Had some fun w/ my GP100 tonite

[Erick]

Usually my handgunning is a bit more serious than this but this time I just had fun.
usually I do mostly updrills from the holster with 38 SPC +P on my 3 inch GP100.

But a buddy rolled me some real HOT 357 Magnum loads so I wanted to explore.

So I broke out my pristine GP100 in 4 inch SS, vs my normal 3 inch GP100 SS.

The reason is that the 3 inch has a slimmed frame and topstrap and with such a hot load I wanted the full strenght frame + strap.
The 4 inch is also noticeably heavier than the 3 inch GP100 for those reasons.

The rounds are 160 gr and according to the excel sheet with this powder load should do about 1580-1590 fps out of the reference revolver.

Like I said HOT... IMO this would be +P+ if there was such a thing for 357 Magnum.

Now my revolver is 4 inch barrel (not 6 inch like the typical reference) so maybe a little less speed but even so...

I got a big fireball w/ every shot and the range master said he could see the condensation like of the bullet in the air as it shot to the target.
Said was first time he every saw something like that.
And the dividers between lanes seemed to shake/vibrate a bit with every shot

It was fun.

The recoil was not bad at all w/ the 40 oz GP100.

I am sure it would have been unpleasant with a lighter revolver like say a S&W Model 65.
I had one of those before and even regular 357 Mag where unpleasant to shoot.

Went home and cleaned the revolver and its nice and pristine now again and next to my bed

 

[Magnumite]

Any chance of seeing pics of the fired cases?

 

[Traveler]

My Dad loaded some like that once. A friend coined the phrase:

"Russ's insane ammo, when it absolutely positively has to be dead."

 

[Erick]

Yes I saved some of them.. Will take pics tonite

 

[Minuteman]

Cool. That's my favorite revolver, exactly as you have it configured. SS with big rubber grips. Clean.

 

[Biggfoot44]

A three inch GP100 would be just as strong, but the longer bbl with full underlug will decrease muzzle flip.

But I'm calling on the vel of the ammo. The OP didn't specify the third hand source of data, but I'm guessing Hogdon's , using the infamous 8.7inch test bbl . I fully trust their pressure reading, and the vels do give a measure of comparison, but the actual numbers don't relate to any actual revolvers.

I won't ramble with a historic treatse on the various historical industry standards for handloads and factory ammo for .357 mag over the decades, but a 160-ish from a 4in bbl anywhere close to 1400fps would definately put you in the big boy club.

 

[Magnumite]

Most likely erode the forcing cone as well. My top end loads are under maximum just to keep the barrel life up there. One cannot shoot a steady high volume diet of full bore loads in magnum handguns and not encounter forcing cone erosion. Unless it is a Freedom arms with a forcing cone insert.

 

[rseymorejr]

Usually my handgunning is a bit more serious than this but this time I just had fun.
usually I do mostly updrills from the holster with 38 SPC +P on my 3 inch GP100.

But a buddy rolled me some real HOT 357 Magnum loads so I wanted to explore.

So I broke out my pristine GP100 in 4 inch SS, vs my normal 3 inch GP100 SS.

The reason is that the 3 inch has a slimmed frame and topstrap and with such a hot load I wanted the full strenght frame + strap.
The 4 inch is also noticeably heavier than the 3 inch GP100 for those reasons.

The rounds are 160 gr and according to the excel sheet with this powder load should do about 1580-1590 fps out of the reference revolver.

Like I said HOT... IMO this would be +P+ if there was such a thing for 357 Magnum.

Now my revolver is 4 inch barrel (not 6 inch like the typical reference) so maybe a little less speed but even so...

I got a big fireball w/ every shot and the range master said he could see the condensation like of the bullet in the air as it shot to the target.
Said was first time he every saw something like that.
And the dividers between lanes seemed to shake/vibrate a bit with every shot

It was fun.

The recoil was not bad at all w/ the 40 oz GP100.

I am sure it would have been unpleasant with a lighter revolver like say a S&W Model 65.
I had one of those before and even regular 357 Mag where unpleasant to shoot.

Went home and cleaned the revolver and its nice and pristine now again and next to my bed

Brought your gun home from the range and then took a couple of pictures of it ON your range!

