat.

 

[LiveLife]

save money on throat reamers ... decided to market those barrels as MATCH barrels

shorter throats ... and went to almost nothing at all

I too thought shorter leade was good for accuracy as deeper seated bullets improved neck tension with less gas leakage, especially for 9mm 115 gr FMJ with shorter bullet base.

But my comparison test between 1.155" and 1.130" showed simply seating bullet deeper in the same KKM barrel with cut throat/longer leade improved accuracy and if I wanted to squeeze out even more accuracy by enhancing neck tension, I seat deeper down to 1.110" (Which Atlanta Arms did for their most accurate 9mm 115 gr FMJ Match AMU from 1.130" in years past to current 1.110").

And I was surprised by how even FMJ/RN bullets that should load to SAAMI max of 1.169" needed to be loaded shorter in short/no leade barrels - https://www.thehighroad.org/index.p...col-for-reference.848462/page-2#post-12249361

• KKM Glock 22 40-9mm conversion and M&P Shield barrels allowed Berry's/HSM/PowerBond(Accura)/Rainier/Remington/RMR/Speer/Winchester/X-Treme/Zero 115/124/125 gr FMJ/RN bullets to SAAMI max of 1.169"
• Tactical Kinetics 40-9mm conversion barrel allowed 1.169" for most but required shorter length for these bullets:
  • Winchester 115 gr FMJ: 1.135"
  • Zero 115 gr FMJ: 1.135"
  • RMR 124 gr FMJ: 1.130"
  • Speer 124 gr TMJ: 1.165"
• Lone Wolf Glock 23 40-9mm conversion barrel allowed 1.169" for most but required shorter length for these bullets:
  • HSM 115 gr RN: 1.165"
  • PowerBond 115 gr RN: 1.160"
  • RMR 115 gr FMJ: 1.130"
  • Winchester 115 gr FMJ: 1.130"
  • Zero 115 gr FMJ: 1.125"
  • HSM 124 gr RN: 1.155"
  • PowerBond 124 gr RN: 1.160"
  • RMR 124 gr FMJ: 1.120"
  • Speer 124 gr TMJ: 1.155"

 

[Howa 9700]

Mentioned this on the powder burn speed thread, but decided this was a better place to put it. Curiosity got the better of me, so made up a couple dummy rounds with 124 gr Nukes. One at my barrel dictated max OAL of 1.105. Another at 1.070. Then drilled out the primer pocket flash hole so I could backfill case to determine what 100% case fill would be at those seating depths.

Tried a couple powders.......Acc#7 and HS6, and with both powders there was still enough room under those bullets to add close to 2 grains of powder over max standard loads and even well beyond +P. No where near compressed load with either one.

So sticking with the plan of 1.060 to 1.070 range will get me a better case fill, but still well under a full case.

 

[LiveLife]

drilled out the primer pocket flash hole so I could backfill case to determine what 100% case fill would be at those seating depths

There's an easier way to determine max case fill without having to destroy a case - Subtract bullet length from OAL to determine max case fill. To mark this inside case to fill with powder, subtract max case fill from resized case length and mark that amount below case mouth using end of calipers (Steel is harder than brass and will scratch a mark). Then fill powder to mark and weigh.

Calculation demonstrated at bottom of this post - https://www.thehighroad.org/index.p...er-target-published-load-data-for-9mm.870180/

 

[armoredman]

I cannot imagine getting that involved, seriously. I use data for an existing bullet that is same in weight and close in size/appearance, measure the results by group size and chronographed speed, find a sweet spot and move on. I have another load of testers for the Nuke to try out tomorrow, this time with Accurate #2.
Edit to add - I load 9mm for generally no farther than about 25 yards, stand ins for my factory SD ammo. Da Boy can shoot it out to 100 yards, but I don't. Soo, if I was loading really high speed/low drag competition long range ammo, I might go to those lengths. Me, in handgun stuff I just load blasting ammo, sorry.

