MY TAC 47 T.A.R.G.E.T. Testing

[clifton 354]

hobbyshooter: During the first round of testing I tried to get the Auto Plug to cycle low brass with the factory front spring by tightening the adjustment screw 2.5 turns. At 2.5 turns the auto plug would not cycle low brass reliably. It was at that point I stopped testing the low brass with the factory front spring. #1 If the Auto Plug wouldn't cycle the ammo, it wasn't important to know at that time if the other plugs would and #2 I figured I was going beyond the Auto Plugs original intent by adjusting it any further. Nevermind what that adjustment would do if I then fired high brass loads.

 

Vicarious_Lee: If you watch the last video I posted you will see that my gun cycles low brass with the factory front spring while using the factory plug (Setting 2) and the Gunfixer (Setting 3). However, what you did not see (because we didn't record it) was the Gunfixer would not cycle the Winchester Univeral at all.

 

Oh. Well, that's different then, and to me can only indicate 2 possibles:

 

1. The Auto Plug is burping off gas even with the lowest of the low stuff.

 

2. Davidson's plug does a better job as a forcing cone for the gas than the Auto Plug on its highest setting.

 

I looked at both plugs after I wrote my post, and did notice that the MD plug has a smaller, tighter vent to the puck. the TAC plug could never possibly have the same profile because they have to engineer the bleed port in the middle of it.

 

I don't know shit about either firearms or engineering, but I can't figure as a layman how the factory plug works better than the TAC plug. Perhaps there's some fluid dynamics stuff in the works that is aided by the shielding of the factory plug. To a tard like me, it seems that both the MD plug and TAC's plug, by COMPLETELY unroofing and unshielding the ports from the puck AS WELL AS making a tight cone for the gas from the low-brass stuff to go DIRECTLY to the puck, would achieve the same maximal result.

 

Let me ask for clarification, Bridis: Did the GunFixer (on it's highest setting) cycle stuff that the TAC did not, and did the factory plug cycle stuff that either did not?

 

I think that question is important, because if so, then there's more physics going on in the gas chamber of our Saigas than would be obvious.

 

Very good thread, and thanks to all.

 

 

 

Bridis,

 

 

Thats your problem, if your gun is cycling, Low brass, it will cycle with ours. Not all guns are the same, when we sent out the plugs we adjusted them Nominally... it is meant to be set to your specific gun. For the love of God Bridis tighten the valve until its stops engaging the valve on Lowbrass. Your valve should not open on the bird shot, it sounds to me you have not adjusted the plug all the way for your guns gas system, its a set and forget thing.. you just need to make it work first on lowbrass then continue from there. I should have thought of this, but I asummed you cranked it down and it would just not work for you.

[Bridis 319]

Vicarious_Lee: Let me ask for clarification, Bridis: Did the GunFixer (on it's highest setting) cycle stuff that the TAC did not, and did the factory plug cycle stuff that either did not?

 

I appreciate your interest in this topic and mean no disrespect, but you keep asking questions that I've already answered. Please take a look at the test chart in my 1st post and watch all of the videos I posted. Pictures/Videos say a thousand words.

 

 

TAC 74: I tightened the plug 2.5 times (does it go any tighter?). I didn't think tightening it any more would be good for my gun while shooting high brass. Because when I returned it to the factory setting and tested the High Brass it performed better than the GunFixer and the Factory Plugs. However, I am still more than willing to take your suggestions and do more testing. I want everyone to come away from the tests we perform knowing that we've exhausted all options while remaining unbiased and fair. Though I do think we have established that my gun is not under gassed.

Edited October 4, 2010 by Bridis

[clifton 354]

Brad,

 

 

Do me a favor, adjust the spring 1/2 turn at a time until you get it to cycle winchester or fed.. then back of 1/4 turn until you get a FTE then forward 1/8th until then you should have the sweet spot for your gun. Let me know Thanks. Oh if you could use the factory front spring and a stick mag..

[Bridis 319]

Brad,

 

 

Do me a favor, adjust the spring 1/2 turn at a time until you get it to cycle winchester or fed.. then back of 1/4 turn until you get a FTE then you should have the sweet spot for your gun. Let me know Thanks. Oh if you could use the factory front spring and a stick mag..

 

Will do.

[Vicarious_Lee 84]

Vicarious_Lee: Let me ask for clarification, Bridis: Did the GunFixer (on it's highest setting) cycle stuff that the TAC did not, and did the factory plug cycle stuff that either did not?

 

I appreciate your interest in this topic and mean no disrespect, but you keep asking questions that I've already answered. Please take a look at the test chart in my 1st post and watch all of the videos I posted. Pictures/Videos say a thousand words.

