Long Chambers on STI Guns?

[hjweiss]

I just got a new STI DVC Limited in 9mm. As an old Bullseye shooter, I sometimes still like to reload for maximum accuracy and to that end I like to load my bullets just off the barrel leade to minimize the jump to the rifling. With a new gun I usually use the "Plunk" test to measure max COAL for an assortment of my favorite bullets. Doing this with my new DVC Limited, none of my bullets failed the "Plunk" test no matter how far out in the case they were seated. Obviously this gun has a very long chamber....longer than any of my other high end 9mm's (Sig P210's, X5, Nighthawk). Just wondering if this is typical of STI guns and whether any of you find this to be a challenge in producing top tier accuracy loads?

[Hi-Power Jack]

You don't define "how far out they were seated", but my TruBor handles 1.175" and

I've heard of some people loading out longer.

Again, you don't define "top tier accuracy loads" but I shot this group out of my

standard TruBor at 52 yards last year ... guess it's NOT Top Tier, but pretty

good for a 71 year old guy who used to shoot a BHP.

[Trent1k1]

I load to 1.165 for 9mm.

I'll probably start an argument here, but reliability is more important to ME, than top tier accuracy. If my gun doesn't go BANG, 100% of the time, it doesn't matter how accurate it is at 18 yard since i'm about to spend 5 seconds clearing the jam. Even a Miss is better than an extra 5 seconds on a stage.

[hjweiss]

Thanks guys. I appreciate your replies. Examples of what I was getting in my testing was a Hornady 124 gr. XTP at a COL of 1.200" and a XTreme Plated 147 gr. HPCB at 1.260"....and they still "plunked" in the DVC Limited's chamber. As to my definition of top tier accuracy....that's a tough one. Certainly it depends on the gun and I don't yet know what the STI DVC Limited should be capable of. For my old bullseye guns it would have been a 3" group or less from a machine rest at 50 yds. I don't know if that is unrealistic for a USPSA gun.

[RippinSVT]

I have two STI 9mm single-stacks built for accuracy matches, a 6" bushing gun, and a 6" bull barrel. Both have the deep chamber you're referring to, both shoot iron-sighted groups as small as 1.2" at 50 yards from bags for 6 shots (when lighting, eyes, etc are perfect). I load 1.14-1.15" with a 115 XTP or Zero and Titegroup. You undoubtably have the same chamber cut. I used to think STI's were loosely built speed rigs only (and some are), but they've made me a believer and will shoot with a Baer any day of the week. For a 130PF target load, try 3.9gr of TG, a good 115gr jacketed conical (XTP, HAP, Sierra, Zero) seated 1.14", a moderate but consistent crimp (no bullet deformation, only a faint shiny ring at case mouth), a Federal primer, and matched brass (Lapua, Federal, Speer, etc). This is the load of loads...it always shoots in any gun I've tried.

[hjweiss]

Thanks Rippin. Good to know that there can be a high accuracy potential with STI. Your "load of loads" is very similar to one of my stand-by loads: 3.8 gr. of Titegroup under a 124 gr. bullet, very light profile crimp, at 1.135" COL. For me these have chrono'd at 1040 fps from a 5" bbl and 1098 from a 6" bbl.

[Hi-Power Jack]

3" group or less from a machine rest at 50 yds. I don't know if that is unrealistic for a USPSA gun.

The group I sent you yesterday was about 3" at 52 yards shot by hand with a rest

(no Ransom rest), in a standard TruBor.

[hjweiss]

Hi-Power. Yes I was admiring that group. That's fine performance from a gun and exceptional benched performance from a shooter. Definitely "pretty good" ....at any age! I always felt that shooting from a bagged bench rest is an art unto itself...one I often struggle with. Can't seem to get enough of the "human" element out of it. Gratifying to know that an STI can have that kind of potential.

[acoop101]

I wonder too if this is a safety measure for people who are going to convert these guns to 9 millimeter major. The longer lead lessens the chance of a high pressure excursion. As I recall most of the Weatherby magnums have the same thing so that you get more velocity as well.

Sent from my XT1080 using Tapatalk

[Kingman]

Most "USPSA" guns of any caliber will run with any bullseye gun. I shot Perrry in 88-90 and I'd take any open gun I have now to any .45 I shot then.

[JRM83]

My STI HexTac will eat 1.2" with no issues. Been experimenting with a 170gr 9mm bullet to use up all that space.

[Slostang]

My STI HexTac will eat 1.2" with no issues. Been experimenting with a 170gr 9mm bullet to use up all that space.

Where are you finding 170's?

[JRM83]

Black and blue bullets carries them

[hjweiss]

Thanks for the replies and info. So far I have just over 600 rds. through my DVC Limited and I'm quite pleased with its accuracy. The long chamber certainly doesn't seem to be a negative or limiting factor. Still experimenting with different bullets and powders in search of that optimal load....but the gun shoots almost everything I've put through it very accurately. I'm starting to really like this pistol.

[twodownzero]

My STI Eagle will chamber ammo it can't eject--1.300" long!

Edited March 29, 2016 by twodownzero