I Plan on relaoding some subsonic this week

[hk33]

Well my form 4s were finally approved and I have my PS90 SBR and Gemtech can. I have read through everything I could find on this forum and others (including the old version of this forum before the crash). I had a lot of time waiting on the forms.

I need to go pick up some primers tonight and then I should have everything I need to start reloading for 5.7x28

Just for a little background info I have tons of reloading experience over the past 40 years. However, I have primarily reloaded for accuracy (benchrest) and volume (full-auto stuff). This is my first attempt at a subsonic load.

My planning load is as follows:

Primer: WSR
Bullet: 55gr FMJ or Nosler 55gr ballistic tip (probably try both)
Powder: True Blue

However, I have not been able to deduce too much info on the powder charge from looking through websites. It looks like somewhere between 3.0gr to 3.5gr. I don’t have a chronograph so I guess I will start out low and work up until it gets a lot louder. Certainly these are well below any danger zone.

Any help on narrowing down the powder charge would be appreciated as I have seen some info that the powder charge needs to be lower than 3.0gr.

Thanks

[f3rr37]

I would work down from a known charge for the 55grain bullets. Something like 4.0grains of TrueBlue. Work down until it becomes sufficiently suppressed. That way you don't accidentally load too light and end up with a bullet lodged in your barrel.

[hk33]

Thanks for the suggestion. That is certainly a good idea.

I was planning on checking after every round anyway even if I have to tear it down and check the barrel to be sure.

[stg2ahn]

Also, if something doesn't sound right, or if you see no sparks(than usual out of a fiveseven) or just a small plume of smoke coming out of the barrel after a trigger pull even though you have more rounds in the mag.


check out this clip
http://www.youtube.com/watch?v=tWygoxV_ApM" onclick="window.open(this.href);return false;
I think there was a squib.

[f3rr37]

check out this clip
http://www.youtube.com/watch?v=tWygoxV_ApM" onclick="window.open(this.href);return false;
I think there was a squib.

No longer available.

[MrSlippyFist]

Nice looking weapon. Be mindful when making those subs.

[Grantness]

This was posted on FnForum :ponder: SS193- 55 grn. bullet- 2.0 grains of Silhouette
Now I believe that comes out to around 2.3-2.4gr TB, but dont quote me on that...I dont know for sure. I dont even know if this guy knew what he was talking about. There is no such thing as an SS193...its called the SB193

[panzermk2]

Be very damn careful playing around with subsonics.

[stg2ahn]

yah know, EA makes subsonic ammo.

[f3rr37]

If I was working up a load for it I would be sure to make sure the barrel was clear after each round.

[abatis]

I only use EA subs or subs made to EA specs by me. I suggest starting at 4.2 grains TrueBlue and walking down from there. Every gun/barrel/silencer combo is different.

[Esteves]

I have a stash of SB193. I prefer EA's QuieTORs.

If the 5.7x28 is generally considered finicky to reload, the subsonics are probably the fussiest of the bunch.
Too much powder is no good. Too little can be even worse. 0.1 grains difference between powder throws is on the order of 5%.

[hk33]

yah know, EA makes subsonic ammo.

Thanks, I have already order 500 rounds of Quietor from EA. I will continue to order from them but I want to load my own as well.

[hk33]

I have a stash of SB193. I prefer EA's QuieTORs.

If the 5.7x28 is generally considered finicky to reload, the subsonics are probably the fussiest of the bunch.
Too much powder is no good. Too little can be even worse. 0.1 grains difference between powder throws is on the order of 5%.

I am going to weigh each load on a digital scale. Good thing I am loading for a PS90 not a P90 because I would not have the patience to weigh every load for a full-auto.

[Grantness]

i like to weigh each charge for all of my 5.7x28 loads. You just cant make any mistakes... and one mistake could cost $1000 (not to mention possible medical bills).

Good thing I am loading for a PS90 not a P90 because I would not have the patience to weigh every load for a full-auto.

Damn...if I could somehow own a legal P90...I sure as hell wouldnt mind developing some patience. :p

[hk33]

Thanks everyone for all the advice. I appreciate it.

[hk33]

This was posted on FnForum :ponder: SS193- 55 grn. bullet- 2.0 grains of Silhouette
Now I believe that comes out to around 2.3-2.4gr TB, but dont quote me on that...I dont know for sure. I dont even know if this guy knew what he was talking about. There is no such thing as an SS193...its called the SB193

I read this info as well. I am just not going to be the first one to try silhouette without some additional data.

I thought FN changed the designation for the subsonic round from SB193 to SS193.

[Grantness]

i actually have no idea. I was just going on some info I read around here from a reliable source.

[Esteves]

I read this info as well. I am just not going to be the first one to try silhouette without some additional data.

Good plan.

I thought FN changed the designation for the subsonic round from SB193 to SS193.

FN's been very consistent about calling it SB193.

[ArtosDracon]

When developing 140gr subsonics for my 9mm I lodged two bullets in the factory barrel before getting the load just right. Notice I said the factory barrel as well. I have a beautiful blued threaded barrel that I use with my supressor but, for development, till I knew I was a whole lot closer, I used the factory barrel and when I bullet got stuck, it got pushed out and I didn't much mide the scorring of the barrel cause I just don't use it anymore. I've got a compensated barrel for the hot loads and threaded one for the quiet loads so that factory one was perfect, hadn't cost my anything, wasn't worth all that much in cash and kept me from dammaging the good stuff.

