Puck Questions

[bamabound 0]

Evening all,

My S12 is still not cycling low brass and am wondering about the physics of various pucks (I'm watching hockey and this popped into my brain cell)

 

I have polished and ground down the bolt and feed ramps and trigger. I have uncovered all of the holes in the barrel (1 was completely covered-it has three now, but I didn't increase the size). It throws high brass about 10 feet and acts stupid with low brass. The bolt lacks about 3/4" in its rearward travel in being successful in cycling.

 

So... do certain pucks have different masses to force the piston rearward?

 

How does the twister puck work or help?

 

And, is the #2 setting the correct setting for low brass?

 

Thanks to all for the tutorials!!

Edited April 8, 2010 by bamabound

[Lone Star Arms 2,047]

Basically, no. The dynamics of a gas piston are primarily governed by size and weight. As long as the piston is around 37 - 39 grams, does not have sharpened edges or burrs, and is the right size, weight, and shape for the gas chamber, it should work.

 

Beyond that, claims of enhanced performance from a particular piston are a matter of personal opinion.

 

To date, no one has presented or documented empirical evidence that one gas piston is inherently better than another, or will improve performance one iota over the factory configuration.

 

Opening up the aperature between your barrel and gas chamber so that your ports are unrestricted is reasonable as long as shape and size of the aperature does not adversely affect the efficient movement of the piston within the gas chamber.

 

Your ports should be .093 inches (or 3/32" for those of us who speak American).

 

I'm not sure what to make of "grinding" the hammer, carrier rails, bolt, and contact surfaces.

 

If you can provide photos of the work you have done, that may be helpful in determining whether or not you have improved efficiency by doing so.

 

There are a number of expert and knowledgeble participants in the forum who can help you to achieve your goals. The more information (visual and verbal) you can provide, the better the chances that forum members can help you along the way.

 

Good luck with your project!

[Wade Pruetz 103]

What kind of forearm if any are you running? How does the gun hand cycle?

[bamabound 0]

Here is the bolt assembly

 

 

And here is the trigger

 

 

And here are the ports

 

I can take a bunch more off the trigger, but I want to not take off too much and mess with the inertia thing.

[bamabound 0]

Here are two more shots

 

 

 

[bamabound 0]

What kind of forearm if any are you running? How does the gun hand cycle?

 

 

Stock forearm and cycles by hand just fine. However if I impede the the forward movement it hangs up 3/4" from going completely forward.

[Lone Star Arms 2,047]

Here are two more shots

 

 

 

 

Thanks for the photos. All three of your ports are now visible...Kudos!

 

I see two major issues immediately. The geometry of your hammer, and the size of your ports. You need to increase port size to 3/32".

 

You also appear to have a "crimp" in your receiver which may be restricting the bolt carrier from moving efficiently.

[bamabound 0]

Here are two more shots

 

 

 

 

Thanks for the photos. All three of your ports are now visible...Kudos!

 

I see two major issues immediately. The geometry of your hammer, and the size of your ports. You need to increase port size to 3/32".

 

You also appear to have a "crimp" in your receiver which may be restricting the bolt carrier from moving efficiently.

 

 

Thanks

 

Do I need to flatten the hammer? And where on the receiver do you see a crimp? Is it on the rails?

[Lone Star Arms 2,047]

Here are two more shots

 

 

 

 

Thanks for the photos. All three of your ports are now visible...Kudos!

 

I see two major issues immediately. The geometry of your hammer, and the size of your ports. You need to increase port size to 3/32".

 

You also appear to have a "crimp" in your receiver which may be restricting the bolt carrier from moving efficiently.

 

 

Thanks

 

Do I need to flatten the hammer? And where on the receiver do you see a crimp? Is it on the rails?

 

 

The hammer geometry as it sits in the receiver needs to be more like that of the stock hammer (as in the original stock hammer and factory FCG). The current geometry doesn't look anything like that.

