I have a T/C G2 Contender in 375 Whisper (action, barrel & suppressor bought through SSK). I'm shooting 300 SGK through it over PowerPistol. At avg. MV of 1050 fps, I'm getting a report (really a crack) like from a 22 LR.....maybe slightly less. Speed of sound is 1125 fps. This is my only suppressor; I've not been around them or used them before. Normal?

I've played with a .300 Whisper with a J. D. Jones upper on a Colt lower. SSK puts an adjustable gas valve for suppresssed and full powdered loads.

I've found it aggravating, trying to load right below the SOS. It seems if you're running it that close, just a bit of variation blows your sub sonic cover.

I guess one has to leave enough margin so that doesn't happen.

I'll bet that .375 Whisper is a hoot to shoot...

I've talked to J. D. on the phone, although some years ago, found him helpful and pleasant. He's getting pretty long in the tooth, must be in his mid 80's or better. Not sure how active he still is in the business. He's done some really interesting things in his career.

DF

Speed of sound is variable depending on atmospheric conditions and elevation above sea level. "Crack" usually means your speeding, try slowing it down and tell us how it sounds.

Agreed. Extremely knowledgeable and kind with his time and advice. Appears he sold the business in last year or two. I had subscribed to American Handgunner for years, so it was fun to get to chat with him.

Makes sense. This was 3000'-3500', low humidity, around 70 deg.

I never had much luck or fun with power pistol in the 338 or 375.
My favorite became ramshot enforcer. If you load for just under 1000fps you should be able to get almost"Hollywood Quiet"
with the setup youve got.

Actually tried both PP and Trail Boss. TB was a complete and total bust; PP was incredibly accurate.

SWAG possibility question:(for if it’s NOT speed related)
Powder causing secondary det in first expansion chamber like many rim fire suppressors? I know I have to run many wet, to kill that first round crack.

There are a couple of different standards at play, one is referenced by your “1125 FPS” number. The other is based on International Atmospheric Standard (IAS). The figure you referenced is predicated on a temperature of 68*F, or 20*C. IAS is based on 59* (15*C), 29.92” atmospheric pressure. That provides a 1116 FPS reference.

While temperature is a practical reference, the measure is strongly influenced by air pressure. Lower atmospheric pressure reduces the threshold. That metric is influenced by temperature, altitude (pressure) and humidity. An extreme comparison is the SoS in water. At about 70* it is 4870 FPS for fresh water.

The difference at your elevation would be small, but there would be a difference.

DD isn't a target max of 1050 FPS a realistic goal? It is what I had decided might be a good milepost. Next would it be easier with 375 Winchester loaded appropriately? Be Well, RZ.

Rusty, 1050 is my limit for suppressed shooting simply because I don’t want the crack. One thing most focus on is bullet velocity. What they should be looking at is air velocity in the flow field around the bullet. Blunt or flat noses can give you a crack even though the bullet is subsonic if one is inclined to tickle the dragon’s tail.