Soft heavy 9mm plinking loads for PCC

Bubba Yugga

Bubba Yugga

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Hey gang, I've gotten interested in developing myself a quiet, subsonic plinking round for my Kel Tec S2K.
I figure using 147 grain FMJ and possibly the Campro 157 would help in keeping the velocity down.
With commercial stuff like American Eagle the report is quite loud, and I suspect there's a fair pressure impulse coming back from the chamber upon extraction contributing to it.
It's a blowback action BTW.
Hornady data shows 3.5 grains of PowerPistol as a minimum which, when I tried it, gave me a much quieter report (I'd guess at least 10 dB) without any noticeable drop in POI at 30 yards.
Feeding and extraction were flawless for the 6 rounds that I fired.
Understandably, 9x19 Luger rounds are optimized for 4" barrels, while I have a nonrestricted 18.6".
I'm thinking that a slower powder will make better use of that longer barrel, while not being quite so eager to punch that unlocked bolt out of battery quite so soon.
I'm thinking something around Alliant 410 or thereabouts might work.
Bit of a balancing act. Any thoughts?
 
It's hard to tell exactly what you're trying to achieve from your post above (a little scattered) but if you're looking for slow(er) 9mm powders I would suggest something like WSF, AutoComp, HS-6, Silhouette etc. Other than WSF (one of my favourite 9mm loads) I generally use fast(er) powders like Titegroup, WST, Clays etc. with heavy bullets.
 
Yeah, I am a bit scattered, but that's because I really don't know what I want or what I'm expecting.
I'm just kinda willing to slip into the unknown and find what's out there.
What I do know is that I've had little luck in finding anyone really taking the 9x19 to task as a PCC round for reloaders.
It's pistol this, pistol that. What about us non-restricted (rural) backyard plinkers that give a crap about the horses in the next paddock?
Thanks for your slower powder suggestions. That's kinda what I'm looking for.
I am surely looking for anyone that might have actually delved into the LOOONG barrel side of the 9mm world and share their wisdom.
 
Perhaps not useful for your project, but I share your tastes in terms of subsonics and slightly less loud noises. Even with custom earpro, I've always been excessively sensitive to noise, so getting my TNW Aero as quiet as is practical with commercial heavy bullets seems the path to take. I've started off using Remington UMC 147gr, which chrony at about 1,040fps average from my non-restricted barrel. They're quieter than the 147gr Winchester JHP I've tried, which average 1,100fps.

But in hopes of keeping the bolt closed a millisecond or so longer, I've ordered a chunk of tungsten round rod 16mm x 40mm. Tungsten is close to 3x the density of steel. The plan is to drill a matching hole into the solid steel buffer weight and embed that did, which weighs 153grams, the swap for steel raising the mass by about 90grams, or a little over 3oz. I tested before ordering by mounting a scrap of hollow brass weighing 90grams to the bolt handle and test firing. It didn't quite eject, though extraction was okay, jamming the new rounds into the sides of the spent cases. So then I unscrewed the stock two full turns to reduce spring preload. That was enough - luckily, as the thing is only threaded in 3.5 turns as stock. Checked flawlessly with the weight in place using the UMC. It seemed a bit quieter to my ears, and my little SPL meter seemed to agree, showing a couple of decibel drop.

So whenever that little scrap of tungsten gets here I'll bore out the buffer weight, use some steel filled JB Weld to glue it in, polish the face,.then take it to the range and start chopping one half coil of spring at a time until it cycles. Probably end up taking out a few turns of the spring as I'd prefer having a few more threads engaged in the stock.

The Aero has a bit of an earned reputation for extraction and feeding issues. TNW's finishing work on things like extractors (tend to be sticky, slightly rough from heat treatment), feed ramps (two short ones with a gap, very rough to the touch with sharp edges) and basically all other moving parts tends to be a bit... neglectful. But it's a cheap carbine at $800 so I'm not bitter. Just spent a bit of time polishing every important thing. Very smooth operation now. But being blowback, I expect it'd complain if I jumped around between radically different bullet weights, velocities, case materials. Luckily I have no intention of doing so. Heavy and slow suits me just fine. And the UMC are pretty accurate out of my barrel. Oh, and as a bonus, it actually seemed there was slightly less recoil with the weight firmly mounted on the bolt handle, so that's nice.
 
My PCC ( GMR15) has a 14.5 bbl and generous compensator, but its still quite with my 147gr, N320 3.3gr load.
 
My PCC is a JR Carbine with an 18.6" barrel. my usual load is a campro 147 grain round nose flat point pushed by 3.5 grains of W231. Flawless performance and very good accuracy from the Carbine. This is also my load for my 9MM pistol for IPSC production minor.
Hope this helps

Ken
 
You would have to use 2 scoops of the right powder to get a 147 super-sonic, so sonic bang is not an issue.

That leaves muzzle blast and accuracy.

If you try to use less of a slow powder (like Power Pistol) you get to a pressure so low that it does not burn uniformly and accuracy drops.

If it is working at 3.4, good.

If you want less velocity, but still good accuracy, Universal is a good choice. Try 3.0 to 3.5. I would use a magnum primer with these small powder charges.

My usual choice for a 147 would be a faster powder, like 231 or TiteGroup, but never tried it in a blowback action.
 
The recipe that I’m using for my FX9 is 3.3gr titegroup pushing 124gr rn Campro bullets with a velocity around 1050 FPS. Very quiet and accurate with no feeding or ejection issues. This is my load for IPSC PCC matches.
 
I use 124 grn Campro prety much the same as listed in the above post in my ruger carbine. 3.2 gr of tightgroup. Not the most accurate load but it cycles and goes bang every time . It's a great plinking load .
 
Okay, so I got myself a chrony, and American Eagle 147 that advertises itself as 1000 fps on the box does 1160-1193 out of my 18.5" S2K.
That's supersonic, even on a warm day.

Hornady book value for 147 out of a 4.5" barrel with 3.5 grains of PowerPistol is supposed to do 750 fps.
I did a ladder going up in .2 gr increments with 3.6 averaging 780 fps, 3.8 @ 828, 4.0 @ 908, 4.2 @ 931, and 4.4 @ 1018.
Speed of sound at 0 deg C is 1085 fps, so with PowerPistol, my sweet spot is at 4.4 grains.

Just for giggles, I decided to ladder down to see where the bottom end is.
With PowerPistol, 3.4 grains gave me 590 fps, which is already suggesting that the bullet is decelerating before reaching the muzzle.
3.3 got 560, 3.2 @ 540 which is into pellet gun territory, and my first round at 3.1 got stuck in the barrel maybe 15 - 16 inches down.
The thing is, the blowback action ejected the casing and chambered the next round, setting me up for a potential train wreck.

So. at 3.1 grains, there's still plenty of oomph to operate the action, but not to push a 147 grain pill out the pipe.
One approach might be to strengthen the spring, another to add reciprocating mass, still another to slow down the powder, or a combination...
 
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