Sti Trusight" Gun Is "legal" For Standard Division

[Matt Cheely]

Though I am no rocket scientist, I would have to take a 180 deg. approach to your use of Bernoulli's principal. (FYI, I'm not totally sure yet that this effect is what the expansion chamber is all about, I'm just going off of TDean's post)

Lets assume that since the bullet still has to have the velocity to make major, it's going the same speed as an identical bullet from a normal 5" gun. The only difference is that in the expansion chamber, the bullet no longer plugs the gas behind it, therefore it flows ahead of the bullet somewhat while in the chamber. This would increase the velocity of the gas, therefore reducing pressure. Not to mention that as the volume of the pipe increases, pressure drops as well. This could all equal less ejecta out the end of the system, thus less recoil and muzzle flip.

Stopping the gas before it leaves the gun certainly reduces recoil. You can relate it to a suppressed firearm. It has less recoil (This is from observation, not actually firing one) than it's unsupressed counterpart.

Anyone else care to interject on the subject, I love technical discussions

Edit: I also think it's kinda fugly. Maybe if they made it look like a 6" instead.

Edited October 10, 2005 by hksniperman

[eerw]

Like the introduction of the sighttracker from SV...it'll be interesting to see what the STI will bring to the table..

It is marketing and development..do we need it..not really, but the manufacturers sure want us to believe we do..

I applaud the development by the manufacturers...they keep trying to incrementally improve upon what is out there...and that is good for everyone..we get more choices and the gun industry tries to stay financially sound.

USPSA and IPSC have established their guidelines..the manufacturers are developing and pushing the envelope to come up with new things..( like mentioned the continual improvement and modifications of production division guns).

The worse thing we can do is change to the rules to disallow the gun, because we do not like it.

.........................................

I thought Limited and Standard had rules against barrel weights and compensators..wouldn't an expansion chamber make that a comp..

if what they are making is an extended bull barrel with the sight mounted on it..wouldn't that be within the rules??? anyone have any other photos??? I do not remember where I found that one..just remember seeing it without any explanation and thinking, "hmmmmmm"

[Matt Cheely]

The worse thing we can do is change to the rules to disallow the gun, because we do not like it.

<{POST_SNAPBACK}>

I agree wholeheartedly with this. I can understand it in production, for reasons that I won't elaborate on here, but for limited, it's not compensating in the normal sense of the word, let it be. If you loose a match, this wasn't the reason.

If it's the same weight as a standard 5", I don't see how they can call it a barrel weight.

Also, since it's not a external modification, why couldn't they put in in a 5" package with a standard bull barrel bored out? Unless of course SVI has thier sighttracker patented and this way STI can also have a front sight out there that dosen't move.

Edited October 10, 2005 by hksniperman

[dirtypool40]

hksniperman - Exactly, and just like the "site tracker" I don't see it as any noticable advantage, and it's too heavy (for me), and you get married to an oddball configuration.

I think the theory (other than the truth of non-moving front site and barrel weight) is something like the old freebored IPSC guns we saw in HANDGUNNER a year or so ago. (I'll edit this later if I remember who made them, it was somebody like Pachmyer or Devel, yeah, I think it was Devel).

Anyway the theory is vaguely similiar to the gain twist AET thing where you are trying to develope less tourqe. In this case, there's just less rifleing, and the last bit of barrel is "free bored" into an "expansion chamber".

But yes, for it's overall length, it should be slower.

Pass.

Edited October 10, 2005 by dirtypool40

[shred]

A while back I had the 'expansion chamber' idea, but bored into a standard bull barrel.. the idea was that if you did it right, you could smack a lot of gas mass into a front-plate, thus reducing recoil, and then let it out somewhat slower, akin to the suppressor model.

I ran it past a big name gunsmith/shooter and he said "yeah, I built one of those once.. found out that while it reduced recoil, the shorter barrel made me need more powder to make major, so it was about a wash for recoil"

Maybe the same thing here..

[wide45]

Sounds like the ticket for a bull barrel in a 6 inch slide. Bore the rifling back to 5" and cut a series of wipes or baffles into the last inch. Should not work well enough to get the BATF interested.

Might be easy to make as a threaded attachment for a standard barrel, like a cone.

Edited October 10, 2005 by wide45

[mcoliver]

I'm trying to understand what you guys are saying about the back-bored barrel. Is the red line in the attached pic how the cross section will look like for a back-bored barrel?

