Objective comp testing

[kneelingatlas]

"Shoots really flat", " the dot never leaves the glass"

It seems like there are a lot of Open shooters emotionally invested in the superiority of their gear and I tend to believe most of them are full of crap

So I recently picked up the new GoPro capable of some decent slow motion work and came up with a method to get some real data on "flatness". I'd like to believe I can be objective about the gear because I have it all! Tanfoglios, CZs, 2011s and dozens of comps. I have pages of load data and the following list of powders in my reloading cabinet:

SP2

3N38

N105

Longshot

HS6

Autocomp

CFE pistol

Silhouette

There's enough possibilities to make your head spin. Today I tested my two shortest, lightest guns (both 38SC): Bedell Super Shorty 2011 with a 4.4" bull barrel with three 1/8" holes and a Ti comp (42.5oz); Tanfoglio custom Y7 Gold Team with a 5", three 5/16" holes and 4 1/8" holes in a V pattern and an aluminum comp (43.3oz). Both guns chrono about the same and the load tested should be right around 165pf: 124gr MG JHP at 1.250" over 9.1gr SP2.

Without further delay, here are the videos:

I have plans to stroke the Tanfoglio by 0.200" and am very excited to compare footage.

[BeerBaron]

Cool stuff. Now I want to see your Akai.

From a quick look it seems the tanfog was a little less in rise and quite a bit less dip on return to battery. Fair call?

[Aircooled6racer]

Hello: Another thing to try is lighter bullets. Keep playing with your reloads and you will finally find the setup you like best. Shooting flat and not leaving the glass is possible as well as softer on the hands. Thanks, Eric

[kneelingatlas]

Hello: Another thing to try is lighter bullets. Keep playing with your reloads and you will finally find the setup you like best. Shooting flat and not leaving the glass is possible as well as softer on the hands. Thanks, Eric

One of these days I'd like to test your comp design Eric, do you have any lying around?

[caspian guy]

It'd be cool if you could get a grid pattern or something on the wall behind the gun so that the video had visual reference for how high the gun rises.

[35WLN]

What I think would be interesting would be to use a ransom rest or something similar that would take the human out of the equation.

[kneelingatlas]

What I think would be interesting would be to use a ransom rest or something similar that would take the human out of the equation.

If anyone has one I can use, send it my way

[gunnit]

caspian guy there is a grid on the wall behind the gun, yes it could be bigger however in this situation doing the testing in an open indoor range, this is actually a pretty good setup and gives people a look at how the guns are recoiling in atlas's hands.

I'm not sure if a ransom rest is a good idea do to how the guns are held. Maybe a sand bag to see how high the gun lifts up off of the bag , but there might still be too many variables.

IMHO, just keep the guns in atlas's own hands, so that his personal grip pressure stays the same on all the testing, and then people can decide for themselves which combination of gun, load, recoil springs, etc. is shooting flatter. It's always good to try different combinations to see what is possible, and find out which feels best in your hands.

Edited September 9, 2015 by gunnit

[caspian guy]

caspian guy there is a grid on the wall behind the gun, yes it could be bigger however in this situation doing the testing in an open indoor range, this is actually a pretty good setup and gives people a look at how the guns are recoiling in atlas's hands.

I'm not sure if a ransom rest is a good idea do to how the guns are held. Maybe a sand bag to see how high the gun lifts up off of the bag , but there might still be too many variables.

IMHO, just keep the guns in atlas's own hands, so that his personal grip pressure stays the same on all the testing, and then people can decide for themselves which combination of gun, load, recoil springs, etc. is shooting flatter. It's always good to try different combinations to see what is possible, and find out which feels best in your hands.

Duh... I see the grid now... sorry about that.

[gunnit]

caspian guy, not a problem, I got caught up in watching the gun recoil also. It's cool to see how different guns react.

I would like to see if the full size guns shoot a touch flatter compared to the shorty's.

I kinda think they will, just because of the little bit of extra weight. But every gun is set up differently so you never really know until you try it out.

Edited September 9, 2015 by gunnit

[kneelingatlas]

Thanks gunnit, here's my first effort with my full sized 9mm with the Binary Engineering Ti Comp, I'll probably re do this one with the checker board and with the same frame rate as the slow ones above (I decided to standardize at 5% speed so they're all the same). Rather than using the same load for all guns tested, I think I could do better comparisons (eventually) using my favorite load for each.

[MrPostman]

One thing to consider is how light the slide is on the Tanfo Goldteam. Mine weighed 9.8 ounces and I ran a light recoil spring (6lbs) which made the gun run super flat.

