9mm Major Silhouette & 124 gr MG CMJ

[fishsticks]

I recently purchased a used open gun. At the recommendation of several experienced local open shooters I bought Silhouette, SRP (CCI), and 124 gr MG CMJ.

The suggested load is 1.17 COAL and 7.7-7.8 gr.

Now the dilemma......

The used gun is a commander length with 3 poppel holes and a 3 chamber comp.

7.7 gr averaged 1306 fps or 162 pf SD was low at 9

7.8 gr averaged 1325 fps or 164 pf SD was low at 10

I searched, and wasn't able to come up with an upper limit. Realizing that velocity likely isn't linear, but attempting to extrapolate would put a 170 pf load at ~8.0 gr.

I don't see any signs of high pressure looking at fired primers, even through this isn't an exact measurement.

Has anybody used Silhouette in a shorty with poppel holes?

[Hi-Power Jack]

That's the disadvantage of a short barrel with poppel holes ...Well, one of the disadvantages.

But, you are already way past the "upper limit" of Silhouette -

keep plodding - you want to get up to PF 170, and lots of people do it.

Just work up slowly with a chrono and keep watching the primers.

Good luck with it.

[fishsticks]

That's the disadvantage of a short barrel with poppel holes ...Well, one of the disadvantages.

But, you are already way past the "upper limit" of Silhouette -

keep plodding - you want to get up to PF 170, and lots of people do it.

Just work up slowly with a chrono and keep watching the primers.

Good luck with it.

What, I can't hear you. This gun is obnoxiously loud.

Seriously though, when you say that it's past the upper limit do you mean past what western powder publishes or past where common sense kicks in? Later in your post you imply there is some safety margin left, so I'm a little confused.

The two people I know have been using 7.7-7.8 for a number of years with no ill effects. I haven't been able to find any references beyond 7.8 here or elsewhere which is why I'm asking.

I get that people are reluctant to share for liability reasons.

Is there a better powder choice?

[Hi-Power Jack]

It's Way Over Western powders publish data - ALL Major (9mm) loads are.

You should be able to push it a little more.

I stay with WAC & HS6, but more adventurous shooters use Sil and other powders.

[jrn1975]

I have loaded silhouette up to 8.2 grains with no issues. My mid/shorty is making 172 pf at 7.6 grains.

With that said what are the Temps where you are? Silhouette is temp sensitive. At higher Temps you will need more powder and lower Temps less powder.

Sent from my SM-N920V using Tapatalk

[fishsticks]

I have loaded silhouette up to 8.2 grains with no issues. My mid/shorty is making 172 pf at 7.6 grains.

With that said what are the Temps where you are? Silhouette is temp sensitive. At higher Temps you will need more powder and lower Temps less powder.

Sent from my SM-N920V using Tapatalk

Thanks.

Temps are moderate, the results I posted were done with temps in the mid 60s F.

[jrn1975]

Interesting as at those Temps 7.2 grains was making pf for me. How many rounds does the gun have on it? Sounds like the barrel is a little slow.

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[fishsticks]

Interesting as at those Temps 7.2 grains was making pf for me. How many rounds does the gun have on it? Sounds like the barrel is a little slow.

Sent from my SM-N920V using Tapatalk

Unknown round count as I purchased it used.

It does have 3 poppel holes.

[kneelingatlas]

I don't have specific experience pushing Silhouette past its limits, but in general with the slower powders I've used you get over a hump where more powder results in less velocity. With my favorite (SP2) it occurs at ~9.7gr under a 115; you can also push it further with longer OALs. 10gr of SP2 made less velocity than 9.5gr.

[JimF38sup]

I don't load 9mm but I do load 124 DP JHP in my 38 sup

Sil 8.0

federal SPM primers

166 pf

STI GM

115 Hor FMJ required 8.9 with CCI SR to make 166