It's a Shootout: Glock 21 vs Sig Sauer's P320, Who Wins?

October 6, 2021 Topic: Glock 21 Blog Brand: The Reboot Tags: Glock 21HandgunsPistolsGuns

It's a Shootout: Glock 21 vs Sig Sauer's P320, Who Wins?

Both of these guns have their merits.

<p><strong>SLIDE AND FRAME</strong></p>

<p>Both handguns having a frame made of polymer means they weigh significantly lighter compared to other full-size handguns that use an all-steel or aluminum alloy frame.</p>

<p>Both also have steel slides, which is why both pistols are in the same weight category. That said, the SIG P320 full size is around a tenth of an ounce lighter than the Glock 21.</p>


<p>The base model .45 ACP-chambered SIG P320 that we’re looking at today has a black finish SIG Sauer calls “Nitron”, while all Glock Gen4 pistols use “Melonite”.</p>

<p>These companies sure like to give fancy names to their guns’ finish. Having been brought up with 1911s and revolvers the only gun finishes I know are blued, parkerized, nickel-plated and stainless, so I decided to do a quick research on how Nitron and Melonite compare when it comes to corrosion resistance.</p>

<p style="text-align:center"><img alt="a picture of the SIG Legion's PVD finish" height="358" sizes="(max-width: 477px) 100vw, 477px" src="" srcset=" 1500w, 600w, 300w, 768w, 1024w, 80w, 265w, 696w, 1068w, 560w" width="477" /></p>

<p>All SIG Sauer P320 pistols use a process called&nbsp;<a data-wpel-link="external" href="" target="_blank">PVD (Physical Vapor deposition)</a>. The slides are&nbsp;<a data-wpel-link="external" href="" target="_blank">bombarded with ions</a>&nbsp;while in vacuum, which results in a protective coating applied to the metal surface by way of metal vapor. This gives the finish&nbsp;<a data-wpel-link="external" href="" target="_blank">a rating of around 70</a>&nbsp;in the Rockwell C Hardness scale. In the case of Nitron, color is added to the PVD process to give P320 slides a black finish.</p>

<p>In contrast,&nbsp;<strong>Glock uses a ferritic-nitrocarburizing salt-bath process called Melonite</strong>&nbsp;(Glock enthusiasts argue that the company has always used Tenifer until 2011 when they first started using Melonite on Gen4 handguns —&nbsp;<a data-wpel-link="external" href="" rel="noopener noreferrer" target="_blank">both Tenifer and Melonite</a>&nbsp;are trademarked processes sold by the same company) to treat the slide’s surface.</p>

<p>Both Tenifer and Melonite are reported to have a rating of 64 in the Rockwell C Hardness scale. The coating on top of the treated slides is a little different compared to previous generation Glock pistols, which results in Gen4 having a lighter shade of gray finish compared to the somewhat blacker finish in previous Gen1 to Gen3 Glocks.</p>

<p>If all these online data on hardness are accurate, the SIG P320’s finish should be a bit more durable than that of the Glock 21.</p>

<hr />
<p><strong>THE SIG P320</strong></p>

<p>In January 2014, the first SIG P320 pistols (chambered in 9x19mm Parabellum) became available in the US civilian and law enforcement market. At first glance these were just the same&nbsp;<a data-wpel-link="external" href="" target="_blank">SIG P250</a>s, the only differences being the early P250s used a DAO (double action only) hammer-fired mechanism and had a steel frame, while the newer P320 uses a DAO striker-fired mechanism and a polymer frame.</p>

<p style="text-align:center"><img alt="a picture of the SIG P320's Components" height="862" sizes="(max-width: 1134px) 100vw, 1134px" src="" srcset=" 1134w, 600w, 300w, 768w, 1024w, 80w, 696w, 1068w, 553w" width="1134" /></p>

<p>But what could be the P320’s most defining attribute which would three years later win it the US Military’s (MHS) Modular Handgun System contract by besting other polymer pistols of competing gun manufacturers is its modularity, akin to the&nbsp;<a data-wpel-link="internal" href="">AR</a>&nbsp;platform.</p>

<p>In fact it’s what SIG designed these pistols for.&nbsp;<strong>Inside the P320’s frame is a trigger assembly housed in a stainless steel chassis&nbsp;</strong>called the FCU (Fire Control Unit). It has the trigger and all the linkages and springs necessary for the gun to fire.</p>

<p>This FCU trigger assembly group can be removed and installed to four different size frame (full size, compact, carry and subcompact) by the user and requires no knowledge of gunsmithing or tools. This is achievable via SIG Sauer’s Caliber X-change kit.</p>

<p style="text-align:center"><img alt="a picture of the SIG P320 FCU" height="272" sizes="(max-width: 482px) 100vw, 482px" src="" srcset=" 747w, 600w, 300w, 696w, 745w" width="482" /></p>

<p>Talking about the trigger, SIG Sauer states in their website that the P320’s trigger reset is&nbsp;<a data-wpel-link="external" href="" target="_blank">short, cleaner and crisper</a>&nbsp;compared to their competitors’ handguns (they were obviously making a reference to Glock’s pistols being their closest rival, as people who own Glocks regularly talk about how mushy the Glock trigger feels).</p>

