"40 Open doesn't make enough gasto work a comp" ...

[JoeyMac]

Now, I don't shoot 40 open or anything like that, and Iknow there's alot of other disadvantages to shooting 40 open... I'm not trying to debate ANY of that. But I was just cruising around the forums and read this statement about 40 Open not working comps well. I've actually seen it mentioned more than a few times. So, being curious, I opened a reloading book to look up some powder charge figures for 40 major.

From some quick searching on the forums for 9mm Major loads other people are using, it looks like like somewhere around 7.5gr Autocomp or 6gr HS-6 behind a 124gr bullet is fairly common. For 40 major, the reloading manuals are showing me that somewhere in the neighborhood of 8.5gr Autocomp or 9.5gr HS-6 behind a 135gr bullet should get you about 170-175 PF. That's about the lightest bullet that is easily and economically found in 40.

Now that gives the 40 Open 13% more AC and 58% more HS-6 than the 124gr 9mm Major...

Which leads me to ask why are people are saying the 40 Open doesn't make enough gas to work a comp?

Edited October 9, 2015 by JoeyMac

[Rob Tompkins]

Its more about gas pressure and velocity than just volume for the comps.

Edited October 9, 2015 by Rob Tompkins

[MrPostman]

With a 135 grain you get the most benefit for sure. The reason why you don't see that many open guns in 40 is due to mag capacity. 24 max in a 170 for 40 vs up to 30 for 38 super or 9 mm. Big disadvantage on certain stages where the 40 shooter would have to reload and the 38/9 guy wouldn't.

[thermobollocks]

PV=nRT.

Cross sectional area enters into it as well.

[Hi-Power Jack]

7.5 gr Autocomp or 6 gr HS-6 behind a 124gr bullet is fairly common.

Just to clarify, you've got these reversed.

More like 6.7 - 7.1 gr WAC and closer to 8 gr HS6.

[Shmella]

7.5 gr Autocomp or 6 gr HS-6 behind a 124gr bullet is fairly common.

Just to clarify, you've got these reversed.

More like 6.7 - 7.1 gr WAC and closer to 8 gr HS6.

Good heads up. Throwing 8 gr of autocomp behind a 124 would be probably be pushing it..

[zzt]

I'm not an expert (yet) on loading for 40 open, but I can tell you that the oft quoted "fact" that 40 does not make enough gas or pressure to work a comp is just pure bs.

Here is an example: a max load of VV N340 behind a Ranier 135gr copper plated bullet make too much gas. It shoots very flat. The dot hardly raises, but is very, very loud and really hard on the hand. Now you can trade more muzzle flip for less felt recoil, but I'm going for flat.

So, if I go with a faster powder to get rid of the excess gas, I don't make power factor. To do that with a faster powder requires a heavier bullet. Let's take the opposite extreme. My Limited load is 180gr TC Poly coated bullet ahead of 3.6gr e3. It makes 172PF. When I fire that load out of the comp'd upper, muzzle rise id reduced, but the dot leaves the glass. If you hold it with a death grip like you do for Limited, the dot travels to the top of the glass and comes back. Clearly, there is not enough gas to work the comp using fast e3. Switching to N340 makes a world of difference. Loaded to 172PF both the N340 and the e3 load shoot the same in the Limited upper, with N340 having a bit more felt recoil. With the Open upper, muzzle rise is noticeably reduced. Adding more powder helps but increases noise and recoil and still does not shoot as flat as I would like.

So the answer is somewhere in the middle. I've been experimenting with the Rainier 155 and 165gr pills, and results are encouraging. I still think N340 is too slow, at least for my comp (3 ports, no holes), so I'm going to experiment with intermediate powders. I'll try Solo 1000 next and find out where I have to go from there. I want to try HS6, but can't find any. Power Pistol doesn't do the job. The only suitable powder my local store has on the shelf is Zip, and I think that may be too fast, at least for the 155s. It will be interesting to find out.

[kneelingatlas]

I don't know who's told you 40 Open doesn't make enough gas, but that's not why I don't shoot 40 Open. It's not an Open gun, but just for comparison's sake, I loaded the same weight bullet (135gr) over the same charge (3.5gr of Clays) in both 9mm and 40, the fired both over the chrono through identical Stock IIs in 9 and 40; what I found was the 40 had a significantly harsher recoil at a lower PF (117 vs 125).

All things being equal, I'll take 9, but all things aren't equal, I shoot 115s in my 9mm Open gun, but I've never seen 40 bullets lighter than 135, and those aren't exactly cheap or plentiful.