[cjfung10]

Hey John - that doesn't look like gopro's capability of shooting 120 FPS. Are you sure you were shooting more than 24/30FPS? Bump it up to 120 fps at the very least. Do you have any NLE software? If not, send the videos my way and I can edit them...I haven't played much with gopro's video editing software but they've had to have made it easy to make slow-mo videos.

[superdude]

As mentioned, a Ransom Rest is an objective method for testing. http://www.shootingtimes.com/ballistics/measure-relative-handgun-recoil/

A summary of the results goes like this: when comparing different gunpowders that produce the same velocity with the same bullet, more gunpowder weight means more muzzle rise. When you put a compensator on the gun, the result is reversed and more gunpowder means less muzzle rise.

This means that if you know how much gunpowder it takes for the different gunpowders to achieve the same velocity, larger charge weights produce more muzzle rise with no compensator, and less muzzle rise with a compensator.

Different gunpowders were tested in a compensated 38 Super in a Ransom Rest and described in this article: Gunpowder and Recoil. Edited by Jerry Lee. Gun Digest 2015, 69th Annual Edition, pp. 238-241.

[msg73]

From your perspective, which comp do you like the best and why? Could you list a relative ranking of them? Do different powders change the relative rankings of the comps?

I know Eric (Aircooled6racer) and have talked to him about his comp design and how it compares to some of the other mainstream comps. My next build will most likely have his comp. My last gun had the CFD comp (fullsize. no popple holes) and I wasn't bad but I wasn't overly impressed either. Was using 7.0gr WAC, 124 MG CMJ, 1.170"

[kneelingatlas]

Superdude,

I've found a distinct range of powders suitable for Open loads with Silhouette/CFE Pistol/WAC on the fast side and 3N38/SP2/N105 on the slow end (I'd consider powders like Lil Gun outliers).

I definitely prefer these slower powders combined with 115gr bullets, but I've seen for each the point where they 'give up' and more powder results in less velocity. More holes in the barrel/shorter barrels sometimes push this point below major. At this point, given the choice between a heavier bullet or faster powder, which do you prefer?

[kneelingatlas]

msg73,

The pistols I have my different comps on are so different in design (barrel length/holes/slide weight) I can't make an objective comparison, but I do have a full sized 2011 w/o holes I plan to use as a test mule for comparing the following: CFD, A Zone, Thundercomp II, McLearn, Cheely and hopefully Eric's as well.

I must say though, my gun with the CFD comp has two holes, and I use 9.4gr of SP2 under 115s so I have a completely different experience of it. I'm my opinion you're not giving it a fair chance with that load; with no holes in the barrel you should be able to make major using a 115 and a slow powder like 3n38 or even N105. I would not go faster than HS6 with that setup.

Edited September 14, 2015 by kneelingatlas

[gunnit]

atlas:

I like your idea of using the 2011 w/o the barrel ports, as a test mule for trying out the individual comps.

Were you also considering, if it's possible, to use the same load every time, to see if there's any significant difference ?

I know this is some-what of tricky situation for you, because people know that every gun out there has it's own preferred set-up to run it's best. So my hat's off to you for taking on this testing of compensators.

Also IMHO, as mentioned above, I still do not think you should use the Ransom Rest in this situation. I believe it's a great tool for testing bullet accuracy. But when bolted down, does it show the recoil that also comes straight back into your hands ?

( On a side note, It's a little bit difficult to bring a Ransom Rest to a match and shoot all the stages with it.

That just doesn't seem to be very practical in a practical shooting application. )

It's been discussed on these forums,( many times before ) , that different people perceive recoil differently. Some prefer more recoil in their hands, and others prefer it to go up instead, ( whatever that feeling might be, or mean, to that individual ).

Personally, I don't want a bolted down machine telling me how the recoil is going to feel in my own hands. I prefer to pick up the gun and decide for myself if this is how I want the gun to respond.

I think the direction your going in works just fine, and I can see in the videos how the guns are recoiling and how they are returning back to the target.

In my opinion this is a great little overview of how different comps react on the same simple platform.

Fine tuning an individual set-up, on a specific gun, is for another chapter all together.

Keep us informed on how each comp's recoil is perceived in your own hands.

Thanks again for taking this on.

Edited September 14, 2015 by gunnit

[superdude]

Atlas, I don't have an answer because I don't have a clear preference. And even if I did, it might apply to only me and no one else. I recognize that folks have different opinions/perceptions about these differences, and that's okay. One thing to keep in mind is that the difference in muzzle rise with a different bullet weight or gunpowder can be rather small with a compensated pistol. For example, with some of my data changing from a 115 grain bullet to a 124 grain bullet at the same power factor (165) with the same gunpowder produced a difference in muzzle rise of 2.4mm - with the gun I used for that test.

