[flyingbrass]

I highly recommend using a chronograph when reloading. Flying by the seat of your pants really sucks compared to having data. You don’t have to spend a fortune. A decent optical chrono works fine and provides valuable information. They cost $150ish these days. I consider it a crucial piece of equipment.

There are multiple factors that will affect velocity even if everything is assembled the same. Moisture content of your powder is a big one. Temperature is another. Plus, you have varying chamber dimensions, throat lengths and angles, bore diameters, case capacities, and so on.

FWIW, though your results will certainly vary, with Autocomp I got:

CZ-75 4.7″ barrel
new RMR brass stamped RMI
Win SP primer
124 RMR nuke 1.070″
4.9 Autocomp
Temp 77 F
5 rounds avg 1089 FPS, ES 28

CZ-75 4.7″ barrel
new RMR brass stamped RMI
Win SP primer
124 RMR nuke 1.070″
5.1 Autocomp
Temp 71 F
5 rounds avg 1118 FPS, ES 30

S&W Shield Plus 3.1″ barrel
new RMR brass stamped RMI
Win SP primer
124 RMR nuke 1.070″
4.9 Autocomp
Temp 77 F
5 rounds avg 984 FPS, ES 32

S&W Shield Plus 3.1″ barrel
new RMR brass stamped RMI
Win SP primer
124 RMR nuke 1.070″
5.1 Autocomp
Temp 72F
5 rounds avg 1022 FPS, ES 26

8 rounds of factory standard pressure Federal 124 HST from the same Shield Plus fired at higher elevation at 73 F averaged 1004 FPS with an ES of 17.

[flyingbrass]

My ProChrono is around 10 years old and still worked fine when I dug it out a few months ago, though I’ve not used it much in recent years. A few years ago I got sloppy and bent one of the screen rods with a .45 ACP bullet. I was too focused on reading the numbers from each shot and got too lazy when essentially point shooting the rounds through. Don’t do that.

I bought the extra bluetooth module soon after it came out (I think it cost $50ish back then). I used it for a little while but don’t bother with it any more. I don’t know about the newer versions with built in bluetooth, but what I have doesn’t offer any control from the user end. I can’t remotely change shot strings, etc. That would be a real pain at a shooting range where I would have to wait until a ceasefire to walk out to deal with the chrono. I’ve not used mine at a range because of this. Fortunately, little of my shooting is done at a range. The radar chronos have a big advantage in that situation.

Years ago my shooting buddy bought a LabRadar, which IMO was a PITA in many ways and not worth the money. It had problems from new picking up shots, and he had a bad experience dealing with their customer service. Recently we have been using a Garmin Xero, which is more of what a modern chrono should be. I have a few nitpicks about the Garmin, but overall, it’s wonderful and practically magical to someone who has dealt with optical and cranky LabRadars over the years. I wouldn’t buy an older style LabRadar today even if dirt cheap. Nor would I buy their newer model even if it’s decent due to previous poor customer service experience.

If I was going to buy a new optical chrono today I’d lean heavily toward another ProChrono because mine has been impressive for the price. Years ago I encountered an odd situation that provided some interesting information.

I had been shooting through my ProChrono from the bed of a pickup. I moved the chrono, still on its tripod, several feet to the side when my friend shot his rifle. I noticed the ProChono was registering his shots and velocities. Bullets were not passing through the chrono. It picked up the shockwaves.

Paste from an e-mail I sent to him about the results:
——
The chrono was registering about 1180 FPS during your shots. It was picking up the shockwaves at the speed of sound.

Sound speed at different temps:

80 degrees: 1139 FPS
100 degrees: 1160 FPS
120 degrees: 1180 FPS

The air temperature wasn’t 120, probably more like 85. The readings are slightly off because the chrono wasn’t perfectly lined up with the origin of the sound. It was rotated a little, reducing the distance between the sensors, which caused the velocity readings to be calculated higher than actual.

Similar happens with bullets, which is why it is important to keep the chrono lined up so bullets travel parallel with the top of the chrono.

