Noob Question #2

[VolusiaJ]

Wow - I am learning a lot. At some point you start think, "oh crap. I don't know what I don't know!"

With that fear (and the fear of appendage loss) I decided that I should buy a Cartridge Gage just to ensure the diameter of the cartridge. I went to Sportsmen's here in Colorado Springs and, while the didn't have any Cartridge Gages they were very helpful and suggested that I take one of the cartridges and see if it will chamber. I did ... and it does but this is where it gets weird. The bullet (a .356 diameter 9mm) won't slide through the barrel by itself. So here is the question to all the gurus out there, should the bullet free-slide through the barrel? Here is a pic of what I am trying to describe. Thanks in advance!

[F. Guffey]

You do not want the bullet falling through the barrel, I use the running start, I want bullet jump for that reason.

F. Guffey

[Jim Watson]

should the bullet free-slide through the barrel?

No.
The bullet has to be "engraved" by the rifling to spin it up and stabilize it.
The bullet is a force fit into the bore.

[mdmtj]

If the bullet was able to free fall through the barrel there would not be enough contact with the lands when fired to properly spin the bullet when fired. You might as well step back in time to the days of the smooth bore muskets.

[AllenJ]

No, the bullet should not "free slide" through the barrel. The rifling in the barrel needs to grip the bullet to cause it to spin, therefore the rifling is actually cut so that it can do this to the bullet.

[F. Guffey]

A 30/06 bullet will almost free fall through an 8mm Mauser barrel, when dropped, the bullet will almost follow the lands, the difference in maximum diameter of the bullet and of the small diameter of the barrel is claimed to be .003”, I know, the Mauser is 8mm, the 8mm is claimed to be .323 and the old ones are claimed to be .318”, back to the barrel, it is claimed the barrel has two diameters, the large diameter is .323” and the small diameter is claimed to be .311” Both the .323 and .318 small diameter was claimed to be .311”, most of my barrels are larger, .314 is more common.

A bad day at the range” A friend offered to zero-in a rifle for a friend, somehow 308W was thought to be mentioned, anyhow the rifle was taken to the range with a new box of 308 W ammo, and taken to the gunsmith with a case rendered scrap in the chamber, the rifle was a 25/06. point? .308” diameter is too much of an interference fit for a .257” barrel.



http://www.saami.org/PubResources/CC...Luger%20+P.pdf

Two barrel diameters, .346 and .356. Bullet diameter .355 with a variation of –.003”. When taking wild guesses your bullet could be .010” larger in diameter than the barrel’s smaller diameter.

F. Guffey

[Sure Shot Mc Gee]

Always when buying store bought bullets or powder. Make sure the container or the packaging hasn't been tampered with or opened. In a un-tamperd condition your assured of getting what you paid for. Sometimes a counter person will offer you a good deal on a product that's been opened. I never bother with those types of deals. He knows he's holding onto a looser product and just wants to be rid of it. (Perhaps at your expense if your not careful. You won't be able to return it as "You bought it that way.")
If you think you have a bullet/bullets that's questionable. Mic it. Weigh it. Do what you have to do. In order to make sure its correct for your application.

S/S

[VolusiaJ]

My main concern is that I have seen discharged bullets at the range and the brass didn't appear to be "grooved" from the rifling of the barrel. Since my second uploaded photo shows the round actually sitting on top the barrel, I was concerned that the.356 might be too big for the barrel. I like my fingers attached and wanted to make sure I was seeing things right.

Good suggestion on mic'ing it Sure Shot. I will do it again.

[Misssissippi Dave]

When loading 9 mm ammo there are some general sizes. Lead and plated bullets are normally .356" and Jacketed bullets are .355". Notice I said general sizes. Many people will slug their barrel to find what size it really is. To do this you force a soft pure lead bullet or ball through the barrel from the chamber to the crown. This is done manually and not shot from a case. You can then use a micrometer to measure the true barrel size you have. There are people with very good calipers and the experience to use them consistently that would be able to get a true reading. Most of the rest of us will do better with a micrometer. With lead and plated bullets you want them to be .001 to .002" larger. This produces a good seal and the bullet will stabilize nicely.

If you don't care to slug your barrel you can try using .356" lead bullets. If you are experiencing barrel leading to a fair degree after about 50 rounds you either are using a powder that doesn't work well with lead or you may need to use a .357" bullet.