<p>And disassembly is also supposedly safer because the trigger does not have to be pulled, eliminating potential risks of accidental discharges (again they were obviously making a reference to how a Glock pistol’s trigger has to be pulled to field strip the gun).</p>

<p style="text-align:center"><img alt="a picture of the SIG P320 in .45 ACP" height="270" sizes="(max-width: 478px) 100vw, 478px" src="" srcset=" 478w, 300w" width="478" /></p>

<p>The SIG P320 chambered in .45 ACP was introduced in 2015, just a year after the first 9mm-chambered version came out. Like all other P320s that came before it,&nbsp;<strong>its frame can be swapped out to a smaller frame</strong>.</p>

<p>But as great as it is, there’s one thing the Glock 21 has going for it that the P320 doesn’t. We’ll talk about that in more detail in a bit.</p>

<hr />
<p><strong>THE GLOCK 21</strong></p>

<p><a data-wpel-link="external" href="" target="_blank">Developed in 1990</a>&nbsp;with the first production models released in the middle of the&nbsp;<a data-wpel-link="external" href="" target="_blank">following year</a>, the Glock 21 is chambered for the .45 ACP and is one of the very few full-size pistols manufactured by Glock.</p>

<p style="text-align:center"><img alt="a picture of a Glock 20 and a Glock 21" height="360" sizes="(max-width: 640px) 100vw, 640px" src="" srcset=" 1024w, 600w, 300w, 768w, 696w, 1068w, 747w, 1280w" width="640" /></p>

<p>The Glock 21 is essentially a Glock 20&nbsp;as far as weight and dimensions, the only differences being the caliber it is chambered for (.45 ACP for the former,&nbsp;<a data-wpel-link="internal" href="">10mm</a>&nbsp;for the latter) and that it uses that octagonal barrel rifling mentioned earlier.</p>

<p>I actually did a comparison between the Glock 21 and the Glock 21, you might want to take a look at it in&nbsp;<a data-wpel-link="internal" href="">this article</a>. One thing I touched upon in great length when I compared those two was the option to convert either model to a different handgun caliber.</p>

<p>Unlike the SIG P320’s fully modular design,&nbsp;<strong>no Glock pistol’s trigger assembly can be removed for installation in another different size frame</strong>. If you bought a full-size Glock 21 and you want a subcompact pistol chambered in the same .45 ACP caliber, the only way you can have one is by buying a Glock 30 or a Glock 36.</p>

<p>But what’s so great about the Glock 21 — and all other Glock pistols for that matter (besides being the reliable handguns they are) — is the fact that you can convert one to a totally different caliber with just a barrel, recoil spring and extractor swap in a lot of cases.</p>

<p style="text-align:center"><img alt="a table with all Glock caliber conversions" height="1306" sizes="(max-width: 700px) 100vw, 700px" src="" srcset=" 700w, 600w, 161w, 549w, 696w, 225w" width="700" /></p>

<p>The same easy caliber conversion can be only done to SIG P320s chambered in either&nbsp;<a data-wpel-link="internal" href="">.357 SIG</a>&nbsp;or .40 S&amp;W (as either caliber uses the same slide and magazine, only a barrel swap is required to convert from one caliber to another).</p>

<p>The SIG P320 chambered in&nbsp;<a data-wpel-link="internal" href="">9mm</a>&nbsp;can be converted to .357 SIG or&nbsp;<a data-wpel-link="internal" href="">.40 S&amp;W</a>&nbsp;but it will require a different upper and a different magazine.</p>

<hr />
<p><strong>THE SIG P320’S CONVERSION ISSUES</strong></p>

<p>Sadly, the SIG P320 chambered in .45 ACP is one very lonely handgun in its caliber category. Firstly, there are no Caliber X-change kits currently available for the P320 in .45 ACP. SIG Sauer does plan to release them, but they’re not available at the moment.</p>

<p>Secondly, the&nbsp;<strong>SIG P320 in .45 ACP cannot be converted to any other calibers</strong>. Not that this is such a big deal, as most gun enthusiasts would tell you to just buy two different guns if you want to shoot two different calibers.</p>

<p style="text-align:center"><img alt="a picture of the SIG P320 45 FCU incompatibilities" height="269" src="" width="480" /></p>

<p>And don’t get me wrong, I think that advice does make sense (especially when factoring in the price of a new Caliber X-change kit from SIG). But still, for a handgun design that is supposed to be fully modular, this is where the SIG P320 in .45 ACP is outplayed by its Glock counterpart.</p>

<p>The&nbsp;<strong>Glock 21 on the other hand has a ton of caliber conversions available</strong>: 10mm,&nbsp;<a data-wpel-link="internal" href="">.50 GI</a>, .400 Corbon, .40 Super, .45 Super, and .460 Rowland, among others. This makes it even more versatile than the SIG P320.</p>

<p>Now I’m aware of posts by people on a few different&nbsp;<a data-wpel-link="external" href="" target="_blank">gun forums</a>&nbsp;saying the P320 chambered in .45 ACP can be converted to any of the three smaller calibers (9mm, .357 SIG, .40 S&amp;W). While they do sound knowledgeable enough to be believed, since SIG Sauer is keeping quiet about this, I would rather stay safe than risk a catastrophic failure and possibly lose a few fingers in the process.</p>