Since the speed of sound is constant at a given temperature, this was a good measure of the chronograph’s precision. 12 shots were recorded.

high: 1192
low: 1180
avg: 1186
es: 12
sd: 4

Specs for the ProChrono say accuracy is “+/-1% of measured velocity, or better.” I can’t vouch for accuracy, but precision was better, at least this time for a single string of 12 “shots”. The ES of 12 is a total variation of 1.01% (+/-.505%).

If the error is linear, which it may be, 1.01% would be an extreme spread of 27.3 FPS at 2700 FPS.

Based on the collected data, that’s what the chrono would show if you could fire shots all going at the same exact speed. It’s not capable of measuring super tight extreme spreads. Sure, it will occasionally report some low extreme spreads in strings of small sample size, but they don’t mean anything. It’s akin to reading ten-thousandths on calipers only precise to .001″.
——

Radar chronos, even super high end ones costing tens of thousands of dollars, can have some precision and accuracy issues also. I’ve had odd average velocity readings from the LabRadar with small base .223 bullets that shouldn’t have been so different and didn’t match what happened on paper at long range to the extent that I don’t trust the readings. For $150ish I think the ProChrono is quite good, and if properly used (shooting straight through) you aren’t losing much if anything that is of practical use as far as results are concerned compared to the consumer radar units costing much more. Opticals are much less convenient to set up and use, particularly when shooting rifle prone and have to get everything aligned just right. Not much of a problem for handguns. Radar, when it works well like the Garmin Xero has so far, is much less hassle.

[flyingbrass]

Interesting test. Other powders likely respond differently to changes in seating depth. If you do more testing along this line, maybe try a faster powder to compare.

Bullet setback from chambering is a real concern and definitely something to keep an eye on. With expensive defensive ammo, when possible I chamber a round using a separate magazine. Having only a single round in a magazine reduces the pressure against the mag’s feed lips and prevents scratching a round below. I also somewhat ride the slide forward, which normally you don’t want to do. This eases the round into the chamber and minimizes dings.

Good advice about using a thin Sharpie to mark bullet position in relation to the case neck. Do that and/or occasionally measure your repeatedly chambered round and compare with unused factory ones. I’ve set a few aside that had shortened some. My reloads often seem to have better hold on the bullets than factory rounds. I often wonder if I’d be better off using cheaper ammo for defensive purposes so I’d be more inclined to cycle through it more frequently.

In guns with floating firing pins, the AR being a common example, don’t repeatedly chamber defensive or other serious ammo. The firing pin contacts the primer each time a round is chambered. Once isn’t a problem, but repeated taps can damage the primer. There are horror stories about this. The last thing you want when your life is in danger is to get a click instead of a bang when you press the trigger.

On a similar note, another caution is about storing guns in vehicles. Some people have a “car gun” or a “truck gun” that lives full time in the vehicle. Others are forced to leave their guns in cars while working, etc. I live in the desert, and vehicle temperatures here get insanely hot in the summer. One summer I had to leave my pistol in the car each day while at work. It was parked in full sun. Late that year I became concerned about the ammo being exposed to so many temperature extremes and swings. I know such things are bad, but at what point does it actually become a problem? I don’t know. I somewhat reluctantly fired all of the factory 124 Gold Dot +P rounds in the pistol as well as all in the spare mag that had been carried with it. They all worked fine. It was an expensive test.

During that shooting trip a friend thought I was being overly concerned about my ammo. He had kept a loaded 1911 in the console of his truck for 2-3 years without changing ammo or firing the gun otherwise and was confident everything was fine. I convinced him to try it. His first shot was a dud. Click, not bang. I wish I had a picture of the look on his face. This pistol was what he would have reached for to save his life. The firing pin strike was normal, but the primer didn’t ignite. He had at least one other dud in that magazine of ammo, maybe 2 more. I don’t remember what ammo he was using. It was factory, and almost certainly good stuff. I’m thinking most likely factory 230 grain Gold Dot.

[flyingbrass]

I’m also curious if the sharp base is present on the 75’s. I’m surprised it is still on the 69’s because I thought I read somewhere that it had been smoothed out in later batches. My 69’s from 5/2021 have it, and IMO it is a problem. I get considerably more runout from that edge catching during seating than with smoother bullets. Plus, I pulled some bullets after seating to find the inside of the neck scratched from the sharp base. This can’t be helping for consistent neck hold. I wish RMR would fix this. It’s the one thing making me hesitate to buy more of these bullets.

