Handbook: threads

Table for determining the type of thread

In order to determine the type of thread on the barrel of your rifle, you will need a caliper.
It is necessary to measure the thread diameter in millimeters as accurately as possible, and then use this table.
How to correctly measure with a caliper is shown in the photo:

Outer diameter, mmInner diameter, mmThread pitch, turns per inchThread pitchBSPMetricsInch UNFInch NPT
9,3-9,78,5-8,928 1/8″   
9,3-9,78,5-8,927    1/8″
9,7-9,98,2-8,6 1,5 M10x1,5  
10,9-11,19,7-10,020   7/16″-20 
11,6-11,910,2-10,6 1,5 M12x1,5  
12,4-12,711,3-11,6    1/2″-20 
12,9-13,111,4-11,919 1/4″   
12,9-13,111,4-11,918    1/4″
13,6-13,912,2-12,6 1,5 M14x1,5  
14,0-14,312,7-13,018   9/16″-18 
15,6-15,914,2-14,6 1,5 M16x1,5  
16,3-16,614,9-15,419 3/8″   
16,3-16,614,9-15,418    3/8″
17,6-17,916,2-16,6 1,5 M18x1,5  
18,7-19,017,3-17,616   3/4″-16 
19,6-19,918,2-18,6 1,5 M20x1,5  
20,5-20,918,6-19,014 1/2″   
20,7-21,118,3-18,714    1/2″
21,6-21,920,2-20,6 1,5 M22x1,5  
22,0-22,220,2-20,514   7/8″-14 
22,6-22,920,6-21,014 5/8″   
23,6-23,922,2-22,6 1,5 M24x1,5  
25,6-25,924,2-24,6 1,5 M26x1,5  
26,1-26,424,1-24,514 3/4″   
26,3-26,723,7-24,114    3/4″
26;6-26,924,3-24,712   1,1/16″-12 
29,6-29,927,4-27,8 2 M30x2  
29,8-30,127,6-27,912   1,3/16″-12 
29,6-29,928,2-28,6 1,5 M30x1,5  
32,6-32,930,5-30,9 2 M33x2  
33,0-33,230,3-30,811 1″   
33,0-33,330,8-31,212   1,5/16″-12 
32,9-33,430,3-30,811,5    1″
35,6-35,933,4-33,8 2 M36x2  
37,6-37,936,2-36,6 1,5 M38x1,5  
40,9-41,238,7-39,112   1,5/8″-12 
41,6-41,939,4-39,8 2 M42x2  
41,5-41,939,0-39,511 1,1/4″   
41,4-42,039,2-39,611,5    1,1/4″
44,6-44,942,4-42,8 2 M45x2  
44,6-44,943,2-43,6 1,5 M45x1,5  
47,3-47,645,1-45,512   1,7/8″-12 
47,4-47,844,8-45,311 1,1/2″   
47,3-47,945,1-45,511,5    1,1/2″
51,6-51,949,4-49,6 2 M52x2  
51,6-51,950,2-50,6 1,5 M52x1,5  
59,4-59,856,5-56,811 2″   
59,9-60,256,4-56,711,5    2″
63,3-63,661,3-61,812   2,1/2″-12 
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