Frame question on a 2nd top end build

[Fantom919]

Hello,

I recently acquired an STI Sentry in 9mm and wanted to have a .40 top end built for it. I had a few questions concerning the build and wad hoping for some input.

As a background, I live in California so buying a complete gun is not really an option except for a fully custom gun which would run about 3500 and some legal loopholes. There are literally no .40 1911s I can buy off the shelf. The closest I can get is a colt or kimber in 10mm and rebarreled.

If I were to make a new top end, is there anything I could do to prolong the life of the frame? I believe the Sentry has a forged frame. I was thinking something along the lines of a coating or if there was any other recommendation on this topic.

Thanks!

[zzt]

The Sentry does have a forged frame. Once you fit the new slide, etc. you can have the frame, or the whole gun hard chromed. That will significantly reduce wear.

Unfortunately, the tolerances most manufacturers hold on slides isn't impressive. You are going to have to fit the slide to the receiver, because it has already been fit to your 9mm slide. You are also going to have to be pretty precise about it, because, believe it or not, a loose fit wears the frame rails more than a proper fit does. I found that out the hard way. That's why I recommend you have at least the receiver hard chromed. That way the surface of the receiver is harder than the slide, instead of the other way around.

If you accidently make the fit of the new slide a touch too loose, you can have that slide treated with one of the Nickel alloy coatings. They physically take up space and can be used to tighten up loose tolerances by a thou or two.

I'd suggest you buy your slide from someplace like Brownells that lets you return goods for any reason. After measuring your new slide you may find that one of the dimensions is already too large.

[BrianATL]

If all else fails there's always accu-rail

[Fantom919]

Thanks for the input! Sounds like getting the frame hard chromed would be ideal. Once funds allow, I'd probably have all of that done at the same time.

[mike4045]

Easy to have done. I have been running one with about 35k on the 40 top and 40k on the 9mm top. About 3.5 yrs of matches. Fitted correctly the first time. Thought about hard chrome on the frame but I hate shiny guns.

[2MoreChains]

I kind of did the same thing a few years ago by having a 9mm top end built for a .40 2011 Eagle. I wanted the 9mm top end for 3-gun, but I also wanted to have the ability to use the .40 top end as a backup to my other 2011 in Limited. 90% of the time the gun wears the 9mm top end but the .40 slide still fits tight to the frame.

I asked my GS to fit the slide to the frame (to keep the frame rails matched to the original .40 slide). I think I ordered the slide (STI) from Shooter's Connection when they were still a STI dealer, added a Kart barrel, small parts from Dawson. and asked for the same kind of sights as the rest of my guns. Total cost in parts was something like $600 or $700, and its still in the white (which doesn't bother me since I live in a dry climate).

Its definitely doable. It just depends on whether its worth getting a second gun or not.

[ericridebike]

So, just want to clarify for my understanding. I have an STI DVC Limited in .40. Could I have a 9mm top end built to use with the .40 DVC frame? I would love to be able to do that to run the .40 for USPSA Limited and then have the 9mm top to use for Steel Challenge and 3-Gun. Shot my Glock 34 last night in a Steel Challenge match and after shooting the STI, the Glock just isn't the same anymore.

[zzt]

I can understand wanting a 40 top end if you only had a 9, but not the other way around, unless you felt 21 in a mag was a handicap for 3-gun. Just load Rainier's excellent 135gr CPTC or Falcon's Falcoated 140 TC down to 9mm levels. It will shoot softer and make less noise.

I also use the Xtreme 165gr CPHP HPCB bullet at 140PF. The muzzle barely rises when fired, and it knocks steel down better than the factory 147s did in my 9. In hindsight, I wish I had bought my 40 first. With Minor loads it outshines my custom 9, and I get to shoot Major for Limited.

[ericridebike]

I can understand wanting a 40 top end if you only had a 9, but not the other way around, unless you felt 21 in a mag was a handicap for 3-gun. Just load Rainier's excellent 135gr CPTC or Falcon's Falcoated 140 TC down to 9mm levels. It will shoot softer and make less noise.

I also use the Xtreme 165gr CPHP HPCB bullet at 140PF. The muzzle barely rises when fired, and it knocks steel down better than the factory 147s did in my 9. In hindsight, I wish I had bought my 40 first. With Minor loads it outshines my custom 9, and I get to shoot Major for Limited.

That's a great point I hadn't thought of earlier. Just getting started loading .40, so will have to work on a load to use for 3-Gun and Steel and see how that goes. For my purposes, being down a few rounds shouldn't make a difference. Thanks for the advice.