 

[Mooseman]

The GP100 is one of my favorite revolvers.

 

[Erick]

A three inch GP100 would be just as strong, but the longer bbl with full underlug will decrease muzzle flip.

But I'm calling on the vel of the ammo. The OP didn't specify the third hand source of data, but I'm guessing Hogdon's , using the infamous 8.7inch test bbl . I fully trust their pressure reading, and the vels do give a measure of comparison, but the actual numbers don't relate to any actual revolvers.

I won't ramble with a historic treatse on the various historical industry standards for handloads and factory ammo for .357 mag over the decades, but a 160-ish from a 4in bbl anywhere close to 1400fps would definately put you in the big boy club.

I didnt roll the Ammo, just quoted the guy who did it for me.
I trust him he's been a really good guy in the past.

I usually expect the reference revolver to mean 6 inch barrel and since mine was a 4 inch it will obviously be less.
There was a lot of unbrunred powder muzzle flashing so I am sure a lot was a lot of velocity left on the table.

Dont claim to be an expert in these matters just had some fun with the 6 shooter.
I'll ask him about the specifics sometime if he isnt on this website already

 

[Erick]

A three inch GP100 would be just as strong,.

I would like to think so but if you compare them closely you will see the top strap is noticably slimmer and thinner.

 

[Erick]

Any chance of seeing pics of the fired cases?

Ask and you will receive

(ignore the date on the pics its incorrect, just put in new batteries)

 

[Traveler]

Yup, one of those primers is a little flattened. I have seen worse though.

 

[Magnumite]

Thank you for the pics. Cases look okay. I have 3 on bench I picked up from a range...textbook examples of too hot. I learned the hard way about forcing cone and barrel breach face erosion years back.

 

[Erick]

Thank you for the pics. Cases look okay. I have 3 on bench I picked up from a range...textbook examples of too hot. I learned the hard way about forcing cone and barrel breach face erosion years back.

Are the forcing cone issues mainly a S&W thing?
I thought GP100s were immune?

Not being facetious here just genuinely curious

 

[Magnumite]

No problem. It is a real occurrence with all magnum class revolvers. Stainless will erode less than blue steel guns. Some powders erode more than others. I've observed when working in the magnum class loadings but not at absolute maximum pressures goes a long way to minimizing erosion.

It is the powder granules and the high attendant heat/pressure which do the eroding. Staying below those top end temps/pressures will keep the barrels healthier.

I have one of the first blue GP 100's to hit the area. It is proof erosion does occur. I had to set back a Security Six barrel back twice then replace the barrel because I insisted on shooting hot loads with a hot burning powder. The shooting of magnum loads was always a huge part of my shooting so I ran some hefty loads in both 357 and 44 Magnum, my favorite. Getting into competitive semi auto shooting probably saved a few guns.

Low pressure loads can be shot forever. Virtually no erosion there.

 

[Erick]

Maybe I'll stay with my factory Fiocchi loads and save these hotties here as a SHTF stash for my trail revolver.

The Fiocchi factory rounds I like, they are hotter but not crazy, 142 gr at 1420 FPS thru reference revolver ( which I presume means 6 inch barrel)

 

[Erick]

PS: I heard the bigger bullets 158 gr and up minimize the forcing cone wear because the bullets is longer and there is less gap for the gases to flow during that splity second thru during firing.
Can you comment on that for me?

 

[AntiGun]

Maybe I'll stay with my factory Fiocchi loads and save these hotties here as a SHTF stash for my trail revolver.

The Fiocchi rounds I like they are hotter but not crazy, 142 gr at 1420 FPS thru reference revolver ( which I presume means 6 inch barrel)

I really like the truncated cone 142's from Fiocchi.
They're my standard diet for magnums and the cases reload just fine.
Stick with those and you'll be in the safe zone in terms of erosion.

 

[Erick]

I really like the truncated cone 142's from Fiocchi.
They're my standard diet for magnums and the cases reload just fine.
Stick with those and you'll be in the safe zone in terms of erosion.

Thats whats been my main diet for my GP100s
Its definitely hotter (I can feel the difference) but not crazy hot.

But these super hot loads are so much fun!