GP 100 speeds

[Tatume]

Hello Folks,

Hodgdon shows 357 Magnum muzzle velocities of almost 1500 fps with Sierra 170 grain bullets and H110, more with Lil'Gun. Using the 180 grain Nosler Partition they achieve almost 1400 fps with H110, and again, substantially more with Lil'Gun. With the Hornady 158 grain XTP they get to almost 1600 fps with both powders. They do not state the gun or barrel length they used.

Are these realistic data with real world guns? I wouldn't want to try it with my 4" S&W Model 686, but could these speeds be accomplished with good accuracy using a 6" Ruger GP 100?

Thanks, Tom

[Wise Owl]

I printed out the Hodgons data sheet for gray wolf and I do believe they used a 10" barrel. Just checked the printed sheet --it's a ten inch barrel to be sure.

[Tatume]

Ah ha! So it is. Thank you.

[Forrest r]

Some interesting reading/reference material.

http://www.ballisticsbytheinch.com/22mag.html

[lar45]

I looked at Quickload and it looks like 1500fps with the 158XTP is doable with 16.7gn H110, and is pushing 35k psi. This is with a loaded length of 1.59". If it is seated out further then a higher velocity could be attainable.

[gray wolf]

I looked at Quickload and it looks like 1500fps with the 158XTP is doable with 16.7gn H110, and is pushing 35k psi. This is with a loaded length of 1.59". If it is seated out further then a higher velocity could be attainable.

Yes but at what barrel length ?? The Hodgon data shows 16.7 for H110 and a 158 grain XTP WITH a 10" barrel and a mag primer to be max, with an OAL of 1.580 for a velocity of 1591 FPS and 40,700 pressure.

With an OAL of 1.590 you would be about .110 short of the crimp groove, and your saying the pressure would be 5,700 less. + reducing the barrel length by 4"

How do you obtain 1500 FPS with a set up like that. I can't believe all those modifications to the load would only loose 91 FPS

The Lyman 49th shows a 10" contender with the same bullet and
16.7 grains of H110 give a velosity of 1540 FPS that is just a tad short of the Hodgon data.

I think the 6" GP 100 will produce more like 1275 to perhaps 1350 FPS with the bullet seeted to the crimp groove.

Don't think 1500 or 1591 OR 1540 would be possible.

Please enlighten me.

[MtGun44]

I have chronoed 125 JHP factory .357 in my Security Six with a 6" bbl at 1495 fps
average.

Bill

[fecmech]

Federal "Classic" 125 gr .357 mag HP's clocked 1512 out of my 6" GP

[roverboy]

I have chronoed 125 JHP factory .357 in my Security Six with a 6" bbl at 1495 fps
average.

Bill

That's balls to the wall speed ain't it.

[lar45]

Yes but at what barrel length ?? .

The original poster said that he had a 6" GP-100 . Experience has show me that in working with revolvers and Quickload "predictions" that you can add about 1-1.5" to the barrel length and get a fairly close estimate of what will show up on the chronograph. So I put in 7.5" for the barrel length.

[MtGun44]

Yep, and they were accurate (JHPs). I really do need to chrono my 16.3gr H110 under
a 150 or 158 gr boolit in several 6" .357s. Never have actually done it. Hodgdon says
well over 1500, but I kinda doubt it, but have no facts, YET.

Bill