Polychoke--Barrel Question

[Gogiants 0]

While reading old threads about Polychokes I came across a post where the poster said the Polychoke changed his point of impact 6 inches. The poster said the reason was because his barrel was drilled off-center. He also said that this is a known issue with some these barrels. Is there i way I can verify that my barrel is drilled correctly before getting a Polychoke?

 

Thanks.

[DeMilled 5]

The only thing that comes to mind is to take a fairly long, about 3 or 4 foot, length of tubeing that is threaded to screw onto the barrel....and screw it on. Then use some sort of fairly long straight edge to visualy check that it is in line with your barrel.

I don't know of any other method to check the alighment of a thread pattern, but machinists may. Do a search of machinists forums etc. and see if they discuss ways to check the alignment of threads.

 

Good luck

[gtnichols 51]

On his you could see it just by looking at the end of the barrel, If I remember correctly, when screwed on the poly choke did not look straight with the barrel. there are pictures of it, and you can really see something is wrong.

[Gogiants 0]

The only thing that comes to mind is to take a fairly long, about 3 or 4 foot, length of tubeing that is threaded to screw onto the barrel....and screw it on. Then use some sort of fairly long straight edge to visualy check that it is in line with your barrel.

I don't know of any other method to check the alighment of a thread pattern, but machinists may. Do a search of machinists forums etc. and see if they discuss ways to check the alignment of threads.

 

Good luck

No

 

 

No, I am not being clear. It wasn't that the threads were goofy, it was that the bore wasn't in the center of the barrel. I'll see if i can find the thread.

[G O B 3,516]

Saiga barrels are hammer forged, including the shotguns. Due to the way they are made the bore is not perfectly concentric with the outside of the barrell. Said another way, the wall thickness can vary considerably around the bore axis. If you have a barrel threaded or bored, it needs to be done with proper equipment that aligns with the inside of the barrel. If it is done by aligning with the outside of the barrel it will be screwed up. It may shoot anywhere, or could even block the bore partially. All work needs to be done with an internal pilot, and that needs to properly fit the bore.

[Gogiants 0]

Saiga barrels are hammer forged, including the shotguns. Due to the way they are made the bore is not perfectly concentric with the outside of the barrell. Said another way, the wall thickness can vary considerably around the bore axis. If you have a barrel threaded or bored, it needs to be done with proper equipment that aligns with the inside of the barrel. If it is done by aligning with the outside of the barrel it will be screwed up. It may shoot anywhere, or could even block the bore partially. All work needs to be done with an internal pilot, and that needs to properly fit the bore.

 

 

 

 

Thanks GOB. But my question that I need help with is, can I tell if a Polychoke will align with my bore?

[Ragnar 10]

I use a Polychoke and have patterned my S12 with a variety of loads.

 

With slugs, and choke wide open, it groups 2" low at 14 feet. Dead-on considering I did not use a hold-over to account for the offset of the fixed sights.

 

With 00 buck 2-3/4" using modified (fuzzy recall) the center of the group was again just weighted slightly below the X at 14 feet.

 

I still need to run the same test without the PolyChoke.

 

I know 14 feet is really too close to measure a group, but since the S10 is a CQB weapon for me, I figured 2x CQB was the max distance I was willing to go. I would think different if I was using it for turkey instead of MZBs.

Edited January 14, 2010 by Ragnar Danneskjöld