[flyingbrass]

I’m using a 16″ AR Performance barrel with a Wylde chamber. A friend and I have done a fair amount of testing with the 69 RMR bullets with TAC and X-terminator. My barrel shoots faster than most. You will likely need more powder than I use to get the same velocity.

My rifle prefers 23.2 grains of TAC, which runs about 2650 FPS depending on conditions. Being a ball powder, velocity varies quite a bit with temperature. I’ve had good groups from this charge weight at temps from mid 60’s through high 90’s (velocity was about 2695 in the heat). I use Wolf Gold brass, CCI 450 primers, and OAL averages about 2.249″ (1.878″ CBTO on my Hornady comparator). For these, I use a Lee full length sizing die with the expander turned down to .2220″. This produces necks that won’t accept a .2210″+ pin gauge but .2205″+ fits all the way through. So, there is a little over .003″ interference fit between bullet and case neck. No crimp.

Often I shoot at 50 yards prone with a backpack for a front rest and a rear squeeze bag, not exactly a precision setup. 1-6X scope. Groups are as much a measure of my shooting ability for a given string as what the load can do. I flub some at times and get some stringing. I’m still working on learning to shoot more consistently with this setup. If everything isn’t just right groups with any ammo open up. I mention this because shooter error can contribute very significantly to group size. Gas guns are particularly sensitive to how they are supported. I’ve recently fired three good 5 shot groups with the 23.2 TAC load during 3 different shooting sessions. Two each measure .33″, and yesterday’s was .36″. All at 50 yards.

22.3 grains of X-terminator produces similar velocity (slightly slower) and also seems to be a good spot for that powder. There is another node up around 22.9 grains of X-terminator, but that runs 2700ish in cooler weather and would be too stout in the heat.

If you haven’t already, test a range of loads in fixed increments. I go with either .2 or .3 grain increments in .223. Test over a decent range of charge weights. You’ll want to repeat this several times to find the trends and help rule out shooter error as you zero in on the nodes. You’ll find the good spots. There can be quite a difference in only a few tenths of powder.

My friend, also using a 16″ ARP barrel, tested seating depth with these bullets, firing 5 shot groups at 50 yards using 24.0 grains of TAC. He used .005″ increments measured to bullet ogive (COAL from approximately 2.260″ to 2.240″). No discernable difference was found. All groups were good, ranging from .40″ to .46″. I experiemented a little with seating depth and didn’t find obvious differences either. YMMV.

[flyingbrass]

Check max COAL yourself in the pistols you will be using. Pistol throat lengths are all over the place, often even within a given model. Some are way long, while others are short.

There are different methods to determine maximum COAL. Some use dummy rounds or pinch in the mouths of fired cases. I do variations of that for rifles, but my preference these days for pistols is to simply load a single finished round. First, measure some cases I’ll be using and select the shortest ones. Size, prime, expand, charge, seat and crimp (be sure to crimp). However, leave the bullet seated out too long.

Crimping will not present a problem for incrementally seating the bullet deeper if you are crimping correctly. However, if you don’t crimp, remaining mouth flare can interfere with the plunk test. With auto pistol rounds you should only be “crimping” enough to straighten the case back out from flaring, not mashing the mouth into the bullet. These cartridges headspace on the case mouth. Further, overly crimping with a taper crimp actually reduces the case hold on the bullet. An overly heavy crimp mashes both the case and the bullet inward, then the case springs back outward but the bullet doesn’t as much, thus loosening the hold in that area as well as deforming your bullet.

Remove the barrels from the pistols you want to test. With the muzzle pointed down, drop your overly long cartridge into the chamber of each barrel. The long round will make a relatively dull thud sound, and when you try to rotate the cartridge with your fingers it won’t spin easily in the chamber. The bullet is making contact.

