STI Open Gun Upgrade

[gdboytyler]

After an extended break from competitive shooting, I decided to give my 18 year old 38S open gun a makeover. I wanted to try out one of the newer comps, so I decided to also try out 9mm major and minor to save money on brass. I was only recovering around 25% of my 38SC brass.

My old 38 SC setup (with Tasco RDS, small comp, 12lb recoil spring) weighed 45 oz. With the old setup, I could consistently shoot 7 yd bill drills with 0.196 sec splits (all A's).

Here's what got changed:

1. Akai Shoto comp because it was new and looked cool.

2. KKM bull bbl because that's what was available. I was also hoping the bull bbl would help reduce the muzzle flip.

3. Replace my Tasco tube red dot because it's old and the newer Tascos are supposedly un-reliable.

4. DAA Thumbrest

Results of the makeover:

1. and 2. As expected the Akai Shoto comp with major 9mm ammo (8 lb spring) is much more effective than my old comp with major 38SC ammo. My 7 yard Bill drill splits immediately improved from 0.196 sec to 0.178 sec (all A's). This was with the Tasco red dot sight. With the old comp, I could get below 0.18 sec splits, but NEVER with 6 shots in the A-zone.

I also tried out the Winchester factory 9mm minor ammo (5 lb spring). I got my best Bill Drills EVER. Splits went down to 0.17 sec, all A's from 7 yards. Quite a change in POI between the major and minor ammo with 5 lb spring.

The factory 9mm ammo also functioned well with the 8 lb spring, had very little POI change compared with 9mm major, but the gun felt sluggish with the 8 lb spring.

Qualitatively, the muzzle blast, recoil and muzzle flip FELT about the same between the old school comp with major 38SC ammo (12 lb spring) and the Akai comp with major 9ammo (8 lb spring). But, the timer don't lie and the timer shows the Akai comp works GREAT!!

3. I knew my best and fastest route for improvement was more practice. So I wanted the Tasco red dot's replacement to make practicing easier and cheaper. One of the reasons I didn't want a C-More is because it would be a hassle to change the zero when switching from 9 major to 9 minor to .22lr.

I had planned to install Leupold Deltapoints on both the Caspian slide and my Tac Sol 22lr slide. Expensive, but the quickest/easiest way to switch calibers. However, it would be a hassle to switch from 9major to 9minor because the POI was very different. Alas, both the 7.5 and 3.5 moa versions were just too dim when I shot indoors and most of my matches and practices were done indoors. So the Deltapoints were returned to Cabelas.

So I went with the Aimpoint Micro, which had been sitting on my SHTF AR. With the Aimpoint, I could easily and reliably adjust the zero when I switched between major 9, minor 9 and .22lr.

With the Aimpoint Micro replacing the Tasco red dot, my 7 yard Bill Drill splits got WORSE; from 0.178 sec to 0.19. Recoil and muzzle flip both felt worse. After a few hundred rounds, I was getting the occasional Bill Drill around 0.18 sec splits. I'm assuming my splits got worse because the Aimpoint setup WITH a tungsten FLGR weighs about 3oz less than the Tasco setup (without tungsten FLGR).

I switched out the 8 lb recoil spring and tried out a 12 lb recoil spring I had available. My splits stayed around 0.19 sec, but I was in the A-zone more reliably with the 12 lb spring and recoil did feel slightly softer. However, with the 12 lb spring, my follow up shots tended to get pushed low.

All the shooting to this point was done with 9mm major ammo that I had bought from a local shooter: 124 gn MG CMJ, unknown powder and velocity. I was taking the reloader's word that the ammo made major.

I was a bit disappointed that I shot the 9mm setup WORSE with the lighter Aimpoint Micro than with the old Tasco.

So the next step was to get back into reloading with a Hornady LNL.

I worked up a 9mm major load that had 124 gn MG JHP, 8.3 gn HS6, and Winchester small rifle primers. My handloads averaged 1405 fps; power factor = 174.2

With my CONFIRMED 9mm major ammo, my Bill drill splits dropped to 0.174 sec, all A's! The HS6 major ammo felt softer, shot flatter and I was also able to go back to the 8 lb recoil spring which eliminated the dipping of my follow-up shots; which made my Bill drill groups smaller and more consistent. With the equipment upgrades and my own reloads, I got my best ever Bill drills with major ammo.

Thanks to the multiple threads that recommended HS6 for 9mm major.

5. When I was testing the Deltapoint, my weak hand slid forward and bumped the mag release (quite embarrassing). This made me realize that I used the Tasco frame mount as a thumbrest, which prevented my weak from sliding forward into the mag release. With the thumbrest installed, no more inadvertent mag drops.

Here's the before photo:

Here's the after photos:

[Whoops!]

Nice write-up, too bad you're smoking crack.

Just kidding.

[67ls7vert]

Thats not very nice! BE NICE!

[67ls7vert]

OOPS! Sorry I'm new to the Dark Side.

[Hi-Power Jack]

Gdboy, thanks for all the great info - looks like you're

enjoying the sport.

If you want to try alternative loads, try 115 grain

bullets, and Win Auto Comp.

The 115's might lower your time on the timer, and the

WAC is cleaner than HS6