10mm In An S_i

[EricW]

I'm interested in converting an S_I pistol to run full house 10mm. Anybody tried it before? Any issues with the grip frames cracking?

(And yes, I realize that this is not an optimal setup for competition.)

Thanks in advance!

E

[HSMITH]

Don't need a 10mm chamber if the barrel is throated for long 40. Loaded long you will have the exact same case capacity as a 10mm and also be running a fully supported chamber.

The only reason I can think of to chamber one for 10 is to use factory ammo for SD.......

You will need to spring it a little heavier. I would go up to a 19 or 21 pound mainspring, a short radius firing pin stop and an 18 pound recoil spring if running true full house 10mm power levels.

[G17comp]

I know a guy who has an STI 10mm carry gun. It's a standard frame with no magwell, and a commander lenght slide. It seems to be as reliable as any other S_I I've seen.

[smokshwn]

When I first started I bought a used STI Eagle in 10mm with the intention of having a .40 barrel fit. It ran great with the little 10 and .40 I ran in it and it didn't seem any worse for wear. With full house 10 ammo it was definitely handful so I can't comment on the durability issue except to say that it was noticebly more violent than anything else I have shot in an S-I frame.

[EricW]

Don't need a 10mm chamber if the barrel is throated for long 40.

OK, the key words here are "full-house 10mm".

I need the chamber to accept 10mm brass. With all the wild-ass variations in the strength of 40 brass, I'm not going to run 40 at 10mm loadings in order to save sending $100 to Starline. I'm not meaning to be horribly rude, but I'm not interested in a competition solution here. I just want to know if the gun will hold up to a diet of 10mm and if there are any practical considerations to doing do.

Thx.

[Larry White]

Don't need a 10mm chamber if the barrel is throated for long 40.

OK, the key words here are "full-house 10mm".

I need the chamber to accept 10mm brass. With all the wild-ass variations in the strength of 40 brass, I'm not going to run 40 at 10mm loadings in order to save sending $100 to Starline. I'm not meaning to be horribly rude, but I'm not interested in a competition solution here. I just want to know if the gun will hold up to a diet of 10mm and if there are any practical considerations to doing do.

Thx.

Rechamber to 10mm and put in a 18# spring. Good to go.---------Larry

[herky]

Jerry the Geek, Oregon, had STI do a Limited gun in 10mm as he didn't like 40 short and weak.

[Catfish]

Sgtsvi on the forum had a 10mm SV that he sold to fund another project. Commander length and ported if I remember correctly. You could probably PM him for details.

There may even be a thread about it here where he posted a picture??

[uscbigdawg]

My buddy back home as a STI Grizzly, 6" in 10mm. Sweet gun and the long sight radius and smoot cycling of the longer slide makes it super fun to shoot.

It's an easy change over Eric. New barrel and new spring and you're good.

Rich

[Jasonub]

have a friend who has one and shoots noisy 240 pf handloads. he has it for about 8 years or so and still continous to shoot reliably. only downside is the damn noise. i swear its louder than an m16

[shred]

If you have old old STI mags, some of them can be problematic with 10mm as the internal shape wasn't good for the long case and TC bullet shapes, combined with the sizing variations from hand-assembly. (AFAIK, this is why the STI 6" Grizzly/hunter 10mms were almost all single-stack grips on STI frames)

[EricW]

Thanks Roy,

That's exactly the kind of thing I was wanting to know.

[G-ManBart]

I've never handled or shot one, but read an interesting article about just such a gun not long ago. Guns&Ammo ran a magazine called "The Complete Book of the 1911"...not sure why they call it a book. It was in the last couple of months that I picked this up. In it, there was an article called "A Long-Slide Custom 10" and it was about a guy who had Novak build him an STI hi-cap in 10mm with a 6" slide. Looked very cool and sounded like it shot really well too. I'm thinking that you might be able to find the article on their website now that it's a couple of months old.

Edit to add: If Novak is building them I can't imagine there are any major issues with the combination (sounded like this is a cataloged offering)...they have way too good a name to jeopardize if the frame won't hold up to it.

Edited April 30, 2007 by G-ManBart

[HSMITH]

Eric, fair enough if you want known 10mm brass. I don't have any problem loading known 40 brass, but your gun is your business.

I experimented some for the last hunting season with known 40 brass in mine, and 10mm ballistics were absolutely a walk in the park. Getting the velocities of Double Tap and Buffalo Bore just weren't problem in my gun.