Turn your seating stem in a little, seat the bullet a bit deeper, and test again in the chambers. Keep repeating this and record COAL measurements as you go. When the bullet no longer makes contact the cartridge will drop into the chamber with more of a tinking sound than a thud, and you’ll be able to spin the cartridge freely when turning it with your fingers because it is seating on the mouth of the case without the bullet making contact with the throat or lands.

You can do another round or several the same way to better pinpoint or confirm the length where bullet contact is lost.

Keep in mind that case length affects the results. 9mm headspaces on the case mouth. By incrementally seating deeper you are changing how much of the bullet protudes from the case mouth, but case lengths vary.

Say, for example, that I get a max COAL of 1.140″ with a case measuring .750″ long. I then pull and reuse the same bullet with a case .740″ long. In the same chamber it would pass plunk at 1.130″ COAL because the same amount of bullet is protruding from the case mouth at that overall length. What really matters is mouth to where the bullet makes contact. For a given COAL, shorter cases have more of the bullet sticking out in front of the case mouth.

I use mixed range brass for practice ammo, and I’ve found occasional cases as short as .734″ before resizing. Most are usually .74-something. I like to allow a bare minimum of .015″ leeway from what I’ve determined to be max OAL (after using a relatively short case to find max) to be sure that a short case won’ t put a bullet into the lands.

The discrepancy found in 9mm throats is really annoying. If you have multiple pistols and one with a super short throat, you either load all ammo to fit in that shortest throat or label your rounds for what pistols various loads are ok for. That really sucks. One option is to ream the short throats to better match the others, which I have done. That’s not always an economical option now that more barrels are nitrided.

[flyingbrass]

If you are using a combo seater/crimper, back the seating stem out more or remove it. If your crimp die was set for WAY too much crimp maybe it was contacting the full diameter portion of the bullets and seating them deeper. I don’t know if that’s possible – maybe. Is something stuck inside the die?

Crimp only enough to straighten the flare made for seating bullets, no more. Too much crimp is counterproductive. Case wall thicknesses vary, but with .355″ jacketed bullets the outside diameter at the mouth after crimping should be somewhere between .376″ and .379″. For many loads I use mixed range brass of probably 100 different headstamps and ages. Case lengths vary greatly. The shorter the case, the shorter distance it travels into the tapered part of the crimp die. Adjusting crimp is a matter of finding a happy medium that works ok with all.

1.150″ is extremely long for the 124 grain Nuke bullets. We’ve measured max OAL with them in 11 different pistols. To do this, using one of my shorter 9mm cases I seat a bullet long, then crimp. If you don’t crimp, the flared mouth will give false readings. Then seat deeper gradually, a few thousandths at a time, until the round plunks and splns in the chamber. Comparing so many pistols was enlightening. There isn’t very good consistency in throat lengths even among the same models of guns. It is almost as if factory pistols are throated by a kid with a hand drill.

Our shortest for the 124 Nuke was one of the CZ-75 SA models at 1.067″. For comparison, that same barrel with other bullets:
115 RMR FMJ 1.136″
124 RMR FMJ 1.136″
147 RMR FMJ 1.136″
124 Gold Dot 1.142″
147 XTP 1.096″
124 RMR Nuke 1.067″

Of the 11 pistols we checked, only 2 would be able to accept a length of 1.150″ for the 124 Nukes, and one of those just barely (1.156″ plunk).

My shortest pistol with the Nukes is 1.091″, so I’m loading them at 1.070″. Keep in mind that case length affects this. The shorter the case, the more of the bullet sticks out at a given OAL. 9mm headspaces on the mouth.

As for Silhouette, I recently got a pound of it as well as a pound of True Blue, which I’m going to test soon with 124 Nukes and 124 Gold Dots (both in new RMR cases).

Our initial testing was with WSF and Autocomp:

RMR 124 Nuke
New RMR brass
CCI or Win standard pistol primers
1.070″ OAL
Temp low-mid 70s
5 rounds each, LabRadar
All charges individually weighed

CZ-75 4.7″ barrel
4.8 WSF 1137 FPS ES 21
4.9 WSF 1156 FPS ES 23
5.1 WSF 1201 FPS ES 22 (different CZ-75 pistol) Too hot.

