Ruger GP-100 in .353 Casull

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Kilgor

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First, read this article if you haven't already.

http://www.sixguns.com/tests/tt353.htm

Would it be possible for a gunsmith such as Hamilton Bowen to fit an unfluted, 5 shot cylinder to a GP-100 and effectively chamber it in .353 Casull? Is the GP-100's frame strong enough? Is it as strong as the Freedom Arms single action? If not, how close to .353 Casull performance could one come with such a cylinder in a GP-100? Would a blued steel GP-100 offer any advantage in strength over the stainless steel version?

What do you think?

P.S. I've thought of a .357 Redhawk, but it's not what I'm looking for. Too large.
 
The 353 Casull isn't a caliber it's just Freedom Arms 357 Magnum on their large M83 frame. Taffin loaded that gun up to much higher pressures than normal but it was still just a 357 case with sm rifle primers.

The GP100 cylinder is significantly smaller than the 353 Casull so I don't belive that even in a 5 shot you could load it up to the same performance level safely. There just isn't nearly the same amount of steel there. The frame I belive would be strong enough - no where near as strong as the FA single action but strong enough, but not the cylinder.

M83 cylinder diameter: 1.751"
GP100 cylider diameter: 1.546"

If you wanted to get that kind of performance from a 357 but don't want a Redhawk (if you could find one) having a 5 shot cylinder for a 357 Magnum Blackhawk would be your next best bet.

Just my opinion, your milage may vary.
 
I realize that the .353 Casull is just a very hot loaded .357 mag with rifle primers. I did not realize that there was such a drastic difference in cylinder diameters. That's a shame. I appreciate the suggestion for a 5 shot Super Blackhawk and may do that. However, if I go single action I may just get the Freedom Arms field grade as its cost is not going to be that much more than the total cost of a converted Super Blackhawk, would it?
 
I think it may depend on who does the conversion. Phillips & Rodgers, Inc. for example is a lot cheaper than having a world renowned smith like Bowen do the work. Their website is pretty broken right now so you can't check current prices but as I recall from the last time I was there a 5 shot cylinder was in the $350 range.

Here's their website, but you won't get much from it tonight: http://www.phillipsandrodgers.com/index.html

Their contact info follows in case you wanted to get a hold of them for any questions:
Phillips & Rodgers, Inc.
852 FM# 980
Huntsville, Texas 77320

(936) 435-0011 Office
1-800-682-2247 Toll Free
(936) 435-0022 FAX

There are several articles about work they've done at http://www.singleaction45.com/articles.htm from those articles it sounds like they do good work.

But even though they're less expensive when all is said and done you might have spent nearly what a field grade Casull goes for anyway. But it doesn't hurt to check into options when you're spending hundreds of dollars. :)
 
Ya, the FA in 357 maggie on the big frame is just *grossly* overstrength for the caliber, so you can load it to some pretty crazy horsepower levels :).

That doesn't make it a good idea for smaller guns. On the contrary, the real problem here is that with the small case volume, pressure is gonna be just nuts. You're much better off going with a bigger bore like 44Spl and keep the pressure to something reasonable...a 240grain hardcast at 1,200fps should be perfectly practical in a 5-shot GP100, at FAR less pressure than a "353" round at the same raw energy level.
 
Would a 5 shot unfluted cylinder in a GP-100 offer much of an increase in strength over the factory fluted 6 shot? Would this allow me a 200 grain LBT gas checled bullet at 1,500 fps with H110 or LilGun?

Jim, I appreciate the .44 special idea and it makes sense, but for whatever reason it doesn't trip my trigger. I do have a question though. With the larger holes wouldn't a .44 special version have fairly thin walls on the outside part of the cylinder even with the 5 shot cylinder?
 
Yes, the 44cal would mean thinner cylinder walls. But the increased chamber volume means less peak pressure to get the same work done - it balances out.

For a lot of discussion on the differences, pay attention to what John Linebaugh writes on the advantages of the 45LC over the 44Mag at:

http://www.sixgunner.com/linebaugh/

Look at pretty much everything under "gun notes". Notice how he gets the same work (bullet weight at "X" velocity) done with 34,000psi in 45LC+P, versus 40,000psi for the .44Mag. And that's with VERY minimal differences in case/chamber volume.