 

OK, got it now. So it seems that "combustion chamber" volume is just as important as combustion chamber design. To me, it looks like the factory plug takes up the most space, then the gunfixer, then the Auto Plug. According to your tests, the forcefulness of recoil on high brass loads also went in that descending order. However, with low-brass loads it seems that both design and volume of the plug are a factor.

 

So, one thing we could do to reduce the size of the chamber is to screw the TAC 47 in as far as it will go and still seat in the correct orientation.

 

Another thing we could do, just for the sake of trying different variables, is to turn the plug to an incorrect orientation to see if that does anything to the cycling.

 

Unless that voids the warranty or something. Then I'll definitely not do that.

[waltham_41 52]

Thanks for the information Bridis, looking forward to more of your vids..... This has been a very informative thread, kudos to all for keeping it civil. I know how passionate we can get about our babies and mods to them.

[Bridis 319]

Sumsky and I were talking about doing a more in depth plug test that would include a V plug.

 

Check out these variables...

 

Bone stock S-12, converted S12 with only bolt work and a converted S-12 with gas and bolt work. But the fun wouldn't stop there. Oh no... Then bring in the Factory Plug, GunFixer, T.A.R.G.E.T. and the V Plug to be tested with all three guns.

 

It will be the Super Bowel of plugs. Before the Super Bowel.

 

What do ya think?

Edited October 5, 2010 by Bridis

[454496 71]

Brad,

 

 

Do me a favor, adjust the spring 1/2 turn at a time until you get it to cycle winchester or fed.. then back of 1/4 turn until you get a FTE then forward 1/8th until then you should have the sweet spot for your gun. Let me know Thanks. Oh if you could use the factory front spring and a stick mag..

 

That is how I adjusted my plug and it worked perfectly. But all the plugs have worked on my S12.

[kmoore 3]

Today Sumsky and I did some more testing with my Saiga 12 to determine whether or not the gun was under/over gassed. I think that you will be able to tell form this video that my gun is not under gassed.

 

http://www.youtube.com/watch?v=VP0-9Q3S_-Y

 

Hey, I've followed this thread, and was surprised to see these work, as I thought they didn't in your original test report. Maybe I've missed something? I hacked out all but the relevant parts of your original data to focus my question. Also, I'm an data analyst, so the numbers always stick with me more than the vids, barely watched most ... would rather read the numbers

 

Anyways, it looks like the cheap ammo didn't cycle with the factory spring, only with the reduced spring?

[Bridis 319]

Since we couldn't get the Auto Plug to reliably cycle low brass with the factory front spring we didn't do much testing, nor did we document any testing in that report.

N/A = Not Applicable.

 

I'm not sure what your question is, because you really didn't ask one. You put a ? at the end of a statement. But I encourage you to go over my report and pose your question . Because the testing in the video above is not represented on my test report, but does support the testing done with the reduced recoil spring.

 

BTW, the videos were posted to support the other information being presented in this testing. Not watching the videos is like getting half the info. I'm sure, as "an data analyst" you can understand how overlooking half the information could possibly lead you to incorrect conclusions.

Edited October 5, 2010 by Bridis

[The_Caged_Bird 474]

OOOH! Wait!

 

I just had a thought about a third possibility (been drinking, bear with me):

 

 

I need some opinions from engine builders and automotive types here.

 

Another thing I just noticed this evening while dismantling my Saiga and checking it out (before beer. Gun's put up now) is that the gas chamber is small and (obviously) finite, and the puck seems to have less than a half inch of travel before it can no longer impart its inertia onto the piston, because it's stopped, and the piston relies on whatever energy was given to it in that short distance to complete the reloading cycle on its own.

 

Now, let's say for this exercise that "Puck" actually equals "Piston" and "Piston" equals "connecting rod". Assume that this would be an internal combustion engine, except that the "piston" is not pinned to the "connecting rod".

 

Now, I think we might be dealing with what could be considered to be a "combustion chamber", albeit one that remains open to the barrel via ports throughout the cycle. More like a 2-stroke engine than a 4-stroke in that respect.

 

So....what Bridis might be dealing with here is the changing of the actual volume of the "combustion chamber".

 

Any time you raise the volume of the combustion chamber, compression ratio drops. Anytime you lower it, compression ratio increases. To me, that means that there's a greater volume of space the expanding gasses have to fill before they start shoving moving parts around. This bleeds off energy and decreases overall pressures, right? Please, correct me if I'm wrong. I don't believe I've ever dismantled an engine enough to hold a piston or con-rod in my hand in my life. Really, I'm talking theoretically here (which is another way of saying "out of my ass").

 

With that said, the smallest combustion chamber will be achieved with the stock plug. It has less cutouts to relieve the chamber and make it bigger. The MD Arms plug has more. The Auto Plug, by necessity of what it's designed to do, has even less material plugging up the chamber than either of those.

