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same 9 major load dif. fps/gas pressure/comp effectivness


fritzthemoose

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Hi all,

I do have a general question with regards to the following issue

I do have 2 9major loads that only differ in the bullet

Load 1

8gr SP2

Federal SP

124 gr S&B TFMJ

S&B or HB cases

I get an average vel of 1310 fps which translates into a pf of 162. So barely major.

Load 2

8gr SP2

Federal SP

125 gr Ares RNCNBB

S&B or HB cases

I get an average vel of 1385 fps which translates into a pf of 173

What does that mean for my gas pressure and comp effectivness?

Is the gas pressure less as the bullet is faster meaning that the gas can expand faster so less pressure?

Gas should be faster which is good for the comp on the other hand the time the gas is working would be less. Would that have any effect or can be neglected?

from the pure feeling point the 125gr Ares snaps more but that has to be expected with the much higher vel. In case of keeping the gun flat I dont feel much difference.

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Fritz,

I don't have the technical knowledge to answer your question(s) about the speed of the escaping gases. But, I think the comp effectiveness is more related to the volumn of gas generated (ie, more gas equates to a more effecient comp.) However, I have a question: What is your pistol? And how are you getting those speeds with 8.0 grains of SP2? I have to use 9.6 grains of SP2 in order make 9Major with a 125 grain bullet (Zero brand 125 JHPs). My barrel is a 5-inch Schuemann AET in a custom built STI.

A-G

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Fritz,

I don't have the technical knowledge to answer your question(s) about the speed of the escaping gases. But, I think the comp effectiveness is more related to the volumn of gas generated (ie, more gas equates to a more effecient comp.) However, I have a question: What is your pistol? And how are you getting those speeds with 8.0 grains of SP2? I have to use 9.6 grains of SP2 in order make 9Major with a 125 grain bullet (Zero brand 125 JHPs). My barrel is a 5-inch Schuemann AET in a custom built STI.

A-G

That was my thinking if its better to have less pf meaning less vel but the gas for longer

First dont forget that we make Major with PF 160 here in Europe

I am using a Seidler III Comp System for a Glock 17. This is a 6 inch barrel with the holes for the comp cut in the barrel (but not hybrid). The comp as such is just fixed over the barrel and is only used for moving the gas in the desired direction. (it is basically the gun in my pic right although mine looks little different but same system, technology) So unlike with most comps where the comp is screwed infront of the barrel I get the advantage of having a longer barrel. The Polygon profile will also help I think.

My OAL is 29,5 mm because I could not fit much more into the Glock magazines. The shorter OAL, (I asume you will be around at least 30mm) will make a difference too I guess.

The difference between the 2 bullets is the coating of the Ares. It gives you something around 7% more PF as they are much faster than normal bullets.

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