[GvU]

Bernoulli's principle states that ....as velocity decreases, pressure increases (works for both fliuds and gasses). The expansion chamber to would seem to decrease velocity of the gasses therefore increasing pressure.  The only place for the increased pressure to go is out the one hole in the muzzle.  This would INCREASE the "rocket effect" and theoretically induce more muzzle flip.

What am I missing here...

<{POST_SNAPBACK}>

Increase in volume (larger area at the front, less gas-velocity? probably no gain at all!)

DVC, John

[XRe]

I ran it past a big name gunsmith/shooter and he said "yeah, I built one of those once.. found out that while it reduced recoil, the shorter barrel made me need more powder to make major, so it was about a wash for recoil"

<{POST_SNAPBACK}>

I shot a gun configured in exactly that way. It didn't seem to make any discernable difference in perceived recoil. All the gas still has to go out the hole, you only get one "baffle" to slam the gas into, and the size of that baffle is limited by the OD of the barrel.

This gun might make a *little* difference, in that the expansion chamber can be bigger, and you've still got a 5" barrel. It would appear, though, that the expansion chamber could be longer than the bullet, allowing gas to pass the bullet and possibly disrupting bullet flight. Further, in order to work the expansion chamber, you need gas - with fast burning powder, you don't have much of that. You'd have to go to slower powder to intentionally work the chamber, which then leads to more mass exiting the chamber at high velocity which.... almost assuredly negates the effect of the chamber in the first place.

I see this entirely as a marketing move by STI to fight the Sight Tracker, and it's an interesting idea, in that light.

I do tend to agree with others, though, that, on the surface, this would appear to violate the rules, but.... realize that special condition 18 only applies to *MODIFICATIONS* to a factory gun, not a gun built in a factory configuration that has sold 500 units (the Sight Tracker technically has a barrel weight, too, remember).

Having never handled one.... looks like it'd be awful muzzle heavy (I find the Edge profile guns muzzle heavy to begin with...)....

[mpolans]

how is it a barrel weight if the part is the same piece as the barrel?

Okay...STI's Trubore barrels have an integral comp. It's not threaded on, it's all one piece.

not arguing, and part of me doesnt think this should be limited legal...but then again if we didnt embrace change we would all be shooting singlestack 45s

Sure, evolution is good. I think unchecked evolution is great...in Open division. If we allow the same degree of evolution to continue in Limited, the next step is a barrel weight if several baffles...then you drill vertical holes in the chambers...then what do you have? My understanding of Limited Division is that it's supposed to be the place for limited modification in order to reduce costs and encourage the use of guns that are more "practical"; clearly, that isn't happening...the only divisions allowing cheap shooting are Production and Single Stack. Right now, the price difference between open vs. limited guns is the cost of a comp ($150), a red dot ($150), and a big stick ($100), or about $400, which is nothing when you consider the outlay to shoot IPSC anyway. Of that $400, I'm hesitant to even include the red dot, because you can always take it off and put it on several other non-IPSC guns, so it's not really Open-specific. Without it, the difference is only $250.

Since lower prices clearly isn't the reason for Limited, why aren't Docters and JPoint slide mounted red dots allowed on a Limited gun? Are those next?

If Limited is going to become a no holds barred arena, why not just eliminate it and institute the Modified rules here in the US?

this should be OK if infinity can have the sightracker, if they meet the production #s it should be OK for limited...since it doesnt weigh more than a 5 inch gun, the only thing thats heavier is the barrel.  what makes this different than the sight tracker?

harmon

<{POST_SNAPBACK}>

Personally, I don't like the sightracker idea either for the same reasons.

[Flexmoney]

I was hoping it they figured out a fixed barrel, gas operated setup...that works.

[Chuck D]

What is this sport coming to?

(tongue firmly implanted in cheek)

Edited October 10, 2005 by Chuck D

[diehli]

The sky is falling!!! The sky is falling!!!

[Harmon]

how is it a barrel weight if the part is the same piece as the barrel?

Okay...STI's Trubore barrels have an integral comp. It's not threaded on, it's all one piece.

not arguing, and part of me doesnt think this should be limited legal...but then again if we didnt embrace change we would all be shooting singlestack 45s

Sure, evolution is good. I think unchecked evolution is great...in Open division. If we allow the same degree of evolution to continue in Limited, the next step is a barrel weight if several baffles...then you drill vertical holes in the chambers...then what do you have? My understanding of Limited Division is that it's supposed to be the place for limited modification in order to reduce costs and encourage the use of guns that are more "practical"; clearly, that isn't happening...the only divisions allowing cheap shooting are Production and Single Stack. Right now, the price difference between open vs. limited guns is the cost of a comp ($150), a red dot ($150), and a big stick ($100), or about $400, which is nothing when you consider the outlay to shoot IPSC anyway. Of that $400, I'm hesitant to even include the red dot, because you can always take it off and put it on several other non-IPSC guns, so it's not really Open-specific. Without it, the difference is only $250.