IME what breaks grips is mags that are too tight when loaded to capacity, not the cycling of the gun.

IF you are serious about this, I would run at least a 19# mainspring and a 21# would be better. The mainspring has LOT more to do with slide opening speed than recoil spring does, and in this case we want to retard the opening speed a bit. Combine the heavy mainspring with a short radius firing pin stop and we have eliminated the battering on the opening stroke of the slide, now we need to provide adequate speed of closing with enough energy to close the slide. We all have a shoebox full of recoil springs so no problem there. A 16 or 18 pound spring should work wonderful here.

If you need a short radius firing pin stop let me know. I have a couple different ones cut for an AFTEC here that I was playing with. If you need a 40 barrel reamed for 10 let me know, I can easily acomodate that as well.

[EricW]

Thanks to Hsmith & all! Sounds like a viable project. Not sure if I'll go 5" or 6". Sorta all depends on whether Kramer will make me an IWB holster for it and if I go with a new heater or start with used.

I'm looking to replace about 3 pistols with one, and this really sounds like the ticket for me. Been thinking about this for a while...

[G-ManBart]

+1 on the Kramer. I have 5 of them (mostly the vertical belt scabbard) and the only non-Kramer I wear on a daily basis is an Alessi ankle rig for the G27. The oldest has had a LOT of use and is still as good as it was when new. I'd be suprised if they wouldn't make you an IWB for the 6".

[peterdaws]

IF you are serious about this, I would run at least a 19# mainspring and a 21# would be better. The mainspring has LOT more to do with slide opening speed than recoil spring does, and in this case we want to retard the opening speed a bit. Combine the heavy mainspring with a short radius firing pin stop and we have eliminated the battering on the opening stroke of the slide, now we need to provide adequate speed of closing with enough energy to close the slide. We all have a shoebox full of recoil springs so no problem there. A 16 or 18 pound spring should work wonderful here.

I am currently building a 10mm for a client in the Northern Territories who has an occupational licence. He needs it to shoot sharks off big game fish and crocodiles off tourists plus, the odd marauding pig.

I like the idea of the short radius firing pin stop for this application. Who makes them?

Peter Dawson

Australia

[Mick]

I put several hundred rounds of factory 180 UMC 10mm through an SV classic a couple years ago. It chrono'd 1125 fps for a PF of 202.5. It was a handful and I believe the gun had a 20# recoil spring as did my own Delta Elite. The owner eventually broke the gun shooting that hot ammo (and not changing springs etc).

I can get within 100 fps loading .40s out to 1.250".

I had a sweet 180 pf load of 5.0 grains of N320 under a 200 grain Precision Bullet (black bullet) that became my sole 10mm load until I rechambered the Delta to .40.

In a single stack I'd rather have a 10 than a 45 but did you see that 60 minutes (or 48 hours?) show about the guy/hiker in Arizona that killed his attacker and scared off his dogs with a 10mm? They made a big issue about him using a more powerful gun than the Cops would use. Well duh! You're out in the woods where there are bears and bigs!

The Cops aren't!

[HSMITH]

Peter, I use the EGW oversized firing pin stop, and cut the radius to whatever I want it to be. It is square edged on the bottom when you get it.

Mick, what broke on the gun you talk about?

[itento]

Eric, I think I'm one of the very few shooting Open with an Sti in 10mm. I had the gun built in 1989. It has a Caspian slide and Scheumann Hybrid barrel. While my buddy keeps badgeringh me to get a .38 Super, I just can't see putting the old war horse to pasture.

I've run a lot of different loads and have never had any problems. Along time ago (175pf) I ran pretty healthy loads (180 to 190 pf). I currently run 180 Zero JHPs in front of 5.1gr of VV320 and WW Lg primers. They run about 170 pf.

The one thing that will probably interest you is the OAL. I run 1.250. Anything much over that will hang in the Sti mags. I run Beven's 170mm (25 rds) and 140mm (20 rds). They have also been flawless.

I have also experimented around with 135 JHP in front of 9.xx grs of 3N37. I may still go back to this. It was a screamer (fast and really loud). It did shoot really flat w/o much straight back kick.

I'll be shooting the 10mm this Friday at the Area 6.

[shred]

I am currently building a 10mm for a client in the Northern Territories who has an occupational licence. He needs it to shoot sharks off big game fish and crocodiles off tourists plus, the odd marauding pig.