 

We already know that something can be gained by "combustion chamber design". Hell...why would the Saiga have a setting that has the cutout forcing gas into the cone for low-brass loads if it didn't? But, what if TAC has bumped up against that efficient design (again, by necessity) and increased the volume of space needed to be occupied by expanding gasses so that it reduces the overall force on the puck?

 

Bridis, your experience here will be invaluable. Maybe you don't have a "bad spring". Maybe the TAC plug has increased the "combustion chamber" in your Saiga so that the cheap shit doesn't cycle it anymore?

 

You are correct, kinda, but to put the S-12 into automotive terms, it would be like the piston compressing and the spark plug trying to fire with the exhaust valve 1/2 open and opening wider (of course we aren't worried about piston to valve contact in this hypothetical situation).

 

That makes for a very interesting situation, not to mention on an AR or regular AK, the projectile acts as a barrier before it leaves the barrel, the gas can't get by it so it's forced up into the gas chamber and then works the action, if the bullet were to fragment mid-barrel, then you'd start having failures. With an S-12, unless you shoot a slug, there isn't any projectile to help hold the gas in the system for a long enough amount of time.

 

Maybe if the plug had a cone that helped direct the gas to the puck it would be perfect.

 

On the other hand, it hasn't been adjusted completely, so maybe it has no flaw, but my worry is that the spring seat pressure will increase with every turn possibly causing an overgas situation but I'm more than sure that Tac has tested for this and built their plug with stops so you can't get to that point...

 

I will tell you though, Vicarious, you've inspired me to get "valve-reliefs" machined into my puck...

[Shadoh 16]

Doesnt the wad serve just as well as a slug? Also, I dont think it matters if there was a cone shaped chamber or not, its a matter of pressure and volume, not direction. The pressure has to fill the whole volume of the chamber equally regardless of the shape before it can move the piston.

[Vicarious_Lee 84]

You are correct, kinda, but to put the S-12 into automotive terms, it would be like the piston compressing and the spark plug trying to fire with the exhaust valve 1/2 open and opening wider (of course we aren't worried about piston to valve contact in this hypothetical situation).

 

That makes for a very interesting situation, not to mention on an AR or regular AK, the projectile acts as a barrier before it leaves the barrel, the gas can't get by it so it's forced up into the gas chamber and then works the action, if the bullet were to fragment mid-barrel, then you'd start having failures. With an S-12, unless you shoot a slug, there isn't any projectile to help hold the gas in the system for a long enough amount of time.

 

Maybe if the plug had a cone that helped direct the gas to the puck it would be perfect.

 

On the other hand, it hasn't been adjusted completely, so maybe it has no flaw, but my worry is that the spring seat pressure will increase with every turn possibly causing an overgas situation but I'm more than sure that Tac has tested for this and built their plug with stops so you can't get to that point...

 

I will tell you though, Vicarious, you've inspired me to get "valve-reliefs" machined into my puck...

 

I think the design of the TAC puck is definitely as direct a "forcing cone" as could be machined into it. Is there any way to compare pucks of different thicknesses?

 

That would probably be awesome and answer a lot of questions. We'd be varying the volume of our "combustion chamber" and probably the amount of pressure that could be maximally achieved.

[The_Caged_Bird 474]

Doesnt the wad serve just as well as a slug? Also, I dont think it matters if there was a cone shaped chamber or not, its a matter of pressure and volume, not direction. The pressure has to fill the whole volume of the chamber equally regardless of the shape before it can move the piston.

 

Yeah, I forgot about the wad... I'm a flippin' idiot...

 

 

You'd think that the direction doesn't matter, but it really does, besides, a forcing cone accomplishes two things, it directs the gas charge and, more importantly, takes up space, thusly raising the "compression ratio" much like domed pistons force the charge into the quench area and raise the compression at the same time...

[Vicarious_Lee 84]

Doesnt the wad serve just as well as a slug? Also, I dont think it matters if there was a cone shaped chamber or not, its a matter of pressure and volume, not direction. The pressure has to fill the whole volume of the chamber equally regardless of the shape before it can move the piston.

 

Yeah, I forgot about the wad... I'm a flippin' idiot...

 

 

You'd think that the direction doesn't matter, but it really does, besides, a forcing cone accomplishes two things, it directs the gas charge and, more importantly, takes up space, thusly raising the "compression ratio" much like domed pistons force the charge into the quench area and raise the compression at the same time...

 

BTW, I meant "Tac Plug" not "TAC Puck". However, I read on their website the their US-made puck "opens up the gas chamber". By our current line of thought, wouldn't that reduce the "compression ratio" and create a greater volume for the limited gas pressure that low-brass crap produces before it acted on the piston?

 

I know the MD Arms Gunfixer plug takes up more space, and it appears to have a tighter "forcing cone". I really want to find the time to test my setups, but I don't think I'll be able to.

 

Thanks again to Bridis for the data and experiments.

