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Pedersoli Choke Tubes -- Interchange with Browning Invector tubes

posted Jul 19, 2010, 9:59 AM by Peter Lucas   [ updated Jul 29, 2010, 2:22 PM ]

 I have purchased two used Pedersoli SxS shotguns on Gunbroker.com over the last couple of years.  Both guns came with only two choke tubes each; one Improved Cylinder and one Modified.  Consequently, between the two guns I had two Improved Cylinder choke tubes and two Modified Choke tubes.  By pooling my choke tubes, one gun could use two Improved Cylinder chokes for shooting skeet and other other gun could use two Modified chokes for hunting pheasants.   However, I really wanted to get a full set of chokes for at least one of the two guns.

Finding Pedersoli Choke tubes was not any easy task.  Neither of the two U.S. Pedersoli distributors had choke tubes in stock.  While the Pedersoli distributors indicated that they could order choke tubes, Pedersoli made choke tubes were going to be expensive.  I also contacted both Dixie Gun Works and Cabelas, as they sell Pedersoli shotguns.  Both Dixie and Cabelas indicated that they did not carry choke tubes for Pedersoli shotguns.

Having struck out locating a supply of Pedersoli made choke tubes, I decided to try Carlson’s Choke Tubes in Atwood, Kansas.  The folks at Carlson’s told me that they did not know of an interchangeable choke tube, but if I would send them one of my Pedersoli tubes, they would see if they had anything which would work.  I was a little concerned about sending one of my four chokes off to Carlson’s.  If the tube got lost, I would have four barrels and a total of three choke tubes.  I swallowed hard and sent one of the tubes to Carlson’s.  A couple of days latter I received a phone call from Mr. Carlson who told me that thread pattern on my Pedersoli tube was identical to the Browning Invector/Winchester choke tube.  I ordered five new flush choke tubes directly from Mr. Carlson while on the phone.

 The choke tubes from Carlson’s came in the mail the next day.  The Carlson choke tubes threaded into my Pedersoli guns perfectly.  However, internal bore diameter of the Carlson choke tubes were a few thousandths smaller than the bore diameter of the gun.  This meant that there was a shallow ridge at the intersection of the gun’s bore and the choke tube.  The customer service representative at Carlson’s assured me that the ridge was normal and would not affect the patterning of the gun.  So, it was off to the patterning board.

 Initially, I shot two five shot strings.  One string was shot from the right barrel with the Pedersoli Improved Cylinder choke tube and one string from the left barrel with the Carlson’s Improved Cylinder choke tube. The load was an equal volume of shot and powder with 1 1/8 ounces of 7 ½ and 2.75 drams (75 grains) of Goex FFFg. The wad column was one 1/8 nitro card over the powder and one thin over shot card over the shot.   

At 20 yards, both choke tubes produced very nice patterns with little or no gaps in the 20 inch center core of the pattern.  Here are the images of the patterns and the number of pellets in the inner 10, 20, and 30 inches of each of the patterns at 20 yards.  The inner circle represents a 20 inch diameter circle from the center of the pattern.  The outer circle represents a 30 inch diameter circle from the center of the pattern.


Carlson Choke Tube      
 Pedersoli Choke Tube
 
 Pattern      Pellets     
 Pattern    Pellets

10"    190
20"    208
30"     48
total  446  
10"     187
20"     181
30"      33
total   401

10"    108
20"    183
30"     90
total  381

10"     205
20"     194
30"      24
total   423

10"    147
20"    189
30"     35
total  371  

10"     167
20"     175
30"      51
total   393

10"    140
20"    197
30"     84
total  421

10"     181
20"     154
30"      63
total   398

10"    169
20"    221
30"     51 total  441

See note:

10"    135
20"    170
30"      91
total   396
Averages:
Carlson IC Choke Tube

10"    150
20"    201
30"     61
total  412
Averages:
Pedersoli IC Choke Tube
10"    175
20"    174
30"      52
total   402

Note: The ninth shot was near the edge of the patterning paper and a portion of the pattern was cut off.

Based on the pellet counts, it appears that this bag of shot was running a little smaller than standard 7 1/2 shot.  The total average pellet count for these loads (including pellets outside of the 30 inch circle) was approximately 450 pellets.  A standard 1 1/8 ounce load of 7 1/2 shot should contain approximately 393 pellets.  Adjusting the patterns to simulate 40yards and using a 450 pellet count per load, the Carlson choke tube averaged 57.5% of the pellets in a 30 inch circle and the Pedersoli choke tube averaged 61.1%,  These results compare favorably with the standard pattern density of 55% for an improved cylinder choke at 40 yards.    

In addition, I shot a ten shot string with the same choke configuration using my muzzle loading shot cartridges.  Both the Pedersoli and Carlson's chokes preformed equally well with the shot cartridges. The patterning results for are included in the article titled:  Making Muzzle Loading Shot Cartridges.

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