I like the idea of the short radius firing pin stop for this application. Who makes them?

Peter Dawson

Australia

Some other guy named Dawson carries them, or EGW..

http://www.dawsonprecision.com/ProductDeta...0002-1126570815

[Mick]

Peter, I use the EGW oversized firing pin stop, and cut the radius to whatever I want it to be. It is square edged on the bottom when you get it.

Mick, what broke on the gun you talk about?

I think he broke a guide rod, a guide rod plug (battered),, knocked sights loose and let the frame come loose from the SV grip...

It seemed to all fall apart but then I shot about 500 rounds of UMC in one day with it and there's no telling how much he did without maintaining it..

[Flexmoney]

Doesn't our very own TDean run 10mm in his STI-based guns ?

He might be able to comment on the feedability and such ?

E, I am guessing the thrust of this is to have a viable gun for the hills and the canoe (carry)...that will also work for games and such?

I really like the idea of 10mm for a good "do all" handgun. For hunting or wilderness defense, it can be loaded up to around 41mag power. In a double stack gun...that's a lot of energy in the mag to put into a target.

I'd have to think that the STI/SV's would hold up. We have shooters doing all kinds of weirdness to them in Open now (plenty of power for the springs/setups and such). If there were weak spots, I think we'd hear of them here.

On the other hand...the Glock 10mm is pretty well proven. I know that is not what you asked about, but...

I'm not sure how much time you might have on the large framed Glock platform.

- It reloads a bit different from the regular framed Glocks (the G17,G35 etc).

- The grip certainly spreads the recoil out...surprisingly soft shooting.

- Mags...cheap...reliable.

- Parts and gear, plentiful.

- Well proven

- light for carry (a bit thicker though)

And, there is always the companion option of the G29.

A G20 with a spring and a barrel swap makes shooting 40 for games or practice easy as pie.

(if this doesn't work for you, maybe others might use the info)

[EricW]

I really didn't want to go down the "application" discussion route, but since it's here...

I do have a G21. It's too large for my hands. It's what I currently take in the woods since it's more concealable than a 44 mag. There's just nothing you can do to a 44 mag that makes it....well....less than a PITA for what I want.

What I'm looking for is a "one gun fits most" solution:

- Compact enough to be concealable "on the street."

- Powerful enough to be worth carrying in the sticks.

- Enough penetration to convince whatever's on the business end that I'm not food or a doormat. I don't need to have it skinned automatically.

- Have a trajectory that's flat enough to reliably engage targets out to 100+ yards. (Because I feel I need the range *and* because I simply enjoy shooting a handgun at 50+ yards for fun. 40 really starts to puke out just past 100.)

Right now, I'm switching around between a G19, a Redhawk, and a G21. And that's not counting the Keltec... It's just a silly # of guns to have to mess with, when I'm nearly certain a 10mm (or hot 40) STI would reliably accomplish every task I set forth for it. And honestly, the 2011 platform has been the most reliable platform of anything I've used - I just have so much confidence in it that it makes sense to "play" with what I "practice" with.

The only real question marks for me were if the grip frame would hold up, and whether there were any mechanical reasons why 10mm might not be the best choice. The real question was STI or Caspian? HSmith does bring up a good point with the 40 brass. I may simply be able to run known, sorted 40 brass and make the rest of the discussion sophistry. That really makes it a viable duty / backup game gun.

Glocks are great solutions, and may well be the best solution. It's just not quite the solution I'm looking for - for whatever reason happens to be my pet peeve du jour.

And this kind of feedback is what makes benosville The Greatest Place on Earth.

[bigbrowndog]

Eric, I've had and shot 10mm's since I believe the early 90's. An STI frame accepted a SA Omega 6" topend, and it shot beautifully, A S&W 1076, commander sized gun that was a decent carry gun and good roaming companion, The earlier mentioned Omega, single stack, and a Glock 20, and 29.

Currently the 29 is my primary carry gun, and provides 4" accuracy out to 30yds, while still doing 1100fps with a 180gr JHP. The S-I, in either a Commander or 5" should, provided like any other that, its built right, last well into to 50,000 round range provided its cared for, and sprung properly.

If you are just going to use it sparingly, the S&W 1076, would make a fine gun for roaming, plus its stainless. You should be able to find one on Gunbroker, for what the parts would cost you for a topend.

One bad thing one the S-I, was that max. OAL was 1.25, and thats it.............no more. The single stack mags seemed to give more fudge room.

Trapr