What purpose does this serve on brass? Federal HST

[Zaydok Allen]

I have to admit my ignorance. Some cases have these marks in them, and I've never understood why. This is a Federal 230 gr HST round. Is this designed to allow for a small amount of expansion when a bullet is seated, so there is no bulge in the case at the base of the bullet? I've noticed on my reloads that there is a slight bulge/line where the base of the bullet sits. All my reloads pass the plunk test, and have functioned fine.

Will these grooves affect reloading these cases?

 

[Jim Watson]

Keeps the bullet from setting back against the feed ramp. I have a tool to cannelure cases for the purpose on reloads.

Sometimes it is just for identification. WW .38 Special wadcutters have two cannelures.

No, it does not affect reuse.

 

[1KPerDay]

Yep, to prevent setback and I suppose help ensure rounds are seated to the same depth during manufacturing. Some GI cases have a deep groove there.

 

[ReloaderFred]

In some cases the cannelure is intended to help keep the bullet in place, along with neck tension, but in other cases it's intended to identify a particular loading. I have Winchester .38 Special cases where the cannelure is approximately 1/8" above the case rim. Some blank cases are also marked with a cannelure near the base of the case, so it has many different uses.

My cannelure tools (CH & Corbin) will apply a cannelure on either bullets or cases, so if I want to add a crimping groove to a bullet, I can do that. If I choose to identify a particular loading in a specific caliber, I can do that, too. The factories do the same thing, only on a much bigger scale.

Hope this helps.

Fred

 

[mdi]

I believe this practice for preventing bullet set back is waning from ammo manufacturers because it isn't all that effective and is used mostly for identification (it started with revolver ammo and how much "set back" happens in a revolver cylinder? I have some old 38 Special brass with cannalures). I've experience no set back in any semi-auto hand gun or rifle cartridges without this cannalure with proper neck tension...

 

[ATLDave]

No effect on reloading. After a few cycles, these tend to get "ironed out" to very small depressions - though not as much with nickel-plated. I have not observed any shorter case life, either, though a little higher incidence of cracking would logically make sense.

 

[Zaydok Allen]

Keeps the bullet from setting back against the feed ramp

Yep, to prevent setback and I suppose help ensure rounds are seated to the same depth during manufacturing. Some GI cases have a deep groove there.

Jeeze, I can't believe I didn't come up with that on my own. Makes total sense.

I'm pretty sure I read that in the February issue of "Duh" magazine. I must have just forgotten.

Thanks all.

By the way, I thought "cannelure" was the correct term, as on many bullet designs, but I guess I'd never heard it associated with brass before. So thanks for clearing that up also.

 

[mdi]

Actually it's a fairly common question. I had the same thoughts in '69 when I started reloading 38 Special brass I picked up at my local police range. It took a lot of research over a long period of time 'cause I didn't ask anyone because it was way preweb and I didn't want to sound stupid...

 

[Walkalong]

Actually it's a fairly common question

Yep,.

 

[FROGO207]

I think it was a far better solution than the new "stepped" brass that is showing up. For both setback and internal volume/pressure issues the new brass has versus standard data.