 

[Howa 9700]

There's an easier way to determine max case fill without having to destroy a case - Subtract bullet length from OAL to determine max case fill. To mark this inside case to fill with powder, subtract max case fill from resized case length and mark that amount below case mouth using end of calipers (Steel is harder than brass and will scratch a mark). Then fill powder to mark and weigh.

Calculation demonstrated at bottom of this post - https://www.thehighroad.org/index.p...er-target-published-load-data-for-9mm.870180/

When looking at all this, I had already done the same calculations as to seating depth of the bullet's base, but had not attempted to make any use of it. Marking the inside of the case, then filling to the mark would do it.

What had occurred to me was to measure the difference in weight/volume of powder between bullets with OAL of 1.107 and 1.070, and calculated a factor of grains per .001 case length, not unlike the volume weight factor Lee lists in the back of their reloading manual. An extension of this would be to measure inside depth of a case, then fill it like is done with a Lee dipper, then weigh that to develop a similar weight / volume factor. Then multiply that factor x depth of seated bullet. Subtract the volume of powder displaced by the bullet and you get your 100% fill factor. Or close enough. If time allows it, may compare all three methods to see if they all give the same answer.

The advantage of using a mouth end fill over my method of pouring powder thru the primer pocket is that does not work with flake powders of any size. And honestly, other than to scratch an itch to get a ballpark idea of where one stands with case fill, no other use would be made of the outcome, so does not warrant a fine degree of precision or scrutiny.

As to what is the point of going to all the trouble.........it is to simply have an understanding of what is going on inside that case. Take away unknowns. That way when going down an unmarked path, and you come to that fork in the road, you can make an informed decision on which way to go.

 

[LiveLife]

point of going to all the trouble.........it is to simply have an understanding of what is going on inside that case.

Yes, if you are pursuing accuracy, max case fill can be a significant reloading variable.

Remember many reloaders/match shooters made a big deal with position sensitive powders with revolver loads and tested powder forward/back differences?

With semi-auto pistol loads, when the round is chambered and powder charge is slammed forward, with some powder/case fill combination you may end up with air gap in front of primer flash hole so primer flash has to jump that air gap before igniting powder charge. I have done limited testing with different powders and 9mm OAL from 1.160" down to 1.150, 1.140", 1.130", 1.120" all the way to 1.110" and found shorter OAL produced smaller groups.

While there is reloading variable of deeper seated bullet base producing greater neck tension affecting more efficient powder burn for more consistent chamber pressure build/average sustained max pressure, deeper seated bullet also ensures powder charge covers the primer flash hole when chambered.

Years ago, I used to load 115 gr FMJ longer around 1.145"-1.150" thinking closer to lands would leak less gas but found shorter 1.130"-1.135" overshadowed by producing smaller groups (I also noticed Atlanta Arms was loading their most accurate 9mm 115 gr FMJ Match AMU to 1.130" so it confirmed my suspicision).

To squeeze out bit more accuracy, I tested even shorter 1.110" particularly with smaller .355" sized bullets (Compared to .3555"/.356" sized bullets) and thinner walled FC/.FC./Blazer/Speer cases and group size got smaller. And I also noticed Atlanta Arms had reduced the OAL of 115 gr FMJ Match AMU shorter to 1.110" which further confirmed my finding - https://atlantaarms.com/products/elite-9mm-115gr-fmj-match-amu.html

 

[Howa 9700]

OK.......on the 100% case fill ideas, I tried the method where I filled the case full, weighed it to get a grains per thousand depth factor. Then subtracted the amount of powder displaced by the bullet and results were within 0.1 to 0.2 grains of being the same as my method of backfilling case thru the primer pocket........and about 100X easier!

Then what I found was at that seating depth, at loads I have been using, the case fill is around 82% with AA#7 and HS-6. . At full max loads with AA#7, that gets close to 87% to 90%. AA#5 is down in 65% range, as would be True Blue. At 4.0 grains, Red Dot would get me to 104%......a slightly compressed charge. There may be a good reason some guys like Red Dot.