Also be warry of lodging a bullet in the supressor, it won't have as distinct of the signs mentioned by MO but they'll still be there. Saw this blow apart a supressor for a PPK once. Talk about scary stuff. 125gr subsonic lodged about an inch from the outlet of the suprressor and the owner didn't notice. Fired another round and the supressor sponanteously disassembled itself into about three pieces. Becasue the supressor was threaded to the interior of the barrel instead of the exterior it managed to bend the end of the barrel as well. The barrel had to be cut to get the slide off so a new one could be pressed in. He hasn't used sub-sonics since, even store-bought.

[hk33]

Well I finally had time to shoot some of my 55gr loads. I loaded from 4.0 down to 3.2 grains of true blue and they were all supersonic.

I'll have to keep going. Unfortunately I don't have a powder measure that I can use for True Blue below 4.0gr, so I have to hand trickle all the loads. (big pain in the a$$)

True blue is so fine it gets difficult to measure in such small quantities. I would prefer to find another powder that would fill the case more but I was still surprised that even though the there is so little powder in the case the loads were still pretty consistent.

[panzermk2]

Be very careful. Personally I would not go down the path of lighter TB loads. All I am going to say.

[NRAshooter]

You could try one of my 77 grain loads. All of them are subsonic at my alttitude but I'm still working up.

[kalikraven]

Be very careful. Personally I would not go down the path of lighter TB loads. All I am going to say.

Detonation from from undercharged loads?


What is a powder for 55gr subsonics that still fills the case above 50%??

[onceA6shooter]

Be very careful. Personally I would not go down the path of lighter TB loads. All I am going to say.

That is good to know. I have played around with Hs6 and AA#7 for my subsonic loads. I could not find any True Blue powder locally to try out since it was suppose to be the "One" for 57 loads. Recently I bought a pound specifically to load subsonics but have not had time to do it.

I have had my best results with AA#7, CCI SR primers, Win 55 fmj.
3.0 = Avg 919.1,
3.1 = avg 937.5, and
3.3 =1047fps, but Std Dev was all over the place. My dillon powder measure was not very consistent with those reduced loads. I was planning on hand trickling the next batch.

[JohnG]

Bit of a thread resurrection here...

Wanting to check-in with the subsonic “rollers” here to see if this is still a viable load-out (AA#7)? Sounds like low loads of TB aren’t recommended. I have been attempting research on 55g subs and there seems to be quite a bit of conflicting info so It’s been a stressful search for solid, consistent data. Any additional insight from experience would be much appreciated!

[panzermk2]

TB and AA7 are way to fast for sub sonics. To try and get the 55gr bullet slow enough you have to downlaod the cases to the point that fast powders like TB, AA5,7,9 instead if burning and expanding pushing the bullet out, the super light powder charge burns so fast it's closer to an tiny explosion. It can blow out the primer, separate the case, or only push the bullet out just enough that it jams up the action.

[JohnG]

That doesn’t sound particularly promising

With that being said, is there a commercial powder that can successfully push a 55g subsonic effectively? If so, I’d love to hear/see the recipe. From what I have seen so far, the 5.7 is most effective as a supersonic load with a bullet weight between ~30-49g but man...after seeing a few vids with the CMMG banshee shooting subs out of a Dead Air Mask, My interest has piqued.

[towerofpower93]

My attempts at using 55gr Hornady FMJBT projectiles for subsonic giggles in an SBR’d PS90 with a High Desert Dog barrel. Of note, once I put a Gemtech SFN57 can on the end the mag would pop out of the catch at least once every 10rds. Never tried to add weight to the bolt or a suppressor with more volume to reduce back pressure.

I’m sure there are better powders for this, but I use Win Auto Comp for my 40gr VMAX loads and picked up a pound of Alliant Steel cheap and didn’t mess with others after I found a supersonic load that’s 100fps faster than SS197 and lost interest in subs.


PS90 SBR
Alliant Steel 3.1gr
Rem 7.5 SRP
Hornady 55gr FMJBT
OAL 1.585"

Unsuppressed

1013
1010
1045
962
1039

PS90 SBR
Winchester Auto Comp 2.7gr
Rem 7.5 SRP
Hornady 55gr FMJBT
OAL 1.585"

Unsuppressed

1021
1059
1029
992.5
995.4

[panzermk2]

That can is designed for 5.7 and should NOT be giving you any issues.

1) Might want to look at your stock's failure points. See here https://youtube.com/playlist?list=PLu1o ... RIQ_WNBcRw
2) Verify barrel was installed correctly and that you have correct amount of barrel free play/Movement.
3)HD Magazine catch spring.

[panzermk2]

That can is designed for 5.7 and should NOT be giving you any issues.

1) Might want to look at your stock's failure points. See here https://youtube.com/playlist?list=PLu1o ... RIQ_WNBcRw
2) Verify barrel was installed correctly and that you have correct amount of barrel free play/Movement.
3)HD Magazine catch spring.