I put on a polychoke and my POI shifted to right?

[Jefe73 0]

I put a polychoke on my Saiga 12 ga. At 25 yd and closer, with a Tromix Shark brake or factory thread cover, the factory sights were "right on" for slugs and though birdshot pattern was loose, it was centered.

Now, with polychoke, slugs (at slug setting and Mod setting) are hitting 6-9 inches right at 25 yds. Birdshot (at mod or full) is also patterning to right- nice dense pattern, but definitely to right.

 

Anyone know whats happening?

 

thanks for any feedback.

[VanKiller 322]

Your Poly sounds to be bored off center or out of true alignment........try one round of light birdshot after backing the entire choke out 1/4 turn, or less, just enough to see if the pattern shifts........then you will have a good idea if the choke was bored off......

 

 

 

I put a polychoke on my Saiga 12 ga. At 25 yd and closer, with a Tromix Shark brake or factory thread cover, the factory sights were "right on" for slugs and though birdshot pattern was loose, it was centered.

Now, with polychoke, slugs (at slug setting and Mod setting) are hitting 6-9 inches right at 25 yds. Birdshot (at mod or full) is also patterning to right- nice dense pattern, but definitely to right.

 

Anyone know whats happening?

 

thanks for any feedback.

[gtnichols 51]

I remember Tony saying he had to "make the barrel an even thickness all the way around" before installing a choke or something ,.. meaning that the barrel he was threading was thicker here and thinner there,, could be yours is too causing the poly to lean to one side or something.. Mine is dead on, and I installed it just like the directions say.

[Jefe73 0]

Gentlemen, thank you.

Will try the quarter turn with birdshoot and see what happens....

 

Bummer- oh, well. Just when you think that you have everything wired....something else...

 

Heck, its shorter with the factory thread cover anyway...

[TonyRumore 1,332]

The ID of the barrel is not concentric with the OD, so when you screw the choke on using the OD, it's not lined up with the bore.

 

To fix it, you would need to cut the threads off, then insert an internal expanding mandrel into the muzzle, chuck it in the lathe's headstock, then run a steady rest back by the receiver. Turn down the threaded area so the ID and OD line up, then rethread.

 

Your barrel looks like this.

 

[Jefe73 0]

Tony, VanKiller and GasGiant- thank you. It is the inner and outer barrel- not concentric etc.

 

Tried the 1/4 turn on the polychoke- still shot to right. Took polychoke off/ put factory thread protector back on and POA= POI at 25 yds.

 

As a side note- recoil seems to be "stiffer" with the factory thread protector then with the Shark Brake or Polychoke mounted.

 

Lesson learned- Saigas may require machine work to get a polychoke to work correctly...bummer... and, I thought it was a simple screw-on. Ha!

 

Anyhow, others will know now...

Edited November 17, 2008 by Jefe73