The volume difference between 357 and 44Spl is far more extreme. You're probably looking at a difference of upwards of 15,000psi between 357 and 44, both shooting say, 200grainers at the same speed. 1,300fps or a hair more from a 6" tube should be possible in a 5-shot GP100 in either caliber, but with less peak pressure the "wear and tear" on both YOU and the rest of the gun will be less in big-bore and roughly equal (low) risk of the cylinder blowing apart.

Once you understand what Linebaugh is saying, you'll see why he went with his 475 and 500 calibers, why Ruger went to the 480 and why S&W is about to ship the 500 - bigger case capacity equals lower pressure.
 
I don't think I'd want to try a 200gr @ 1500 fps in a 5 shot GP100, that's above some 44 Magnum loads.

Fluted or unfluted won't make a difference, it's strictly cosmetic. The weak point is going to be either the chamber wall to the outside or between chambers, since fluting is done between the chambers it doesn't effect cylinder strength.

You're right it will have pretty thin chamber walls in 44 Special so you won't be able to crank the pressure up nearly as much as you would with a 5 shot 357 but as Jim said you've got a far greater case capacity to work with in the 44 Special vs the 357.

(typo edit)
 
Last edited:
I OWNED THE FIRST FA 353 4 3/4" EVER MADE.

I could get 1600fps with 180gr bullets with only one propellent. If I pushed it to 1650 the primer pockets opened up to near LP primer size, but the brass would fall out of that FA pistol. NOW LISTEN TO THIS: NO 353 LOAD IS SAFE IN ANY 357MAGNUM PISTOL EVER MADE EXCEPT THE FREEDOM ARMS 353 MODEL 83 REVOLVER. I AM DEAD SERIOUS ABOUT THIS!!!!!!!!!
 
Folks, Terry isn't kidding. The loads he's talking about right there would blow a Ruger Blackhawk to Kingdom Come. I don't have charts handy but it wouldn't surprise me if he's talking about pressures up near 80,000psi or above.

200 grain at 1,200 should be doable in a five-shot 44 GP100 (with a 6" tube and the cylinder as big as the frame window will take). Maybe 1,300...MAYBE. 1,500, no way.
 
Terry and all,

Your company, Corbon, lists the Cast Performance 200 gr. hardcast flat point at 1,200 fps in .357 magnum. This load I assume has to be safe in all revolvers chambered in .357 magnum correct? I know you test your loads in real guns, is this a 4" or 6" barrel?

If you can safely push a 200 gr. hardcast at 1,200 fps in a K-frame as an example, then that should be easily doable in a stock 6 shot GP-100. If the 6" GP-100 is fitted with a 5 shot cylinder, then how close to 1,500 fps could one safely come with Cast Performance's 200 grain hardcast? Keep in mind that Hardcast are shorter and provide less friction than their jacketed counterparts which means lower pressure.

On www.sixguns.com I read where several writers have loads for 200 grain Hardcast at 1,400 fps from 6" Super Blackhawks. How would a 5 shot cylinder in a GP-100 and a 6 shot Super Blackhawk compare in strength?

Jim,

I've read Linebaugh's work and it makes perfect sense. However, I can get a 200 gr. @ 1,200 fps with a higher penetrating bullet (due to sectional density) in the stock GP-100. I like the .357 and would like to stay with it for this project. Thank you for the refresher though. :)
 
Kilgor: if I recall right from the Cor-Bon site, the 180 and 200 "hunting loads" in 357 are measured out of 6" tubes. Not unreasonable for the intended use. The "self defense line" is measured at 4".

Let's get real here: if you shoot a Cor-Bon hunting-grade 357 in a Scandium S&W snubbie, you deserve the resulting broken wrist. A K-frame can shoot a few of 'em but I wouldn't recommend it. Those rounds are for "real 357s" that can handle the "original formula" involving a 158 doing 1,550ish from a 6". That means Blackhawk/Vaquero/Redhawk/GP100 on the Rugers, S&W L/N frames, big Dan Wessons and a few others.

Now having said that, once you go to a five-shot GP100 cylinder, sure cylinder strength goes up. Fine. But run pressures up around 60,000 and jeez, you're also stressing the crane, crane latch and similar parts.

