U0, U1, U2, U3 and U4 explained.....its simple.

Muller Chokes has simplified things for you.  We produce 4 different constrictions (and you can special order a cylinder choke--if you really must have one).  Our 4 regular constrictions are referred to as:  U1, U2, U3, U4 (for close, medium, far and farther). If you pattern them at the distances they were created for, you will immediately see how they shine.

Lets take the U4 for example. In my Beretta 303 with Fed 1-1/8 oz 7.5's at 32 yards the pattern, though impressive, is still underdeveloped. When I repeat the shot at 40 yards, this is what the patterning paper showed:

  • Inside the 30" circle which I drew 8 quadrants on. The inside being 20" with 4 quadrants. The outside at 30" with 4 Quadrants.
  • The inside four quadrants had a total pellet count of 188. Top left quarter had 45 pellets, top right 46, bottom left 50, bottom right 47.
  • The outside had a total of 135. Top left quarter 33, top right 34, bottom left 35 bottom right 33.

In summary, 188 + 135 = 323 total hits in 30" circle at 40 yards out of a total of 389 pellets (avg count from 10 shells). 323/ 389 = 83% pattern.

So, the U4 even though it had not developed fully yet at 40 yards produced a very even and impressive pattern considering that the definition of a Full Choke is 70% at 40 yards in a 30" circle.

IF you take the U3 at the same 40 yard distance you will see it absolutely shines with the numbers of pellets to the outer  fringe evengreater than the U4.  Why? Because I developed the U3 to be optimal at 40 yards!! The U4 is made to be optimal at 60 yards. The reason I am posting it this way is to help people understand that the even pellet distribution that Muller chokes provide is not hype and they do exactly as advertised PROVIDED they are tested the way they are meant to be used.

Up to now, all the good chokes out there offered a hot core with a very open fringe and that fringe was hardly consistent hence your golden BB breaks or clean misses when only off slight amounts.  Well, that is no longer the case. You are no longer are stricken with hot cores and sparse outer fringes, so here is my closing statement: Please don't confuse more open patterns with even pellet distribution, because folks...it is far more advanced than that.

Comments (13 Comments)

Would like to see an image of your pattern board so I can do similar pattern testing, can’t get a handle on the quadrants you describe

Posted by Jeff on January 09, 2014

It there any idea of making a U0? for super close stuff?

Posted by Sheila on February 26, 2011

Yes Sheila, I make a U0 special order. It is designed to give predictable, consistent Cylinder diameter patterns that break targets like a skeet Choke. It is awesome for targets inside 20 yards, especially Rabbits.
To order, just contact me at Jim@mullerchokes.com

Posted by Jim on February 27, 2011


I have single set of your choke tubes. I’ve been shooting skeet with U1 in the under barrel (first shot)and U0 in the over barrel. Would your recommendation be to purchase another U0?


Posted by Dan Gallagher on September 26, 2011

Yes Dan. For American Skeet, I use and recommend 2 U0’s. International Skeet, I recommend U0 & U1.

Posted by Jimmy Muller on May 30, 2012

And Jim’s service is second to none! I’ve never anyone follow up on an order like Jim has!!!!

Posted by Ray Morris on January 23, 2011

All the good things said on this blog are true
Luigi Torchia N.S.C.A. life member 535386 Mtl. Can.

Posted by luigi torchia on January 29, 2011

Makes sense! I asked because we have this one station at our club that throws a L>R crossing dome-on bird that starts at 35 yards coming in slightly with a good break point at 30 yards. In a test, I was able to break (broken, not crushed) that bird 8 for 8 with your U1 and #8’s. I use U2/U2 almost exclusively, but was impressed with that performance.

Posted by Jack on February 05, 2011

MULLER CHOKES are the BEST no matter how you look at it
Good scores=MULLER CHOKES.
Luigi Torcia life member N.S.C.A.535386 Mtl.Can.

Posted by luigi torchia on January 22, 2011

MULLER CHOKES are the BEST no matter how you look at it

Posted by luigi torchia on January 22, 2011

Jack, it really all depends on target presentation, but basically the U1 is optimal at 25 yrds and the U2 is at 35 yrds, the U3 is usually most optimal at 45 yards. Really there is no “specific” yardage, just approx because target presentation can optimize patterns differently! For example if your shooting a 90 MM target on edge at 40 yards I would recommend the U3, but if the target was a chandelle, overhead or fully open Battue, I would recomend the U2.

Posted by Jimmy Muller on January 22, 2011

Keep posting stuff like this i really like it

Posted by medical billing on January 20, 2011

You mention U3 is optimal at 40 yards (far) and U4 optimal at 60 yards (farther), but what specific yardages are U1 (close) and U2 (medium) optimal at?


Posted by Jack on January 21, 2011

Post Comment