Tag Archives: Bullet Test

How to Bullet Drop Test a Barrel?

Plenty of AK barrel have seen heavy use and some are pretty much sewer pipes at this point – blown out, dirty and most of the rifling a distant memory.  A quick way to check is to take a cartridge of the correct caliber, such as 7.62×39, and put it in the muzzle.  If it stops before the case hits, there is hope.  It the case hits or even goes into the muzzle, the barrel is pretty much history.

Pass:

 

Fail:

 

I’m not saying the barrel is perfect but it may still be useful.  I built both M70 stubs on their original barrels and they shot good enough – about 8-10″ – at 100 yards fired with iron sights with cheap ammo.  Still a fun rifle to shoot though.

If a barrel fails, I would definitely get a replacement and not even bother trying to use it but that’s just me.  I’ve known a few guys over the years that proudly built and fired sewer pipe rifles.

How to Bullet Drop Test a Barrel

One of the challenges with older AKs is to figure out what kind of shape the barrel is in.  Yugos especially are famous for shot out bores.  The slang term is “dark bore” meaning the barrel is so corroded that it is no longer shiny and usually they are pretty shot out but not always – it pays to do some testing.

One quick way to check is known as the “bullet drop test”.  Basically, you put the bullet end of a cartridge into the muzzle and if the cartridge stops on the bullet then there is still some life left.   If it drops in such that the case is hitting, the barrel is pretty well worn out. It’s not a perfect test but it is quick and easy.

Pass on a Yugo M72 barrel

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Fail on a Yugo 72 barrel – notice how the bullet can’t be seen at all.  The rim of the case is sitting in the bore.  This isn’t too bad – I have seen some that drop in all the way into the shoulder of the case!

DSC_0048 DSC_0049

With that said, I have known tons of builders who went ahead and built battlefield pickup style rifles or just “fun guns” where they could more or less hit a man sized target at 100 yards.  Personally, if I am going to all the effort to do a build, I’d rather have an accurate rifle vs. one with a worn out bore.

Now, there are new “endoscopes” that are 5.5mm and can let you look into the bore of rifles.  I reviewed a $17 GiraffeCam that connected to my Android phone and was pretty amazed and what I could see especially given its low cost.  Click here for the full review.


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