 

The "crimp" or restriction appears to be at your hammer axis area. This could be a couple of things. It may be that your retaining device is causing it, or that your hammer needs to be adjusted on the BHO side. Or I could be completely wrong - and it may be that what I am seeing is due to your wide angle lens.

 

If you find the bolt carrier is binding as it approaches your hammer axis - you need to check that area to make sure that nothing is pulling or pushing on the receiver at the axis.

 

The same goes for the trigger group axis.

 

Good luck!

[africamagical 5]

id also throw in the stock hammer and try a reduced power hammerspring

[Rabid Robert 74]

Hard to tell whether you have mechanical bolt(and or hammer/spring) problem from your posts but we get the light load cycling question all the time.

 

There is a basic summary of how to make light loads cycle at

http://forum.saiga-12.com/index.php?showtopic=45743

 

To Answer your question directly about the TwisterPuc, If you lack complete cycling the TwisterPuc wont solve the problem by itself. The TwisterPuc works mostly by keeping the Gas Tube clean. We do have them in different configs for light vs heavy loads, but that has more to do with keeping the cycling rapid and matching the amount of initial Gas (air) volume before ignition. Once you get things tuned, the TwisterPuc will give you a LOT more rounds before failure due to gas tube fouling.

 

About the comment to replace the hammer spring, we get a lot problems with the OEM hammer springs and there are some very good aftermarket spings out there so replacing it is always a good idea. As the above referred post states, one trick is the recoil spring Strength which is SO simple to replace.

 

Of course as Waffen S has pointed out if your geometry is messed up everything else is academic

Edited April 16, 2010 by Rabid Robert

[bamabound 0]

Hard to tell whether you have mechanical bolt(and or hammer/spring) problem from your posts but we get the light load cycling question all the time.

 

There is a basic summary of how to make light loads cycle at

http://forum.saiga-12.com/index.php?showtopic=45743

 

To Answer your question directly about the TwisterPuc, If you lack complete cycling the TwisterPuc wont solve the problem by itself. The TwisterPuc works mostly by keeping the Gas Tube clean. We do have them in different configs for light vs heavy loads, but that has more to do with keeping the cycling rapid and matching the amount of initial Gas (air) volume before ignition. Once you get things tuned, the TwisterPuc will give you a LOT more rounds before failure due to gas tube fouling.

 

About the comment to replace the hammer spring, we get a lot problems with the OEM hammer springs and there are some very good aftermarket spings out there so replacing it is always a good idea. As the above referred post states, one trick is the recoil spring Strength which is SO simple to replace.

 

Of course as Waffen S has pointed out if your geometry is messed up everything else is academic

 

Thank you for the info.

 

I am putting the stock hammer back in and reshaped the conversion hammer. let's see if either works.

 

I also have a new hammer spring, but I don't think that is the culprit.

 

I should have checked the size of the ports when I had the gas block apart, but live and learn.

 

The recoil spring will be the next adventure if none of the above works.

[G O B 3,516]

DO NOT MIX FIRE CONTROL PARTS! Re shape the hammer to clear the bolt like the original. AK's have a much smaller bolt than a S-12, so flatten the hammer face accordingly. Have you fired a couple hundred high brass rounds to break the gun in? If not then do so immediately.

[bamabound 0]

DO NOT MIX FIRE CONTROL PARTS! Re shape the hammer to clear the bolt like the original. AK's have a much smaller bolt than a S-12, so flatten the hammer face accordingly. Have you fired a couple hundred high brass rounds to break the gun in? If not then do so immediately.

 

 

OK! Thanks

 

I have fired about 150, with 30 being low brass.

 

Would you bore out the gas ports or shoot the brass first?

[a782482 0]

DO NOT MIX FIRE CONTROL PARTS! Re shape the hammer to clear the bolt like the original. AK's have a much smaller bolt than a S-12, so flatten the hammer face accordingly. Have you fired a couple hundred high brass rounds to break the gun in? If not then do so immediately.

