I police my gun pretty close. How would I check the Diameter of Hunter , light and heavy Varmint barrel for taper ? what would it be at 20" from action ?
It would depend marginally on how much your gunsmith cleaned up the breech end of the barrel, but otherwise, you could work it out mathematically from the barrel makers' spec sheet for those barrel types.
The IBS and NBRSA rules are defined from the bolt face.
I already had the max dimensions drawn up on my cad/cam program because I manufacture barrels.
At 20" from the bolt face IBS Hunter class .918
NBRSA Hunter class .886
HV IBS & NBRSA 1.031
LV IBS & NBRSA Same rules as HV
If you are going to use this to challenge someone at a match-- I would strongly advise against it unless it is extremely obvious that the barrel is oversize and it is a registered match. Remember these numbers are from the bolt face and you don't have that number. This would cause a big rumble at a match.
If you need this to check your rifles then PM me your distance to the bolt face and I will get you your max numbers. Just use a rod to measure from the bolt face to the end of barrel.
The barrel contour rules can be found in the rule books for NBRSA and IBS. The hunter class rules differ between IBS and NBRSA.
Very good reply!
Along with the mirage shades, in the lid of my gun case, I carry a [NBRSA Hunter Class] maximum barrel-profile silhouette cut-out - just in case there's a question. I like my barrels short and fat. Any profile which fits inside the silhouette is a legal contour. Keep 'em ON the X! RG
P.S. Per oliver88 (above), these numbers are close enough to mine to make me think I [correctly] did the math! At 20" from the bolt face IBS Hunter class .918
NBRSA Hunter class .886
I understand that if you purchase a Varmint or HBR barrel from any of the major manufacturers of custom barrels, that there is no way you can render it illegal for it's intended application as far as the OD dimensions are concerned.
By the rules, if one were to use the largest allowable barrel for Hunter Class and utilize the entire 4" of 1.250 and cut both barrels at 24", the IBS allows a muzzle diameter .040" larger than the NBRSA. .835"vs .795"
That being said, every barrel maker I know of makes standard HBR barrels that are NBRSA legal, which allows them to be used in both organizations.