There are a lot of other things to factor in such as bullet lube etc., but these are the basics and should cover the minimum you need.

[Jim Watson]

My main concern is that I have seen discharged bullets at the range and the brass didn't appear to be "grooved" from the rifling of the barrel.

You may be looking at bullets that were shot from a Glock or other gun with "polygonal" rifling without sharp lands and grooves to engrave the bullet.
Or you may be looking at bullets loaded by somebody who thought the bullet should slip fit the barrel.

Load your ammo right, not by trash you pick up off the ground.

You DO have a manual, don't you?

[RC20]

Its good you re asking, but you really need to get some books and manuals and a lot more reading as you missing very basic details and that is not a good situation.

I hope you don't take this wrong, but the bullet should never slide down the barrel and thats as basic as the sun rises in the East (North East up here).

If you don't understand the basics and mechanics you will not know you have gone wrong. We can help with a problem but basic education you need to have down.

The cartridge gauge is a more advanced users tool (I know they insist we should all have one but we did not have them years back and you just used the chamber to check if there was any question )

And yes, for a semi auto, a good test is to take the barrel out of the gun and see how your cartridge sits int he chamber. It should drop in all the way.

Cartridge gauges are made to precise specs and depending on the cartridge, brass and resizing a perfectly fine cartridge may not sit down in the gauge.

The mfgs of the guns go to the maximum allowed spec (that avoids a picky chamber) and the cartridge will seat fine.

The gauge is a useful took but takes a bit of interpretation and can wig you out.

For my 9mm, some brass drops right in, most sits up a bit but chambers just fine.

[VolusiaJ]

Jim I do have the manual and I am reading through but there is no replacement for personal expertise, such as the men and women on TFL - I'm still working on mine.

I am currently working my way through Modern Reloading - Second Edition. Is there another you guys would suggest?

[Jim Watson]

You gotta be careful about Us Internet Experts.
There are a lot of people who think the wide place on a barrel slug or casting is "bore diameter." Which leads to funny ideas about slip fitting bullets.
But they will sure tell you the difference between clip and magazine PDQ.

[Bart B.]

Jim, good comments well said and very good for this thread.

Which explains why there's at least 42 definitions across thousands of folks for a given thing in firearms and reloading stuff.

I like to use SAAMI's glossary of terms:

http://www.saami.org/specifications_...tion/index.cfm

Click on "glossary" then the letter for the first letter in your terms search. Totally amazing how much this differs from what a lot of folks use.

At least, it's a "standard."

[Gbro]

My main concern is that I have seen discharged bullets at the range and the brass didn't appear to be "grooved" from the rifling of the barrel.

You may also be looking at bullets fired from a muzzle loader shooting sabot's
as in this picture; {Edit: violates board policy on posting copyrighted materials} That plastic Sabot has replaced the linen patch used in the past and still used by many today. {Edit: same violation}
The plastic sabot will be on the ground about 30 ft downrange and will bear the rifling imprint normally found on a fired bullet. There are also micro grove barrels that don't leave remarkable evidence like this; {Edit: same violation}

[Unclenick]

Gbro,

Please read the board policy on posting copyrighted materials. In addition to the copyright issue, when you hot link to images it forces the original web site to bear the bandwidth burden of supplying the image to viewers here. This costs him money. That makes them mad. We had a situation about three weeks ago where a mad owner of a site with a photo of a m.1911 replaced the photo with a lewd photo, so that was what showed up in the post until the link was removed.

You can put links up with instructions for how to find the photos, but unless you get express permission from the site hosting it, you can't use it.


VolusiaJ,

Despite the photo issue, the example was correct. Bullets are stabilized primarily by gyroscopic precession, which causes them to tend to constantly correct their noses into the wind. If they aren't spinning or aren't spinning fast enough, they tumble, at which point their ability to group on a target falls apart.

In order to force them to spin bullets fast enough, the rifling has to dig into the bullet. So the bullets are made at or just over the diameter of grooves in the barrel and are forced into the lands. If that weren't so, not only would the bullets tumble after exiting the muzzle, there would be a lot of gas bypass around the bullet, making velocity inconsistent or gas cutting bullet bases, which also contributes to inaccuracy.

Some bullets don't leave normal rifling marks, as with the polygonal rifling. Also, a lot of muzzle loaders use a plastic sabot that receives the grooves instead of the bullet.