 

is there a particular reason why you cant swap the hammers? thanks

[going12220 125]

can you check the puck diameter? I've found at .827" works well with low brass and a lighter recoil spring in the front helps 1911 style 12 or 13 pounder (but put the regular one back for high brass)

Edited April 20, 2010 by going12220

[Lone Star Arms 2,047]

DO NOT MIX FIRE CONTROL PARTS! Re shape the hammer to clear the bolt like the original. AK's have a much smaller bolt than a S-12, so flatten the hammer face accordingly. Have you fired a couple hundred high brass rounds to break the gun in? If not then do so immediately.

 

is there a particular reason why you cant swap the hammers? thanks

 

In a literal sense, you CAN swap hammers, but that doesn't mean you should. Just as the Tapco hammer sits higher in the receiver with the Tapco hook, the Russian hammer will also sit higher and at a different angle than with the factory FCG. Simply swapping out the Tapco hammer for a Russian hammer will not cure the geometry problem with the US trigger group. The Russian hammer also tends to hang on the Tapco disconnector unless properly modified.

 

The geometry of either hammer can be modified to work more efficiently with the Tapco trigger platform. There are some good posts on this subject in the technical section, and if you want it done professionally there are a couple of forum sponsors who can walk and chew gum around this kind of work.

 

Good luck!

[G O B 3,516]

DO NOT MIX FIRE CONTROL PARTS! Re shape the hammer to clear the bolt like the original. AK's have a much smaller bolt than a S-12, so flatten the hammer face accordingly. Have you fired a couple hundred high brass rounds to break the gun in? If not then do so immediately.

 

is there a particular reason why you cant swap the hammers? thanks

The parts are made to work as an assembly, and one manufacturers parts will differ dimensionality from another's - often with drastic consequences. You should never mix critical parts between manufacturers they were not engineered to work with each other.

[a782482 0]

DO NOT MIX FIRE CONTROL PARTS! Re shape the hammer to clear the bolt like the original. AK's have a much smaller bolt than a S-12, so flatten the hammer face accordingly. Have you fired a couple hundred high brass rounds to break the gun in? If not then do so immediately.

 

is there a particular reason why you cant swap the hammers? thanks

 

In a literal sense, you CAN swap hammers, but that doesn't mean you should. Just as the Tapco hammer sits higher in the receiver with the Tapco hook, the Russian hammer will also sit higher and at a different angle than with the factory FCG. Simply swapping out the Tapco hammer for a Russian hammer will not cure the geometry problem with the US trigger group. The Russian hammer also tends to hang on the Tapco disconnector unless properly modified.

 

The geometry of either hammer can be modified to work more efficiently with the Tapco trigger platform. There are some good posts on this subject in the technical section, and if you want it done professionally there are a couple of forum sponsors who can walk and chew gum around this kind of work.

 

Good luck!

 

Thanks, I was just wondering.. I spent alot of time my self modifing the trigger FCG including the hammer the most of all.. if TROMIX modified trigger is truley "drop in" as they say, I highly recommend to anybody "1st timers" spend that extra $15 on the modifed one. Because you dont know how much and where exactly to grind/sand, I had to reinstall FCG at least 5 times, fiting and sanding it bit at a time. Now that I know the exact places and areas to grind its really not that big of a deal might as well save that $15 and get to use my Dremel

[a782482 0]

DO NOT MIX FIRE CONTROL PARTS! Re shape the hammer to clear the bolt like the original. AK's have a much smaller bolt than a S-12, so flatten the hammer face accordingly. Have you fired a couple hundred high brass rounds to break the gun in? If not then do so immediately.

 

is there a particular reason why you cant swap the hammers? thanks

The parts are made to work as an assembly, and one manufacturers parts will differ dimensionality from another's - often with drastic consequences. You should never mix critical parts between manufacturers they were not engineered to work with each other.

 

Gotcha, I though the reason not to mix is to have that one extra US made part

 

BTW OP, srry not trying to highjack your thread.