 

[kcofohio]

Okay, so there is a big reason that we don't publish a recommended OAL for the NUKE. And that is that many of the newer guns (glock gen 5, canik, CZ, and a couple others) have decided that they don't want to buy throat reamers and they're sending out guns with pretty much no leade. I refuse to recommend seating a bullet all the way to the ogive. What we really need is about a million gun owners to shame those manufacturers into cutting leades into their barrels so that there's a little bit of wiggle room for loaders to play with.

I have a 9mm throater reamer. I should go back through the barrels and see which ones don't have the leade cut.

 

[WSM1955]

Consensus on........COAL.......and maybe load data to follow.

Consider this:

View attachment 1164887

From left to right: - line on bullet is where nose stops when inserted into empty case......ballpark area where bullet will engage lands when fired:

Hornady 124 gr XTP recommended COAL = 1.060
RMR 124 gr Nuke recommended COAL = ???
Sierra 125 gr JHP recommended COAL = 1.030
Hornady 124 gr. XTP same

As can be seen, when loaded to same COAL, both the RMR nuke and Sierra are not going to be seated as deep. RMR nuke and Sierra are almost exact twins, except nuke is actually 0.005 shorter.

Well known warning......all things being equal, seating deeper can increase the pressure. If that is true, then it must follow that not seating as deep decreases pressure. Sierra and almost every other source of load data out there has this 125 jhp seated to 1.030. The lone exception I'm aware of is Lyman 50th, which has load data seated to 1.075. Their powder loads are jackeup up over what Sierra and other listing it show. But certainly not out to 1.120 or so that old nuke load data shows.

So lacking exact load data for the new RMR nuke, what to do? Use data for the old nuke, which had a longer nose profile? Use data for the Sierra, exactly as is? Use Lyman data for Sierra 125 JHP?

So far, I've been using load data for the Hornady 124 gr XTP......which is found in abundance...... and loading nuke to same 1.060, which it clearly does not match up to, but seems uber safe way to do it.

Stay with that plan or ????????

 

[WSM1955]

I used RMR 124 gr 9mm: 5 gr Sport Pistol; col 1.13. Excellent groups, kicks like a +P expensive super defensive round, primers flat but not excessive pressure.

 

[armoredman]

Deleted.

 

[Howa 9700]

When I started this thread, what I was looking for was some consensus on a good OAL for the the RMR 124 gr nukes, as I have lots of them. We never came away with any consensus, and for good reason. There can't be. Differences in pistol chambers don't allow it. But what I did come away with was a much better understanding of the process I needed to follow to get the load data I sought.

So step 1 has to be finding the max OAL I can load for any bullet. Nuke or other. The process outlined in NMexJim's link in post #2. Until you know what you got, you are just guessing. You can load it and plunk it, but all that really tells you is it will chamber. That isn't even half the story, and without knowing that, you are just feeling your way around in the dark. Just turn the light on so you can see what you are doing.

After that, there are two "similars" to the Nuke One is the Sierra 125 gr JHP, for which most load data is built using the curiously short 1.030 OAL. The other is the Nosler 124 gr JHP, for which Nosler offers load data built on OAL of 1.120. So two similar bullets, which bracket the nuke with two OALs, min and max. If followed, the base of the nuke would be seated further out than the Sierra, and deeper than the Nosler. So a min, a max and some idea on what load data to use, depending on where you can load to, depending on what your barrel and chamber allow. I don't think I could use the Nosler data, as I don't think it would plunk in my barrel. So would have to seat deeper and that invites trouble with pressure.

Edited to include......yet another "similar" is the Speer 124 gr JHP Gold Dot. Bullet is same length as Nosler, and Speer load data also to 1.120. Except those guys are NUTS! They really pile in the powder. They don't show their load data as +P, but is must be that or beyond.