[The_Caged_Bird 474]

Doesnt the wad serve just as well as a slug? Also, I dont think it matters if there was a cone shaped chamber or not, its a matter of pressure and volume, not direction. The pressure has to fill the whole volume of the chamber equally regardless of the shape before it can move the piston.

 

Yeah, I forgot about the wad... I'm a flippin' idiot...

 

 

You'd think that the direction doesn't matter, but it really does, besides, a forcing cone accomplishes two things, it directs the gas charge and, more importantly, takes up space, thusly raising the "compression ratio" much like domed pistons force the charge into the quench area and raise the compression at the same time...

 

BTW, I meant "Tac Plug" not "TAC Puck". However, I read on their website the their US-made puck "opens up the gas chamber". By our current line of thought, wouldn't that reduce the "compression ratio" and create a greater volume for the limited gas pressure that low-brass crap produces before it acted on the piston?

 

I know the MD Arms Gunfixer plug takes up more space, and it appears to have a tighter "forcing cone". I really want to find the time to test my setups, but I don't think I'll be able to.

 

Thanks again to Bridis for the data and experiments.

 

Yeah, but I'm a car-guy so if make my puck look like the top of a piston in a car, then after we get done shooting and we are cleaning our weapons, my buddy will see it, and he'll probably get a huge kick out of it...

[hobbyshooter 59]

Today I tried my mid barrel braked gun with Federal bulk birdshot in the md20 drum and the extra spring tension prevented the gun from running. I closed the auto plug cap screw all the way to the point that it was blocking much of the end exhaust port and it still wouldn't run with only 5-6 rnds in the drum.

 

The gunfixer plug on 3 stove piped the first 4 rounds of a fully loaded drum then ran through the remaining 16.

 

That confirms Bridis' results that the gunfixer plug does more to cycle low gas guns than the auto plug.

[Bridis 319]

I don't have the Video yet to show it, but Auto Plug testing went really well today. I adjusted the tension screw as recommended by TAC 47 and was able to cycle everything really well. Even better than the Gunfixer. I was able to consistently cycle the Winchester Universal with the Auto Plug, which always gave me problems with the Gunfixer. However, there is still a big "but" here. BUT I didn't do any testing with high brass. My fear is that I may have had to adjust the tension screw to the point where high brass rounds will do more than normal damage to my gun. Though previous testing does show the Auto Plug does less damage with high brass. Either way I'm happy that it works.

 

More testing to come...

[hobbyshooter 59]

I don't have the Video yet to show it, but Auto Plug testing went really well today. I adjusted the tension screw as recommended by TAC 47 and was able to cycle everything really well. Even better than the Gunfixer. I was able to consistently cycle the Winchester Universal with the Auto Plug, which always gave me problems with the Gunfixer. However, there is still a big "but" here. BUT I didn't do any testing with high brass. My fear is that I may have had to adjust the tension screw to the point where high brass rounds will do more than normal damage to my gun. Though previous testing does show the Auto Plug does less damage with high brass. Either way I'm happy that it works.

 

More testing to come...

 

I can't wait to see your results with high brass on your tightened setting. I have an auto plug in my home defense gun, but for now my mid barrel ported gun is keeping the gunfixer plug. Setting 2 runs kent #5 shot and remington sluggers 100%, mixed mags. And I reduced the spring tension on my MD20 drum to cycle federal birdshot on setting 3 which matches the performance of my Surefire mags.

Edited November 7, 2010 by hobbyshooter

[clifton 354]

I don't have the Video yet to show it, but Auto Plug testing went really well today. I adjusted the tension screw as recommended by TAC 47 and was able to cycle everything really well. Even better than the Gunfixer. I was able to consistently cycle the Winchester Universal with the Auto Plug, which always gave me problems with the Gunfixer. However, there is still a big "but" here. BUT I didn't do any testing with high brass. My fear is that I may have had to adjust the tension screw to the point where high brass rounds will do more than normal damage to my gun. Though previous testing does show the Auto Plug does less damage with high brass. Either way I'm happy that it works.

 

More testing to come...

 

 

Thanks for the update Bridis!

[USP40 1]

Just came back from shooting range. AUTO PLUG work fine after some adjustment.

[zenman223 460]

So im curious, does the auto plug actually do what it was intended. as in allow for shooting of low brass to high brass without adjustment.(once properly set) without causing excessive damage to the gun with high brass?

 

It seems the plug does work but i havent seen any comments about how well it does what it was designed to do? can you really "set it and forget it"? at least for 2 3/4, i know it may be too much to ask for it to work with 3'" and low brass without damage.

[Bridis 319]

Since I've got my Auto Plug working, I'll be testing that soon.

[clifton 354]

[bigmegina 3]

if you are concerned about carrier hitting the trunnion with high brass,just get a recoil buffer.i have 1 in my sagia and no problems.