Since lower prices clearly isn't the reason for Limited, why aren't Docters and JPoint slide mounted red dots allowed on a Limited gun? Are those next?

If Limited is going to become a no holds barred arena, why not just eliminate it and institute the Modified rules here in the US?

this should be OK if infinity can have the sightracker, if they meet the production #s it should be OK for limited...since it doesnt weigh more than a 5 inch gun, the only thing thats heavier is the barrel.  what makes this different than the sight tracker?

harmon

<{POST_SNAPBACK}>

Personally, I don't like the sightracker idea either for the same reasons.

<{POST_SNAPBACK}>

limited division guns should always meet the production requirement, they should not allow ports, comps or any for of electronic/optical sights.

there is nothing in the existing rulebook that says what this gun that STI built is illegal(except the production numbers)

its no more a barrel weight or device to control/reduce recoil than a long dustcover or tungsten sleeved barrel.

should we start banning everything that is new? or say if you want to shoot that particular iron sighted, non compensated pistol theres a place for you, OPEN!

san someone explain to me why a company can build a gun, race car, softball bat, ect ,ect by the rule book and suddenly it gets banned becasue its different or better?

take a good look at the limited guns anyway, they are not practcal, but gamey tools of the sport. whats different with the new sti gun?

Harmon

[Interceptor]

Most people will buy these and be no better for it. TGO and Travis T both shoot standard steel frame hi-cap pistols and beat everyone like a drum. A back-bored barrel will do nothing for anyone's mastery of the fundamentals, and IMO, that's all that really matters anyways, and what creates victories.

As long as it meets the rule requirements, who cares.

My .02

Edited October 10, 2005 by Interceptor

[mpolans]

limited division guns should always meet the production requirement, they should not allow ports, comps or any for of electronic/optical sights.

there is nothing in the existing rulebook that says what this gun that STI built is illegal(except the production numbers)

its no more a barrel weight or device to control/reduce recoil than a long dustcover or tungsten sleeved barrel.

should we start banning everything that is new? or say if you want to shoot that particular iron sighted, non compensated pistol theres a place for you, OPEN!

san someone explain to me why a company can build a gun, race car, softball bat, ect ,ect by the rule book and suddenly it gets banned becasue its different or better?

take a good look at the limited guns anyway, they are not practcal, but gamey tools of the sport. whats different with the new sti gun?

Harmon

<{POST_SNAPBACK}>

My apologies, I might not have been clear enough before. My main concern isn't a question of the Trusight's and Sighttracker's legality within USPSA rules, but rather, if we allow such radical modifications, what is purpose of the Limited division?

And for those who are comparing me to Chicken Little with their snide, flippant comments, how about a detailed response? What do YOU see as the purpose of having a Limited division?

[diehli]

And for those who are comparing me to Chicken Little with their snide, flippant comments, how about a detailed response?  What do YOU see as the purpose of having a Limited division?

<{POST_SNAPBACK}>

Okay. Limited is Open with five (5) restrictions:

1)No compensators.

2)No optics.

3)Minimum production numbers. No prototypes.

4)Mag length of 140mm instead of 170mm.

5)No external devices to control recoil.

That's what Limited is and that's what it should be. Don't try to make it into something it isn't.

BTW, I'm all for getting rid of numbers 3 and 5.

[Matt Cheely]

BTW, I'm all for getting rid of numbers 3 and 5.

<{POST_SNAPBACK}>

I agree as well.

[stiracer]

I was hoping it they figured out a fixed barrel, gas operated setup...that works.

<{POST_SNAPBACK}>

I like your thinking Flex! Sorta l;ike what Craig LTD was working on and got figured out years ago but was way to expensive to sell back then!

These days i would bet he'd sell more then he could produce!!!!

[mpolans]

And for those who are comparing me to Chicken Little with their snide, flippant comments, how about a detailed response?  What do YOU see as the purpose of having a Limited division?

<{POST_SNAPBACK}>

Okay. Limited is Open with five (5) restrictions:

1)No compensators.

2)No optics.

3)Minimum production numbers. No prototypes.

4)Mag length of 140mm instead of 170mm.

5)No external devices to control recoil.

