Rifling marks

[legion]

After some range work with sako 22/250 ammo i noticed rifling marks at the end of the case neck. Is this normal- i thought the bullet should just touch the lands so i am puzzled. Help.

[casts_by_fly]

yeah, that would be too long brass. What is the length of a fired case? Have you trimmed them? How many times have they been shot?

 

Likely it isn't the rifling though. I saw it on another forum (can't remember which) where a guy had what looked like rifling marks but it was actually from the powder burn (I think)

 

Thanks,

Rick

[Ronin]

A picture tells a 1000 words.

 

 

 

If the case has rifling marks it is way too long - by a long way as the throats on 22-250's (factory ones) are pretty long.

 

I imagine the case neck would be grossly overlength for this to happen.

 

What length do you cut your brass to?

 

Max length for 22-250 is 1.912".

 

A safe case length should be a minimum of .005" LESS than that.

 

 

You need to identify the problem before shooting the rifle further, as if the case is too long it could cause overpressure.

 

The bolt would be difficult to close if the case mouth touches the end of the chamber...

 

 

It may be that the neck area of the chamber is scored or damaged leaving mirror "image" marks on the fired brass - borescope examination would idntify this.

 

 

Please post a picture or two of the marks.

[Laurie]

Legion,

 

you say

After some range work with sako 22/250 ammo

which suggests it was factory ammo?

 

If so, short of using the wrong design of cartridge in the rifle, a rifle with some major problem in the way it's been chambered, or something else really wierd, the case-neck will never ever get near the rifling. As Ronin says, even many times fired and never-trimmed cases would have to be extraordinarily over-length to suffer this problem.

 

AR-15 type rifles leave lengthwise scratches on case-necks caused by the barrel locking nut that also has multiple lug recesses machined in marking the case on its way in and out of the chamber. However, since we're talking .22-250 Rem that's an unlilkely rifle-cartridge combination.

 

What I suspect you're seeing is factory case-mouth crimp marks. After firing, the crimp indentations don't disappear completely despite the neck being blown out against the chamber walls. I seem to remember that some Sako .243 ammo I once used was all heavily crimped and left marked necks. If so, there will be transverse lines around the neck just behind the mouth plus three or four very short indentations from those lines to the end of the case, or something similar, caused by a collet-type crimping die.

 

The only way anybody on the forum really giving an opinion is for you to post a photo.

 

However, there is one quick and easy way to put your mind at rest. Does a new .224" bullet (or the exposed part of one in an unfired round) slip into the neck without major resistance? If the case-neck has expanded beyond the point where it will still grip a bullet, nothing has stopped it expanding fully in the chamber, so the case is not over-length. (Cases fired with light loads and/or in very tight custom gun chambers often don't expand beyond this point either, but as this is factory ammo, it should be full standard CIP pressure.)

 

Laurie

[legion]

I will get the days chores out of the way then post some close up pictures up for a closer look along with some hornaday cases for comparison, this is the great thing about this site- some real knowledgable guys on here. Thanks for all your input.

[Ronin]

Never considered the crimp marking on some factory loads , never used factory ammo for years so apologies

[Andrew]

I agree. If you saw rifling marks on the case mouth you probably would have had to search for the rest of the casing!~Andrew

[legion]

I am having trouble downloading the pictures, hows it done. cheers.