Go to any gun forum on the internet and you will see posts asking for opinions on this caliber vs. that caliber and which has less recoil or is easier to shoot. We have all seen and participated in these types of posts offering what insight we can to assist fellow shooters, but how good is this information really? Using myself as an example, I have been shooting for nearly thirty years. I own handguns in various configurations in calibers ranging from .22LR to .475 Linebaugh. I shoot a lot of big bore revolvers and have become accustomed to heavy recoil. For me to say that the recoil of a given caliber is not abusive or unpleasant may not be the most objective view. Not to mention such variables as hand size of the shooter, configuration of the gun, loads being shot and a multitude of others. This lead me to an idea for a long term experiment that began this summer and may continue well into my elderly years, but so far it has been fun and educational, so I thought I would share what results have been gathered so far.

This all began with the common question of "should I get a .40 or a .45?" I first asked myself how these two should be compared, as they really are very different critters. My opinion, though never tested objectively, was that I preferred the .45. My reasoning was that the larger caliber, loaded with bullets of the same or similar weights at similar velocity, was more pleasant to shoot due to lower pressure. Why bullets of similar weight and velocity? Simply because within these two calibers, factory ammo is readily available within these parameters, and I wanted this to be a comparison of caliber vs. recoil, not power (however you decide to determine it) vs. recoil.

To conduct the experiment, I needed two identical guns, but chambered in the two calibers. I already had a great shooting custom built STI in .45, so why not just build the same gun in .40? Problem solved! Now for ammo... I selected a 180grn bullet for use in the .40 and a 185 in the .45. These are readily available not only in component form as well as factory ammo, although the initial tests are being done with handloads. These two calibers are a wonderful set to compare because when using simlar weight bullets, max pressures in each cartridge achieve almost identical velocities, with a wide difference in pressure. In researching SAAMI specs for the two cartridges, I found that the max operating pressure for the .40 was listed as 35,000psi and the .45 as 19,900psi, a difference of 15,100psi. The .40 will drive a 180grn bullet at 1,000fps near the top of its pressure range. The .45 will do the same with a 185grn bullet near its max pressure.

Loads were assembled and shot across an Oehler 35P chronograph, then adjusted as needed to arrive at 1,000fps +/- 50fps. The load used for the .40 was 5.3grns of Unique and a 180grn cast bullet from Midstate Cast bullets for the .40, for an verage velocity of 1012fps with a standard deviation of 26fps. For the .45 was 6.4grns of Universal for 1008fps average and an SD of 16fps. Both of these loads generate about 425 foot pounds of energy for those who prefer that measure of power.


Now for the shooting…but who should do this shooting? If I do the shooting, as was stated earlier, it certainly would not be objective. I struck on the idea of going to the local range and asking random shooters there to shoot each gun and then fill out s short survey giving their impressions as preferences. The testing was conducted blind, so that the shooters did not know what caliber they were shooting (unless they cheated and observed the ejected brass), and every round was fired over the chronograph to verify consistent velocity. Each gun was loaded with ten rounds, and each shooter shot a total of twenty rounds through each gun, alternating between the two. After shooting both guns the shooters were asked to answer the following questions.

1. Could you feel a difference between the felt recoil of the two guns?
2. If a difference was felt, was it a matter of recoil force or recoil speed?
3. Did you prefer one gun over the other and if so, which one?

Keeping in mind that I am not a professional researcher, have no formal training in such matters and that there are certainly things that were not taken into account, I think the results are at least as valid, if not more so, than single opinions from various posters on any number of forums. My goal was to get general impressions from a wide variety of shooters, and I think that has been accomplished. A total of 210 shooters participated, all of them, strangers to me, and of various levels of experience. The results were as follows.

Of the 210 shooters, 178 (84%) shooters could feel a difference in recoil.

Of those 178 shooters, 143 (80%) of them felt it was a matter of speed rather than force.

Of the 178 shooters that were able to feel a difference, 156 (87%) of them preferred the .45 over the .40.

Of the 32 shooters that could not feel a difference, there was a pretty even split on preference of guns, with 15 (47%) preferring the .40 and 17(53%) preferring the .45. (Please do not ask me how people who could not feel a difference were able to select a preference. I can only speculate)

Please keep in mind that this was not intended to prove that one cartridge is better than another. No aspect of performance difference of the cartridges was considered. I will leave that up to others to debate. It was simply a comparison of recoil between two cartridges loaded to equal performance in terms of energy, with vastly different pressures. While this portion of the experiment only compared two cartridges, loaded with custom built loads to achieve the same ballistic performance with regard to bullet weight and velocity, some myths can be refuted.

A .45 does not necessarily have more recoil than a .40. The load makes the difference. A 230grn bullet is not the only option for a .45, just as a 180 is not the only choice out there in .40. Factory ammo is available in the weight and velocity range tested, in both range and self defense ammo. If you are a handloader, the options are even greater.

Higher pressure does not necessarily equal higher velocity, particularly if there is a significant bore diameter difference. This is for the same reason that a larger hydraulic cylinder will do more work than a smaller one operating at the same pressure. Having a larger area for pressure to work over creates significant improvements in work capacity.

The .40 has proven itself to be a very capable cartridge that has performed well for a significant span of years. The .45 has a 100 year history that shows similar effectiveness. I will let others argue about which is better, but here are some advantages of each:

.40S&W-
-More capacity in same size package
-Flatter trajectory due to higher velocity, and sectional density
-Slight advantage in cost when using handloads. Powder and bullets are bought by the pound, no matter how ya slice it and dice it.
-reasonable selection of bullets available.
-one of, if not the most popular semi auto cartridge on the market, making ammo and loading supplies readily available.

.45ACP-
-Larger bore diameter. I know that this is a hotly contested issue, but I think you would be hard pressed to show this as a disadvantage for most applications.
-wide selection of bullets available ranging from 155 to around 250 grn.
-Still one of the most popular cartridges currently in use, making ammo and components readily available.

I am glad I do not have to choose between owning one or the other, as they are both fine performers in their own right, although I give a slight edge to the .45 because it is so flexible in the roles that it can fill for a wide range of shooters. Through the use of handloading, it can be loaded to what I believe is a much braoder range of applications than the .40 can, even if handloading for it as well. Your mileage may vary.

As a side note, an idea came to me late in this experiment. I had several shooters compare the comfort of shooting the STI in .45 to my alloy framed, full size Kimber , also chambered in .45. While I did not keep records of this comparison, a noticeable majority preferred the STI. I can only speculate that this is a result of the shape of the grip, with the STI having a wider back strap, thus spreading the recoil over a wider area of the shooter’s hand.


This is not a completed project by any stretch of the imagination. Future plans include doing similar tests with a variety of factory ammo. This will obviously require a substantial financial investment, so is not on the slate for the near future. Other comparisons that I would like to make are .357mag vs. .44 special .44 special vs. standard .45 colt loadings heavy .45 Colt vs. .44mag . others may be done, but it is hard to say, largely because I feel that any comparison needs to be done in identical guns. This could get even more expensive than it has already! I encourage anyone to take on such projects as you are able to. Not only is it a lot of fun, I think that these types of comparisons can truly challenge our own beliefs and preferences.

(Edited for a typo)