What Can You Expect from a Barrel Upgrade?

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One of the biggest benefits of a semi-drop-in barrel upgrade is that you can fit it precisely to your slide for consistent lockup.

Service pistols shoot amazingly well considering that they’re produced by the trillions. OK, maybe millions, but they’re still mass production items made mostly by machines. If you have a pistol that’s hand-fitted, you’ll be paying a lot more than the $500 give or take a few Benjamins.

The most significant difference between hand-tweaked guns and production ones is the tolerance slack built into every part. When you make eleventy-trillion barrels to mate with eleventy-trillion slides, you need to build in a bit of play so you can be sure that any barrel will fit any slide. The result is a perfectly good pistol, that’s reliable in part due to the slightly loose tolerances, but it will never be as accurate as one with carefully fitted parts.

A little gentle filing on the high spots is all it takes to fit the new barrel.

A little gentle filing on the high spots is all it takes to fit the new barrel.

But what if you want to accurize an off the shelf model? Is it worth it? I decided to do a little test and got my hands on an Apex Tactical semi-drop-in barrel to plunk into a Smith & Wesson M&P 2.0 9mm pistol. Off the rack, that gun produced five-shot groups from 25 yards in the 2.5 to 3.5-inch range. Not too shabby, but I was guessing it could be improved.

Semi-drop-in means that you’ll need a pillar file to make it perfect. It’s an easy process provided that you take your time. Please, sir, step away from the Dremel tool. Barrel upgrades have full instructions available, but in short, the process involved removing a little bit of metal up near the muzzle and shortening and narrowing the barrel hood extension so that it perfectly mates with the slide.

Let’s look at a quick before and after snapshot of 25-yard, five-shot group performance.

Factory Barrel

Hornady Critical Duty 135-grain: 3.55”
Hornady Critical Duty 135-grain: 3.74”

Sig Sauer V-Crown 124-grain: 3.46”
Sig Sauer V-Crown 124-grain: 2.67”

Semi-drop-in Barrel Upgrade

Hornady Critical Duty 135-grain: 2.41”
Hornady Critical Duty 135-grain: 1.89”

Sig Sauer V-Crown 124-grain: 0.74”
Sig Sauer V-Crown 124-grain: 1.04”

That's a five-shot group from 25 yards. Not too shabby!

That’s a five-shot group from 25 yards. Not too shabby!

Umm, yes. I’d say it made quite a difference. After you install a semi-drop-in, you’ll see exactly why. Before, the tolerance slack resulted in a little front to back and side to side shake between barrel and slide. After, because I fit the parts together precisely, that movement was reduced to practically zero. The result speaks for itself.

  • Mike S

    For the benefit of us noobs – would you explain the measurements? FI – are they horizontal & vertical extremes or ??
    Tks

    • http://mygunculture.com/ Tom McHale

      Sure – they are the group maximum diameter. Basically I measure the two shots in the five shot group that are farthest apart (so all others are within that diameter) The idea is that the group size defines a circle in which all five shots will fall. Does that help?

      • Mike S

        Almost – I don’t understand why there are 2 measurements for each brand in each barrel.

        • http://mygunculture.com/ Tom McHale

          Gotcha – I just shot multiple five-shot groups to get a better idea of real performance. In a more formal test you’d shoot five different five-shot groups and average the results to get an accurate representation of performance. In this case I just shot two of each. That helps eliminate outlier results.

          • Mike S

            Thanks – After I get more involved in stuff like that I hope I’ll be able to understand sooner.

          • John Fernau

            You are doing one of the smartest things you can do, you are asking questions. Don’t ever stop especially when dealing with firearms. Just remember that no one knows everything and to check a few different sources to get a consensus of thought .You will find that there are some who like to spout off just make themselves look good. Good luck in your future endeavors with firearms .