Less capacity, more expensive components, heavier bullets, more recoil, how are those for reasons?

[ChuckS]

I played with 125 gr .40 three times. They were frangible bullets and were about the same form factor as a 180. They shot real nice. Much like my 9 but with (and I am guessing) more recoil than the 135s. I was given a bunch by Beven Grams who used to be sponsored by Sinterfire. That was the load he used for .40 open. They shot real nice but were very expensive. West Coast (the forerunner of Xtreme) came out with a line of frangibles and they were not that much more money than lead. WC went out of business and the line did not come back with Xtreme. I then got some IMI surplus rounds that shot nice but I could not find a reliable crimp. If you over crimp, the bullet will crack and the upper portion will fall off. In the ammo can, in the mag, in the chamber. They were just not reliable. So I stuck with 135 Rainiers. They worked great and are not super expensive.

I load with N340. I did not like faster powders and slower powders just left unburnt powder. Heavier bullets did not feel right so I never played around with them. Yup, there is recoil. Some day I will bring the .40s and my 9 out to do a same day comparison. I do get 26 rounds in a STI 170 mag, but having 30+1 is kinda nice.

I started with .40 open before major 9 was on the books. The 38 super shooters at the time were typically getting 28 rounds in a big stick. So the .40 was one target short but the brass was virtually free at the time while super was $0.10 each. Had the rule change for 9 been in place, I probably would of gone that route.

There is fun stuff to read in the mother of all 40 open threads: http://www.brianenos.com/forums/index.php?showtopic=77956&p=902806

Later,

Chuck

[superdude]

The 40 makes plenty of gas to run a comp. If the 40 and 9mm shot the same bullet weight with the same gunpowder at the same speed, the 40 would have less muzzle rise in a compensated gun. Why? Because, as you've discovered, it requires more gunpowder than the 9mm. The 40 would have more muzzle rise without a compensator for this same reason. The smaller bore round is more efficient when shooting a bullet of the same weight so it requires less gunpowder and this means less gas force. That is demonstrated here: http://www.handgunsmag.com/competition/recoil-comparison-pistol-competition-cartridges/

People say the same thing about a 45. Not enough gas. But the real difference is that the 45 shoots heavier bullets. If you shoot the same bullet weight in a 38 Super and a 45 Auto in a compensated pistol to the same velocity, the 45 has LESS muzzle rise than the 38. Why? Same reason, the 45 requires more gunpowder than the 38 to drive a bullet of the same weight to the same velocity. The additional gunpowder in the 45 produces more gas and this end up as more downward force exerted via the compensator's effect. This has been tested and demonstrated here: http://www.shootingtimes.com/ballistics/compensated-45-vs-compensated-38/

Gas volume and gas pressure at the muzzle drives a compensator. More gas volume (more weight of the gunpowder) for the same velocity means more gas pressure. http://www.shootingtimes.com/ballistics/compensators-pressure-gas/

[Big Nick]

If it wasn't for a mental meltdown on the last round of the last stage I would have shot a better score with my .40 Gold Team then my .22 MARK III Ruger last night shooting steel plates. 8.4gr AC under a Rainier 135gr plated bullet gets back on target darn quick. The kid shooting the 9mm didn't have a chance.

[Garmil]

Superdude

that .45 vs. .38 comparison is pretty flawed to say the least.

There is really no value in comparing how 2 calibers perform with the same bullet weight.

The real test is finding the best load for each. And I dont think many people use 160gr or higher in an open .38 like that article tested.

[superdude]

Superdude

that .45 vs. .38 comparison is pretty flawed to say the least.

There is really no value in comparing how 2 calibers perform with the same bullet weight.

The real test is finding the best load for each. And I dont think many people use 160gr or higher in an open .38 like that article tested.

That 45 to 38 comparison is not flawed, it's educational, and tests the physics behind how compensators work, and busts the myth that comps don't work on the 'low pressure' 45 or that the 40 open doesn't make enough gas to work a comp.

The reason that comps don't 'appear' to work well on a 45 is simply because they normally use such heavy bullets, such as a 230 grain, but they actually work reasonably well with 185 grain bullets and some folks who used the old 152/155 grain cast bullets in compensated 45s reported that they worked quite well, which makes sense, and is why 135 grain bullets in the 40 work so well. But in our gun games, capacity rules, and by any measure the 45 is a low capacity platform - unless you're restricted to 10 rounds. That's also why the 9mm/38 is preferred to the 40 - the smaller rounds hold more ammo in a magazine of the same length.