That's what Limited is and that's what it should be. Don't try to make it into something it isn't.

BTW, I'm all for getting rid of numbers 3 and 5.

<{POST_SNAPBACK}>

Okay, you've stated the definition of what Limited division IS, but WHY is it defined that way?

For example, you say you don't mind getting rid of #3 and #5, but why? Why not get rid of #4 and/or #2?

What is the RATIONALE behind the rules that define Limited?

[diehli]

And for those who are comparing me to Chicken Little with their snide, flippant comments, how about a detailed response?  What do YOU see as the purpose of having a Limited division?

<{POST_SNAPBACK}>

Okay. Limited is Open with five (5) restrictions:

1)No compensators.

2)No optics.

3)Minimum production numbers. No prototypes.

4)Mag length of 140mm instead of 170mm.

5)No external devices to control recoil.

That's what Limited is and that's what it should be. Don't try to make it into something it isn't.

BTW, I'm all for getting rid of numbers 3 and 5.

<{POST_SNAPBACK}>

Okay, you've stated the definition of what Limited division IS, but WHY is it defined that way?

For example, you say you don't mind getting rid of #3 and #5, but why? Why not get rid of #4 and/or #2?

What is the RATIONALE behind the rules that define Limited?

<{POST_SNAPBACK}>

A'ight. When I said "Limited is Open..." I meant that Limited is a full-on, balls-to-the-wall racing Division that has a few restrictions. Limited isn't like Production which is a "put go-fast bits on your family car" Division. It's called Limited (and not Standard) 'cause it's a Division in which we want to put a limit on the "equipment race/race equipment". Think of it as World Super Bike (Limited) versus Moto Grand Prix (Open). The primary difference between Open and Limited is the type of sight.

So, the hot-shiitake-bits-needed-to-be-competitive that were at the core of the "equipment race" were optics, comps/ports (i.e. recoil reducers), and capacity. Limited is, primarily, an iron sight Division, that's why optics aren't allowed. Getting rid of comps/ports jives with the V of DVC. Getting back to initial single-stack capacity wasn't in the cards, so they went for 140 (and .40) on that one. To further curtail the equipment race they went with something along the lines of "you must start with a small-block Chevy motor" and put in the production number requirement.

Unfortunately, I think that some of the latest "interpretations" of the Limited Division rules have been less than true to the way the rule is written (if not its intent)—it clearly says "or components"— which has helped to further muddy the waters as to what, exactly, Limited is.

The rationale, then, behind the formation of Limited Division was something akin to: "Allow a place for more normal looking/acting guns to race." An additional consideration might have been that this would make USPSA more accessible to the average Joe 'cause the requirements made the guns look more like what he had at home and, thus, something that he could come out and play with.

[Skywalker]

Okay. Limited is Open with five (5) restrictions:

1)No compensators.

2)No optics.

3)Minimum production numbers. No prototypes.

4)Mag length of 140mm instead of 170mm.

5)No external devices to control recoil.

That's what Limited is and that's what it should be. Don't try to make it into something it isn't.

BTW, I'm all for getting rid of numbers 3 and 5.

<{POST_SNAPBACK}>

Welcome to Standard Division (almost) ...

[diehli]

Okay. Limited is Open with five (5) restrictions:

1)No compensators.

2)No optics.

3)Minimum production numbers. No prototypes.

4)Mag length of 140mm instead of 170mm.

5)No external devices to control recoil.

That's what Limited is and that's what it should be. Don't try to make it into something it isn't.

BTW, I'm all for getting rid of numbers 3 and 5.

<{POST_SNAPBACK}>

Welcome to Standard Division (almost) ...

<{POST_SNAPBACK}>

Right... take away the box and include the EGW mag gauge and it's what both Standard and Limited should, IMO, be.

[ErikW]

What we need to do is marry the STI TruSight barrel with the SPS Pelican frame, to make something that would really get mpolans' panties in a bind.

I don't have a problem with an expansion chamber. One hole in the barrel that says "entrance" and one for "exit" and it's good with me. (Except I think silencers are comps and I appear to contradict myself.)

Limited (and Standard) sorely need innovation. It's pretty sad that one (ancient) design dominates the division. The only changes have been long/wide frames, slab slides, bull barrels, fiber optic sights, etc. on the same design. Banning innovations such as these is pretty much just trying to create a 1911 division.

[diehli]

Limited (and Standard) sorely need innovation.

<{POST_SNAPBACK}>

I was waiting to see what would become of Fred Craig's latest creation... then he went to the sandbox....