Subsonic 9mm Ammunition Performance and C&R SMG's

[Rekraps]

So, for those of us that like to shoot suppressed SMG's of the 9mm persuasion, especially C&R type guns, the issue of reliable, affordable and compatible ammunition is always at issue. I'm speaking about suppressed "K's", STEN's, Sterlings and M76's in particular. All these guns were adapted for silencers during and after WW2, whilst MP40's, PPSH's, PPS's & Beretta Model 38/40's were not. 

Although about 1/2 of the available commercial round nose 124 grain 9mm runs just below supersonic, the overall report is still louder than an old man like myself would like. the obvious choice (yes I know there are more choices) with respect to availability/price is 147 grain. Naturally subsonic, this round is a perfect solution to C&R SMG's. Unfortunately, as far as I know only Fiocchi is the only commercial (meaning larger long-time established, industry recognized) manufacturer that makes round nose 147's. 

Round nose 147's are critical to feeding the old C&R's as the single feed, single stack and single feed double stack magazines and the feed ramp into the chambers of these guns do not perform well with flat head ammo. Flat head rounds will get tied up in the loading cycle. Yet another unfortunate circumstance is that most commercial 147 9mm is in fact flat head. UGH.

What we want to avoid is squibs, so as a practice I do not hand load SMG ammo. Not taking the chance. What to do?

The two tier two ammo manufacturers that I have used with success are Precision ONE, and Freedom Munitions. Both companies manufacture 147 gn 9mm round nose using new brass and can deliver 1000 rounds at about $0.32/round. Not bad at all. That equates to 30 - 35 magazines per order. 

I have now shot several thousand rounds from each company and found both to be reliable, with no squibs and no failure to feed or misfires. The impulse is more than sufficient to drive the firing sequence and most importantly, the report is pleasant! No hearing protection required. With an average velocity of right around 950 fps, these two choices are perfect for suppressed applications. Best range is <150 feet, so low crawl to your target! Perfect for off the back deck shooting.

If you're interested in cans for the "K" or M76, Joe Jones (now with Shaw Armament Services) makes custom units that perform and look great!

 

[StrangeRanger]

Trust your Dillon

Xtreme or Berry's plated 147 RN and 4 gr of W231/HP38.

 

 

[johnsonlmg41]

I have a case of Remington 147's that work well.  Have one other brand as well, but can't recall what it is.

The other option is a sterling MKV or an MP5SD.....then you can shoot cheap regular ammo!  When you get to .40 a round 9mm, you may as well just shoot .45 suppressed and call it good?

[Rekraps]

On 12/23/2023 at 8:29 AM, johnsonlmg41 said:

I have a case of Remington 147's that work well.  Have one other brand as well, but can't recall what it is.

The other option is a sterling MKV or an MP5SD.....then you can shoot cheap regular ammo!  When you get to .40 a round 9mm, you may as well just shoot .45 suppressed and call it good?

Are those flat nose?

And you are right, my "newer" SMG's eat flat nose, but the older ones don't seem to like it.

[Rekraps]

And you're right (again), the 147 new production, round nose is running about $0.32 to $0.39 per round (not including tax or shipping).

[Lewisfan]

My K feeds 147 gr Speer "Lawman" truncated nose (flat tip) flawlessly.  Maybe I'm just lucky...

[Rekraps]

On 12/24/2023 at 4:16 PM, Lewisfan said:

My K feeds 147 gr Speer "Lawman" truncated nose (flat tip) flawlessly.  Maybe I'm just lucky...

You are! 

[Rekraps]

I just went out and shot Winchester 147 Flat nose and it is substantially louder than the purposefully made "subs" from Freedom Munitions or Precision One. I think the WFN run close to 1100 fps, the others are in the mid-900's. Big difference.

[n0mad187]

On 12/13/2023 at 7:18 AM, StrangeRanger said:

Trust your Dillon

Xtreme or Berry's plated 147 RN and 4 gr of W231/HP38.

 

 

I would shy away from plated projectiles when using a can personally. If you are using the mixed brass the varying case thickness can overcrimp and scoring of the plating. That can lead to jacket/plate separation and baffle strikes. In addition Berrys in particular are very soft, which sometimes can lead to feeding and set back issues, and in the case of open bolt guns out of battery problems.

I personally would recommend sticking to a FMJ for those sorts of applications. YMMV 

[StrangeRanger]

But FMJs have an exposed lead base which clogs up a compensator.  What does that do to a can?

Edited January 1 by StrangeRanger

[n0mad187]

On 1/1/2024 at 5:20 AM, StrangeRanger said:

But FMJs have an exposed lead base which clogs up a compensator.  What does that do to a can?

 Most modern pistol cans are user serviceable and not fully sealed. Those cans can be cleaned. I haven't noticed any lead build up as a result from running FMJ's. The majority of build up in cans I have examined has been carbon, not lead. With the exception being 22lr cans. 

I have one sealed can I use for PCC/SMG guns, but it is also rifle rated, so a few rounds of full power 308 tends to shake loose any build up. 

I played around with plated projectiles for a few years, and I could never get good accuracy or consistency,  I'd always end up with at least one bullet out of 50/100 tumbling. I primary shoot uspsa, so the accuracy mattered to me. If you aren't using mixed brass, and very diligent with your reloading practices you may have better luck than I did. I typically load 10-20k a year and it's just not worth it.

I wouldn't personally trust plated projectiles that I loaded to not tumble or cause issues in my can. As always I'm talking about my personal experience and YMMV.