Shield Plus 3.1″ barrel (long throat)
4.8 WSF 1049 FPS ES 15
4.9 WSF 1052 FPS ES 31

A friend loaded 5.1 WSF to try (same OAL), which was too hot. 5.1 grains ran 1114 FPS in his Shield 1.0 (4.8 averaged 1085 in the same pistol). 4.9 of WSF is the upper limit for me. I’m going to stick with 4.7 grains. WSF is reverse temperature sensitive, so pressure will increase in cooler weather.

CZ-75 4.7″ barrel
4.9 Autocomp 1089 FPS ES 28
5.1 Autocomp 1118 FPS ES 30

Shield Plus 3.1″ barrel (long throat)
4.9 Autocomp 989 FPS ES 32
5.1 Autocomp 1022 FPS ES 26

There may be room to move up somewhat with Autocomp, but I’ll probably stick with 5.1 grains.

[flyingbrass]

>Has anyone gotten good results with H335 or AA2230?

I’m having good results with X-terminator, which shares load data with AA2230. I have 8lb of AA2230 that I plan to use next. From what I’ve read, X-terminator and AA2230 were different powders years ago (prior to 2007? – don’t recall the year). Then, they became the same exact powder. For a time they were the same exact thing in different containers with different labels. Then, a few years ago a representative from Ramshot said they had diverged but still share the same burn rate and load data. He said AA2230 is supposed to be more temperature stable, while X-terminator has additives to reduce copper fouling. That’s what I’ve gathered anyway from researching online. One thing for sure is that they share the same load data.

I’m using a 16″ AR Performance barrel. My particular barrel runs a bit fast, about 40-50 FPS faster than a friend’s same model.

Wolf Gold brass
CCI 450
CBTO ~2.250″
X-terminator
LabRadar 72 degrees
5 shot average:
22.3 grains 2649 FPS
22.9 grains 2712 FPS

Both work well for me. 5 shot groups are generally around .8″ at 100 yards if I’m not screwing things up. This is from prone with a bipod and rear bag. I guarantee there is some shooter error involved.

Lately I’ve been working with TAC. I need to do more testing, but so far, the best charge weights are ones that produce similar velocity to my X-terminator loads.

Wolf Gold brass
CCI 450
CBTO ~2.250″
TAC
LabRadar 91 degrees F
5 shot average:
23.2 grains 2671 FPS
23.6 grains 2730 FPS

With TAC, my buddy is getting the same velocities using .4 grains more powder than I am. That’s in both his 16″ ARP barrel and 5 rounds he chrono’d with a 16″ PSA. My barrel seems to be the oddball. After considerable testing, he had settled on 24.0 grains of TAC (for 2730ish FPS depending on temperature). He then did a seating depth test by firing 5 shot groups at 50 yards. COALs were from 2.240″ to 2.260″ in .005″ increments. Surprisingly, they all shot about the same, with group sizes ranging from .40″ to .46″. These bullets seem to be tolerant of different seating depths, at least in his barrel. I gave him 5 of my 22.3 grain X-terminator loads during that test, and my load in his rifle was his second best group of the batch even though it clocked 40 FPS slower than I get in my rifle (his avg was 2611 FPS with air temp of 74 F).

I fired a 5 round group on paper with 23.6 grains of TAC at 500 yards (prone, bipod, rear bag, 1-6x scope). Vertical spread was 3.8″ and about double that sideways due to varying wind. My friend also fired a 5 round group using the same charge with his rifle at 500 yards with vertical measuring a touch under 5″. So, these loads hold up at distance.

Overall, I think these are great bullets for the price. I have one nitpick that I haven’t seen anyone mention. The bases are sharp instead of rounded where the boattail transitions into full diameter. This isn’t the case with any other bullets I’ve used. The sharp edge tends to scrape the insides of the case necks, and I think is also responsible for the higher runout I get with these bullets than any others I load. Some seat quite crooked. I’m using a Forster 3-in-1 trimmer, which provides a VLD angle chamfer, but I think the sharp base still tends to snag and cause bullets to tip as the seating die begins to press them into neck. I’ve tried several different seating stems, all of which fit the 69 RMRs fairly well, without any difference in runout. I think they’d seat straighter without the unusual sharp bottom edge.

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