The value to testing how two calibers perform with the same bullet weight applies more to the 40 and 9mm since they are closer in size as are their bullet weights. The 40 can use commonly available 135 grain bullets in a compensated pistol, and the 124/5 grain bullet is commonly used in 9mm pistols. The weights are close enough to suggest that the .40 / 135 bullet combination would be really close to, and possibly equal with, the 124/5 9mm load with respect to a compensator's effectiveness on muzzle rise.

In the old days, some folks used heavy bullets in their compensated 38s because they could make Major at reasonable pressures and reduced the risks of case blowout 'super-face' in unsupported barrels. Nowadays, we're using 115-125 grain bullets in the 38 Super because we have supported chambers to handle high pressures (as well as a lower power factor) and, as we know, lighter bullets work awesome in a comped gun.

"The real test is finding the best load for each." This is absolutely correct.

[splashdown]

It's what I've been saying all along. You can easily make too much gas in a .40 open gun, so you need to tune your load.

Shooting open is fun. For some of us, doing it in .40 will get us there for much less cost.

Most everyone on here is not a contender to win major competitions, but these guns can work and are a lot of fun.

See the links below for my input.

http://www.brianenos.com/forums/index.php?showtopic=77956

http://www.brianenos.com/forums/index.php?showtopic=210801&p=2365605

https://youtu.be/zVDUhUzTUj8?t=7m45s

[truborshooter]

Fired a 40 with 155 bullets and Accurate #5 in a TZ silver team for many years.

Easily made major, A-box head shoots at 35 yds and dot never left the sight screen.

Only changed to 38 Super for the extra mag capacity.

[JoeyMac]

Thanks for all the replies. Super educational.

And as I mentioned, I really didn't want to open the can of worms of 40 vs 9/38 in Open. I just wanted to understand the origin of the statements about 40s and compensators not being ideal. It sounds to me like there's no real issue at all there other than a bit more personal load experimentation to find your ideal combination... because less known data points are out there due to the overwhelming popularity of 9mm/38 in open.

[kk4364]

So if I were going to run a glock 35 with stock ammo and a comp, I wouldn't be able to make major pf?

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[Garmil]

So if I were going to run a glock 35 with stock ammo and a comp, I wouldn't be able to make major pf?

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Most factory ammo is well above major you would be over. The comp just wouldn't be making much of a difference.

[kk4364]

Gotcha thanks for the info. Thats kind of what I was thinking.

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[superdude]

So if I were going to run a glock 35 with stock ammo and a comp, I wouldn't be able to make major pf?

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Select factory ammo with the lightest bullet weight to get the most from a compensator.

[kk4364]

Thanks for the information!

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[JoeyMac]

PV=nRT.

Cross sectional area enters into it as well.

PV=nRT being applied to combustible flow?

F-

[Absocold]

Back in the late 80's and early 90's you saw a lot of people using .45's and all of them had a compensator on them. Comps work just fine on a .45, don't let anyone say otherwise. There's not a lot of pressure to work with but there's plenty of gas volume.

The switch to 38 super came about partly because it was easier to get the comp working but mostly because of magazine capacity. Which is exactly why .40 isn't popular.

Now that the major level has been reduced to allow 9mm to compete, there's even more reason not to bother with .40's. And the poor .45 is now a relic of days gone by.

Good, cheap, easy. Pick two. Since we're competing, "good" must be one of the options. Good and easy? 38 super. Good and cheap? 9mm.

[DenverDave]

Took a suggested load for my Tanfoglio Gold Team 40 S&W to the range to test today.
The load is 135gr Rainer 8.5gr Autocomp 1.130 OAL
I did the test of putting cardboard 1" from the muzzle (2 shots) (see attached picture)
Recoil was not bad in terms of keeping the dot on the target, but it had a bit more kick to it than I thought it would be compared to a factory

box 180gr load.
I have not tuned the springs yet, just working on the load at this point.
Based on the pictures, where should I go with this?
To me as someone new to open class and relearning loading, looks to me that there is quite a bit of powder residue.
Should I consider a faster burning powder?

Any recommendations would be appreciated.

[superdude]

It's not clear that the paper tests tells you what you need to know with respect to how the gun acts when you shoot it. What matters is how the gun tracks for you, i.e. where the dot ends up after the shot. And different shooters might have different preferences with respect to powder and bullet weight, even with the same gun. Gunpowder residue on a piece of paper doesn't tell you any of this. (No disrespect to Bob Londrigan.)