Changing gunpowder from the 'fast' group to the 'slow' group is a similar difference in muzzle rise, but it depends on which powder you're changing to. The difference might be as little as 1mm or as much as 4mm. The larger the difference in the weight required to make power factor, the larger the difference in muzzle rise. An experienced shooter can discriminate between some of these small differences, a non-experienced shooter might not see much of a difference.

The Ransom Rest is good for demonstrating the physics behind the recoil impulse with different bullet weights and gunpowders, but it does not take into account people's perception of how a particular load feels to them in their gun and how they react to that recoil impulse. Every person interacts differently with their gun than the guy or gal next to them interacts with their gun. A different grip strength, different muscle tension, different reflexive reaction to the recoil, etc. can significantly influence their perception of the recoil impulse.

You also have different compensator designs, number and size of vertical and lateral ports, popple holes, slide weight, barrel and comp weight, frame material/weight, bore axis, etc. You end up with an almost infinite number of possible configurations, especially when you pair that with an infinite number of shooters. And the perceived difference might be small or large depending on who you talk to because the perception of the recoil impulse is so subjective. I'll leave that to the individual shooter to decide what they prefer.

[Dranoel]

Superdude,

I've found a distinct range of powders suitable for Open loads with Silhouette/CFE Pistol/WAC on the fast side and 3N38/SP2/N105 on the slow end (I'd consider powders like Lil Gun outliers).

I definitely prefer these slower powders combined with 115gr bullets, but I've seen for each the point where they 'give up' and more powder results in less velocity. More holes in the barrel/shorter barrels sometimes push this point below major. At this point, given the choice between a heavier bullet or faster powder, which do you prefer?

The real trick to loading for ANY handgun is to find the powder with the proper burn rate for your barrel length. This means you must also take into consideration things like poppel holes. The shorter the barrel the faster you need the powder to burn. In the case of poppel holes, the hole closest to the chamber is going to be the effective length of the barrel for purposes of pressures and powder burn rates.

Once there is a pressure escape any unburnt powder is useless. What I'm usually looking for is a powder that is going to burn out half an inch before the end of the barrel. This way you still have a clean burn and max pressure right up til the bullet leaves the barrel and all the pressure is released. This also means that as soon as the bullet reaches the first poppel, you are done building pressure and are now releasing it. REGARDLESS of how fast or slow your powder burns.

So let's take two barrels as an example. Both chambered for 9x21, both firing major PF loads, one is a 6" longslide with no poppels and no comp. The other is a 4.5" commander with 4 poppels and a 4 chamber comp, 1st poppel opens at 2.5".

I can run AA7 in the 6" without any problems and the powder is consumed by the end of the barrel. This gives me positive pressure the full length of the barrel. (or at least to within 1" of the muzzle) But if I run Something like WW231 or AA5, the powder has burnt out by 2.5 inches into the barrel and the pressure is dropping from there. I could add more powder but the pressures would VERY quickly become dangerous.

In the 4.5", the poppels essentially mean I have a 2.5" barrel. ( again for purposes of pressure and powder burn rate) So WW231 or AA5 work very well. They burn out before the first poppel and give the best pressure before it can escape. But try running AA7 in that same barrel and your are gonna see fire coming out of the poppels and a lot of unburnt powder coming out everywhere. This is because the pressure is escaping faster than the powder burning can replace. (This is also why I don't do poppel holes. half your pressure is gone before the bullet and the high pressure gasses reach the comp where they do the MOST good)

So, if you are playing the Open game and you are spending a small fortune on a good gun, be prepared to spend another small fortune testing different powders for the loads specific to that gun. Yeah the loads for your other gun might work but unless it is an absolutely identical setup, you will NOT get optimum results.

Edited September 15, 2015 by Dranoel

[Big Nick]

I don't know how "flat" my gun shoots but here's what I do know. With the load I'm shooting currently, the dot settles down before I have the next target in my sights. It appears to me the dot is not moving vertically at all. This is the sight picture I get when shooting plates as fast and accurately as I can. But when I'm shooting slow and deliberate, I lose sight of the dot for a moment. So my gun does not shoot as flat as it seems when shooting in a speed competition, but it doesn't matter because it's settling down faster than I can get the dot on the next target.

Edited September 18, 2015 by Big Nick

[kneelingatlas]

720p, 240FPS, narrow field is the ticket!

[Aircooled6racer]

Hello: Just a quick question is the comp hitting the slide in the last video? Thanks, Eric

[coltlover]

Looks normal to me

[BeerBaron]

Pretty hard to say. If when locked up it has the proper clearance between comp and slide then it should never hit. As slide comes forward it would be pushing the barrel forward from the rear.