More bad news: once you get up into mega-pressure territory in a smallish case like the 357, the difference in powder to make 80,000+ as opposed to a "sane" 60k is NOT LARGE. You get to a point where the pressure rise isn't at ALL linear for the amount of powder added. Sneeze at the wrong moment, knock a few stray granules into the case and whoops, you just shot up to 90,000 and dude, Ruger builds strong guns but there's a friggin' LIMIT, ya know? Or during testing of handloads, you could have one round that "sticks just a little but is otherwise OK" but the next increment in powder of a half a grain or whatever is handgrenade city.

There's a REASON people don't play that high on the pressure curve unless A), they're pulling the trigger with a 30ft string while ducked behind a berm or B), they've got something silly-strong like the FA '83 frame originally built for the 454Casull, or a Thompson Center or whatever.

Sigh. Relax, dude. *Live*. What you're talking about just isn't safe.
 
THE CORBON 357 LOADS ARE TESTED IN A 4" GP100.

ALL OF OUR LOADS ARE WITHIN SAAMI SPECIFICATIONS THOUGH RIGHT AT THE TOP OF THOSE SPECS.
The FA 353 loads we used to sell were all tested in a 7 1/2" FA fivegun in which they were delightful. They were also loaded to LOA specs that precluded their use in anything but a FA 353 revolver.
IF YOU NEED MORE POWER THAN YORE 357 DELIVERS BUY A GUN WITH A CALIBER STARTING WITH THE NUMBER "4".
A pal of mine in Colorado has a REDHAWK 357 MAG with a 5 1/2" bbl. He loads a LYMAN 225GR SWC bullet [ can't remember the number of it to save my soul ] at 1425FPS and has for many years. That sixgun is one shootin' sumbiscuit with that load and shoots flatter than a moonbeam, I'll tell you!!

ALSO: ALL SUPER BLACKHAWKS ARE 44MAGS NOT 357's.
 
You're right I was mistaken, they are Blackhawks.

John, Jim, and Terry thank you for your input.
 
Here's a picture of what it would look like.

2.jpg


This is a .44 special 5 shot conversion by Dave Clements. Thanks to JohnK for pointed me in his direction via PM.

http://www.clementscustomguns.com/
 
Yup, that'll work. If Keith could get a 250grain hardcast moving at 1,200fps from a Colt SAA, it's a certainty you can do the same or more from that GP100, given both the metallurgy and modern powders.

Looks like Dave made the cylinder dimensions absolutely max for the frame size.
 
Just found that the Corbon 200 grain hardcast does 1,307 fps 759 ft.lbs from a stock Ruger GP-100 6".

http://www.thehighroad.org/showthread.php?s=&threadid=1335&highlight=.357+*cast

I'm thinking I may just be happy with 1,300-1,350 fps with a 200 grain hardcast in a factory 6" GP-100 for now. I still think that with a large, unfluted 5 shot .357 cylinder in a GP-100 one could safely reach 1,500 fps with a hardcast (not jacketed) bullet. I don't know, but I'll keep the 5 shot conversion in the back of my mind for now.

Again thank you to those that allowed me to bounce the idea off of you. Your input is greatly appreciated.

Kilgor
 
Kewl :).

Kilgore, I hope you don't feel we "came down on you" too hard, that certainly wasn't our intent. Besides yourself, there's other people reading a thread like this and when very "edgy" concepts like this are discussed, it's absolutely critical that people (not just you!) realize how borderline the ideas are.

Basically, Terry and I and others could probably have been more "polite", but at the risk of somebody's safety.

Anyways. I just hope that's clear.
 
FIRST, RESPECT YOUR ELDERS

Especially someone who's been "shooting the 9mm since 1960".

Second, even the 357 Redhawk is NOT the FA, but I'm crazy.

Third, you can buy 41 or 44 Magnum revolvers so you don'y have to blow up your 357's.

Fourth, the GP100 is optimum in 357 Magnum (until Ruger punches it out to the 10mm; listening?).
:banghead:
 
FIRST, RESPECT YOUR ELDERS
Especially someone who's been "shooting the 9mm since 1960".
Click to expand...

Tim,

I'm not sure I follow what you are trying to tell me???
 
Gp-100 sammi

What SAAMI can the GP100 in 6"bbl handle? I am looking loading up a recipie that lists SAAMI @ 42,500 using 5.5gr 231.

Will the GP100 handle that much CUP?
 
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