Slugging the Bore

[dak0ta]

Hello,

I was wondering if you wanted to slug the bore of a milsurp rifle like a Soviet Mosin Nagant, could you perform a general test by using a 7.62x54R military surplus round with known bullet diameter and insert it bullet first into the muzzle? I know this test is used to measure the bore's wear and rifling at the muzzle assuming that it isn't counter-bored. But if the bullet doesn't sink too deeply into the barrel, does this indicate that the rifling is strong and that the bore diameter is smaller or the same as the bullet.

For example, a military surplus 7.62x54R round uses a .312 diameter bullet, and when you put the bullet into the muzzle, it doesn't penetrate very deeply. Does this mean that A) The rifling is strong at least at the muzzle and B) the bore diameter is .312 diameter or even smaller like .311? I would also make an educated guess that if it was of .308 diameter, the bullet wouldn't even go any measurable distance into the muzzle.

I saw some videos on YouTube showing people ramming a lead ball down and using calipers to measure it after it came out the other end. The process will give you the exact measurement of the diameter, but could a general test as the one I mentioned above suffice without having to buy all the materials to figure it out to 3 decimal places? If you figure it's in the .312 or .311 ballpark, you can just experiment with those bullet diameters and find one that works. If not, try .308. More guesswork through my process, but you would eventually narrow it down?

This is just a thought, please inform me!

 

[loadedround]

The best way to slug your barrel is with a round slug of pure lead slighty larger than your bore diameter. Front of slug should be slightly tapered for easy insertion and be lubed slightly. just force into your rifle's muzzle and drive through with a heavy cleaning rod or wooden rod that just fits your bore and tap in with a hammer. I prefer a wooden rod (dowel) to prevent possible bore damage. Never attempt to do this with a jacketed bullet, I guarantee you will get it stuck about half way down your barrel.

 

[Uncle Mike]

An easier method is to plug the bore just past your spot in question and use Cerrosafe chamber casting metal.

If your going to do the lead slug, which is what I prefer, loadedround gives you excellent advice, just remember to remove the barreled action from the stock, and a jig which distributes the hammering forces to the recoil lug is the best way to go, but I have pulled the bolt and placed the rear of the receiver on a good piece of leather on the concrete floor. Just don't tell anyone I did that! lol hehehehe

 

[Maj Dad]

I use the torpedo shaped lead slip sinkers. Find one that's a bit over your bore/groove diameter, wipe it in a grease of your choice (I have used Vaseline in the dark & distant past) & put a dollop ahead of it. Then start it down the bore with a short piece of dowel rod & knock it on through (like loadedround says, try to use a rod that is close to your bore diameter - helps avoid splitting/splintering). If the rifling is 2 groove, like on some 03s/03A3s, British Enfields & others, make sure you measure across the groove engravings (they will be the highest, the shallower ones being the land engravings; it's a negative image, so to speak). Once upon a time I used a piece of leather & a piece of 2x4...

 

[Orange Boy]

Sorry, meant to start a new thread.