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.45 GAP vs .45ACP
Do the gunzines get it right?
by Mark E. Freburg

[The following article assumes the reader is familiar with the new .45GAP (Glock Auto Pistol) cartridge and the Glock 37 pistol which fires it.  There isn't room in this article to lay out the background, but it shouldn't take much effort on the reader's part to get up to speed on this new cartridge and the controversy between it and the .45ACP round that the gunzines are trying to create to beef up magazine sales.]

I recently picked up Autoloaders Buyer's Guide 2004, a Shooting Times Magazine annual.  I read the article by Dick Metcalf 45GAP Versus .45ACP: The .45  GAP Wins!  A Glock 37 and a Colt Commander are tested with loads in each caliber, respectively.  The header of the article reads "In this real-world, apples-to-apples performance comparison, the .45GAP trounced the .45ACP in all performance categories with all bullet weights."  The Merriam-Webster Online dictionary defines trounced as meaning "to thrash or punish severely; especially: to defeat decisively."  Let's see what Metcalf's idea of "defeating decisively" really is.

Here is Metcalf's chart, so you can see what I saw:

According to Metcalf, the .45GAP "develops an overall average of eight percent more velocity and 14 percent more energy than the longer case .45ACP cartridge across the board."  Percentages don't always paint a clear picture; so let me also give you the actual figures for all three bullet weights.  According the the article, the GAP averaged 957.7 fps.  The ACP averaged 887.7fps.  The difference in velocity was 70 fps.  Okay, fair enough.  Let's talk about how he got to those figures. 

Metcalf claims he used every .45GAP load made in his tests for a total of nine loads.  All good.  He also used twelve .45ACP loads, which also sounds good.  However, in actuality Metcalf only tested five equivalent loads.  By that I mean he only tested five loads that used the same bullets as loaded by the same company.  That is significant. 

For example, although there are two .45 GAP loads from Federal, Metcalf tested no Federal loads in .45ACP.  He did test four .45ACP loads from Winchester, but only two correspond to the .45GAP loads from Winchester.*  Of these five loads, three are FMJ (TMJ in Speer talk) loads.  They round out the data but FMJ loads have no real place in real world self-defense.  Here are the five loads that compare between the cartridges:

Lawman 185 TMJ  GAP 1037fps      ACP 1018
Gold Dot 185 JHP  GAP 1070   ACP 1003
Lawman 200 TMJ  GAP 982     ACP 930
USA 230 FMJ GAP 809     ACP 807
Ranger SXT JHP    GAP 878     ACP 839

   total 4776  total 4597
      average 955.2    average 919.4

The difference in velocity of these five loads, the only apple-to-apple loads compared, is 35.8 fps.  That is half the 70fps you get from Metcalf's figures.  Of the two JHPs, the GAP velocity average is 974fps, the ACP 921fps.  If you are a guy who already has his favorite bullet weights in each caliber, you are likely to choose either 185gr. or 230gr. loads (the only two we have to compare here) before you choose anything else.  In that case the GAP is 67fps faster than the ACP in the light-fast load, the GAP is 39fps faster in the slow heavy load (my own bullet weight choice in .45).  The more I look at these numbers the less I see a trouncing.

Metcalf makes a point in the article to emphasize that the Glock has a barrel 4.49" long and that he had pistolsmith Dick Heinie take a match-grade Kart 1911 .45ACP barrel and cut it down to 4.49".  He doesn't comment on what type crown was used or what finish was put on the muzzle.  I'll give him benefit of the doubt and assume it was a quality job.  My main problem here is that the Kart barrel was conventionally-rifled.  As you know the Glock barrel is polygonally-rifled.  If you have been paying attention the last twenty-plus years you surely already know that ALL else being equal, a polygonally-rifled barrel develops notably higher velocities than a conventionally-rifled barrel.  I do not have this data in front of me but I will say that on average, the differences between two barrels of the same length shooting the same exact ammunition are easily as much and probably more than the differences between the GAP and ACP loads given in this article.  If Metcalf was really interested in apples-to-apples comparisons, he wouldn't have ignored something as significant and time-proven as the difference between conventional and polygonal rifling.

If that isn't enough food for thought, let's add the comment that the standard 1911, the .45ACP pistol used in this test, comes with  five inch barrel, not a 4.49" barrel.  Granted there are many 4.5", 4", 3.5", and even 3" .45ACPs out there, but the fact remains that the common, full-size 1911 has a five inch barrel.  Perhaps Metcalf should have tested something that comes in full-size guise with a comparable barrel?  Say a SIG P220 or a Ruger P90? 

There is another glaring omission in this article.  Metcalf admits up front that the .45GAP operates at the same pressures as the .45ACP+P.  Yet all testing was done with standard pressure .45ACP loads.  No explanation was given for totally omitting the .45ACP+P.  It would seem to me that if one wanted to compare apples-to-apples (yes, I'm getting sick of hearing that phrase too), one might actually compare apples with other apples!  While I can't and won't do Metcalf's homework for him, let's look at some ammunition maker's claims for .45ACP+P loads.  Speer, the developer of the .45GAP, only lists one +P load, a 200gr Gold Dot JHP at 1080fps in a five inch barrel (again, the standard length for this cartridge).  Gee, Speer's lighter 185gr Gold Dot in .45GAP only tested 1070fps in Metcalf's tests.  Federal, sister company to Speer and another GAP ammo maker, doesn't list a .45ACP+P load at all.  Neither does Winchester.  Remington, the originator of the +P load in .45ACP, list 1140fps for their +P Golden Saber 185gr JHP.  Whoops, that's quite a bit faster than the .45GAP 185gr. Gold Dot. 

I'm beginning to have some problems with the term "trounce" here. 

On one hand it is understandable that there are few +P loads.  Since .45ACP guns have existed since the year 1911, it stands to reason that makers are hesitant to use the +P pressures for loads that may make their way into antique firearms that are not strong enough to handle them.  This would be entirely operator error, but ammo maker's are understandably lawsuit shy.  But does this also explain why we see no .45ACP+P loads tested in the article?  Perhaps, but consider that the author is trying to make you believe that in this "real-world, apples-to-apples performance comparison, the .45GAP trounced the .45ACP in all performance categories with all bullet weights."  Draw your own conclusions.

Here's my opinion.  It seems that the .45GAP will be a good addition to the cartridge options available to defense-oriented shooters.  Above all it will play big with Glock fans, who until now really had no .45 caliber option that they could get their hands wrapped around...quite literally.  I can see the makers of other double stack pistols also getting on the .45GAP bandwagon, like HK and Para-Ordnance.  Will 1911 makers join in?  Will SIG, Ruger, S&W, and other makers of single stack pistols add the GAP to their line-ups?  It's too soon to say, but at this point there doesn't seem to be a great incentive for any ACP shooters using single-stack pistols to switch.

What is the bottom line?  I'm not trying to criticize the Glock 37, the .45GAP, or push the .45ACP.  The .45GAP is no doubt comparable to the .45ACP.  I suspect they can co-exist peacefully.  But if you are a likely candidate to spend your hard-earned money on a GAP-chambered pistol, do your homework and read between the lines.  Reading articles in the popular gunzines and taking them at face value will not serve you well.  You've been warned. 

*There is a possibility that there is a typo in the article as two "Winchester SXT 230gr. loads" are given for the .45ACP (see chart).  As I don't really know if there are in fact two loads--I doubt it--I presume this was a typo, but I'm not giving Metcalf or his editor any credit for failure to verify the copy before publishing.  So while there may be a sixth ACP load that corresponds to another GAP load, I'm not assuming my conclusion is fact.

Uploaded: 6/21/2004