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I have a few used barrels that came from full auto's and am trying to get an idea of wear in terms of rifling etc. Are there any signs to look for to determine the condition and amount of use? I have examined the rifling of several barrels but to my untrained eye they look sharp. I guess the definition of "sharp" is what I am looking for. Also signs of wear at other areas....trunion etc.? Any help is appreciated. Thanks.
 

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greetings from ireland.....


a barrel wear gauge is your best bet !!! brownells have them for 5.56 cal barrels.... other than that you may look for bulges or puckers which show up as shadows as you look up the barrel.... check for pitting

even trained eyes wont give you a good indication as you cant tell the how many or what kind of ammo was put through it in its life so gauging is the only way !

hope that helps !!

slan

phillip
 

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The checking procedure depends on exactly which barrel you're talking about.

For example, on a G3/HK91:

The barrel is unserviceable if a 7.69mm plug gauge can be inserted more than 387mm from the rear end of the barrel.

The armorer's manual for the MP5 isn't as specific. It states that the following are indicators that a barrel may be worn:

Key holing
Velocity decrease of 5-10%
Groups opening 5%
Barrel bulges within 4mm of the muzzle (I suspect if this should really be 4cm from the muzzle, 4mm seems like it would be way to close for the rifling past the bulge to restabilize the bullet).

Like gunhappy says and you suspect, qualities like "sharp" are too subjective. Besides, sharpness isn't a very good factor to measure anyhow, as polygonal barrels have NO sharp edges. The critical thing to know is the diameter, and compare it to known good or new barrels.
 
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