The remaining wild card is that the max load in 9mm loaded to SAMMI max is really not the max for most pistols. Beyond SAMMI max is +P and beyond that......Major. So bumping up against the max load for SAMMI is not as scary as it would be for rifles or shotguns.

So I have load data for Sierra to 1.030......both SAMMI and +P, and and the nuke seated to that depth is still going to be seated further out, so should be safe for all data. If barrel allows it, same for Nosler for SAMMI loads. Then there is the Lyman manual, which has Hornady 124 gr XTP loaded to 1.060 and Sierra 125 JHP seated to 1.075. The nuke loaded to either of those should be safe......and should plunk and chamber in most barrels if loaded to the same.

That has been the process I've adopted and followed and so far, of the 4 or 5 powders I've tried all have yielded mild to mid level loads that plunk, go BANG, cycle the gun and show no signs of pressure. One thing I am absolutely certain of........you would not want to be standing in front of any of them when they go off.

 

[nettlle]

4.4 grains Bullseye/1.075" COAL

 

[NMexJim]

I was playing at my press yesterday and happened to think of a bullet comparator. Do you have one? I checked posts on here and the general success over a wide range of bullets hasn't been there, however for similar bullets such as Nuke and a similar profile maybe a Sierra, you might be able to come with a figure. I don't know as I haven't played with the idea as yet.

Anyway.....

 

[Howa 9700]

I have a comparator for the rifle calibers i load for. Don't know if that comparator would work for 9mm. Also not sure it is as critical, as pistol stuff seems to strive for a safe, zippy MOA of beer can at 15 paces, vs. sub MOA or holes touching at 100 yards. But until I perfect my marksmanship skills as a pistolaro, accuracy won't really matter much. Having said that, I suspect the stuff I'm putting together will be as accurate as most plinking blammo that is out there.

One thing that helped me with bullet differences was to do the math to measure the amount of seated bullet depth.....one vs. the other. It can be calculated. Knowing the nuke is not seated as deep as the others takes the pressure off. Literally.

 

[armoredman]

Disregard

 

[oncewaslost]

I have a 9mm throater reamer. I should go back through the barrels and see which ones don't have the leade cut.

The more I think about it, this seams to be a really good option for me rather than loading shorter for multiple pistols.
Now its just a matter if I want to pay someone to do it for me, or buy a reamer and do it myself.

 

[Howa 9700]

More information, may need help interpreting it.

I have 5 different 124 grain JHP bullets (technically the Sierra is 125 grain). On a whim, I decided to see where all of them would end up if seated to the same depth setting on my seating die. This is what I got:



So the math was to take OAL as seated, then subtract a standard case length of 0.750, which would give me the exposed area of the bullet. By then subtracting that from the known length of the bullet, I could calculate the amount of bullet seated inside the case. These were then graphed.

So from this, it appears that if I change nothing as far as the depth of the bullet seating stem, A Hornady XTP and Sierra 125 gr JHP will seat to nearly the same depth inside the case. Same internal case volume. Different OAL, but same depth. Load data for the 124 gr XTP almost always shows seating depth of 1.060. The Sierra would be seated to 1.035. The Nuke to 1.048. By doing so, I ought to be able to use any of the XTP or Sierra load data for the Nuke.

The other two bullets on the right are Precision Delta 124 gr V1 and V2. As is, the V1 seats to same depth as XTP, but has a longer nose profile. The V2 is an almost exact twin to the XTP so XTP load data ought to fly, but seating depth would have to be adjusted to make them the same. The reason for the PD bullets is the 124 gr V1 was used all this guy's tests, and I wanted to use those loads to test various powders: http://www.natoreloading.com/9mm/
Ironically, as the V2 is now shown, it very closely matches the above COAL length for Nato's V1 load data. Confused yet?

The one thing I thought ought to stand out, and maybe does, is where my lands are. Have concluded it is at the small tick marks below the nose.